Running more than 200rwhp with n/a ?
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From: Pittsburgh/Johnstown, PA
I'm planning on doing it when I get my engine together. S5 TII irons streetported pretty aggressively, rotor housings ported pretty aggressively, S5 NA rotors with beveled edges, rebalance, and clearancing if budget permits, RB streetport exhaust, S5 NA intake manifold with the lower intake runners welded then reported to match the 4 port engine so I can use VDI. O ya, also using a Megasquirt to run everything. Eventually I will build my own intake manifold and exhaust setup to pick up those last few ponies. And don't worry about torque, first off the engine is going into a first gen so it doesn't have much car to push, secondly, you can always upgrade to 4.44 or 4.88 gearing in the rear end to really wake the car up, especially with a light flywheel.
Bridge porting will get you over 200, even with a 12A, but you'll have to do several other supporting mods, especially with a full bridge. The car also won't be as pleasant to drive on the street, especially without fuel injection and computerized ignition control.
This is all assuming the engine is built well, setup properly. (proper intake manifold, exhaust header, engine management, ect)
Bridge porting will get you over 200, even with a 12A, but you'll have to do several other supporting mods, especially with a full bridge. The car also won't be as pleasant to drive on the street, especially without fuel injection and computerized ignition control.
This is all assuming the engine is built well, setup properly. (proper intake manifold, exhaust header, engine management, ect)
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From: Pittsburgh/Johnstown, PA
Originally Posted by Rotary20B
I have
295 rwhp, extend (street) port, decompressed rotors
295 rwhp, extend (street) port, decompressed rotors
Look at the name. Thats what an extra rotor will do for you. Very nice setup regardless. How much torque @ what RPM did you get from that and what are you using for an intake manifold?
Originally Posted by BlastinSideways12A
Look at the name. Thats what an extra rotor will do for you. Very nice setup regardless. How much torque @ what RPM did you get from that and what are you using for an intake manifold?

It still breaks down to 100 rwhp per rotor though, which is still pretty impressive for a decomp na extend port, the port isn't a large na port, it has been left small enough to allow turboing later on.
I'm using a custom intake, that alone gave a gain of 50 rwhp over the turbo 20b intake
Not sure about the torque, dd doesn't give an accurate reading
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From: Pittsburgh/Johnstown, PA
Originally Posted by Stevan
Originally Posted by Stevan
239 hp(FD Racer's car) minus 15% driveline loss = 203.?
Isn't 15% the standard used for drivtrain loss?
I don't know why the Renesis would only get 185 from 238, thats 22%.
I guess it depends on the car, I've read that the loss can be calculated on the dyno by measuring the the deceleration drag with the car in neutral.
Isn't 15% the standard used for drivtrain loss?
I don't know why the Renesis would only get 185 from 238, thats 22%.
I guess it depends on the car, I've read that the loss can be calculated on the dyno by measuring the the deceleration drag with the car in neutral.
yeah...its marginal...i was using a 17% drivetrain loss (which i read somewhere). anyways, like Blake says...only an indication...need a proper dyno test with rwhp.
So unfortunately....unless i see a rwhp dyno sheet i'm not going to give him benefit of the doubt.
So unfortunately....unless i see a rwhp dyno sheet i'm not going to give him benefit of the doubt.
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From: Pittsburgh/Johnstown, PA
rwhp is the real measure of performance. That being said, FDRacer's car is VERY nice and I am in NO way downplaying it. It is VERY well built and tuned. We need more people building streetported NA engines like that. Mine is going into my FB for now but eventually will see its way into a Miata (probably our 95 M edition with a hardtop). Talk about a handling beast!
don't get me wrong. i've seen the pics of that car. it is awsome. looks very 'street' on the outside, but open the door and u see the rollcage, seats, custom gauges etc. then re the motor its got throttle bodies, management system etc.
yep...we splitting hairs because we don't know what the rwhp is. it could be slightly under 200..maybe slightly over. what we do know its 239 at the flywheel. and what we also know is that a stock s5 tii is 200 at the flywheel. so he is like 20% more power and ex the turbo, a very creditable achievement
me...am only 157rwhp so lets make that say 190 at the flywheel. I'm like 50hp off the pace !!!!
for me to go throttle bodies and management system is just going to kill my budget. I'm going to have to make do with current system and tune for ideal jetting. If push comes to shove, and i open her up next year some time, then will (1) def install 9.7 compression s5 na rotors and (2) extend that street port...maybe even bridge.
yep...we splitting hairs because we don't know what the rwhp is. it could be slightly under 200..maybe slightly over. what we do know its 239 at the flywheel. and what we also know is that a stock s5 tii is 200 at the flywheel. so he is like 20% more power and ex the turbo, a very creditable achievement
me...am only 157rwhp so lets make that say 190 at the flywheel. I'm like 50hp off the pace !!!!
for me to go throttle bodies and management system is just going to kill my budget. I'm going to have to make do with current system and tune for ideal jetting. If push comes to shove, and i open her up next year some time, then will (1) def install 9.7 compression s5 na rotors and (2) extend that street port...maybe even bridge.
According to the 1st gen race preparation manual, a 12a peripheral port with a weber 48 will make approx. 240hp. That's using a lot of specialty components though, and I'm not sure if that's the wheel horsepower.
If you want to run 200 hp on an N/A 12a, you can kiss your torque goodbye. 13b is another story
Originally Posted by craigw1
186rwhp but only 133nm torque ?
Last edited by RustyRotary; Aug 13, 2006 at 04:18 PM.
Originally Posted by RustyRotary
According to the 1st gen race preparation manual, a 12a peripheral port with a weber 48 will make approx. 240hp. That's using a lot of specialty components though, and I'm not sure if that's the wheel horsepower.
If you want to run 200 hp on an N/A 12a, you can kiss your torque goodbye. 13b is another story
If you want to run 200 hp on an N/A 12a, you can kiss your torque goodbye. 13b is another story
A race prepared full bridgeport with large IDA carb, and no emission or noise limitations will produce 205rwhp in short run tune.The torque:power ratio will be low but suitable for the race environment operating in the 6000+rpm range.
Fuel consumption will be in the 4-6mpg range but who cares when you are having fun. The engine will require rebuilding on a regular schedule. Ideally you need a two engine set-up; a parallel 'run one- rebuild one' approach. A good garage, several rotary friends, and a understanding girl friend are useful operating conditions, plus a well paid day job.
Originally Posted by RustyRotary
According to the 1st gen race preparation manual, a 12a peripheral port with a weber 48 will make approx. 240hp. That's using a lot of specialty components though, and I'm not sure if that's the wheel horsepower.
If you want to run 200 hp on an N/A 12a, you can kiss your torque goodbye. 13b is another story
If you want to run 200 hp on an N/A 12a, you can kiss your torque goodbye. 13b is another story
That is huge for N/A motor!!!
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From: Pittsburgh/Johnstown, PA
Originally Posted by RustyRotary
According to the 1st gen race preparation manual, a 12a peripheral port with a weber 48 will make approx. 240hp. That's using a lot of specialty components though, and I'm not sure if that's the wheel horsepower.
If you want to run 200 hp on an N/A 12a, you can kiss your torque goodbye. 13b is another story
If you want to run 200 hp on an N/A 12a, you can kiss your torque goodbye. 13b is another story
Your not losing any torque, actually you will gain a little torque through modification. The difference is that the torque is shifted higher into the RPM range, yielding more horsepower. Power is torque and RPM. A 13B won't make that much more torque over a 12A if both are built the same. The reason that the 13B has a better reputation for torque is the fact that most NA 13B engines were 6 port and had EFI, definately helps with bottom end torque.
Originally Posted by PaulFitzwarryne
A typical pp will produce 240rwhp. The factory prepared pp engine at full tune could produce 250-252 rwhp, but were marginally detuned for reliability. Bench tested they could get 305 hp at the flywheel.
A race prepared full bridgeport with large IDA carb, and no emission or noise limitations will produce 205rwhp in short run tune.The torque:power ratio will be low but suitable for the race environment operating in the 6000+rpm range.
Fuel consumption will be in the 4-6mpg range but who cares when you are having fun. The engine will require rebuilding on a regular schedule. Ideally you need a two engine set-up; a parallel 'run one- rebuild one' approach. A good garage, several rotary friends, and a understanding girl friend are useful operating conditions, plus a well paid day job.
A race prepared full bridgeport with large IDA carb, and no emission or noise limitations will produce 205rwhp in short run tune.The torque:power ratio will be low but suitable for the race environment operating in the 6000+rpm range.
Fuel consumption will be in the 4-6mpg range but who cares when you are having fun. The engine will require rebuilding on a regular schedule. Ideally you need a two engine set-up; a parallel 'run one- rebuild one' approach. A good garage, several rotary friends, and a understanding girl friend are useful operating conditions, plus a well paid day job.
Race 13B BP
http://www.rotary20b.com/dyson2006/phil.wmv (7.2 mb)
Street 13B BP
http://www.rotary20b.com/dyson2006/13bbp.wmv (5.8 mb)
Originally Posted by 13 BEEF
my mates GURU PP makes 395nm of torque
That is huge for N/A motor!!!
That is huge for N/A motor!!!
Something doesn't sound right there


