ccrispy

Can anybody please tell me what and how I can find out how fast my C55 is? I am not sure I know what dyno is? I thought my car was 362 horsepower is this not true?

Eurocharged Rick

do you want to know how fast your car is? or do you want to know how much power it has?

a dyno is a device that you put your car on (usually at a performance shop) to determine how much power your car is actually making at the rear wheels...

your car has 362 hp at the engine, not the rear wheels, because of drivetrain loss...the usual amount of loss is 18% for an automatic transmission which in your case would be about 300 hp to the wheels...

IanGreening

1FASTC32, is this what they mean by bhp(brake power) and hp (horse power)?
BHP is the power at the engine and HP is the power at the drive wheels?

It's weird I asked a high performance driving instructor what the difference between BHP and HP was and he told me BHP and HP were the same thing, not sure

Eurocharged Rick

he is correct... HP and BHP are the same thing, it is HP as measured at the crank or engine.

the difference here is between BHP and WHP(wheel HP)...this is the difference between the HP that is measured at the crank or at the wheels...

JBrady

BHP stands for Brake Horse Power and comes from the use of a dyno (dynamometer) brake. The brake excerts force against the engine to measure TQ (torque) and then HP (horsepower) is calculated with the simple equation TQ x RPM / 5252 = HP.

So, BHP and HP are typically considered the same rating.

WHP (wheel HP) or RWHP (rear wheel HP) are chassis dyno terms that measure the power that is actually transmitted to the ground and as mentioned above varies from car to car and transmission type and more. 15% is usually used as a rule of thumb for manual transmission cars and 20% for automatic transmission cars.

Sometimes the manufacturer rates the engines accurately, other times not. In the case of the 2003+ 600 series twin turbo V12s the orginal rating of 493hp was WAY less than actual output.

IanGreening

so, if I'm reading an article that talks about BHP, can I just subtract 15-20% and pretty much estimate HP? Lots of these british mags give ratings in BHP.

Bobby Dazzler

The figure quoted in British magaizine will be the power output at the crank, ie before transmission losses.

So, subtracting 15-20% will give you a rough guide to the amount of power at the wheels.

Just compare like with like and you'll be fine.

British magazines provide the power output quoted by the manufacturer. Whilst the quality magazines will measure performance using timing gear to independently verify it, they very very very rarely measure power output.

Out of interest, which British magazines are popular in the US?

Quicktwinturbo

https://mbworld.org/forums/c32-amg-c55-amg-w203/167833-dyno-d-my-car-kinda-raced-my-buddy-s-m3.html