i did my dyno last weekend and my car readings were 265 RWHP, so thats 315 HP, and 295 tourque, so 354 lb/tq. this reading was without my ecu tune due to dealer reflashing it. so renntech, pulleys, exhaust, green filters equal 12 hp. i was let down

 

Get that chip reflashed and get back to us

 

That's terrible... Those mods equal 12 hp is BAD!

 

evo sport says the pulleys is 12hp by themselves

 

At what RPM does it hit 265 RWHP?

 

Hey Omar... maybe the Girls Gone Too Wild and slowed down the Dyno test????

 

I think all your gains are coming from the renntech airbox (questionable) and the pulley. A couple of vendors on here have even said the exhausts add very little performance, and are mainly for sound purposes. Air filter..........maybe, maybe not? If you calculate a 17% powertrain loss, its about 320 hp. SO, you gain about 18 hp. Not sure what that's worth to you in terms of monetary value, but an extra 18 aint so bad.

 

what is the info on the dyno (dynojet, dyno dynamics, mustang?) also what was weather like.

 

the dyno was a dyno jet 224. It was about 80 degrees out that day. I wasn't expecting any real HP gains from the exhasut, but the the pulleys, evo stated dyno proven 12HP gain. My calculations may be wrong, but isn't 17% of 265 45HP, so that would put mee at 310. I ran it twice that day they were all constant, except when i switched out the renntech for the amg airb box, which gave me 10 more HP. I'm going to dyno it again soon now that my ecu tune kicked in

 

320 x .17= 54.4.........320-54.4=265.6. According to your run, the airbox does make a difference then. Good luck with the ecu reflash!

 

oh ok i was taking 17% of 265 not 320

 

The math for your powertrain loss is:

RWHP / (1 - PowerTrainLoss)

So if you saw 265RWHP and assume 17% powertrain loss (not my number, so don't quote me), then engine HP is 265 / .83 = 319.3HP.

(Your original quote said 265 => 315, which means a (1 - 265/315) = 15.9% powertrain loss. I don't know which number to pick, just offering some math.)

 

is it for all dynos a 17% power loss, bc the dyno folks were telling me 20%, and another shop told me it was 25%.

 

http://www.mwrench.com/Whitepapers/Dyno.pdf

I'm hardly a dyno authority, but the PDF makes a good point that using a flat % loss number is not realistic, since the transmission loss is more likely a constant loss in terms of HP not %. If you tweak your engine, and gaining RWHP, then you are not also gaining transmission loss.

It also says "most BMW big car powertrain loss will be 50-70HP", with autos having more. If we assume BMW is like Merc, then it's likely that a CLK500 powertrain is losing around 70.

Then that would suggest 265+70=335HP

But that's just a guess. You really need someone who has experience taking a CLK500 engine out of a car and seeing how it dynos. Maybe Brabus does?