bhp output

Andy Coupé

Senior Member
rushy said:
3D cost a bit more and are specific to your car and your mods ( no car is ever the same no matter if on paper they look the same). With 3d the car is usually run quite a few more times than a standard remap. He might have ment that you can have more BHP but to the detriment of the drivability and torque. A guy on vectra c had his 3.2 up to 256 bhp on chipped rollers and could have gone for more but the peak power was in a very small band so would have actualy been slower if he increased the bhp. You can have a lower bhp and be faster due to the power being spread over the band if you see what I mean.

Yes i understand, i have a before and after graph from the rollers and the increase of both BHP and TRQ was around 10 right accross the rev range.
 
Giving more hp on an engine doesnt always make it faster.
The better/faster car will be the one with the longer usable power band.

Also, you can get 10 cars, all with the same milage, all with the same mods and all give different power.

The way a car has been run-in, the way the owner drives it, wear and tear etc etc all plays a massive part.
 

Daz

Former Staff
Senior Member
I think some of us on sat had done the same mods to the cars and the bhp varied between cars...
 

coopa

Member
Some points:

Don't forget that a dyno is a piece of mechanical equipment and the results it produces will become more innacurate over time.

Part of my day job is to calibrate customer dynos annually. It is not uncommon for the force measurement on even a high quality dyno to be 2% innacurate after a year. Ok that's only 3 bhp, but multiply that by 2 or 3 years and it starts to get very significant.

Even when calibrated most dynos are only up to 1% accurate at best, so it's a waste of time quoting your vehicle's power output to 1 or more decimal places.

Getting your dyno serviced and calibrated by an independent body like us is an expensive business, none of our customers are tuning houses or other places that offer to dyno customer cars such that you might find.

Makes me wonder if they even bother to calibrate at all, given the variation in power figures that people experience from place to place...

Has anyone ever had any dyno work done at a place where they had the dyno calibration certificate for the year on the wall? I wouldn't accept being nicked by a gatso that wasn't properly calibrated, so why accept a power figure from a dyno that isn't?
 
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