Imidazole

Well guys... Dynoed my 04 RX8 with 5500 miles on it. M6, every option package.

Held down the TSC button to turn off TCS and DSC - like when I autocross.

Was performed on a Dynojet, did two pulls in 4th and one in 5th to try to get closer to the 1:1 ratio.

I'll post the dyno sheet later... But she only made 175hp? There is an occasional odd little dip in power, barely noticible.

Slightly warmed up, and completely warmed up really didnt make much of a difference.

How much are you guys dynoing? I mean... this seems low. For a car that is advertised for 238hp. Hell, the AT's are advertised at 197 - what do they dyno for?

Thats a good 26.5% drivetrain loss - assuming it does make 238hp at the flywheel! That sounds outrageous to me... What about you guys?

Fill me in here?

roket rider

welcome to the rx 8 club. We all live with that number because we like the cars and like to drive such a fun little ride. If the car didn't look as good as it does, i would have traded mine for a GTO or whatever a long time ago.

irish8

Imidazole......this HP figure seems consistant with other Dyno tests I have read and heard. One of the Dallas guys dyno'd his 8 about 6 months ago and posted approx 173rwhp!!

The 238hp is at the crank, not the wheels. There is always a loss of HP by the time the power hits the rears. 26.5% is about right!! If this power loss is accurate the AT would dyno at approx 145rwhp!! This is the same with all cars. The 05 G35's are listed at 298HP, which means HP at the wheels is about 25% less at approx 220rwhp.

- Irish

Imidazole

Here is a link to the Dyno graph, in its full image quality bandwidth sucking glory:

http://www.serversunderthesun.com/My%20175HP%20Dyno.JPG

Here is the same graph, but sized down in a more appropriate fasion:

http://www.serversunderthesun.com/My...P%20DynoSM.JPG

Imidazole

Maybe I am just missing the way GM does it. The 325-325hp rated Camaro I had actually dynoed 235 to the wheels.

The 400hp new GTO dynoes 352 or so hp, thats only a 12% loss.



Where is the weak link? High rear end ratio? Exhaust or intake? Tranny ratios? Do we have a steel driveshaft or something?

Cam

iTrader: (1)

Our cars run pig rich from the factory. I dynoed my car last weekend and pulled a 179180/181 all in 5th gear (1:1 ratio). However there was one member who pulled a 206 (uncorrected) completely stock.

Check out https://www.rx8club.com/series-i-tech-garage-22/anyone-know-200-whp-stock-rx8s-i-saw-one-today-53891/

dmp

fwiw, you can't compare a dyno on that machine with a dyno jet machine...different animals they are.

SharkDiver

we have a carbon fiber drive shaft and I would say the weakest link is the 1.3 liter motor.
shark

therm8

carbon fiber driveshaft. There's no way the car has 26% drivetrain loss. That leaves flywheel horsepower as your culprit.

Xyntax

I wish someone would just dyno from the flywheel and get the story closed once and for all. There's just too many speculations, but one idea stays true "This is not a 238HP Machine at all".

Fanman

I dynoed at 179 whp with the RB cat back so that is consistant. I honestly think even the 238 hp at the crank is optimistic. In Europe it is rated at 228 hp. That seems more in line with the dyno #'s. Maybe even around 220's. Many people are dynoing there turbos are getting in the low 230-240 whp range (about a 60 whp gain). That is what the stock 350Z is dynoing at (claimed 287 hp at the crank) so it comes in line with about a low 220-228 hp car.

RotorManiac

I went to the dyno too. I had only the MS flywheel on and the colder greddy plugs.
I experimented with the MS air fIlter.
-stock filter (4th gear) 184.9whp (emissions test run, one exhaust tip was blocked)
-stock filter (5th gear) 187.7whp, 17.7kg/m torque
-no filter at all (5th) 191.1whp
-MS filter (5th) 188.6whp, 18kg/m torque

Dyno model is the Dynapack. The computer, after each run, came up with a correction value, depending on that day's conditions (temperature, pressure...). It showed 0.03% variation. Not sure if its correct, but the guy that owned the dyno told me my last run result is actually 194.3whp....

brothervoodoo

Racing Beat has.........

dmp

216hp, If I recall correctly.

RX-Nut

:o

RX8-TX

Follow my sig....you are about in my same ballpark with a similar trim.

Charles R. Hill

iTrader: (7)

In order to predict future performance I have always used 220 fly/180rw as starting numbers. I also used a G-Tech which showed about 180 net when the car was stock. By using these figures along with a 40 h.p. drivetrain loss (stock flywheel) and 25 h.p. (9.75 lb flywheel) I have been able to predict 1/4 mile performance with pretty good accuracy. For the most part to go from stock 15.0(+/-) to 14.0 requires about an additional 40 horses. This is usually gained by using a lightweight flywheel, light pulleys, cat removal, and other easy bolt-ons. To go from 14.0 to 13.0 requires another 50-55 h.p. which is usually nitrous or a turbo with about 5-6 psi. To go from 13.0 to 12.0 will require higher levels of boost whether from turbo or nitrous. All of this assumes stock-sized street tires are being used and no other weight is removed from the car. Most people have followed this same course of action with similar results.

CRH

rkostolni

Has anyone ever tried to contact Mazda and ask them what the hell is going on with this? I think it is pretty clear Mazda that Mazda has overexaggerated the claims. I'm just curious what they have to say regarding this.

RX8-TX

Search Button is your FRIEND!
https://www.rx8club.com/showthread.p...zda+horsepower
https://www.rx8club.com/showthread.p...zda+horsepower
https://www.rx8club.com/showthread.p...zda+horsepower
https://www.rx8club.com/showthread.p...zda+horsepower
https://www.rx8club.com/showthread.p...zda+horsepower

:D

Print them up, and use them as night reading material!

Other_Dave

Did you get a CEL while dynoing?

rkostolni

I know about the stated reduction from 250hp to 238 which is what all those links discuss. But what about the fact that it is not even making 238. Maybe 215-220 tops.

RX8-TX

What?? j/k

Just keep reading, it all unfolds.

01Racing

I guess I should be happy that my 13B with a 650 Holley Carb was 220.4 at the rear wheels! Imagine what it could produce with fuel injection. By the way a 20 - 25% drive line loss is normal for small displacement engines. Remember any stock rotary engine has a very heavy flywheel to compensate for the lack of torque, so you can get your car moving from a dead stop. That will have a big effect on rear wheel horsepower.

Rxdriftingaction

so many things will effect the output of rotary engine..!! and the output is not that constant ...of rotary engine!! as I know so far..!!! but it shoudn't get that lower output number..!!!!!!!!!!!!!!!!!! feel ur pain man!!! haha!!!!

Charles R. Hill

iTrader: (7)

Actually, 84, the new top-of-the-line Holley carbs have more precise tunability than even fuel injection, believe it or not. With all of the new air bleeds available for tuning it gets pretty darn precise. In addition fuel injection, alone, does not equate to higher h.p. nor better drivability versus carbs. Like everything else, it depends on who is doing the tuning.

As far as driveline losses there are two major theories on that and I tend to shy away from the percentage-type except in automatic transmission vehicles. With manual trannies I use 20-25 h.p. loss on FWD, 40+/- on RWD and 55 on AWD drive with stock flywheels. Those numbers usually work well for me in predicting the end result of certain mods and combos. The problem I find with using percentages on M.T. vehicles is that I cannot figure where the extra drag comes from just because an engine has higher torque, nor can I find the higher heat values anywhere in the trans.

Whatever the case may be, it is not uncommon for the RX-8 to dyno out at 175-180 RWHP.

CRH