Dyno'd at 132 lbft and 180 BHP
 

I saw this new tuner show on Speed or Spike TV in which they modified a red RX-8. They dyno'd the car before mods and came up with only 180 BHP and 132 lbft of torque at the real wheel.

They added a NoS system which boosted torque to 200 lbft but the stock 132 seems a bit anemic to me.

Yeah rotaries dont have alot of torque but they make up for it with their 9000 rpm redline

if you had done some research, you would know that dynoing the RX8 is tricky. When all 4 wheels aren't moving, the car kicks into safe mode and decreases power.

Or you could do some research and realize that's a bunch of nonsense that Mazda made up, and the car really is making around 180 whp.

How can a 3000lbs. 180 rwhp do mid 14's in the 1/4 mile. it doesn't add up.

I don't want to have the same argument in two different threads. Go jump in the frey with this thread if you want to continue the discussion.

https://www.rx8club.com/showthread.p...threadid=21499

Thanks,
Ike

Re: Dyno'd at 132 lbft and 180 BHP
 

compared to what? you should take a look at the gearing:

Boxster:
engine torque ................... : 192 ft-lbs
1st gear .......................... : 3.5:1
final drive ......................... : 3.56:1
total gearing ..................... : 3.56 * 3.5 = 12.46 (in first gear)
approx peak wheel torque ... : 12.46 * 192 * .8 = 1914 ft-lbs (in 1st gear)
approx weight .................. : 3000 lbs

RX-8
engine torque .................. : 159 ft-lbs
1st gear ......................... : 3.76:1
final drive ....................... : 4.444:1
total gearing ................... : 3.76 * 4.444 = 16.71 (in first gear)
approx peak wheel torque ... : 16.71 * 159 * .8 = 2125 ft-lbs (in 1st gear)
approx weight .................. : 3000 lbs



and:

RX-8
engine torque ..... : 159 ft-lbs
1st gear .......... : 3.76:1
final drive ....... : 4.444:1
total gearing ..... : 3.76 * 4.444 = 16.71 (in first gear)
approx wheel torque : 2106 ft-lbs (in first gear)
approx weight ..... : 3000 lbs ?

2003 auto Impala
engine torque ..... : 205 ft-lbs
1st gear .......... : 2.92:1
final drive ....... : 2.86:1
total gearing ..... : 2.92 * 2.86 = 8.35 (in first gear)
approx wheel torque : 1182 ft-lbs (in first gear)
approx weight ..... : 3300 lbs ?


comparisons provided by buger(R)

I would assume that they would disable TCS, DCS before dynoing the car. This should alleviate the four wheels not turning issue.

not really when tcs and dsc are disable it just stops the car from trying to compensate with braking. however it still gets the signals from the abs sensors. when it detects the difference in speeds from the abs sensors it retards timing dropping power output.

Re: Re: Dyno'd at 132 lbft and 180 BHP
 

The torque converter multiplication? lets be generous and say 2:1, and the engine torque at stall speed is 175 ft-lbs so 175 X 2 X 2.92 X 2.86 = 2923 ft-lbs X drivetrain effeciency = ~2500 ft-lbs at launch

ike what does the WRX dyno at? Last night my friend in his 03 WRX couldnt keep up with me on the highway.

1) im new to stick... he has had stick for since ive known him 6 years

2) i did go up to about 8.5 rpms in 1st n 2nd

3) he admited himself he couldnt keep up?

this is not a shot at ya. im just asking this because if the RX8 is dynoin at 180 what does the WRX dyno at? ive always thought the RX8 would be comparable to the WRX but if these dyno numbers are correct the RX8 would not be on the level of the wrx.

btw, dont say he doesnt know how to drive stick.. if anyone doesnt know how to drive stick its me. ive only driven 1300 miles of stick.

Depending on the Dyno and the particular car usually around 165 whp so from a roll he shouldn't be able to keep up with you, especially once you get into the triple digits where the 4th and 5th gear of the WRX is very tall. From a stop he should be able to take you if he knows how to launch his car properly, but you will gain on him as the speeds increase.

Ike

Man, I sure wish I was in my 8 racing ol' Ike in his wrx- as a matter of fact, chasing him (and catching him) would be even more fun!

I will race you in my 944 :)

let's do it- do you have Ike tied up in the trunk or something>?- I need some kinda motivation here!

I've got a little "test strip" near where I work. On that strip I have managed to get the RX8 to 74mph, and my wifes WRX wagon to 72mph. No clutch dropping to get a hard AWD launch, but not grannying it either.

On the same stretch, a new STi hits about 81, as does my STi V conversion. Just for the sake of comparison.

You seem to be under the assumption that I'm stock, it ain't happenin big guy :p

I guess IkeWRX is biting his nails to come up with reasons why he bought that ugly subaru. Nevertheless 180hp at wheels seems reasonable. To give you some reliable data Honda Accord LX v6 rated at 200hp measures 151 hp at wheels (looks like a 25% loss), Ford Mustang GT rated at 260 measures 193hp at wheels (almost 26% loss), saab 9-5 aero rated at 230hp/ 180 at wheels (22% loss). So dont be bitching at 180 at wheels with 238 at crank it is only 24% loss. Sound reasonable doesnt it? One more issue is that there might be a limp mode. For example you cannot dyno m3 since it limits revs at 6300rpm (7900rpm peak) when front wheels are not spinning. Mazda might be using a different method air/fuel mixture for example. Anyway if youre not happy with rx8 buy yourself wrx 227 hp - 165 at wheels (27% loss) yeah, yeah I know its awd - two more diffs to propel... but its ugly as hell...

data source: c&d, nov 2001, "regular or premium" by Frank Markus, page 134

"You seem to be under the assumption that I'm stock, it ain't happenin big guy " HOW DID YOU KNOW I WAS A BIG GUY?? I am pretty quick too. So this is just a question here Ike- but are you stock as far as a body kit goes>?

I recently watched two episodes of best motoring and the RX8 got killed on the straights by every car on the track except the Mazda Miata, which I think they added to the group so the RX8 wouldn't look like it was totally off the back. It even got passed by an Acura RSX (integra).

Just something to keep in mind for the aspiring street racers of the group.

Ouch.

Somehow, though, I don't find myself regretting my choice.

The handling, the sound, the control, the ride.....it all somehow adds up to more than its parts.

I went and test-drove a used C5 Vette Z06 before I drove this car. If I wanted fast, I would have bought it. It would have beaten 99% of cars on the road.

You know what happened? I was in second gear accelerating like a bat out of hell, when I realized I was doing 30 over the speed limit on I495, and I had tapped about 20% of the car's ability. The car didn't handle all that well, it didn't corner all that well, it was just DAMN FAST.

I then realized I would be paying more money than the RX8 for a car that I would only enjoy on the rare occasion I decided to drive insanely fast. The rest of the time, I'd be stuck driving a boat with a latent warp drive engine in it.

The RX8 is the opposite. It's all style, handling, control, and fun....but without the warp-speed engine. It's simply quick, not spine-compressingly fast.

0-60 in 5.9 is far faster than my 92,500 mile MX-6 can do :)

Uh... I think the RX-8 is simply fast, but not spine-compressingly quick. The quick but not fast is the SRT-4.

0-60 times only measure how quick the car is. Maximum speed measures how fast the car can go.

Does anyone know if the % driveline loss is the same when you look at the torque and the hp? If so... torque is only a 17% loss at 132 lbs.ft. based on the 159 rating but the hp at 180.... Yikes! Only 218 at the crank!?!? Is my math correct?

Yes it is, but if you use new math the 238 HP total makes perfect sense ;)

No, because the further up the rev band you go, the more the ecu richens the mixture and kills power.