Dyno results

[stigmundfreud]

thought I would share this from another forum I post on:

Here's my graphs. Really pleased with the fueling and the curves. Going to try and go for a 13:1 afr rather than 12.6:1 got some scope with timing too

One question, the dyno guy used the same gearing for both the vxr and the standard cv8. With the difference in diff (vxr 3.71, cv8 3.46) would this skew things if there is a difference in gearing I'd like to know how it could alter things for the 2? ie if both were tested with CV8 gearing would a 3.71 diff produce skewed results and visa versa?

http://www.clicketyclicks.co.uk/dyno1.jpg

http://www.clicketyclicks.co.uk/dyno2.jpg

Really pleased with the ATW figure as thats an improvement over what it was and by myself too (with help from here!!).

Just wanted to say thanks as efilive has helped me learl lots and felt I've done something for myself. Next I would like to mod the intake as its stock other than a foam filter.

[Aint Skeered]

nice. looks like a nice power curve.

[rally1]

Hi there, most dyno software takes into account diff and gear ratio buy comparing engine RPM with Roller RPM and then uses engine RPM to calculate torque, heres the tricky part Torque will increase with a diff ration but power will not change, this may sound strange so I will try and explain it, Power = Torque x RPM / 5252 so if you have an engine with 300ft torque at 4000rpm you would have 228 hp (300ft x 4000rpm / 5252) at the fly wheel, if you then put it through a diff with a ratio of 4.1 you RPM at the wheels drops to 1000 rpm but the torque will increase to 1197ft but when you work out the power you will still get 228hp (1197ft x1000rpm / 5252) that is why you will sometimes see very high torque readings on some dyno sheets as they are using roller RPM to calculate torque which is being inflated buy the diff ratio, the way your dyno report is done is using engine RPM so changes to the diff ratio will make no effect to your torque or power readings. I hope I have expanded this correctly :D .

[stigmundfreud]

Cheers

the dyno wasnt plugged into the car the rpm was purely off dyno. I had the scan tool plugged in for some extra ve logging :D

[rally1]

What you may find is that the dyno operator would have calculated engine rpm from roller rpm, on our dyno we use a set number like 4000rpm, we take the engine up to 4000rpm in the gear we are going to test in and when we are bang on 4000rpm we hit a key on our keyboard, the software can then calculate engine rpm from roller rpm, we only use this if we are having troubles picking up a good rpm signal from the engine as it is not as accurate.