Hi All. Does anyone know what the rear wheel bhp is on supercharged 4.2 xkr?
I have read 420bhp. But is that at the fly wheel?
Would like to know how many horses have escaped from mine.
.....Cheers.

 

Every dyno is different but anywhere between 320 & 340 at the wheels is about normal for a stocker, depending on weather, fuel, and general condition of the engine.

The 420 is the flywheel number.

 

Jaguar XKR supercharged 4.2-liter V-8 touts a supercharged engine that makes 420 horsepower and 413 lb-ft of torque. Don't know if its the front end or rear wheels. This info from a auto write up.

 

Thanks for quick reply. I had a dyno baseline run done today before I do pulley mod. I am getting 368bhp at rear wheels. I was curious how this stacked up. So if 320-340 approx. is normal then I am happy so far. Can't wait for the pulley mod.

 

Like I said, every dyno is different. 368rwhp seems pretty optimistic for a stock engine to me!

I would be less worried about the actual number, the main thing is to see the improvements for the modifications.

 

In what gear? I was getting 373 in 4th gear after an exhaust mod and around 415 in 5th.

 

It was in 3rd gear. As cambo351 says it will at least give me a good base line to work from. I will be using the same dyno and same conditions for the next run once the pulley has been added.

 

Isn't the rule of thumb about 17% reduction at the rear wheels.

 

17% give or take, maybe even a little less with these cars that have a lockup torque converter.

+1 on the dyno being a comparison tool and trying to match the conditions as exactly as you can. The absolute numbers are near meaningless.

 

17% is a pulled out of the air 'generalization' that might have been accurate for one car on one day. There is no fixed number that applies in all cases.

 

I don't understand what difference the gear makes. Can someone educate me?