3.0Si Coupe Rolling Road session
- Thread starter Z43.0Si
- Start date
every engine is different bud... few will roll out the factory with exactly 265, also every dyno will record differing results, air temp.. lack of forced induction by not actually moving, mileage the engine has done with wear and tear all affect the result, I dont think what you recorded is unreasonable at all
id be happy with that, the dyno itself isn't the most accurate of things..... I've had runs in the high 530s then had one run as low as 490 something on a hot day different dyno. So many variables, as long as the car is running right and fueling right just be happy imo.
Z43.0Si said:
If it's a wheel figure, then allowing for transmission losses, your horsepower at the fly will be higher. It's not unreasonable to expect 15%+ transmission losses, meaning your flywheel horsepower figure should be near enough 265bhp.....
Also, as has already been said, temperatures have a significant effect on power figures. Bear in mind during an engine dyno session which I'm sure BMW would use to provide the official figures for their engines, the dyno rig will have a consistent flow of temperature controlled air, and proper cooling for the coolant too, ensuring the most stable results are obtained. When you take a car to a dyno, and they're trying to replicate airflow during driving with what in some cases can be quite a small fan blowing a bit of air at the front of the car whilst the operator is ragging it through the gears to get the figures, it's a far cry from the average driving temperatures/conditions, let alone the BMW engine dyno rigs!!
Also, silly things like how tightly strapped down the car is can have a significant effect on the results.
End of the day, dynos should never never be taken as gospel imo - they're a useful tool for obtaining a ballpark figure but that's about it!!
Can't state it any better than Ed here 
If you bring the car to another dynamometer, the readings may be different as well!
This is a good article to read up on as well explaining rolling road dynos:
http://www.revotechnik.com/support/technical/rolling-roads-explained
If you bring the car to another dynamometer, the readings may be different as well!
This is a good article to read up on as well explaining rolling road dynos:
http://www.revotechnik.com/support/technical/rolling-roads-explained
Ed Doe said:If it's a wheel figure, then allowing for transmission losses, your horsepower at the fly will be higher. It's not unreasonable to expect 15%+ transmission losses, meaning your flywheel horsepower figure should be near enough 265bhp.....
Also, as has already been said, temperatures have a significant effect on power figures. Bear in mind during an engine dyno session which I'm sure BMW would use to provide the official figures for their engines, the dyno rig will have a consistent flow of temperature controlled air, and proper cooling for the coolant too, ensuring the most stable results are obtained. When you take a car to a dyno, and they're trying to replicate airflow during driving with what in some cases can be quite a small fan blowing a bit of air at the front of the car whilst the operator is ragging it through the gears to get the figures, it's a far cry from the average driving temperatures/conditions, let alone the BMW engine dyno rigs!!
Also, silly things like how tightly strapped down the car is can have a significant effect on the results.
End of the day, dynos should never never be taken as gospel imo - they're a useful tool for obtaining a ballpark figure but that's about it!!
It's more than I'd of expected at the wheel to be honest.
E86montego
Member
Do BMW rate their figures at the wheel or fly wheel?
E86montego said:
Every manufacturer quotes figures from the flywheel.
E86montego
Member
Right okay, so 245 at the wheels seems rather impressive?
You would be surprised how much new oils, filters and a fuel cleaner will make. Can't remember the name of the show on tv but with a 15 year old 2.0L golf they gained 15hp with all those changes. So with the extra power we have you could see that getting it back to 265hp. Also as previously stated your might have come out of the factory with less anyways.
Yes you are right, however the car was serviced by BMW 500 miles ago, not sure if the plugs were changed so will need to check.
My thoughts are with the induction kit, something tells me it's having a detrimental effect?
The car has a Cat back Supersprint exhaust as well but I imagine if anything this would help and not hinder?
My thoughts are with the induction kit, something tells me it's having a detrimental effect?
The car has a Cat back Supersprint exhaust as well but I imagine if anything this would help and not hinder?
