Quote:
Originally Posted by Sgbimmer8888
i confirmed with my tuner that the units were hp not KW on the mustang dyno. So 288wrhp is indeed extremely off.
Another workshop told me that it could be related to the TCF, and that if a tuner uses a TCF of 1.2/1.3 instead of 1.0, the numbers you get will be falsely elevated.
He suspects that my tuner used a TCF of 1.0, and hence my rwhp results are significantly lower than many others.
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The dyno TCF (Transmission Correction Factor) will impact the calculation/estimation of engine/crank HP. It does not impact wheel HP which is actually measured by the dyno. If 288hp is your crank number and not wheel number, then you have even bigger problems. Secondly, TCF=1.0 implies that there are zero drivetrain losses. I would be wary of using any dyno where the operator doesn't understand what a TCF is and how it's used.
A sanity check you can do is to take the manufacturer claimed engine hp, minus drivetrain losses, and that shd give you your wheel hp. I typically use 12-15% losses for FWD, 20% for RWD and 22-25% for AWD. Add another 3-5% for automatic transmission (DCT is considered manual). Of course many will come and say its not as simple as that, and drivetrain losses are not always a fixed percentage, but as a general rule of thumb its good enough. So BMW claimed 414hp minus 20% drivetrain losses is 330hp. I've owned enough cars and done enough dynos that I know these percentages are close enough for me.