Torque figures

[Dracoro]

What are the torque figures for most commonly used engines in wesites?

e.g. What is the likely torque figure in my VX 2.016V with twin 45 webers? and so on for the other injuns.

[Blatman]

I *think* you can calculate it, but I'm not 100% sure... Try

Horsepower x 5252 / max rpm

So for a Vx 180bhp x 5252 / 7200rpm = 131.3ft/lb's

But I'll stand to be corrected...

[Matt Seabrook]

A Vx will make about 160ish lbft peak if the engine has been unmolseted. May engine makes 190lbft at 5500rpm but is running t/bodies cams etc.

[Blatman]

Your Vx makes more than my Cossie? I doubt it

[Matt Seabrook]

Oh well mate just the figure I got from the rolling road mate you know what they are like.

Was this spec cam

[Arm]

Nat asp 2L 16v motors struggle to break the 180 lb ft mark.

[Blatman]

253bhp x 5252 / 8000rpm = 166ft/lbs.

Yeah, I know *just* what rolling roads are like...

[Bananaman]

I *think* you can calculate it, but I'm not 100% sure... Try

Horsepower x 5252 / max rpm

So for a Vx 180bhp x 5252 / 7200rpm = 131.3ft/lb's

But I'll stand to be corrected...

According to that calculation mines putting out 172lbs assuming max bhp@8000rpm

[Blatman]

I'm still waiting to be corrected on the calc though...

[Gazza]

.... interesting to compare with the turbo 434inch V8 on American Hotrod that was being set up on the engine dyno:

690ftlb ... that was BEFORE the boost comes in  

What torque do people have from their Seight V8's, ot of interest?

[geelhoed]

I *think* you can calculate it, but I'm not 100% sure... Try

Horsepower x 5252 / max rpm

So for a Vx 180bhp x 5252 / 7200rpm = 131.3ft/lb's

But I'll stand to be corrected...

g gravitational acceleration

T torque

P power

w angular velocity

    bhp = 550 lb * ft /s  * g

    rpm =  pi/30  rad/s

the product of the angular velocity and the torque is the power so

P=16500 / pi  T*w = 5252 * T* w

So the value is correct, but to take the maximum rpm is strange

you have to take the power value at the specific rpm to get the torque at that rpm

So from the graph: 6500 rpm  - > 220 bhp would give 177 torques.

[Matt Seabrook]

Nat asp 2L 16v motors struggle to break the 180 lb ft mark

Yep agreed Ash just the only thing I have to go on is what I got from the rolling road and SBD's quoted   figure for the cam spec.

Heres one to make you smile then

Could only come from SBD

[ChrisG]

Yep, Blatman's calc is only calculating the torque at peak power, not necessarily the maximum torque of the engine.

[Blatman]

Yep, Blatman's calc is only calculating the torque at peak power, not necessarily the maximum torque of the engine.

[Blatman]

Lets try a backwards calc.

(Torque x Engine speed) / 5,252 = Horsepower

(190 x 5500) / 5252 = 198bhp.

Either Matts/SBD's torque figure is wrong, or you need to calculate it at max rpm (8000rpm in Matts case according to the graph), which gives 289bhp. I don't think so... So, somethings wrong somewhere with Matts/SBD's quoted figures...

Have a look here.