Twin rotor Peripheral port

[Grizzly]

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.

[stuart wizy]

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??

[MikeLMR]

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

[Glenn Butcher]

Excellent thread guys, some more info.:

From http://www.mazdatrix.com/faq/rotorwgt.htm

Rotor Weight and Compression Chart

This 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

[Glenn Butcher]

I 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!

[Grizzly]

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!!).

[Grizzly]

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)).

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.

[stuart wizy]

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.

[Glenn Butcher]

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?

[Grizzly]

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??)

[stuart wizy]

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!

[Grizzly]

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?

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.

[banned advertiser]

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?

[Grizzly]

Right off to wath England.... Seems they have just scored by the sound of it

[banned advertiser]

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?