sup3rbad

why is it that the rx-8 that has 238hp only has about 180 whp and a Acura TSX that has 200hp has 179whp? just confused by that, and was wondering if anyone can teach me a thing or two about claimed HP and WHP. thanks

Gord96BRG

That's a trick question - it seems that a 238 hp RX-8 does NOT only have 180 wheel hp, but that when testing it on a dyno the engine falls back to a safe mode that reduces engine output at high rpm. Therefore, the dyno runs that showed 180hp are inaccurate and not representative of what hp the car really puts to the road.

Regards,
Gordon

sup3rbad

still a bit confused... can anyone else add to the topic or know if others car that test whp have the same safe mode

poison123

Gord96BRG is that fact or just speculation? And does any and I mean ANY other car do this while on a dyno or is it just another Mazda say so?

Gord96BRG

Check out these other threads (especially posts from the last week or two):

https://www.rx8club.com/series-i-tech-garage-22/just-finished-dynog-2-rx-8s-9553/
https://www.rx8club.com/series-i-tech-garage-22/dyno-results-w-hard-data-known-dynojet-7863/
https://www.rx8club.com/showthread.p...threadid=10823

Paul Yaw has figured this out himself, and RotaryNews.com was told on the side by Mazda that this safe mode when dyno testing existed.

There are several other cars, notably the BMW M3, that have this same issue - when running on a dyno with the front wheels stationary, sensors think something is wrong and reduce max power at high rpm.

Regards,
Gordon

poison123

So is their any possible way to properly Dyno this car to find out the exact HP it is putting out?

sup3rbad

if you check out the last link from Gord it will have an explanation of the dyno problems regarding the safe mode

poison123

Interesting read the complete last thread he posted and someone still says that the G-Tech devices are still recording the same Dip in the dyno's where the HP drops like a rock. Gonna be real interesting to see, also Mazda had to have some way to test the in car HP, so I'm assuming there's a code to kill that function of the ECU from retarding the car like that.

Gord96BRG

Perhaps, but the results are only as good as the operator. Mazda (through RotaryNews) posted timeslips from a dragstrip for 3 different cars where they were still running 1/4 mile around 14.5 sec and at 96 mph, just as the magazines reported in April. Another GTech user recently posted his runs, where he achieved a 14.5@96 run and a 14.0 sec @ 101 mph run! The power is definitely all there for those runs.

Regards,
Gordon

sup3rbad

the answer came to me in a dream last night... i know this might sound ridiculous but i actually had a dream about a friend tryin to dyno my 8. so he used a device to crank and turn the front wheels while he was dynoing the rear wheels...wierd