Well I got back from Emerald just a little while ago. The readings Seem a bit off.

I know there are differences between dynos and how they read and base their information on.

The stock US spec '02 WRX I read about was dynoed on a Dynapack
and had these results at the wheels:
168.8hp @ 4113rpm 56mph
164.8lb-ft @ 4126

advertised HP 227 and 217 ft-lbs @ 13.5psi max

My US Spec '02 WRX
all stock
225.5bhp @ 5957 rpm 213.1 ft-lbs @ 4303 108mph
Boost reading 12.9psi

The first run it made 224.3 and 216.7 but the boost guage for the machine was hooked to the wrong port and only read 5psi max (even though the car was actually making 12.9)

The thing that I cant figure out is why at the wheels it only shows 145.3????

Anyone know how to make sense of this?

Steven

 

because of tranmission loss, friction, etc, etc, etc....

try here if you're interested...

http://www.pumaracing.co.uk/trans.htm

and

http://www.epi-eng.com/FND-PwrTrq.htm

 

The dyno they used is a Sun Ram 12. I understand about drivetrain losses but I think 145 at the wheels is terrible.

What are y'all getting to the wheels on a stock WRX?

 

With drive train losses at or about 80 hp you are on the money aren't you ie 225 at the flywheel.

bob

 

Thoses figures look totally screwed up, and dont make any sense.

4113rpm, and 4126rpm are close enough that they can be used as a cross reference.

Torque to BHP conversion.
164.8 x 4126 / 5252 = 129bhp.

BHP to Torque conversion.
168.8 x 5252 / 4113 = 215.5ftlbs.

If you have 164.8ftlbs of torque at 4126rpm, you have 129bhp at the same RPM point. NO if's or but's.

This applies to having 168.8BHP at 4113RPM, it equates to 215ftlbs at the same RPM point.

13rpm is neither here, or there, so regardless of what the drivetrain losses are, something is wrong with the figures they have given you.

I would ask them to re run the car.

Mark.

 

I am going to have the car dyno'ed again at Clive's shop in Norwich on the Feb 22nd. I'll be taking the print out with me to compair.

I spoke with a few guys at the WRX meet Sunday and they really couldnt give me much advice. 165-170 to the wheels is typical on the popular dynos in the US for my car so when I saw 145 here I almost fell over. 20hp is a HUGE difference!!!!