Cerbie 4.5 RR Power Characteristic Question

[pbrettle]

As previously stated, environmental variances make a big difference to the actual figures derived from a rolling road. If you want to get "all legal" on this issue (trading standards etc) - there is NO comment in the TVR literature on exactly how they do the testing...

As long as they get 420 when they do the tests then that is sufficient in the eyes of the law. Variances are part of the deal with cars - something that you just have to put up with.

Cheers,

Paul

[AndrewD]

quote:

quote:

Yeah - but then you need the power to get down the straight again

But I can outdrag you (to about 70-80mph anyway)

[dannylt]

Why do environmental factors make a big difference? Decent roads correct for atmospheric differences, so what else is there? Unless the car's mapping doesn't compensate well of course.

danny

[paulk]

It makes a big difference, if say you test your car at sea level on a cold day than say test your car at altitude on a hot day. The same car at sea level will perform better. As the air is more dense at sea level so you can burn more fuel and get more power.

Hope this helps

[dannylt]

Did you read what I originally said? The loss of power you get from changes in pressure/temperature/humidity are COMPENSATED for by the rolling road back to standard conditions. I.e. if it was colder, you'll make more power than at the standard 20 (or 25 can't remember) degrees, and the "corrected" value will be marked down.

Therefore it shouldn't make any difference. In practice, my car has been done under various conditions, and the corrected output has been within a couple of bhp all times.

[GreenV8S]

quote:back to standard conditions

Make that ... "back to one of the many 'standard' conditions" (and they usually won't bother telling you which standard they use)

[dannylt]

The standards are probably a lot closer to each other than they are to the average british weather . I think it was printed on mine - will check.

danny


>> Edited by dannylt on Friday 15th March 13:55