I bought a nice fd the other week with no compresion on back rotor.
the motor is running std twins with jap chip ecu with upped boost.
Ive already got the motor out but i dont know what port size to use on the rebuild.
Im planning on using stock twins at around 12 psi like my last fd which made 280rwhp.
has anyone got a half bridge with stock twins and bigger exauhst ports?
im thinking of rebuilding the motor with half bridge, slghtly larger exahust ports, power fc, 1300cc secondaries, and then using the car for a while until i get some money together for a quality single turbo.
I dont want mega power or high revving, just a good streetable road car with the brap!.
Any ideas?
The car already has full decat exahust and greddy std mount ic
I maybe wrong but did\'nt Geff at reworx run a Half bridge with twins on for a while??
I think you may have a heat problem though, a half bridge would spool twins up rather fast and it may act like a restriction as they are quite small.
Sorry, I hate to sound dumb but what are you refering to when you say half bridge.
Chris
This is not going to help you much if you don\'t know much about the rotary engine, But a Bridge is a Type of Port that involves cutting a slot that runs parallel to the origanal, this does two things, it opens the Intake port alot earlyer (like a high lift cam in a Piston engine) but also creates more overlap so it makes a diffrent noise on tick over (and tends to drink more fuel at low speed etc)
In a nut shell....
This is an Extended port (basicly the stock shape port opened up slightly for more flow without the Bridge slot)
Cool cheers for that Grizzly. That does actually make sence (good way of explainning it):)
I assume then that you wouldn\'t want to use bridge ports on a high powered engine as there would be a little more restriction with the bridges than with out?
So for the thread High Jack :p but at least I understand it now. Sound like a sweet setup, dude.
Thanks
Chris
No you have missunderstood....
The Second slot is cut to make a Bridge. The stock port looks like the Extended Port at the bottom then they cut a slot so there is enough of the origanl port left to hold the Corner seal (so it does\'nt fall into the port)
The Bridge is Huge compaired to the Stock port and where it\'s let down by the high over lap at low rpm\'s it makes up with better Mid range spool up and Alot!! better Mid-high range Power.
As i say its the rotary version of fitting a Big valve head/Race cam all in one....
In a nut shell if you are looking for BIG hp, not to fussed about the long term life of the Engine, Not going to use it in trafic or at low speed alot?? and last know a good tuner that can get the best out of a High overlap turbo engine then a Bridge is for you.....
If you are looking for Good Power increase whilst keeping alot of the low end making it more Drivable in trafic with not such a dramatic MPG decrease as the Bridge and whilst still getting a good hp increase and more reliable then an extended port is more suited to you....
If you still fancy a Bridge you have two options, If you want a Full blown Fire breathing monster that Ticks over at 1800-2000 rpm then thats a Full bridge, and if you want it more of a tame Bridge with a little easyer botom end you can leave the Primary Ports in a Extended port design and only Bridge the secondrys (Half Bride or Semi Bridge), this works better if you are running a Divided Intake (No Plenum) so the Secondarys are 99% shut at Idle and very low speed.
Quote from: stuart wizyI dont want mega power or high revving, just a good streetable road car with the brap!.
Any ideas?
MMMMMM Full bridge with a T51R.
Don\'t it sound sweet....... Brap.....Barp.....Brap....
http://www.vosko.net/media/rotary/full%20bridge%20idle.WMV
This was alf Johnsons before he finished his Tour in Japan and had to brake it to get his money back :(
Note!! its got no exhaust on!!!! that is why there is NO ONE!! in the workshop at the same time as thats running and its why its not as much of a Brap (No back presure)
I could listen to that until I go deaf!! :Laugh
I would think a Street/Extended port would be best for road use if your not after huge power. :3gears-lh
good link grizly, imagine that sound at 8 in the morning on your drive way, music to your ears!
I dont really want mega power, just a little brap but still being reliable with controlable fuelling.
I just love the sound of the brap!!
any guys with a half bridge, whats the fuelling like running low boost? do you need to run lot more fuel through than an extending port? and I take it you need to be very pally with an mot garage on emissions!!
Imagen, I\'ve been there...... Half Bridge,T04R and a 3" exhaust with no baffles. It did\'nt last long, the novelty wears off realy quickly when you have to watch what time you start it, a mate of mine said he could here it going down our bypass 2 miles away!!!! At the time this was my every day work car and i was getting pulled 3-4 times a week...
A few things on my T2 that got it swaped for an Extended port was it had a On/Off twin plate Clutch, A BIG secondry Bridge with a Plenum (so it acted like a full Bridge) and it was\'nt set up that well so it was evil in Trafic.
As you proberly already know High overlap engines don\'t like any sort of Back presure, so its going to be loud!!! and its going to attract atention.
The brapping can be easily attained by adding more fuel at idle you don\'t need a bridge.
No point in running a bridge with stock twins far too much back pressure. You would be much better off with a street port. Wastegate will probably cause you issues with it being so tiny, so will probably need porting also.
Sadgoth had a half bridge with stock turbo II turbo 2. Its not an ideal set up though. Lots of compromise for a bit of noise, i would give anything to make my car quieter without losing power. There is nothing worse than lots of noise and no go!
Quote from: rotaryimports.comThe brapping can be easily attained by adding more fuel at idle you don\'t need a bridge.
No point in running a bridge with stock twins far too much back pressure. You would be much better off with a street port. Wastegate will probably cause you issues with it being so tiny, so will probably need porting also.
I sort of agree, Any sort of Bridge wants a Big Turbo hot side but it can be run on Stock Turbo\'s but short term (kind of a run in measure). I can imagen there would be a Heat issue before long, not to mention the wastegate Problems.
what are emisions like on half bridge anyone, I might sack the twins and try a single then.
It seems a shame to strip and rebuild the motor when i can half bridge it myself, I was thinking garret gt35 with half bridge and bigger exahust ports to spool up quicker, the question is would it pass mot on emisions and sound??
If i put a large silencer where the cat goes and using a larger back box aswell, would this cure the noise till i get home from mot centre?? or do u need the cat on for co levels?
Come on guys I know tims built a few half bridges out there, what did the mot man say on your last visit??
my mot guy dosnt check noise emmisions.. didnt think they needed to? lol.. but as for the co levels they will effect that a fair bit id of thought, my last rex cost me a fortune to do the co2 emmisions.. guy left the stick in 2 long n it melted :D
May be worth speaking to Pip about it.....
I think it can be done by playing with the PFC but it\'s just for the MOT and not some thing you drive there.
out of the 370 people who viewed this post surely a few are running bridge ports,!!!
someone help me out here, can a half bridge pass mot ??