Does anyone know the sum how to work out what bhp you have at the fly when you go on rollers and get the figure at the wheels?

Does this sum change for different models of car ie add 15% for a MK4 and 25% for a mk6, figures just made up for example I have no idea

Also how can you convert bhp to ps?

Cheers for any help, also if there is a link I have missed for this please point me in the right direction

Steve.

By the way does anyone know what a standard 1800 zetec bhp & torque should be ?

 

 

I believe most RR operators use a "run down" system Ste. This is where they measure the drag from the drivetrain as they coast the car down in gear after they hit peak revs and then add it on top of the @ the wheels figure.

 

cheers Ian there was a load of 180rpm to limiter not sure what that means but this must be the figure that works it out

 

 

Why do you want to know flywheel HP ????

It doesn't mean anything, its just a bigger number than the one you get at the wheels.

 

whats the spec of yours? I think the standard GTi (1hich is 1800) is 115bhp.... although mine is more than that I am sure

 

The reason is that I had my car on the rolling road at the weekend and a few people are doubting the results I got due to the bhp loss I got but this place I got it done at was a very good respected company

heres the results, I was told the power at the wheels should have been more to get the figure of 144.6bhp I got, but some else said its like that because of the rollers load they put on I understand none of this hence the questions

 

1800 Si, Kent 1802cams, Kent Verniers, Power Boost Valve, K&N induction kit, magnex exhaust & mapped evolution chip by motorsport developments and shell optimax petrol if that helps

 

i think a standard rst has 132bhp @ fly and summat like 98 @ wheels. not sure tho pal.

 

It is very common for people to be disappointed with their results on the dyno. Everyone thinks they have more power than they actually do.

The thing with dynos is that as long as they are repeatable, you're fine. Absolute numbers are mostly irrelevant (except for bragging rights)

If you go to a dyno and you make tuning changes, as long as it is repeatable, you can see if it was a positive (hopefully) or negative change.

There is no specific 'formula' to determine the drivetrain losses. The only thing you can really say with any certainty is that AWD/4WD drivelines tend to have more losses than a 2WD one. Other than that, its pretty much a crap shoot to come up with actual figures for losses, since they vary widely.

 

See this is what I dont get is it something to do with the load the RR operators put through the rollers as a mate of mine with a S2 ERST has also been in a RS2000 and in my car and said my car responds better

 

Thinkim set for approx 85bhp then! I wish someone could take mine out for a spin and see what they think.... I find it undriveable in the wet in first and second but maybe thats my shite tyres

 

Cheers I will be in the Rolling Road section of Fast Ford mag with it so I will compare it with the others on that day

 

The only way you could compare them would be to put them on the same dyno on the same day (pretty much back to back) so that you remove as many variables (like conditions) as possible.

Otherwise, you're comparing apples and oranges

 

Ive got Toyo T1S on all 4 corners and think they are brilliant

 

It was all on the same day but I didnt get chance to see the other results of the other cars so I am waiting for all the results to become public

 

Here is the link to compare my results i am Steve Cowan on the table at the bottom
http://www.feoc-uk.com/modules.php?n...article&sid=46

 

think its low 120's mate. something like 121lbs

 

Cheers Dan

 

PS meaning Pferderstarke (Powerhorses) is near as damn it the same as BHP. But if you want to be 100% accurate 1 PS = 0.986 BHP. Hence your 144.6 BHP = 146.6 PS.

 

Cheers mate