RWHP/TQ vs. BHP/TQ
#1
Staging Lane
Thread Starter
Join Date: Sep 2007
Location: Beaufort, SC
Posts: 56
Likes: 0
Received 0 Likes
on
0 Posts
RWHP/TQ vs. BHP/TQ
So does anyone know around how much tq and hp is lost through the resistance in the drive train of a 6-speed f-body on stock 3.42 gears?
#2
um. Ill be corrected if im wrong, but whp is wheel horsepower and bhp is brake horsepower, so your drivetrain/gears make no difference since the only variable being changed is rotational mass of the wheel.
#3
there is HP loss in the drivetrain. For example all LS1's dyno in the ball park of 350 hp at the flywheel. But depending on the drivertrain of the transmission, gears, tires, power to the rear wheels will be significantly lower.
I i remeber corectly the M6 usually has a RWHP # that is approx 10% lower than FWHP.
Im not sure what BHP is measured at, but i know that FWHP and RWHP are big differences.
I i remeber corectly the M6 usually has a RWHP # that is approx 10% lower than FWHP.
Im not sure what BHP is measured at, but i know that FWHP and RWHP are big differences.
#4
TECH Regular
Join Date: Mar 2006
Location: Rolesville, NC
Posts: 471
Likes: 0
Received 0 Likes
on
0 Posts
On a Corvette, not sure about F-body:
Manual is about a 15% loss
Automatic is about 18% loss
So for a 350 BHP rated ( Brake HP or at the Fly wheel )
Manual is ~ 297 RWHP ( Rear Wheel Hp)
Automatic is ~287 RWHP
These are good estimates, but do very.
Manual is about a 15% loss
Automatic is about 18% loss
So for a 350 BHP rated ( Brake HP or at the Fly wheel )
Manual is ~ 297 RWHP ( Rear Wheel Hp)
Automatic is ~287 RWHP
These are good estimates, but do very.
#5
TECH Fanatic
iTrader: (21)
Join Date: Feb 2006
Location: Allen Park, MI
Posts: 1,370
Likes: 0
Received 0 Likes
on
0 Posts
i dont get why its a percentage. use 15% for instance
if a car makes 500 at the flywheel, it will make 425whp, so it loses 75hp through the drivetrain
say now it makes 1000 at the the flywheel, with a 15% loss it will only make 850whp, it loses 150hp, so why does it take more power to turn the same drivetrain.
i think the percentage system is bullshit
if a car makes 500 at the flywheel, it will make 425whp, so it loses 75hp through the drivetrain
say now it makes 1000 at the the flywheel, with a 15% loss it will only make 850whp, it loses 150hp, so why does it take more power to turn the same drivetrain.
i think the percentage system is bullshit
#7
Staging Lane
Thread Starter
Join Date: Sep 2007
Location: Beaufort, SC
Posts: 56
Likes: 0
Received 0 Likes
on
0 Posts
bhp is at the flywheel, that is what I meant. It is a common misconception that bhp is measured on the hub w/o the wheel but it is actually the correct term for the more common term fwhp. sorry for the misunderstanding.
Trending Topics
#8
Staging Lane
Thread Starter
Join Date: Sep 2007
Location: Beaufort, SC
Posts: 56
Likes: 0
Received 0 Likes
on
0 Posts
i dont get why its a percentage. use 15% for instance
if a car makes 500 at the flywheel, it will make 425whp, so it loses 75hp through the drivetrain
say now it makes 1000 at the the flywheel, with a 15% loss it will only make 850whp, it loses 150hp, so why does it take more power to turn the same drivetrain.
i think the percentage system is bullshit
if a car makes 500 at the flywheel, it will make 425whp, so it loses 75hp through the drivetrain
say now it makes 1000 at the the flywheel, with a 15% loss it will only make 850whp, it loses 150hp, so why does it take more power to turn the same drivetrain.
i think the percentage system is bullshit
#12
TECH Fanatic
iTrader: (21)
Join Date: Feb 2006
Location: Allen Park, MI
Posts: 1,370
Likes: 0
Received 0 Likes
on
0 Posts
thats saying that my car takes 75hp to turn my 6speed and 10 bolt, then if i spray a 300 shot its going to take 120hp to turn the same drivetrain.
dont worry about drivetrain loss, a 6 speed car is going to dyno higher than a th400 car, those are just numbers, track numbers are what count
dont worry about drivetrain loss, a 6 speed car is going to dyno higher than a th400 car, those are just numbers, track numbers are what count
#13
10 Second Club
iTrader: (5)
thats saying that my car takes 75hp to turn my 6speed and 10 bolt, then if i spray a 300 shot its going to take 120hp to turn the same drivetrain.
dont worry about drivetrain loss, a 6 speed car is going to dyno higher than a th400 car, those are just numbers, track numbers are what count
dont worry about drivetrain loss, a 6 speed car is going to dyno higher than a th400 car, those are just numbers, track numbers are what count
#14
TECH Regular
Join Date: Mar 2006
Location: Rolesville, NC
Posts: 471
Likes: 0
Received 0 Likes
on
0 Posts
I agree. YES the percentage does very depending on all the drive line components, but the 15% is GOOD ESTIMATE.
The only real way to know is to do run the engine on an engine dyno. Install the engine in YOUR car and do a rear wheel dyno.
The only real way to know is to do run the engine on an engine dyno. Install the engine in YOUR car and do a rear wheel dyno.