Quote:
Originally Posted by Jeeves915
Also, take into account that the 335i is rated using the NEW SAE engine output measuring system. Now, I'm no engineer (nor do I play one on TV), but, from my understanding, this system takes into account the engine accessories (alternator, A/C Compressor, and a few other whosits and whatsits.)
As a rough comparison the difference between the "new" SAE spec, and the old one is 10%. This means that if your engine was measured using the old system, you'd be pulling around 330hp, at the crank (M3 territory, which makes me happy).
12-15% are the common numbers I've heard tossed around for powertrain losses in RWD cars. Coralred's guesses seem pretty good to me.
One thing that needs to be considered is that the engine was a "ringer" when it was tested. Perhaps the test engine had more drag on it, or 91 octane fuel. This means that given the right conditions (installed in the car, not the engine dyno, 93+ octane, etc), it will produce a touch more power. This would result in the higher than 300 when the chassis output is corrected back to find the engine output.
Shiv from Vishnu has put the 335i's STOCK output on a dyno (specifically the AMS Dyno) at around 275hp. This means a rough at the crank number of 316 (and some change) hp. Corrected to the OLD SAE spec (using my seat of the pants 10% value) puts your car, with the steptronic transmission, at 347.8 HP.
Now, is it just me, or does that make anyone else retardedly happy?
Also, just for giggles sake, lets see what a Procede'd 335i is doing at the crank. We'll use 320hp as our untuned value for a procede (Shiv's numbers from a few weeks ago).
Correcting to the crank
320*1.15=368hp
Correcting to the OLD SAE spec
368*1.10=404.8hp
...yea...
-Adam
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Wow, that's a really intelligent post. Didnt know that about the new rating.