Engine Torque/ Power

[akaluggage]

Hey,

Sorry for asking such a simple question, but as we have not dyno'd our engine yet I am working with reported figures for my final year project (driveline).
We are going to use either an R6 or possibly an FZ6 for this years entry, so I have made all my figures to that for now, while we dyno the engine. To find out the torque going through the differential and hubs, I have used 54Nm @ 7500rpm and 70hp @ 11300rpm (both at the engine), which I found to be about average for a 2005 R6. When I input the gear ratios, should I be using the primary ratio (crank-clutch) as well or can I ignore this value and only use the gear and final drive ratio to get the torque at the differential?
I ask as I was looking at the drexler differentials, which can take up to 1200Nm of torque. If I use all 3 of the ratios it exceeds 1200Nm where as if I use only 1 it doesn't. So it either means that they have accounted for tyre limitations or I have my theory wrong.

Can someone point me in the right direction please.

Thanks

[akaluggage]

Hey,

Sorry for asking such a simple question, but as we have not dyno'd our engine yet I am working with reported figures for my final year project (driveline).
We are going to use either an R6 or possibly an FZ6 for this years entry, so I have made all my figures to that for now, while we dyno the engine. To find out the torque going through the differential and hubs, I have used 54Nm @ 7500rpm and 70hp @ 11300rpm (both at the engine), which I found to be about average for a 2005 R6. When I input the gear ratios, should I be using the primary ratio (crank-clutch) as well or can I ignore this value and only use the gear and final drive ratio to get the torque at the differential?
I ask as I was looking at the drexler differentials, which can take up to 1200Nm of torque. If I use all 3 of the ratios it exceeds 1200Nm where as if I use only 1 it doesn't. So it either means that they have accounted for tyre limitations or I have my theory wrong.

Can someone point me in the right direction please.

Thanks

[kcapitano]

The engine torque gets multiplied through all gear reductions in the engine, so yes you need to include the primary ratio.
For our calculations we used the max engine torque to compute single cycle yielding, and max tire torque to determine fatigue life. There are some good threads here on how to determine drivetrain loads, so maybe look at those.

[Sormaz]

You've got your theory dead on. You need to multiply by all gear ratios, as kcapitano confirmed.
What values are you using for the drop gear, gear reduction and final drive? I'm not familiar with R6's but assuming it is similar to an F4i, you should be around 1.8, 2.8 and 3-4, for a total ratio of ~20 (for sanity, that puts your torque at ~1000Nm, spot on with the drexler)

PS, you are using two items which 'make things stay together' to solve all problems. Might consider trading one of them out for some WD40

[akaluggage]

Ahh ok, as from first glance I used the 54Nm and the R6 (in first gear) with a 4:1 final ratio goes 1.955*2.846*4 meaning I hit 1201.8Nm (assuming 100% traction) so I sat there scratching my head.

Thanks guys I'll have to have a good old hunt.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Sormaz:
PS, you are using two items which 'make things stay together' to solve all problems. Might consider trading one of them out for some WD40 </div></BLOCKQUOTE>
How naive of me! I also forgot the trusty mallet!