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Had it tuned today. My tune was pretty good, but now the car is amazing. Starts and runs beautifully. So, red 202, 40thou over, standard bottom end, ported head, larger intake valves, X2 setup and extractors, medium Crow cam, electronic dizzy. That lot is good for 100hp at the treads and the worlds flattest torque cruve (it's a torquey cam). But i'm unsure of actual torque, cause the side of the dyno dynamics sheet says 420 Lb, but this motor doesn't make 420 lbs of torque. Who knows how to correct the numbers? Edited by user Tuesday, 13 January 2009 7:45:36 PM(UTC)
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What gear was the dyno run done? The torque may say 420 ft/lb, but you have to consider that the ratio from engine to wheel changes it. There is the gear used (usually 2nd), the diff ratio, and the tyre diameter.
The flatness of the curve is what to lo |
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Pretty basic dyno sheet. Just gives HP, wheel speed and Lb. I can only assume 4th, 1-1? Indicated speed tells me thats the gear they were in. 3.55 diff i believe, and tyres are, well, 225x65r14. Too late to do the maths now...haha. Torque cruve is a b Edited by user Tuesday, 13 January 2009 7:49:33 PM(UTC)
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Checked with the dyno operator: he said its a straight reading of power and torque at the wheels. So max is around 450 lb/ft, in a flat line till about 4700rpm (guessed using indicated speed in 4th) where it tapers to 420 then continues to drop away, as e Edited by user Wednesday, 14 January 2009 5:05:24 AM(UTC)
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Gday mate, nice numbers...
The dyno cannot reproduce "torque" as such, torque is a rotational measurement whilst the chassis dyno measures in a linear manner.
The correct term is "tractive effort" and should be listed in N (newtons) or Lb (pounds) a
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For example, I know my 355 holden engine makes around 410lb/ft* of torque, and 470hp...
*I have corrected my typing error in the above quoted torque figure...
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Here is a link to the before and after dyno runs on my VZ Cross 8 (blue before - stock, red after = exhaust and tune). The missing rpm is 5470. Apparantly there is about 20-25% awkW loss compared to rwkW. This shows you what a flat torque curve looks like |
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Ok, so its tractive effort. How do i work out lb/ft then? That explains the amazingly high Lb numbers. Cheers guys. Edited by user Tuesday, 13 January 2009 10:56:46 PM(UTC)
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