JPSC Forum

I've just spent the day at ChipWizards in Rochdale letting Wayne Schofield set up my PowerCommander on his rolling road. He spent most of the day on it and covered 130 miles without going anywhere. The difference is awesome. Not a big jump in power but but it feels a massive improvement on the road. Huge improvement in driveability though after Wayne spent ages working all the way through the power and rev range.

The trip home was a bit too congested most of the way but a small detour allowed me to open the gas...OH MY GIDDY AUNT! It took off like a scalded cat...absolutly flys.

adrian

PS. 150 @ wheels and 170 @ flywheel (at Stoneleigh it was 152 @ flywheel)

Umm...sounds good, best I get my hi-lift cams fitted before the next trackday we are both at

...and I have plans a-foot for an ARB.

adrian

Going to speak to Rob ?

At least I'll still have talent on my side

Maybe I'll speak to Rob or set about it myself. My engine bay is a bit "busy" down there so I'll have to work out what will fit. After RAF Valley this weekend I have to report that my bag of tallent is rather empty!

Hi Adrian,

Interesting stats. When I was on the RR last week my earlier engine did 158 flywheel, 124 wheels.

So I'm losing 34 in the car and you're only losing 20. Have you got a TRT propshaft? Anything else different in your transmission compared to mine? I'd expect the losses to be similar. Unless it's just different results from different RR's. Or my diff is sick...

Ian

Yeh I saw the difference in our run downs. Wayne didn't strap the rear down on mine. He doesn't unless he's getting excesive slip, as it affects (adds to) the transmission losses. Was yours strapped down at the back? He's fairly confident that the numbers are accurate given stuff he's had on before; His modded BUSA clocks 185bhp at the flywheel for example, so they aren't silly high numbers. The actual numbers are only relevent in the pub anyway. What matters is repeatability so you know whether things are improving or getting worse as you setr it up, and the shape of the graph.
Of course it could be that I realy have 34 loss as well so my flywheel figure would be 184

adrian

Remember the only thing actually measured is the torque, wheel HP is calculated from the torque. Most RR either guess the losses (typically 15% for a RWD car) or use rundown losses which are pretty much meaningless as well. Tyre pressures will effect the results signifcantly.

The only way to compare is the same dyno on the same day (with in minutes) with the same operator and look at the wheel figure. All this from a man who has spent a fortune chasing RR figures with various Audis !

adithorp wrote:Was yours strapped down at the back?

adrian

Yep, mine was strapped down good and proper! That probably explains the large difference.

Ta, Ian