Some intersting gross vs wheel HP numbers
Thread Starter
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
Some intersting gross vs wheel HP numbers
I tune part time (for fun) at a local dyno shop and I am always looking for and comparing engine dyno data to actual wheel HP. I do not always have this information but when I do have something relevant I like to check numbers. Last week I tuned a 1995 LT1 auto vette that had a mild 355 built that on the engine dyno made 416 HP. I am sure it was run with headers on the engine dyno and a holley EFI stand alone. (Did not see the test but know the dyno shop)
On the chassis dyno the car made 342 RWHP after I was all done tuning it with HP tuners and a OBDII conversion system. (Torque head if you care). In this situation the vette had 3.07 gears/auto trans/stock convertor/ and headers no CATS free flowing exhaust.
That works out to a 18% drivetrain loss. Just some interesting info.
I have seen drivetrain losses as high as 30% with very high stall convertors but this 18% fell right in line with what I expected.
On the chassis dyno the car made 342 RWHP after I was all done tuning it with HP tuners and a OBDII conversion system. (Torque head if you care). In this situation the vette had 3.07 gears/auto trans/stock convertor/ and headers no CATS free flowing exhaust.
That works out to a 18% drivetrain loss. Just some interesting info.
I have seen drivetrain losses as high as 30% with very high stall convertors but this 18% fell right in line with what I expected.
Thread Starter
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
I read somewhere that one could expect ~15% DT loss with a stick shift and ~17% with an A4.
When drag racing my prior 35th anni., with a 2,000TC that 17% came out on the money.
One night at Englishtown some guy pulled in with a dyno so I got the RWHP numbers and I had trap speed as well as weight to calculate CHP and the difference was exactly 17% DT loss. That was on a 300chp TPI motor.
When drag racing my prior 35th anni., with a 2,000TC that 17% came out on the money.
One night at Englishtown some guy pulled in with a dyno so I got the RWHP numbers and I had trap speed as well as weight to calculate CHP and the difference was exactly 17% DT loss. That was on a 300chp TPI motor.
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