An RX-8 engine on an engine dyno only does right around 225hp. Hymee in Australia got 227 on his engine dyno tests. Some of those cars dyno at 180 rwhp and others can hit 200 rwhp. There are differences however between those engines due to improper lubrication of the apex seals from the dual oil metering jets pointing outwards that lead to slight apex seal warping and wear in the center. This causes drastic mileage and power differences between those engines. Speedsource had their stock Renesis engines tuned to 260 hp on an engine dyno. When they measured the same engine in a car on the chassis dyno, they'd get right around 230 rwhp. Losses through a drivetrain are only about 10%-12% or so but nowhere near 20%

Keep in mind a 500hp race car losing 12% through a drivetrain is losing 60 hp worth of heat. Of course it needs a transmission cooler. Even a lowly 200 hp street car is only on average wasting about 5-6 through the drivetrain while cruising down the highway. That doesn't need a cooler. Take that same engine and put it in a race situation where it's average power is up near 200 most of the time and it's suddenly a very different story. Suddenly you need to dissipate 20+ hp of heat. You may need a cooler now.

 

Completely off topic, but I'm the Op so who cares! Has anyone been watching what MS3's are doing. Either Mazda is underrating how much power they make stock, or they've engineered a great drivetrain. They're averaging only an 8% drivetrain loss.

 

Hyper4mance2k
do you have a video or sound bite of your exhaust, i am doing my GSLSE exhaust soon, just wondering how loud it is?

 

Are you Retarded, or does he just have a huge boost leak. 13 psi on a 13bt, lmfao.

 

No i don't have a video camera. I'm hoping percent shows up to the dynoday tomorrow to get video's. All my time and money goins into the car, so I dont have money for a camera.

 

hmm you know, it might be calcuable... in a 15 minute race you dont need a cooler, but in the 25 HOUR race, you bring an extra trans or 2...

 

Actually, I was reading an interesting thread on eng-tips involving a circuit racing Old English Car of the Midget/Sprite variety. Definitely not high up in the power scale. Anyway, they were having problems with transmission failures, and the consensus from people who also beat their head against the same wall:

The failures were due to heat.

Instead of adding a cooler, running THINNER gear oil would be an effective solution. As proven out in practice.

I wish I could find the thread... Oh wait here it is: http://www.eng-tips.com/viewthread.c...=240331&page=1

 

These quarter mile calculators work. Our strips are a genuine 1/4 mile long, and compared to the youtube video's I have watched, are a league above the standards seen in USA and Mexico.

These Australian built dynodynamics dynamometers are accurate. The problem you are having, is that your chassi dyno's are reading HP somewhere between RWHP and BHP, sometimes erring on the side of BHP. We have this problem here too. Its all too easy to take your car to a typical JDM tuner shop and spit out 180rwkw even tho its really only 180rwhp.

You are just getting told what you want to hear, with these 190-230rwhp dynos. It just doesn't happen, you can't beat a turbo RX-7 with a street port in the same chassi. I have heard of NA rotaries beating turbo rotaries, but what it takes is a bridge port and a smaller chassi.

As a side note, so you don't think I'm blowing smoke up my own ****, what do you believe the serious limit for the stock TII turbo is? Because I honestly believe it is 260BHP/195rwhp/145rwkw.

I'm sure you will be able to present 260rwhp dyno sheets to prove my point.

 

The 14mi calculators work to get crank HP. I just plugged my latest numbers in to the one on DSM.net (because it's the one I remember) and I got expected results.

Weight: 2700lb (2500lb car, 200lb driver, as actually measured. My car's a pig )
ET: 14.36
MPH: 98.01

And the results were 180hp from ET calculation, 198hp from MPH calculation.

Most cars running that quick are launching much harder than I can (tall gears, 10lb flywheel, no torque) and cutting better short times than my pathetic 2.26. So if I was launching like MOST cars(*) that run in that range, it'd have been maybe 14 flat or so, which also corresponds to just a little under 200 HP.

Yes, I am talking crank HP. The (*) is because the calculations used are the ones that Chrysler engineers extrapolated from observed 1/4mi runs and they were concerned with crank horsepower, not wheel HP which is a bit nebulous because there are many different factors.

Fuel injector duty cycle meshes with this. I'm peaking out around 95% duty cycle. I am running two 680cc injectors, which is 130lb/hr total flow at 100%. 95% of that 123.5lb/hr. Guesstimating .55lb/hp/h BSFC, I get fuel use for 224hp. Guesstimating .60 BSFC, I get 205hp worth of fuel. (So either way, I'm probably a tad rich, or maybe my timing is off WB says I'm running about 13.5 for most of the range and then richening to 12.7 over 7000)

And that is the next point I am to make: Wheel HP will depend entirely on the dyno type and methodology used.

My car made 170whp, on a Dynojet dyno, four times in a row with no cooldown. This correlates well to the 15% rule-of-thumb often noted. A completely stock FB was also at the dyno day and it made 85hp at the wheels, which - yep - is 15% down from stock rating of 100hp.

I first heard of the 15% rule from Mike Ancas, who had IIRC a Mustang dyno.

My same car, running richer than 10:1 at the top end thanks to a tuning goof, made 154hp on the Dynapack at Defined Autoworks. After a couple minute cooldown it did something scrody like 145hp. Is going from 10:1 to 12.7:1 worth 10-20hp? Maybe. Maybe not.

But two things should be noted: I asked Logan to test my car the same way he tested his own car. And, his own car recently posted 230hp. So, I can believe a street port N/A 13B making over 260 crank HP. I can even believe a 300hp one at this point.

"You seen it! You've heard it! And you're still asking questions?"

But IN THE END, dynos and quarter times are just measurements. 1/4mi times have the advantage of measuring the driver as well as the car's acceleration, which is kind of good, because power is just a tool for making acceleration, acceleration is the main goal, so that is what should be measured. And, cars don't drive themselves, so the driver must be tuned for best acceleration. (I get best acceleration shifting at 7900 with the flat-shift OFF. How sad, the bang-bang is slowing me down...)

 

Nice numbers Hyper. My car (see sig) only ran 160rwhp on a Dynapak. My port is basically a small streetport but I have RX-8 rotors. I believe I have a 3rd gen pulley so my timing marks were off. Once we get the correct pulley to set timing and switch to an S5 intake (with VDI and working 5th and 6th ports) we are hoping for 175rwhp.

I am running a Racing Beat Streetport System. I know they don't make the most power but they keep the car quiet and are very durable. My 12A car is way to loud for my tastes with Pacesetter headers and a Magnaflow into a Borla. That setup was on the car when I got it.


Oh by the way Dynapaks consistently read 10-15% lower than Dynojets from what I understand.

Greg

 

I went back to Intec Racing where I dyno'd 138 in November. Well I didn't make it to 200rwhp, but there's still more tuning to come.
190.5whp@7300rpm today. Tuesday when I get back to work I'll post the Dyno sheet. Percent was there today taking video, so he should get that up soon.
Changes that I made from last time 189.65 to now 190.5; port matched the intake manifold, aluminum flywheel, new clutch, BR9EIX plugs, Mazdatrix underdrive pulley. On a good note my extra work has paid off. Lasttime peak hp can and fell off rapidly, now it holds power until 7500 rpm. I didn't take it any higher, but I wonder what if, if I would've reved it higher? I doubt it, but Tq curve is much flater now. The dip at 5500rpm is all but gone.
More proof that aluminum flywheels do not make more power. they just let the engine accelerate faster, but that doesn't make any more torque. Remember you can't argue with physics.
Horsepower=torque x RPM / 5252

 

Those are some great results for your efforts.

 

I got back late, so I'll try to get the videos posted tomorrow.

I don't think it's been mentioned yet, but you should make a heat shield for your header. Seems like heat is your biggest enemy left.

 

Nicely done.

I don't think most of the more educated people say that lightweight flywheels make more horsepower. They just free up the horsepower that would normally be used to spin a heavier flywheel. Since it is no longer being used to spin a heavier flywheel it gets sent to the wheels. Compare the dyno graphs from before and after the flywheel swap and you should see an improvement in the low RPM torque.

 

Video is up:
http://www.youtube.com/watch?v=U0vbPTuvCzs

 

That sounds sweet!!

 

Sounds pretty good.

The hp on my car started falling off around 7700rpm if I remember correctly.

 

Sweet, my car sounds neet. I never get to hear it form outside!!

 

Sounds awesome man.

 

I'm very impressed with the sound of it. I bet that 190 horsepower in that car is fun as well.

 

Replying here instead of in PM because this is just neat and everyone should see it:

https://www.rx7club.com/forum/showth...2A#post1354471

Engine that made 260hp on an engine dyno went into the car and did 220whp on a Dynojet.

And it was a N/A 12A so it probably revved a bit high

 

Wow awesome thread!

I'm about to pick up a RB Streetable Header- Collector for my stock GSL-SE.

Trying to determine the rest of the system after reading this thread.... but, after this thread, it seems that reducing back pressure with bigger pipes (vs. the standard RB system) is essential!

I'm probably locked into the RB pre-silencer just due to the need to have the back-port accuator. I ws thinking 3" pipe from there back to a magnaflow. Probably not as slick as what Hyper2K has done, but I don't have the Road Race header to start with...

 

You don't need crappy power killing back pressure to actuate your aux ports.
http://www.rotaryresurrection.com/2n...elec6port.html
Dont use the presilencer that is the power killer, that and their 2" collector. If you have the 2nd gen header with the 2.5" collector you're not as bad off, that's actually a nice header. You can't just go 3" after the presilencer and expect to gain much power. My first exhaust was a full RB street system then I went 2.25" from the silencer back through a Apex N1 muffler and only saw a 2whp gain in power. Waste of $200 and time.
Run the RB header. Get a megaphone from here: http://www.coneeng.com/index.html or http://www.woolfaircraft.com/index.html
Then run what ever mufflers and cats after you megaphone in what ever size exhaust you're going to run.

 

https://www.rx7club.com/2nd-gen-archive-72/how-air-pump-auxilary-port-activation-330310/
uno mas aux trigger writeup 4 u

 

Well, I was picking up a used 1st gen header/collector. Really sounds like I should go to the RR header after reading all this, and pass on the 1st gen streetable header.