Saw a post where a guy said he was 275 whp & 343 at the engine What is the accurate % ratio between engine & wheel
I got dyno tuned at 275 whp - They said it was around 300-310 at the engine does this sound right ? Im sure you lose less with front wheel drive than you would with rear wheel drive

 

Looks like maybe they got 275 at the wheels and arbitrarily assumed 20% loss to get 343. 20% seems a little high.

275/(1-.20)=343.75

 

Only way to be absolutely sure of flywheel horse powder is a couple of pulls on an engine dynamometer.
But the BHP is the important number , the chassis dynamometer will tell you what HP is being applied at the tires to road.
and all that HP depends on how wel those tires grip that road.