If an RX8 motor can produce around 200 horse power with no turbo(s) (i appriciate the porting is different on the rx8 engine) what could a Peripheral ported 13b make with no turbos.
just curious
300+
some of the bridgeported engines in Aus are meant to make a whole lot more than that too. I seem to recall 380hp being banded about.
judge Ito\'s 13B made 310HP at the rear wheels and thats a partial peripheral port (peripheral port/Bridgeport combo) He plans to make a whole lot more than that with the N20 too :) (a 300 shot is typical in Peurto Rico apparently!!)
All depends on how hard you rev it, how big the ports are and what fuel you decide to run it on. But 300bhp is achievable more than that and you are looking at spending many, many £££££££££££\'s!
As Mike says, add laughing gas and you\'re looking at well over 500bhp...
and this is non turbo
yes, no turbo\'s no blowers, no Nitrous (not unless you want to shoot for the high 500\'s anyway!)
what about the RPMs realisticly do you have to rev something like this hard to get good drive/ power if you see what i mean. With alot less heat and stress from the turbo etc surely you increase the revs safely
yes, making power without turbo\'s is all about RPM, the faster you can spin that engine the more air and fuel you can get through it
so with weight loss of turbo(s) intercooler and all the other bits that you loose how would a 350bhp Peripheral port compare to 350bhp turbo charged 7 on the road/track
i must say i\'m intreasted in the whole concept
also the loss of turbo lag
Quote from: McCARTHYso with weight loss of turbo(s) intercooler and all the other bits that you loose how would a 350bhp Peripheral port compare to 350bhp turbo charged 7 on the road/track
i must say i\'m intreasted in the whole concept
Welcome to old school bud...heheheheheheheheh No turbo No gas...... :cheers
All motor :god Its the way forward :D
Bear in mind you will probably want to invest in lighter rotors and general increase the strength of every component you can, plus lighten whatever you can. (For track use you can lighten the flywheel, for drag use theres probably not much point)
I think 10,000rpm is possible if you can get all the right bits, and then get it all right.
What\'s the torque like betwene the two comparisons?
Turbo motors have more grunt for sure ................
Just out of interest if the propshaft is running at 10k does this mean that the rotors are running at 30k. Don\'t they turn 3 times for every turn of the prop shaft. Thats some shifting if true !
Shaun
Quote from: oldoneTurbo motors have more grunt for sure ................
so if you have 2 FDs both with 350 bhp one turbo charged one P ported then the turbo will generate more torque .
on track tho how would the performance compare
The tubbie would win! :cool
I thought rotors were travelling at 1/3rd crank speed?
Quote from: shaunwilJust out of interest if the propshaft is running at 10k does this mean that the rotors are running at 30k. Don\'t they turn 3 times for every turn of the prop shaft. Thats some shifting if true !
Shaun
Shaun, I think you mean the ECCENTRIC shaft.
The Rotors turn at 1/3 the speed of the Eccentric shaft. THerefore, if shaft speed = 10 000 rpm, then Rotor speed 3 333 rpm.
McCarthy, the problem is with these ports that they really dont work at low rpm. Per port is not conducive to a road car.
to be honest i\'m just playing with ideas at the mo. i have the FD as you know but i\'m building that for track use and so it will become more of a fun car thatn an everyday car like it is at the moment.
i\'m looking at buying something old skool kind of mk1 escort shape (i\'m not saying i\'m buying a mk1 escort to to give you an idea of what i may be looking for) and may do the PP rotary engine in that. a bit of old skool cool :cool
Noise might be easier to control for track use on a non-turbo rotor... The turbos really respond well to a lack of back pressure (assuming you can control boooooost) and n/a genreally copes with a little more. Might allow you to run more sliencing and be more track friendly.
Reliability would be interesting - much less to go wrong and temps in the system would be significantly lower.
Simplified intake system and exhause would be more efficient than directing both through the turbos as well.
Clearly a 3-rotor n/a would be very cool and help somewhat with torque issues.
I promise noise will be an issue, you would deffor have to fit a proper silencer :yes
i looked at three rotor option just the cost more than doubles in cost, longer fuel rails, 2 more injectors, another throttle body new crank shiftting the motor back to get weight distribution a little better..... this will just a bit of fun if i do it
proper silencer will go on i would be interested in having a silly loud run around
Quote from: iaintNoise might be easier to control for track use on a non-turbo rotor...
Hmm, N/A rotors often are louder, no turbo to adsorb any thing...
the bore isn\'t as big on the exhaust so that must help a little and with a decent silencer
A silencer is the only thing thats going to help I\'m afraid :yes
Quote from: McCARTHYso if you have 2 FDs both with 350 bhp one turbo charged one P ported then the turbo will generate more torque .
on track tho how would the performance compare
The only real advantage the turbo has on the circuits ,is the sheer accelleration(sp) in a straight line.It is extremely difficult to set the turbo car up for the circuit.Non turbo is a lot more user friendly and more predictable... :Typing
I would have thought a well built turbocharged car would last longer (engine wise) than an N/A engine too, high rev\'s = high maintenance
Another point to note is the cost of building is it more realistic to DIY build a relatively low power turbocharged lump as apposed to pushing the ragged edge with an N/A engine.
Quote from: MikeLMRI would have thought a well built turbocharged car would last longer (engine wise) than an N/A engine too, high rev\'s = high maintenance
Another point to note is the cost of building is it more realistic to DIY build a relatively low power turbocharged lump as apposed to pushing the ragged edge with an N/A engine.
A well put together motor is the answer both ways,more stress in a turbo motor.....higher revs does not always mean high maintenance.Yes it easier horsepower with a turbo for those who cannot build a decent carb fed motor....heheheheheheheheh
Around 5k is the price after speaking to WGT for a P ported engine with all the right lightened toys.
Also the standard FD gears are not the best suited for a PP engine with the final drive being to high. Apparently close ratio gears are the best way forward on this.
Quote from: McCARTHYAround 5k is the price after speaking to WGT for a P ported engine with all the right lightened toys.
Also the standard FD gears are not the best suited for a PP engine with the final drive being to high. Apparently close ratio gears are the best way forward on this.
Dont agree with the 5k but agree on the ratio side............... :Typing
Judge ito\'s car is a semi P/P engine of his own design ;) I belive it was built for a Class of Drag racing which is NA.
http://video.google.com/videoplay?docid=2981005728491480378
There are lots of levels of P/P engine\'s, its possable to build one that has less overlap (brap) than a Bridge, There are a few old schoolers who run P/P Na engines in there road cars without much issue. When i was looking into it quite a number of people said tame P/P engines can be compaired to a small Half Bridge but a large P/P can be compaired to a Small Full Bridge (if set up correctly and has the correct timing). TBH i was more intrested in Building a Turbo\'d P/P (which is harder due to the Port timing) so i did\'nt realy look into the NA side of the P/P world too much.
TBH if i was going for a full drag car then yes i agree a turbo would be the route i know of one FD running a 4 rotor twin turbo on a PP and thats making 1000bhp in Auz. I have a feeling its rebuilt an awful lot!!!
This will be just abit of fun when i do it. i have yet to find a suitable oldskool chassis worth gracing with this type of engine so its not an imetdiate thing at the moment.... and the FD needs a little TLC first too....
With any Big overlap engine the more Rotors you have the more behaved it will be, TBH i have only every been in one 2 rotor NA with Big P/P and that was a Track day car, was an Experiance :) (Just had two seats and a Cage and was LOUD!!!)
Turbo\'s don\'t mean it has to be a Drag car? I wa told to do a small P/P as high up the housing as poss then fit a Turbo, this way it would be alot easyer to drive on the road.
easy to drive on the road!!!!! thats no fun :p
5 k !!!!!!!!!!
does that come with solid gold rotors!
5k to bore 2 holes and turn 2 ali inserts and press the inserts in the housings!
If anyone needs exact procedure and tolerances to do a pp port
email me on stuart.wiezniak@ntlworld.com.
Ive got exact method to bore the housings , tolerances, centre point from bottom face etc etc.
The inserts are turned to more or less the same size as the bore, then frozen to shrink, then pressed in to the housing,and left to warm up and expand for an interference fit.
You could take your housings to any decent machine shop with this method for boring, and get the ali inserts turned to suit for a lot lot less than 5k man.
A very helpfull engine builder from aus was kind enough to share his usefull info on pp boring and turning so I will pass on this info to fellow members.
+ individual throttle bodies, linkage, custom inlet manifolds, injetors, rails etc etc etc installed built rebuilt etc etc... In prob getting this engine done in Auz eitherway
cheers for info buddy i\'ll drop you a line it would be very very helpful :Thumbs-up
with this method you can buy 2 tube bent throt bodies from racing beat or auz to bolt on the inserts that u get turned.
The ali insert has a face on the end that has 2 holes drilled through to bolt your throt bodies on.
any decent turner and borers would p@ss these of mate , trust me!
How did you set the timing? my Turbo P/P\'s are not round? they are simalar to the exhaust port\'s shape.
A simple P/P are round and if your not to fuss\'d about the amount of overlap or getting the max out of your Comp stroke then you can just bore a big hole in the housing and put a tube in, This is mainly how Na\'s are done as the Port Timing is not as important.
Up until recently you could buy Genuine Mazda P/P housings (not sure if you still can??) and they where d shaped. I don\'t know alot about Porting but i am under the impresion all that extra work shaping the ports to a D will have some sort of benifit.
You also have to read up on Inlets and Throttle sizes, you have to also decide if you want a plenum or not? If i was you i\'d go and talk to some one who has run and tunned lots of difrent P/P setups and will know what you will need. You may not get a good power band buy drilling two P/P\'s and putting on a Manifold thats pre made to some one elses ports, the manifold may be for Drag racing and you want it for the Track?? or you want to get as much low end power from the P/P as poss but the manifold/Throttles are for Top end?
They bore the hole breaking through the inside of the housing, then bore 6mm bigger leaving a step in the bottom of the bore for the insert to push up against , the wall thickness of the step face is 5mm on the thinest edge.
The insert is then pressed up against this step so the required port shape can pe ported out to whatever port shape on the inside of the housing just like porting out exahust ports.
The d shape seems to be popular for drag racing in aus.
ask the qusetion on ausrotary explaining what use you want out of the motor and what port shape to go for ie round or d.
I\'ll post the spec\'s of the engine when they have been sorted properly.
Any of you guys speak English on this thread ;) :rollin
Makes me realise how much i dont no about these engines. Should read up more i guess :)
Adam
This is a large NA P/P for those who don\'t know what we\'re talking about :)
If you don\'t mind me asking why would you want to put a P/P twin NA in an FD?
If you get 300RWHP out of it your going to have a small power band? if you stick to a Turbo side port you can easy make 300RWHP and have a bigger power band making it more usable.
Now if you where going old scholl and buy say a Rx2 then i could see why you\'d want to P/P it or run a Bridge, Novelty factor.
Wizy you are right, There is loads writen about making P/P\'s there relitivly easy to make if you know what your doing, but if i was using £700 of new rotor housings i\'d want it done properly by a pro who had lots of experiance running them.
Just changing the subject sligtly didn\'t Pip have a P/P triple Race car?
who do you think bores them out for pip?
ive been down to his place and cant see no boring machine, he must sub it out to a machine shop.
I know what your saying grizly about 700 quid housings but surely all pip does is take the housings down to his local machine shop with drawing and dimensions to get bored.
I should imagine evry tuner does, thats no secret, but I am unable to build and engine so would have to pay someone to do it.
Its great this knowledge being shared and I find it fascinating, please keep it up, but please dont keep on trying to make vendors look expensive. If you put it all in to perpective, you employ 6-8 people and then tell everyone you can rent a warehouse, pay there wages and still build me an engine for £1500.00.
This is a great thread can we keep it tech (not to tech so I can follow) and leave poor Pip alone.
Thanks LOL
im in business my self gary and have employees, rent yard, office etc etc.
Im not trying to make vendors look expensive mate, just sharing my knowledge and experience as a mechanical engineer for over 11 years.
Ive worked in a large machine shop turning boring milling and grinding so i know how long it would take.
I know how much it would cost to have the boring and turning done at a large machine tool firm with over 300 engineers and its 600 quid max.
The build of the engine is then exactly the same method as a side port after blocking side ports up or so ive been told.
Quote from: GrizzlyIf you don\'t mind me asking why would you want to put a P/P twin NA in an FD?
If you get 300RWHP out of it your going to have a small power band? if you stick to a Turbo side port you can easy make 300RWHP and have a bigger power band making it more usable.
Now if you where going old scholl and buy say a Rx2 then i could see why you\'d want to P/P it or run a Bridge, Novelty factor.
i\'m going oldskool with it so no FD involved too hvy for the engine spec i want
Quote from: rotaryart.uk.comI should imagine evry tuner does, thats no secret, but I am unable to build and engine so would have to pay someone to do it.
Its great this knowledge being shared and I find it fascinating, please keep it up, but please dont keep on trying to make vendors look expensive. If you put it all in to perpective, you employ 6-8 people and then tell everyone you can rent a warehouse, pay there wages and still build me an engine for £1500.00.
This is a great thread can we keep it tech (not to tech so I can follow) and leave poor Pip alone.
Thanks LOL
I think the point being made is, like any other business or industry if you can do a lot of the work yourself there are savings to be made. If you want to pay a professional to complete the work you naturally expect to have to pay extra for it. You pays your money and you takes your choice :Thumbsup!
Quote from: stuart wizyim in business my self gary and have employees, rent yard, office etc etc.
Im not trying to make vendors look expensive mate, just sharing my knowledge and experience as a mechanical engineer for over 11 years.
Ive worked in a large machine shop turning boring milling and grinding so i know how long it would take.
I know how much it would cost to have the boring and turning done at a large machine tool firm with over 300 engineers and its 600 quid max.
The build of the engine is then exactly the same method as a side port after blocking side ports up or so ive been told.
How do you know Pip didn\'t qoute to build the engine from scrach (New parts) as thats the best way of getting good Compression and winning those extra few hp. I\'m sure if you spoke to him he\'d tell you that a one off engine like this has tobe built right becouse of the Rpm it will run at (becouse the power band will be higher) and theres a matter of warrantee, I think Pip would cover His work?
When i got my engines parts together i did not have alot of change from 10k and thats without building it up? (but i did have an extra rotor)
Your quite right this was all new parts. the shell the engine is going in needs alot of restoration and i\'m going to get that all rebuilt welded etc properly, hence i would like the engine to be the most reliable it can be.
10k on a motor :eek:
cant wait to hear the 3 rotor at full chat grizly!!
Where in north west are u bud?
its nice to see people getting into pp port rotarys and 3 rotor motors by the way boys.
maybe in a couple of years the rotary boys will be ruling the street class over here!!
Yeh my engine cost me alot becouse of its nature (Short block Triple) but tbh i have not touched it in about two years (Lack of funds due to buying a house :))
Like any project i started off with a Budget in mind and by the time i bought 3 new Rotor housings + porting, three lightened Rotors with the Custom Two pc Crank, over 1k of Apex seals, £800 of balancing and race clearancing it add\'s up fast, and i still need to get the Oil system sorted. :eek:
Thats why when some one says they want to build a twin P/P thats going to be NA i think 2pc Crank with center bearing some realy nice lightened Rotors and some of those custom Bolts machined over size and matched to the Plates and housings.... MMMMMM Lots of cash but imagen a P/P NA engine at full chat on a Track at 10.000 rpm. Thats what its all about.:mmmm But it has to be Old school to make it work right :Laugh
Wow Grizzley
Some project, shame its on hold, totally undrestand why though.
Look forward to seeing you post its under way again.
Keep the thread full of this great chat
I\'ve looked into building a 13B PP in a serious way and can confirm that the Porting is the cheap bit, its the rest of the kit to go with it that pushes the price up :yes
LOL Cheap...
£300 for the housing and £150 each port so your looking at £450-£500 each rotor housing before you start if you want it done right. :)
Thing is there int alot that you can use second hand in a proper race engine, so its always going to be expencive (£250 each end plate £300 center plate,£1200 for a proper E-shaft so you can run your 10,000 rpm o yeh and the £1000 rotors ) ;)
Nah, DIY the whole way :yes
Yeh i looked into DIY way, but they just don\'t make the HP, the compresion will always be lower on a engine built from USED bits so your going to loos Hp all the way through the rev range. There is also stuff like bearing clearancing and Rotating assembly Ballaning that you just can\'t do in your Garage as a DIYer.
My Triple may yet end up be a semi DIY build though, i\'ve spent the money on all the proper parts but i may assemble it myself knowing its all new and within tolerance.
I think I,ll stick to used parts mate
gunning for 600 bhp+ out of the fc with the t45 with 8 injectors.
If it pops its cost me a set of 3mm atkins tips :cool
If side housings are clocked flat I cant see the difference from using new to be honest, i know the nitride wont be as thick on a used housing.
If u wanted to check for super toleranced flatness u need to use a surface plate with engineers blue brushed on , then rub it on all side plate surfaces which will show you how flat they are. ie blue spots on side plate is a high spot all silver areas are low spots.
This his how we used to scrape machine beds flat to 5 microns for grinding machines in 20 degc temp controled rooms,
you could then lap the high spots to get plate flatter for better side compression.
grizly if u wanna go real precise I have surface plate and micron clocks bud!
Not blowing my own trumpet but ive built griding workheads with hand scraped phospur bronze bearings, that rotate to 3 microns on runout.
give us a bell if u wanna borrow clocks, verniers or micrometers.
stu
07762331845
LOL how do you get a rotor housing flat? if you take the chrome off won\'t it be goosed? if it has been used won\'t it not be 100% flat?
Yeh you can always go to an Engineering shop and go that way but its hardly DIY??
nothing is ever 100% flat mate
side housings not rotor housings lol
you can lap by hand with a flat block and grinding paste
Ok Point made, But how long have you been and engineer??? For a DIY guy in his garage at home would you say its possable to build a 10,000 rpm P/P engine? Of course if you have an engineering shop at your beckon you could proberly make a housing?? but i still say for a PROPER race engine without 20 years of experiance and an engineering shop you have to go new.
Quote from: stuart wizyside housings not rotor housings lol
?? Where do you get most of your Comp from??? Rotor housings??
the side housings are cast iron with nitrided faces that are around .020" thick.
my fc side housings were clocked flat within .003" all over, this is within tolerance but could be better, now they are within .0005" all over.
you get what your given with rotor housings, yep thats were comp comes from, but not 100% of it.
Just out of interest what mirons per meter surface finish do you need for this type of work, Too high and it\'ll pass gas through ?? You could get something like this flat by using lapping paste and a proved flat block. They make diamond paste with 1micron partcles in it the fluid. Even if you had a machine shop it isn\'t easy to get something completely flat.
Interesting topic !
Shaun
What sort of a diffrence are you expecting?
Experiance engine building is where the Comp comes from. For example side seals, did you know race engines are set up with no gap?
2mm seals will handle 10,000 rpm but 3mm\'s are too heavy and tend to bounce causing chatter.
you dont need a workshop to check flatness,
you need dti with mag base or straight edge and feeler gauges.
new rotor housings are 250 quid each or 100 quid used of tim.
my used housings loooks brand new that i got of tim.
LOL so do mine... But i stil bought new ones for my triple. You knever know what the used Housing has been exposed to, Over heated? or it may be cracked? you never know at least with new you know what your getting.
what gap do u mean mate?
rotor housing width minus rotor width.
Side seal to corner seal gap
You set them up with the min of gap (just so the corner seal moves freely) the centrafugal force will open the gap enough for expansion, its a old racers trick to get more Compresion.
Theres lots of things like that that racers tend to do to get there compresion as high as possable.
tell u sumat else i learnt of a tuner over here.
for a high reving motor on the edges of the rotors were the corner seals go, as the u shape rises to hold the apex seal on each 6 corners of the rotor,
mill or file back these corners by .010 to .015 for flex at high revs.
prertty hard to descibe that without a drawing really!
just out of interest could a 2nd hand one be stronger because all the stress relief from previous life cycle ? Bit like the old bmw f1 turbo engine ?
Shaun
Quote from: stuart wizytell u sumat else i learnt of a tuner over here.
for a high reving motor on the edges of the rotors were the corner seals go, as the u shape rises to hold the apex seal on each 6 corners of the rotor,
mill or file back these corners by .010 to .015 for flex at high revs.
prertty hard to descibe that without a drawing really!
Yeh its part of Race clearancing, If its what i think you mean.
They usaly skim the Bath face of the rotor if thats what you mean?
i will do that griz cause i havent fitted side seals yet!
i dont know anything about lightened rotors and excentric shafts,
my fc just has std rotors 3mm grooves , side clearenced like i just tried to explain!
also std shaft and std bearings.
i dont expect the motor to last long to be honest, but thats what drag racings all about!!!!!
Not the best pic but its all i could find quick of a Lightened Rotor, they Skim the sides then leaving 2mm to hold the Side seals and corner seals remove a good 2-3mm from the fat area at the side of the rotor, the Rotor faces are also skimed but i am not sure how much was removed.
O yeh and snap ring the rotor gear in place too, they tend to Vibrate out at high RPM\'s you can just about see it done on the pic.
Quote from: stuart wizyi dont expect the motor to last long to be honest, but thats what drag racings all about!!!!!
LOL, Thats where we differ, i like track racing, so i go for more power bands rather then HP.
If you want to see some proper Sexy stuff have a scan on here. (Check out the 2 pc crank ;))
//www.xtremerotaries.com
http://www.xtremerotaries.com/main2/engine_services.htm
have you got lightened rotors griz? if so i would like to see them to see how theyve been machined
When I unpack at the new place,I will take a pic of a lightened rotor from one of my circuit racing motors,wil be interesting to compare with above pic posted..... :Typing
yeh, I have all the Triple engine componants all greased up in wax paper in my loft :)
Sorry right of subject i just have to post this pic, i am going to have to buy one of these for my FD at some point (when i find this money tree every one raves about)
Oldone, Thats a Mazdatrix Rotor for refrence.
Mine where done in Japan, I bought them as brand new rew 20b kit i belive they are reworked by Scoot.
Quote from: GrizzlyOldone, Thats a Mazdatrix Rotor for refrence.
Mine where done in Japan, I bought them as brand new rew 20b kit i belive they are reworked by Scoot.
:cheers :cool :Typing
i cant fathom out of that pic whats been machined on the rotor,
somebody show me and im gona do mine!
Its either milling or turning surely to take weight of the side faces.
its milling, mine looks like its CNC\'d very uniformed milling marks.
ive got a nice lightened exeddy flywheel that came of the fc engine, so lightened rotors could be a good idea
this is an in progrest shot that i\'ve just found, looks a bit rough but it stands out the basic look.
I did read up on Lightened rotors and its important to leave a gap of 2mm or more at the side seal (ovious realy)
fek me thats even easier if its cncd!
does it follow the shape of the side seal grooves and corner seal bore and outer oil control ring stood of same all round, if so can u measure the depth and width of piece left in please mate.
Just a quick head back to the whole DIY thing, I dont know about Stuart, but I\'m lucky enough to have a full workshop, been in the family for years, added to ad modernised as time passes. Also have access to CNC :) I did hear of someone whop had the prgram for milling the rotors (cincinatti mill IIRC) I might have to start chasing up the rumour..... :D
i don\'t have a light in the loft so it\'ll be tomorow.. But i\'ll dig one out and give you the dimentions.
Yeh all they do is follow the Side seal staying 2-3mm away then remove aprox 3mm of the side of the rotor. its been a while since i\'ve looked at them but i don\'t think they left any round the Oil seal groove.(don\'t hold me on that though my memorys not what it was it could have the same 2mm left round the Oil seal too best check.)
Hey if i help you with these rotors you going to make me one of those RB 2pc cranks ;)
ive got program for bridgeport slot on hydenhain brett, but cant give it out cause its tims port template!!
brett, thats been done on selfindexing head or round table.
Once one segment is programmed, just rotate rotor for next segment!
Piece of ****,
if someone lent me a rotor i could get a programm wrote for next week.
you\'ll like this :)
http://www.racingbeat.com/FRmazda2.htm
Bugger, Can\'t link it direct.
//www.racingbeat.com Go to 93- then check out Light weight rotors...
They lighten the hole assembly, E-Shaft,Rotors,Counter weights the lot :)
Click the rotor, got a bigger pic. LOL
that pic shows milling going over the oil seal groove and leaving chamfer all round side seal grooves and corner bores.
Its a weird alloy that the rotors are made out of, when i milled my 3mm grooves out, the swarf come of like zinc! must be some mad alloy of some sort.
im glad i asked you about lighter rotors griz!!!
look what happens when people share knowledge!! :cool
If we get a program and proove one of, i,ll mill u some out mate.
Quote from: shaunwilJust out of interest what mirons per meter surface finish do you need for this type of work, Too high and it\'ll pass gas through ?? You could get something like this flat by using lapping paste and a proved flat block. They make diamond paste with 1micron partcles in it the fluid. Even if you had a machine shop it isn\'t easy to get something completely flat.
Interesting topic !
Shaun
shaun the finish on side housings and rotor housings are almost mirror type.
The side housings are lapped flat at factory and i presume the rotor housings are held of centre, with the centre line of each half bore clocked true and then spun in a chuck and ground on some type of internal grinder.
If you look at a rotor housings claerly u can see 2 half bores.
Quote from: stuart wizythat pic shows milling going over the oil seal groove and leaving chamfer all round side seal grooves and corner bores.
Its a weird alloy that the rotors are made out of, when i milled my 3mm grooves out, the swarf come of like zinc! must be some mad alloy of some sort.
I think they have some sort of coating on them, I had a quite badly damaged rotor that i used to keep the Garage door open :) stayed out side for quite a while and where the top coating had been damaged had rust but the rest was in quite good condition. So i thought they where cast steel with some sort of Coating.
Do you know they also take the face of the rotor down? I read its to add clearance to compensate for e-shaft flex at high hp/Rpm i have some pics on my old computer of components of an engine that been used for high rpm runs with stock rotors fitted, it had be built to see what needed to be done to make a high rpm engine (what catches etc) and they found with the weight of a Rotor at Rpm\'s of 9k and above it was possible to bend the e-shaft, there was marks where the rotor had made contact with the Housing.
if u look at the side corner of a well use rotor, the apex groove where it meets the end of each slot is always swaged out slightly through side presure of the tip pushing this weak spot open. this pushed out from the face .006" on my fc rotors and would have been almost touching the side housings.
even when i milled all the slots out, this weak area of the slot is wider after milling.
these corners on the side of the rotors are the only bits ive clearenced on mine.
if u turned .005" of the sides going over the side seal groove, youd burr all your side seal grooves up i thought,
or do you clearence the full faces of the rotor??
there are also some photos of lightened rotors on Paul Yaws site (interesting on to read through as well if you\'ve not seen it)
http://www.yawpower.com/picture.html
http://www.yawpower.com/pic7.html
Excellent thread guys, some more info.:
From http://www.mazdatrix.com/faq/rotorwgt.htm
Rotor Weight and Compression ChartThis chart is included in our Website for reference purposes. The weights listed are for production, unmodified rotors.
| Engine | Year | Compression | Weight (Grams) | Weight (Pounds) |
| 12A | 76-82 | 9.4 | 4603 | 10.15 |
| 12A | 83-85 | 9.4 | 4353 | 9.6 |
| 13B | 74-78 | 9.2 | 5253 | 11.58 |
| 13B | 84-85 | 9.4 | 5253 | 11.58 |
| 13B N/T | 86-88 | 9.4 | 4553 | 10.04 |
| 13B Turbo | 86-88 | 8.5 | 4553 | 10.04 |
| 13B N/T | 89-92 | 9.7 | 4328 | 9.54 |
| 13B Turbo | 89-92 | 9 | 4328 | 9.54 |
| 13B T/T | 93-95 | 9 | 4328 | 9.54 |
| 13B Renesis | 04-on | 10 | 4218 | 9.3 |
| | | | |
Thread on RENESIS rotors:
http://ausrotary.dntinternet.com/forums/viewtopic.php?t=23282
Quote from: GrizzlyI did read up on Lightened rotors and its important to leave a gap of 2mm or more at the side seal (ovious realy)
G\'Day Grizzly/McCarthy and all.
One thing that may be of help also - I had a set of lightened rotors in my old racecar many years ago. I actually had a failure where all sorts of things had happened, upon looking at it closer when we pulled the engine down we found that the outer oil control ring didn\'t appear to have enough support from the machining that had taken place next to the oil control ring (on the rotor face), the outer ring had actually cracked through!
The rotor gear had also cracked - so it was a mess! Main reason though behind the failure was a slight overrev ;)
My old RX-4 13B PP had a aluminium flywheel on it, and I think a 7 1/2 inch tripple plate clutch - it was the fastest revving rotary I think I have ever heard - was like a motorbike! :) 12MB video here: //www.4rotor.com/general/rx-4_pitlane_flyby.mpeg - note the downchanges ;)
As for the general NA route - in a light car, it is an incredible combination. I\'m sure you would have all seen some of the videos, but I\'ll post again just in case - http://www.cityperformancecentre.com/customers/circuit/jstein/jstein.htm - videos at the bottom.
Phil Laird in Australia (Rotary Wizard) put a standard RENESIS 13B into an 808 Wagon and ran high 11\'s I think. He told me that they made around 300fwhp from it (with a MoTeC ECU, large exhaust, and LOTS of revs - but standard intake I believe (not sure about injector size)).
Top thread again guys!
How doooo Glenn. :)
I spent a few hours last night chatting to the guy who did my Housings, he seemed to think fitting lighened rotors to a Turbo is a waste of time, he agree\'s with Glenn, flywheels and clutch\'s will make a masive diffrence to a track or road car. (BTW Glenn that vids the Nads :driving ) Internal lightening is mainly for NA\'s that need to be rev\'d, Turbo\'s tend to develop there power quite low down the rev range so reducing the strenth in the rotors is not realy an advantage.
He also told me he uses a Stock FD flywheel on his drag car becouse it helps keep the engines momentum up when he changes and reduced Bog of the line.
Another topic i asked about was the E-shaft mod (fitting a weber jet to the e-shaft to keep the jet open at low revs/Idle), after he had stoped laffing :3Confused He asked why would i want to replace a jet nearly 2.5mm for one thats 1.2mm it will just ristrict oil flow at wot? it don\'t make sence and if i use a 2.5mm open jet it will blow blue smoke on idle. So i guess that trick is a mith, when you think about it it don\'t make sence. I can\'t belive i did\'nt think about it!! and asked the question (Noob!!).
Quote from: Glenn ButcherPhil Laird in Australia (Rotary Wizard) put a standard RENESIS 13B into an 808 Wagon and ran high 11\'s I think. He told me that they made around 300fwhp from it (with a MoTeC ECU, large exhaust, and LOTS of revs - but standard intake I believe (not sure about injector size)).
Glenn, I spoke to a guy on Nopistons called Judge ITO (if you\'ve heard of him?) he was telling me he likes to keep the stock FD ports as stock as poss and with some clever runner work he says he can make the port flow more then most Extended ports without touching the exit shape itself. I find this realy cool. I\'ve spent lots of time reading up how this is done but this is one of the Black arts that no one lets out of the bag ;) There realy is alot of skill and knolage involved in building and setting up these high rpm or high HP motors, when you look into what is involved you have to realy respect these guys.
my mates drawn the rotor profile on cad today, all i need to know is the depth of cut and how much to stand of side seal grooves and outor oil ring recess.
were going to use a small 45deg tip milling cutter so it leaves 45 chamfer all round for strength like the racing beat rotor.
Hi Grizzly, yes - I know of Judge, he posts on AusRotary a bit. Making some serious power with his car! Big respect! Yes - I would like to know how he is doing it, it is a PP/Semi Bridge or something isn\'t it?
The IPRA (Improved Production Racing Association) in Oz produces some amazing results from NA Bridgeports, with rumours of 12-13,000+rpm engines. (Phil Laird is the King of IPRA in Oz).
Stuart - awesome stuff! Out of interest - do you have a target weight? or have you calculated the amount of weight in material that you can remove? And what rotor\'s are you using? FD?
Ok, my rotors, they have been cut 2mm deep there is 1mm left around the Oil control rings and 1.2mm left suporting the Side seals.
The hole side of the rotor also seems to have been ground, i will take it too work tomorow and measure the total with of the rotor to see what they have taken of it. Also as i\'ve said before the outer flats of the rotor have been machined as well (possably to give more clearance to the Rotor housing or maybe to drop the compresion a bit??)
hi glen
rotors are fc turbo 2 with 3mm grooves
no idea of target weight, just want to lighten them like racing beat do!
that should be good enough for me :Thumbsup!
Quote from: Glenn ButcherHi Grizzly, yes - I know of Judge, he posts on AusRotary a bit. Making some serious power with his car! Big respect! Yes - I would like to know how he is doing it, it is a PP/Semi Bridge or something isn\'t it?
The IPRA (Improved Production Racing Association) in Oz produces some amazing results from NA Bridgeports, with rumours of 12-13,000+rpm engines. (Phil Laird is the King of IPRA in Oz).
Stuart - awesome stuff! Out of interest - do you have a target weight? or have you calculated the amount of weight in material that you can remove? And what rotor\'s are you using? FD?
Have you seen ITO\'s vid (i put it on this thread a bit back) he has spent long time building his Semi P/P Drag car, i think hes using a Small P/P cut into the secondry runner then hes opened up the side ports and hes away :)
I think he has had enough of working for himself so he\'s gone here //www.realdealmotorsports.com He\'s gone a bit quiet recently, he was selling port Templates and i think he has been pestered to death.
I belive my Rotors are rew, I know they are the higher Comp rotors. Apart from a slightly better finish on the twin turbo rotors i belive the S5 T2 and the Fd rotors are very simalar.
Can I ask, why can piston cranks rev to 20k and much shorter shafts in rotaries go to 12k, there must be less whip or is it the centrifugal forces that make the difference?
Right off to wath England.... Seems they have just scored by the sound of it :)
Is there a optimum compression for turbos.
ie low comp with x psi boost making the same power as high comp on low boost, is there a benefit one over other if same power, or is it not possible to create same power?
Quote from: rotaryart.uk.comCan I ask, why can piston cranks rev to 20k and much shorter shafts in rotaries go to 12k, there must be less whip or is it the centrifugal forces that make the difference?
One word...... MONEY!!!
But Rotarys have a problem, The faster the Rotor spins the harder the apex seal pushes on the Housing and the harder it pushes the more friction it casues until it Burns out and looses Compression, You could make it rev realy High but you\'d need some real Light Apex\'s (carbon are the wepons of choice)
Quote from: rotaryart.uk.comIs there a optimum compression for turbos.
ie low comp with x psi boost making the same power as high comp on low boost, is there a benefit one over other if same power, or is it not possible to create same power?
The Compression being lower on a Turbo makes it more stable to tune at higher Boost levels. So effectivly able to run more Boost safely but the down side is it will spool slower and feel less responcive.
The higher the Comp the more likly it is to Det, but the higher the Compresion the more Hp per PSI you get.
NA\'s are basicly the same, If you have a higher Comp you will find it harder to set up but you will gain more HP at the end. NA\'s are all about getting the Compression as good as you can.
Quote from: GrizzlyOne word...... MONEY!!!
But Rotarys have a problem, The faster the Rotor spins the harder the apex seal pushes on the Housing and the harder it pushes the more friction it casues until it Burns out and looses Compression, You could make it rev realy High but you\'d need some real Light Apex\'s (carbon are the wepons of choice)
Perhaps one for Stu, as you are experimenting/building now.
Please forgive my ignorence.
If it pushes harder the faster it spins, whats to stop a slot to be cut in to the seal and some sort of stop or pin to stop it raising above a given height, so no matter how hard it spins, the seal stays at max height.
Sorry for over simplifying things.
Thats an interesting question what stops you from milling a t-slot in the end of the rotor and having a t-shapped apex ?
Shaun
thinking about it, you could not do it on 2 piece, and one piece dont seal as well, would like to know though if its possible?
how exactley do the two peice work ??? If they where next to each other you could have a t-slot and 2 opposing l shaped apex\'s !
Shaun
Gary and all - have a read through this thread (long thread though!): http://ausrotary.dntinternet.com/forums/viewtopic.php?t=74605&highlight=thought
good idea gary about the seals, but dont the seals wear down like brushes in a motor with springs behind pushing the seal out more and more as the seal wears down?
when i took the old fc apex seals out, they are 3mm shorter than new atkins seals in height.
if u stopped the seal from being pushed out so far it would eventually loose compression.
Quote from: shaunwilhow exactley do the two peice work ??? If they where next to each other you could have a t-slot and 2 opposing l shaped apex\'s !
Shaun
the 2 piece seals are both angled of at 45deg on one end , the spring goes under both seals with the angles crossing each other on ends of 2 seals.
when the longer seal is pushed up by the spring, it pushes the shorter seal up to.
Quote from: stuart wizygood idea gary about the seals, but dont the seals wear down like brushes in a motor with springs behind pushing the seal out more and more as the seal wears down?
when i took the old fc apex seals out, they are 3mm shorter than new atkins seals in height.
if u stopped the seal from being pushed out so far it would eventually loose compression.
Yes they do, but if the springs had say 1-3mm of play before hitting stop that might be better then not being able to run 18-20k rpm.
Also this would undoubtedly be a race car, so would be stripped and seals only replaced, dont know how much wear you would get from 1 race, maybe a whole season would be equivelent to the 3mm wear. Just ideas mulin round to get the high reving race engine. See a problem and look for a cure. Sorry I do over simplify things as Im not an engineer and dont appreciate what you need to over come
Quote from: rotaryart.uk.comPerhaps one for Stu, as you are experimenting/building now.
Please forgive my ignorence.
If it pushes harder the faster it spins, whats to stop a slot to be cut in to the seal and some sort of stop or pin to stop it raising above a given height, so no matter how hard it spins, the seal stays at max height.
Sorry for over simplifying things.
Urm, a few things, The first if you cut the seal it will create a weak point, the seal has to move in and out or it would brake off so you can\'t hold it back.
To simplify things, the weight + Centrifugal force. If you add more weight the force will get greater for a given RPM, so there is two things you can do to reduce this the first is less rpm the second is to make the seal ligher.
Quote from: rotaryart.uk.comYes they do, but if the springs had say 1-3mm of play before hitting stop that might be better then not being able to run 18-20k rpm.
Also this would undoubtedly be a race car,
This would mean it still is being pushed against the housing with its own weight so would still be subject to the extra load.
As far as i can see there are Three big problems with running very high RPM, the first is the apex seals, the second is the E-shaft flex and the third is the harmonic vibration. this alone can cause some serious problems with the Bolts holding the engine together (tends to ither snap them or loosen them)
The first on a race engine that see\'s 10.000rpm and gets rebuilt alot will use Carbon seals, There usless for road or high hp use but there is not better seal for Big RPM runs.
The second is the most easy to put right, you can Lighten the Rotors, Clearance to suit or Fit a E-shaft with a center bearing.
The Third Can be a royal pain in the Rear, as i\'ve never build a high Rpm NA i\'ve not looked into it too much but i\'m told oversized Bolts that are matched to the Housings/Plates is the best way but people put rubber tube over the stock bolts to dampen the Vibrations (i\'m not sure if this works though??)
O yeh the one i forgot, Flywheels exploding at High RPM and with a good amount of power.
this is no bull now, but when i was 2nd year aprentice at holroyds there was a pair of billet machined mazda type rotors on a pallet in inspection dept for months!
my foreman at the time said they where mazda car engine rotors that we were machining for holroyds jap rotor sales guy- sanechi terasoa.
im going back 10 years but always remeberd the jap guys name going over tannoy!
I think this guy had something to do with mazda and the rotary.
glen u might no something about this guy.
as long as i was there, the rotors never got finished and stayed on the pallet gathering dust! so nothing ever come of it.
at the time i knew nothing about rotary engines so didnt take much notice!!
they were turned and milled to shape with billet pieces left on both faces of the rotors to grip on but side seal grooves where never cut.
all the rotors that holroyds make are screw type rotors for compressors, aircraft, fridges, fuel pumps etc etc,
for really high revs you need different bearings than white metal.
workheads on grinding machines have main drive spindle normally using phosphur bronze bearings with oil grooves in the inside bores for good lubrication, some spidles can spin well over 30 000rpm,
just think of a turbo , main shaft on a loose fit (sloppy) phosphur bronze bearing, these will spin at 150 000 rpm but need the oil big time/
Out of intrest How would you expect a Billet Rotor to wear? I\'m not to clued up on Metals but would it hold its shape ok for example Apex grooves or Side seal grooves?
I always though a set of rotors made from somthing lighter than cast iron would be good in a Rotary but Mazda must have made them like that for a reason??
Quote from: stuart wizyfor really high revs you need different bearings than white metal.
workheads on grinding machines have main drive spindle normally using phosphur bronze bearings with oil grooves in the inside bores for good lubrication, some spidles can spin well over 30 000rpm,
just think of a turbo , main shaft on a loose fit (sloppy) phosphur bronze bearing, these will spin at 150 000 rpm but need the oil big time/
Yeh i have just read Glenns post on Aus Board and the bearing load was brought up. I wounder if you could get round it by upping the Oil presure? or cross drilling the Crank??
Glenn they don\'t mess about on Ausrotary do they.......
Quote from: GrizzlyGlenn they don\'t mess about on Ausrotary do they.......
Some very clued up guys on there. The really treasured information is kept close to heart of course. :(
I have heard of quite a few people doing things like grinding the sides of the rotors down around the apex seal area to help with high revs and big boost etc. - I\'m not sure if that is also done in NA engines? Obviously only to a point - as again I believe that the rotors tend to wobble about at high rpm.
A lot of the high revving stuff was covered in that thread, mainly came down to there being a need for less rotating mass to reduce stress on the shaft - so lighter rotors (maybe a different material?), stronger e-shaft (again maybe a different material), supporting centre bearing would help, better lubrication, and again other materials to help with harmonic issues.
Thinking about it though, all the stuff we are playing around with on the RX engines is all around 10+ years old, apart from the RX-8 bits. So in theory, there should be better materials available now - cost less to produce now etc.
If and only IF! Mazda would attempt Le Mans again with a full on Factory Based effort with millions of $$$ - it will be just individuals trying to make the engine better - more of less using the standard parts.
Guys like you Stuart could have a head start on Mazda if you start playing around with these things - maybe try some other materials??? chat to your boss! ;) ;) ;)
Are rotors made of cast iron ?? Couldn\'t you make them out of forged alumiunium, machine them and then nitritide them to give them a good hard surface ?
Do F1 use carbon fibre bits in engines ? Could you do the same with a rotor ?
With Turbo technology now what would stop people using roller bearings for the e-shaft to be able to get the rpms up ?
Couldn\'t you have a step down before the clutch and flywheel to reduce the spinning mass after the engine, if it only saw the original rpm then it wouldn\'t be a problem ?
This thread is really interesting read :)
Shaun
Quote from: shaunwilAre rotors made of cast iron ?? Couldn\'t you make them out of forged alumiunium, machine them and then nitritide them to give them a good hard surface ?
Do F1 use carbon fibre bits in engines ? Could you do the same with a rotor ?
Forged ali would have a vastly different expansion porperty than iron (or steel) - it\'d expand far more for a given temp rise:
Linear Expansion Coeficient (10^6 K^-1):
Fe (Iron): 11.8
Al (Ali): 23.1
Ali may be light but it\'s very soft in comparison and not good for hot environments where tolerances must be tight.
Jim Downing :god (Amercian RXracer) designed his own "in house" ali alloy rotors and running with success.
that\'s what I heard long ago.
But isn\'t the housing aluminium nitrided ? Wouldn\'t that mean you would get more constant expansion and contraction between the housing and the rotor ? You would still have the apex seals in the original materials but you reduce the overall mass of the rotor.
Whats the difference with titanium, could that be the material of choice ?
Shaun
titananium is mega mega expensive, ive machined small pins and shafts bolts etc for a guy who was building a racing bike to lighten anything possible.
Its amazing material u know, holding a piece of 50 mm dia bar, feels a lot lighter than ali and is the strongest material available.
I dont know how it copes with heat, ie warpage and expansion.
the f1 guys use titanium con rods and cranks, thats why they get the revs.
like shaun says ali rotors should work well with nitride coating to protect from combustion temps, you would need to fit apex seal slots to the rotors though made from steel or the apex tips would wear an ali slot out in no time.
glen holroyds rotors are the most acurrate in the world.
they got the queens award for technological achievement for making milling and grinding machines that mill and grind a pair of screw rotors with 5 micron clearence between the pair.
the rotor milling and grinding machines made by holroyds are used all over the world, but there not interested in making wankel rotors!!
they make rotors for trane ,compair ,atlas copco, ingersoll rand, used in most of the air conditioning units and air compressors worldwide, also for superchargers, fuel pumps etc. its a massive firm with production cells worldwide.
have mazda not got the rights to the wankel, is it not illegal to reproduce mazda parts?
If not, there could be a nice little project coming on here, I need to get the real tech boffins who design the machines ,from holroyds design team in on this!!!
Quote from: iaintForged ali would have a vastly different expansion porperty than iron (or steel) - it\'d expand far more for a given temp rise:
Linear Expansion Coeficient (10^6 K^-1):
Fe (Iron): 11.8
Al (Ali): 23.1
Ali may be light but it\'s very soft in comparison and not good for hot environments where tolerances must be tight.
Is the Housing that the Rotors spin in not alloy?
Does anyone have any more info on Jim Downing\'s Rotors?
Quote from: shaunwilBut isn\'t the housing aluminium nitrided ? Wouldn\'t that mean you would get more constant expansion and contraction between the housing and the rotor ? You would still have the apex seals in the original materials but you reduce the overall mass of the rotor.
Whats the difference with titanium, could that be the material of choice ?
Shaun
Shawn, the Rotor housing is chrome plated and the Iron Plates are Nitrided. I understand one of the problems Mazda had with there Race engines was the Rotor Expanded quicker than the Cooled Alloy Housing so it was possable to make contact with the End plate in a race or prolonged load.
It does beg the question, if it was as easy as changing the meterial the rotor was being made from why use Cast steel that is heavy and quite hard to work? I\'m guessing they did it to keep the Groove shape (Eg. a Seal moving in and out all the time with little lubrication), I supose Cast iron would resist wear better than say Alloy?????
Also i was thinking about the centrifugal force thing, at first i thought a Lighter alloy would be better, but Then i thought what if Mazda made the Rotors from cast for a reason?? eg. to add more weight to the Rotating assembly there for making it smoother.... Or a stock Rotary drive better... But at the end of the day its proberly more like it did the job and was alot cheaper to produce??
the hardest thing to machine on a billet rotor would be the oil galeries inside.
The rest is turning and milling, to get a patern made to make cast ali rotors with the same oil galeries as a std rotor is pretty dam hard to do.
I think the only way to make them is from billet ali, with large holes drilled through the rotor ,to feed the rotor gear, ie- similar to the original cast rotor oilways but drilled.
Then you need some sort of steel inserts fitted to the rotor for side seals, apex seals and corer seals, these inserts need to be fixed to the ali rotor somehow.
I thought of machining the middle of the rotor out completely the same way that the racing beat rotor has been, but instead of 2mm deep, go full depth of the rotor, this could then be pressed and fitted onto an ali middle section with bores, oil grooves, gear all re machined in the inner ali section of the rotor,
this way u can still use the original apex grooves side seal grooves and corner seal bores, and save a **** load of weight with the inside of the rotor being ali.
but are we not getting back to the Expansion problem??
Could they not be forged? or is this just very expencive way of making a rotor?
I would be intrested to see how Jim Downing has made his??
MMMM i see what you mean about the Oil ways inside the rotor.
to forge a rotor you need to make a pattern with all the inside oil galeries being the pattern basicly, the rest of the forging can be any shape as long as its bigger than the outer shape of the rotor because it can all be machined.
http://www.autoracing1.com/GoodBoys/001107hans2.htm
Trying to find about Jim Downing\'s rotor but came along a brill device :Thumbsup!
You would probably fing the reason why its cast is purely because of the oiling galleries, these would just be silica inserts in the casting mould and would be easy to mass produce.
Does anybody know any info about the new wheels from bbs with hollow chamber technolgy ??? Could this be adapted to make lighter steel rotors ? Also could it be forged with two open ends and then blanked off with a plate ?
Certainly an interesting thread !
Shaun
shaun, if you look at grizlys sectional pics of the galeries, it looks like the wall thickness from inside gallery to outside of rotor is 3 or 4mm max. I think the galeries (hollow section) are to lighten the rotor and the webbing in between is for strength.
dont forget all these galleries are full of oil when engine is running by the way.
if u made billet ali rotors u wouldnt need all this hollow space inside of the rotor cause the weight reduction from steel to ali would be massive, however you do need to drill oilways through the rotor for the gear though.
your idea of making the rotor in 2 halfs is a good one shaun
The other big question is how much flow of oil is required to cool the rotor ? Is it groved out like that for getting enough oil in it to cool it properly ? Maybe if you had an alloy rotor you whould have to cool it more to keep the expansion of outer and inner similar !
Shaun
Out of intrest do you know how Mazda changed the Rx8 Rotors? They are the same side and shape but lighter? I read some where they have changed the casting technique.
Also does anyone have a 1989-92 Turbo 2 rotor handy? i\'m interested what weight stamp its got? Looking at the weight chart etc they should be the same as an FD but they have a diffrent Part number?
Does anyone know what the coating is on the rotors? mine are ceramic coated but it looks diffrent to the stock coating?
I was looking at some of my old info on my other Computer today and came across this pic, it was how i was thinking of running my Triple but it would have ment me running Six Throttles and thats just silly.....
I belive this is made by Scoot too... I think its a pic of the Inlet and Housings of there red Options Semi P/P Turbo (the 700hp one that has been going round for the last few years) Note the Stock Primarys and P/P secondarys.... ;)
Wrong button....... :)