BHP?
Thread Starter
8th Gear
Joined: Jul 2001
Posts: 8
Likes: 0
BHP?
i am sorta new to all this and was wondering what bhp is. I went to check out some ligenfelter cylinder heads and came across this way of measuring power. Also, is there a formula to convert this to rear wheel horsepower.
Thanks,
Nick
Thanks,
Nick
Burning Brakes
Joined: May 2001
Posts: 1,188
Likes: 0
From: Dallas TX
Re: BHP? (Nick k)
BHP stands for base horsepower (or hp at the flywheel).
RWHP stands for rear wheel hp (hp measured at the rear wheels).
I've seen formulas which multiply a percentage to the BHP to calculate RWHP, but each car is different. The formulas get you close, but I've seen some stock cars totally defy the formulas on the dyno.
RWHP stands for rear wheel hp (hp measured at the rear wheels).
I've seen formulas which multiply a percentage to the BHP to calculate RWHP, but each car is different. The formulas get you close, but I've seen some stock cars totally defy the formulas on the dyno.
Safety Car
Joined: Nov 1999
Posts: 3,891
Likes: 2
From: Houston, TX
Re: BHP? (RajunCajun2001)
BHP= Brake Horsepower.
Brake horsepower is measured by taking a drum filled with a fluid and attaching that to an engine. The power required to turn the drum is the brake horsepower - as the drum is ‘braked’ by the fluid.
Brake horsepower is measured by taking a drum filled with a fluid and attaching that to an engine. The power required to turn the drum is the brake horsepower - as the drum is ‘braked’ by the fluid.
Pro
Joined: Aug 1999
Posts: 638
Likes: 0
From: Simi Valley, CA, USA CA
Re: BHP? (Nick k)
The power output of American automobile engines is quoted in "brake horsepower" (BHP)
BHP = "Brake or shaft horsepower is commonly used to indicate the pratical ability of the engine, or the maximum performance, which is indicated horsepower, minus the power lost through heat, friction, and compression.."
BHP = "Brake or shaft horsepower is commonly used to indicate the pratical ability of the engine, or the maximum performance, which is indicated horsepower, minus the power lost through heat, friction, and compression.."
Melting Slicks
Joined: Mar 1999
Posts: 3,071
Likes: 939
From: Apex NC
Cruise-In II Veteran
Cruise-In III Veteran
Re: BHP? (Nick k)
To add to the above post,
'Brake Horsepower' was an improvement over the old 'gross' rating used in the 60's 'muscle car era. In those days, HP was rated without any accessories at all :eek: So these numbers are greatly inflated for practical purposes because, who can drive an engine with NO accesories? BHP was an improvement in the rating scale BUT does NOT take into account the parasitic losses encountered thru the drivetrain. So RWHP (rear wheel horse power) which is what is measured on a dyno, is the actual HP you car puts to the pavement. In my view, this is the figure that should be used from the factory, but it isn't. Many tuners use bhp as a way to compare their numbers with those from the factory (or the cynical would say, to make their number sound higher than they actually are in ref. to the fact that many talk in terms of RWHP) I am no expert, just my understanding of the concepts. Anyway, you will notice autos generally dyno lower than 6 spds, all other things being equal, as more HP is lost in the drivetrain of an auto than from a 6 spd. :cheers:
'Brake Horsepower' was an improvement over the old 'gross' rating used in the 60's 'muscle car era. In those days, HP was rated without any accessories at all :eek: So these numbers are greatly inflated for practical purposes because, who can drive an engine with NO accesories? BHP was an improvement in the rating scale BUT does NOT take into account the parasitic losses encountered thru the drivetrain. So RWHP (rear wheel horse power) which is what is measured on a dyno, is the actual HP you car puts to the pavement. In my view, this is the figure that should be used from the factory, but it isn't. Many tuners use bhp as a way to compare their numbers with those from the factory (or the cynical would say, to make their number sound higher than they actually are in ref. to the fact that many talk in terms of RWHP) I am no expert, just my understanding of the concepts. Anyway, you will notice autos generally dyno lower than 6 spds, all other things being equal, as more HP is lost in the drivetrain of an auto than from a 6 spd. :cheers:
Safety Car
Joined: Nov 1999
Posts: 3,891
Likes: 2
From: Houston, TX
Re: BHP? (AVETTE)
If the factory quoted the RWHP, they would have to have different HP ratings for the 6-speeds and the autos. In my opinion, the BHP is the best way to quote the number from the factory. You are quoting the power output of the engine and that is it. 
JMHO,
JMHO,
