Ok, When you look in the 1966 Mustang Shop manual it says the 289 with 2v has 200 bhp. Doesn't bhp mean hp at the wheels. I know they dont have that much HP, so how much is a stock 289 2v getting at the wheels with a C4 with stock rear end. I believe my gears are around 2.80.1

 

I think I found what youre looking for, it says right here that its about 140 to the wheels. But i dont know how reliable this site is.

 

bhp means braked horse power and this is the defination i found.----The measure of an engine's horsepower without the loss in power caused by the gearbox, generator, differential, water pump and other auxiliaries. The actual horsepower delivered to the driving wheels is less.

 

Wasnt the way HP was listed changed in the early 70's from NHP (net HP) to BHP (brake hp)? So the nbrs you see could be the old NHP? There was quite a difference between the 2.

I could be wrong about this but I think they did change around 70-73 or so.

 

Maybe I got my terms backwards!

 

This cleared it up for me. Takes it a bit more time for me to let things sink in!


Torque is power is force x distance (ft-lb). It's what turns the crankshaft.
Horsepower is work is torque x time (torque x rpm ÷ 5252).

Brake horsepower is measured on an engine dyno and is taken at the flywheel or transmission output shaft (depending upon standard). Originally, dyno used a water brake to apply resistance against which the engined worked. SAE Gross HP was measured on engine in which ALL accessories were driven by external power source, even the water pump, and engine was hand-fitted to provide largest capacity using off-the-shelf components (blue-printing). This standard provided a rather theoretical figure and was used until about 1970. SAE Net HP required actual production engine with all accessories and transmission attached. This gave a much more realistic horsepower figure the car buyer could actually expect as it takes into account the power needed to spin the accessories. Still taken on an engine stand though dyno is now typically an eddy-current dyno, though water brakes are still in use.

Wheel horsepower is measured at the wheel, naturally, on a chassis dyno. This accounts for driveline losses that SAE Net test doesn't see.

 

What really matters though, is what HP you have at the rear wheels.

 

Very true! The only problem is that a lot of sources (Mfg's, builders, speed shops) that list HP don't always use the same designations.

 

Yeah, usually they only list the highest number they can get away with without lying about it which would be the dyno with an outside source for running the water pump, etc.

 

A good Dyno test will tell you the true Hp to the wheels.