figuring eng hp
Team Owner
Joined: Dec 2003
Posts: 57,408
Likes: 164
From: queensbury ny
hp
you lose about 16% or thereabouts from flywheel to the rear wheels.so,rear wheel hp x 16%,and add that result to the rear wheel hp number,and there you go.it might be 17%,or 15% that you lose,but you get the idea and 16% is close enough to get a good idea of your flywheel hp.
Race Director
Joined: Aug 1999
Posts: 15,466
Likes: 0
From: GARDENA Ca, State Of Konfusion
St. Jude Donor '05
I do not believe in these formulas. I had 350rwhp with 3.43 gear, I changed the gear to 3.73 now I read 338rwhp. Now did my engine (BHP)hp change, NO!! If I put my 2.73 back in I would probably read 365rwhp. Pull your engine and out it on a engine dyno.
Safety Car
Joined: May 2000
Posts: 4,827
Likes: 351
From: Albuquerque NM
Al: You are talking apples and oranges. Apples: Is there a formula to relate RWHP to FWHP? Yes, for manual trannies you lose 12 to 15% from flywheel to rearwheels. For Autos it's more like 16 to 20%.
Oranges: Did your engine lose HP because of the gear change? No, but the chassis dyno BECAUSE OF THE WAY IT CALCULATES HP will read lower. I saw a 10 HP loss with the change from 3.42's to 3.73's.
You're a drag racer, you know what's important is the change in ET's and MPH. RWHP and FWHP are for bench racing. Besides, now you can say you are going quicker and faster with less HP.
Oranges: Did your engine lose HP because of the gear change? No, but the chassis dyno BECAUSE OF THE WAY IT CALCULATES HP will read lower. I saw a 10 HP loss with the change from 3.42's to 3.73's.
You're a drag racer, you know what's important is the change in ET's and MPH. RWHP and FWHP are for bench racing. Besides, now you can say you are going quicker and faster with less HP.
