Guys
Just wondering. What is this engine capable of in the NA form? Do we know yet? For instance. If the ECU was not a factor what could we get out of this baby beer barrel? 250? 275? What capability are we chasing here?
All you people more knowledgeable that me please fess up.
I'm thinking around 260-275 with a street port job, usual other stuff and high flow cat/midpipe. This is of course an everyday drive car I'm talking about.
olddragger

 

Inquiring minds would like to know! I still am interested in a new final drive set. I'm hoping it would make a difference as well.

 

NA, I would say maybe about 220 whp. Most engines are starting at around 180 whp. Not sure where you would get much more than that. You have cars getting about 200 whp with piggyback ECU, exhaust, hi-flow cat & air intake. Not sure if porting will give you that much more.

 

What is NA capable of with just bolt ons and piggy back or with port and polish and all that good stuff NA?

 

I posted this awhile back:

https://www.rx8club.com/showpost.php...&postcount=317

Also, didn't Maurice aka "Canzoomer" himself hit 250 RWHP?

 

to clarify---- my oridginal question was hp at the crank. I stand corrected in that rwp would be a better estmate. If I could get a daily driver that was quiet(like just a cat back sound) easy to keep in tune and dependable with 250whp I would be very happy. I believe what most of us are going to see is about 210-220. Thoughts?
Olddragger

 

I honestly think that 200-210 whp is about the limit with all the add ons & maybe a street port. 250 whp is FI territory.

 

I agree. Is that the consensus everyone?
olddragger

 

Short of new intake runners and more revs, I concur. More revs is getting into mud wrestling with the ecu, and the ecu is a pig.

 

I think THIS GUY might take exception to your comment.

240whp (starting from 190whp stock) with CanZoomer Stage 2 (non-tuned), Headers, Air Filter, CatBack, and Flywheel/Clutch. Definitely a lot of room to grow there too.

 

I think that was a european guy & his dyno is weird, as he stated it measures hp at the wheel but adds back in it's own correction factor to calculate power at the crank. He actually had a devil of a time with the Canzoomer, and went to a different ECU upgrade at first, before everybody on the board worked with him. That is an extrapolated 240 hp at the crank. Look at his first posts he said he was disappointed because in Europe the RX8 is rated at 228 hp, & he couldn't get that. 190 whp (+18% correction factor) is about 231 hp at the crank. That 240 hp is at the crank.

Also, there has been a CZ car that ran like 225 whp, but the timing was so aggressive that it began to detonate from all the advance timing.

 

I've spoken to a tech from Dragon Motorsports in Miami, FL and he said porting and polishing (polishing what, I have no idea myself) yeilds around 20+ whp. He also claim that with a configured ecu, full exhaust, plugs & wires, intake, and fuel upgrades yeilded close to the 250 whp range. Only thing is why pay 4 grand for porting and get 20+whp if you can pay 3 grand and get 60+whp?

 

Neo,

Hate to say this but this guy over at Dragon MS is theorizing. Even if porting & polishing gives you 20 rwhp (on say an average 180 whp RX8) he is claiming that a full exhaust (hi-flow cat, cat back exhaust & a non existant header), plugs & wires, intake & fuel upgrades will give him 50 rwhp. Yea right Let him show me a car that did this. CZ/CZ customer did an NA car around 220 rwhp once but the timing was so advanced that they had issues. We have numerous RX8 cars here show that intake, exhaust, cat & CZ was yelding about 200-205 whp. Unless, wires & a mythical fuel upgrade (which is not needed on this car), & porting deliver another 50 whp I'm afraid this guy is blowing some serious smoke up your tail. He is theorizing from the porting & polishing work done on RX7 over to the RX8. Different engine. Also he is seriously overestimating the hp increase from the rest of this stuff. Again probably theorizing what it did on an RX7 over to the RX8. Nemesis had a good chart on expected/realistic hp gain, and if this stuff added up to 50-70 whp, I'll give you a $1,000 (But if it doesn't then you give me the $1,000).

 

Porting + stand-alone ECU + intake + exhaust + blueprinting + aggressive tuning = about 270-280 hp, maybe more in a few years of development. Realisitically, expect to get about 15-20% gains with ECU tuning + intake + exhaust.

 

180 whp + 20% = 216 whp. Haven't seen it with just intake, exhaust, & CZ Piggyback ECU (& even with the hi-flow cat). Results were more like 200-205 whp. You can advance the hell out of the timing to get 220 whp, but then the car isn't really drivable on a daily basis. Remember, we aren't really starting at a real 238 hp. Dynos suggest we actually have closer to about 215-220 at the crank. If we started from 238 hp then maybe with the stuff described above you can get close to 280 hp (or even better 250 whp). As it is right now these stated gains are unrealistic. If you are looking for 240 whp+, you are looking at FI or Nitrous area.

Maybe Guitarjunkie can comment on gains made with porting & polishing and/or porting/polishing with additional mods. 20 hp from porting might be realistic, but another 50 whp gain from this other stuff is not. This engine is pretty well tuned to the hilt. If Racing Beat isn't finding this extra hp, I doubt anybody else is either. From the numerous dynos that posters here have done, and in various magazines you are getting about 5-8 whp from exhaust & intake together. Where are you going to the other 42-45 whp ? It ain't going to be from tuning the engine.

 

Agreed.
In my uneducated opinion, one of the biggest things that limits the NA gains available is the fact that there is no overlap between the exhaust and intake port timing like there used to be. It used to be that a set of tuned headers could get 20-30HP just by scavenging. Since we no longer have that overlap, there is no way to scavenge. Headers used to be one of the biggest NA gains to be made.

I would have agreed with you on this a couple of months ago. But, then came that guy from Scotland with that wierd dyno that claimed to read crank HP. I did a little reading on it and here is how I think it works: You spin-up the drive train and then suddenly depress the clutch. It measures how fast the thing takes to spin-down to zero. From this, it can estimate drive train losses which includes the inertia and friction of the drive train. Once you know this, you can easily back out crank HP. Fanman, I know you remember that guy's dyno sheet. Someone posted it again recently in this thread. It showed 238 crank HP - which validates Mazda's claim. So now I think we have a 238HP engine with really crappy drivetrain losses!!

My bet for NA: about 220 WHP. That's with a piggyback, port job and the breathing mods. I think once you get the ports a little more optimized, the intake and exahust will be -slightly- more effective.

 

Compression and RPMs. That's the key. And fuel. And Spark. We're talking a full point higher Compression, RPMS to 12-14K...Lots of fuel, and spark, and a way to control those things. That'd do it.

 

When I said 'ECU-tuning', I didn't specifically mean CZ, even though that's basically the only option right now. CZ can only go so far in terms of modifying and fooling the ECU. My belief is that the fueling maps are designed to promote cat life by running excessively rich, reducing cat temps. Furthermore, there may be benefits to changing when the secondaries and aux ports open, especially in combination with an intake and exhaust. There will be more ECU options coming in the next few years.

AFAIK no one has built the Renesis to racing trim yet. If you look at whats been typical in E-production engines, a gain of 50% over stock isn't unreasonable. Blueprinting and porting the engine for top-end hp + aggressive tuning via a stand-alone ECU should yield this. Redline could probably be raised also. However, reliablity and driveability may suffer, perhaps dramatically.

Finally, it may be possible to achieve the scavenging effect of a perhiperal port exhuast in the Renesis by proper porting and tuning. I would think the trick would be in maximizing velocity of the exhaust at the target rpm (probably 9k for a race motor).

 

http://www.starmazda.com/cars.htm

and since one of the drivers luis schiavo is a member here he could tell us exactly what the engiens are putting out in that trim

 

I guess I am missing something. It says its a 240HP engine on that site. But that car only ways 1000lbs! :D

 

I don't think so. The Star Mazda engines are sealed engines supplied by Mazda for a spec series. Its likely that the only differences between those engines and the Renesis in the rx-8 are only for reliability or mounting, not for hp gains.

The rx-8's running in the SCCA Grand Am series claim to be using a Renesis-derrived engine, but really its a 20B peripheral port. I don't think anyone has really built a Renesis to race trim yet.

 

speedsource cars are running renesis engines

http://www.speedsourceinc.com/index....1&news_id=1796

 

sorry link to the cars/engines

http://www.speedsourceinc.com/index....&section=mazda

i think you are thinking of the 3 rotor they built for the American Lemans car

 

zoom44: Yeah you're right. Still, they list the hp at 238, which makes me wonder if SpeedSource can't modify the engine per the rules? And if they can, I doubt they would want to give away how much hp they are making. I'm not very familiar with the rules in this series.

 

I found on a racing forum that the SpeedSource cars are using stock Renesis engines (which I assume means no porting / blueprinting) and Motec ECU and are making about 250 hp at the flywheel.

They are apparently experimenting with ceramic seals of a different shape. They comment that there is not much to be gained from headers or from porting the intake, but they believe the exhaust can benefit from porting. They are running zero split timing between leading/trailing (which is kind of odd). Also, they changed the oil injectors to have two injectors dump directly into the housing side-by-side.

Whats more interesting (altho off-topic for this thread) is that they are using stock brakes and stock rear sway.

http://www.nopistons.com/forums/inde...ic=34414&st=0&