PoLaK

iTrader: (1)

Dear God some people should stop spouting off when infact they don't know what they hell they are talking about.

The RX-8 Dynos 209-220hp at the crank on an engine dyno can't say who said that because they are in bed with Mazda.

A MAF sensor input voltage variance is the cause of the varying amounts of Horsepower. I my self have dynoed 187rwhp (best dyno out of 15tries total on diffterent days etc..)
Some people have gotten 197rwhp with high octane gas and no air filter.
The cars that dyno 160's-170's would greatly benefit from tuning because they run so much richer to begin with.

My Article in the July issue of Rxtuner is available for you to read now.
http://www.rxtuner.com/

I'm also making a thread in aftermarket performance to discuss the article.
see: https://www.rx8club.com/showthread.p...855#post503855

PoLaK

iTrader: (1)

You should read more i trapped a 14.58@94.55mph see: https://www.rx8club.com/rx-8-racing-25/14-58-%40-94-55mph-37357/

This car makes very good use of Sdias tuning and at above 55mph it has a significant ram air vortex bubble infront of the nose. If you stuck our car on a dyno with a turbine blowing 30,000 cubic feet of air at 75mph i would have no doubt it would produce a NUMBER that simulates what you would get in the real world.


(end rant)

PoorCollegeKid

Driver skill affects ETs much more than trap speeds. This is why trap speeds are indicative of how much power a car is putting to the ground while ETs are indicative of the quality of the launch and driver skill. That's also why most members who run a 1/4 drag in 15.5 still trap in the low 90s, while those running in the 14s only trap a few mph faster, if any at all. As we all know, accurately estimating things like drag, elevation, and grade of a hill is rather hard.

Oh, and about the WRX- on Vishnu's Dyno Dynamics dyno, a stock WRX pulls ~160-168hp. Add 10hp to the WRX's total from an exhaust (but only if it was a quality one, not just a muffler or an axle backm, those could post very low gains), remember that your car has better gearing than the WRX (especially on the top end), remember that the WRX weighs ~50lbs more (could be an even bigger weight discrepancy than that, depending on options installed), and assume that you were a better driver than s/he is and it is perfectly reasonable to assume that your 170-180rwhp RX8 could beat a 170-178awhp WRX. Stock for stock, a WRX traps about the same as an RX8, but because of your gearing advantage you should definitely be able to take a WRX from a roll given equal drivers. Remove the stipulation of driver equality, and nearly anything can happen.

Your run (along with Judge Ito's) is actually one of the ones that I was referring to, as it shows what a good driver can get with an RX8. You are trapping in the mid-90s, which falls within the range of low to mid 90s that I said. Another car that has trapped 94mph stock is the RSX-S, a 2850lb car with 200hp and a power to weight ratio of 14.25. Since power to weight ratios play a large part in determining trap speed, it can be interpolated that an RX8 has a similar power to weight ratio as an RSX-S. Figuring that an RX8 weighs in at around 3030 with a p:w ratio of ~14 (since it is a hair faster than the RSX-S), this gives the RX8 216hp, which falls neatly in to place with the engine that Racing Beat dyno'd and members' reports of dynos in the 170-180 range. Therefore, I fail to see how your ET/trap speed disproves anything that I've posted.

I'm sure that placing a high capacity fan in front of your RX8 when you dyno it would improve your dyno numbers. I'm also sure that doing this to any other car would also improve its dyno numbers. Unless an RX8 benefits from the effects of moving air far more than, say, a Ram Air T/A, a 350Z, or an intercooled WRX, this does not change the fact that an RX8 puts less power to the ground than it should if the 238hp claim is accurate. If every other car dynos within a predictable percentage of its claimed power, then why should the RX8 be any different? It's not just a rotary thing, either, since the old FD turbos, cars that really would have greatly appreciated a large amount of cool air streaming past their radiators and intercoolers, dyno above 200rwhp and are rated at 255hp. They don't even have the RX8's advantage of a light weight carbon fiber driveshaft, either. However, you have to look at it this way IMO. Does this "lack" of horsepower make the car any less fun to drive? According to most of the posts that I've seen here, the answer to that question is an emphatic, resounding "NO!", and that's really the only thing that matters.

PoLaK

iTrader: (1)

You said that ETs point to it putting down 170-180. That’s not true at all.
Take your RSX example, the Stock RSX TypeS dynos 172.2wph (just a sheet I’ve seen). Yet the RSX runs a 15.2@92.7mph (R&T). Does that ET "point to 170whp?"
There’s not a lot of cars i know of that run mid to low 14s (my 14.5 and itos 14.3) without putting close to 200 to the wheels in real world conditions. Dynos are just a number they are only useful when trying to gauge the difference your mods have made.

There is a lot more going on then HP in trap speeds, it's usually an semi-accurate indicator. However there are many other variables that should be considered such as gearing as the Rx-8 pulls very well on cars from 100mph+ such as the WRX.

JimW

Racing Beat registered 217 H.P. at the crank using a chasis dyno. The car also had a K&N Typhoon intake in which they confirmed a registered 6 H.P. Yes folks, this car's H.P. is way underrated. However it is still a great car and loads of fun, but how much better would it be with the original advertised power? We can only hope.

PoLaK

iTrader: (1)

Do you have a link for this info? Speaking to the guys at racing beat on the phone i was told to keep hush hush.

zoom44

i have seen dynos of stock rx8s of 190rwhp. that is a 21 percent drive train loss from 238- pretty normal now adays. i have also seen dynos of 175rwhp which is a 37% loss from 238- completly unbelievable that any modern sports car could have that kind of loss. there are several plausible explanations for this- 1. different dynos provide different results. 2. not enough airflow at the dyno 3. the pcm locks down the run- i saw this happen on 2 cars back to back and they both pulled between 175 and 180 4. varying altitude humidity etc conditions at the dynos 4. one persons car is making 238 bhp while another 's is only making 217.

the last is the one i find hardest to believe. dynos are for tuning. you get a base line hp then you add your power parts,do your tuning and run on the dyno again to see what percentage increas you managed to make. that is the only thing you can take away from a dyno run. the rest of this discussion is moot until one of you pull your engine and stick it on a dyno as completely as able turning of the pcm functions and find out how much power your engien is making. even that wont mean anything compared to what someone else has.

doubleohsmurf

The real good news is that you are wrong...and that the high RPM warning beep isnt stupid.

JimW

Polak, I think it was on the visit or tour of racing beats facility threads. I will do a search. I think the thread was posted around 4 months ago. By the way, thanks for the correction. It is overrated.

JimW

PoLaK, the only way I could find this is by searching for Racing Beat. Then on page 7 of the search pages, look at Racing Beat Focus Group Update. Specifically Post #17.