As you would know I recently had my car dyno tuned for a very successful 140kw at the wheels. The only problem is that I can not find out my torque. On the graph the torque figures are obviously in another measurement that we are not used to (Torque Slave??) which on the graph peaks at 1420. Now when talking about torque I am used to figures somewhere in the vacinity of 250-550 depending on the cars power and mods. Does anyone know how this is converted back to the other figure? Any help would be greatly appreciated

P.S. update on my car, I am talking to RPW to have a new mod done soon that is still in the design phase can't say much secret. Will let you know what gains I get

[quote:aaba5ec829]graph peaks at 1420[/quote:aaba5ec829]

i dare say its 'tractive effort' but jezzart!!! *** me! god damn. dont put my booya to shame soo early :lol:

where is your graph? my graph gets to me 2morrow :D

I wanna relocate to PERTH!!!! Magna Mods County!


mmm... I think Gamisou has the same Torque figure reading as you.. in the form of the 1000s....

Tractive effort should be in the thousands of Newtons (N), depends on RPM, gear & tyre size.

This is what I wrote previously on one of these Magna forums:
6000N at the wheels does not equate directly to engine torque after applying T=Fd.

Remember the gearing has an effect, so we need to know diff ratio, gear ratio for gear the test was run in and tyre size.

T1w1 = T2w2. T = torque (Nm), w = angular velocity (RPM).

A 5.7L GENIII engine (235kW @ 5200RPM, in SS Crumpledore) produces 465Nm @ 4400RPM. 3rd gear is 1.30:1 and diff is 3.46:1. Tyre size 235/40R18.

For 3rd gear:
Engine RPM: 4400
Gearbox output RPM: 3384.6
Axle RPM: 978.21
Tyre diameter (m): 0.6198
Road speed: 114.28km/h

T1 = 465Nm
w1 = 4400
T2 = ?
w2 = 978.21

T2 = (T1*w1)/w2
= (465*4400)/978.21
= 2091.5754Nm (hence the dyno would show 2092Nm @ 114.28km/h)

So the 'tractable force' would then be:
T = 2091.6
d = 0.3099
F = ?

F = T/d
= 6749.1946N

Hence a chassis dyno graph of torque is only useful for 2 things: how much torque is present at the wheels to drive the car forward and how it varies with speed. It does not indicate engine torque.

its just in one eye and out the other, bypassing all thought capabilities...

e = mc2 :roll:

Engine:
Engine's torque (between 300 and 400 Nm for you)

Gearbox:
Torque gets multiplied and a bit gets lost.

Differential:
Torque gets multiplied more and more gets lost.

Wheel:
Dyno gives either force applied by the tyre's contact patch or the torque about the drum.
If torque around drum then you need to treat the wheel and drum as another torque multiplication.
If contact patch force (tractive effort), you need to know your tyre's diameter to convert to torque.
More torque gets lost.


Now, you can sort of convert back to an engine torque if you know the gear ratios. But this doesn't take into account all those torque losses. So the figure will be 15, 20, 30 whatever % less than the engine's real torque.
To convert you simply get the wheel torque (around wheel, not drum) and divide by the big number in the overall gear ratio.

Cool, I've noticed that you too have your hubcaps taken off. :)

yeh i am a bit confused cause on the dyno sheet is does say "nm" not just "N"

yeah my torque on my dyno graph shows 1396Nm at 90km/h.

140kw atw.. Not too bad at all :)

Dam i need to hurry up and get my gt30 in...