I just dynoed my JDM 99' S with has only 6000 miles on the clock, yeah it may seem odd but the car was lying around unsold for three years untill I got it recently.

The thing is, I only got 211 engine hp, compared to official claims of 240. And the lambda reading shows a very rich air/fuel mixture.

We use 97 RON unleaded in Malaysia and it could be a factor. Atmospheric corrections had been applied in the dyno calculations so the high local temperatures isn't an issue.

What other reason's could there be? Apart from the possibility of the corrupted dyno operator who wants me to install his A'PEXi V-AFC.

I'll post the chart up if any of you are interested.

Thanks.

 

240 hp is at the crank, about 200 hp at the rear wheels is normal.

 

Thanks for the quick reply. The dyno guys clocked 191hp at the wheels before calculating the 211 engine hp.

It's also the rich fuelling that bothers me.

 

Hmmm... You mention high local temps... The ECU is known to pull timing when it incounters high Intake Air Temps. That might explain your slightly(-5 to -10 Hp) lower than normal rwhp readings.

 

For a given dyno on a given day, 191 at the wheels is well within the expected range. A few of the many, many factors that significantly affect dyno readings are:
- Dyno's design/age (alone, can contribute +/- 15 hp or more)
- Dyno operator's expertise
- Ambient temp/weather
- Engine coolant temp
- Fuel octane
- Wheels and tires (for roller-style dynos)
etc. etc.

We've seen stock cars dyno anywhere from 160-220 depending on the combination of circumstances. Looks like you're right in the middle.

 

I would like to really know what "formula" the dyno guys used to calculate crank from wheel hp!! Considering the transmission losses varies a LOT from model to model (and even from car to car)

 

People often use 15% drivetrain loss for manual transmissions, and 20% loss for automatics. It has been pretty close for every stock dyno graph I have seen, but I cannot verify the authenticity of all those dyno graphs.