Power V Torque

[rhys86]

THis may sound like a stupid question but are tuners able to tune a car to get more power and not as much torque??

Or is it a hand in hand thing. When you increase the power the torque automatically goes up??

[South]

Power is a mathematical calculation, without torque and revs, you have no power gain.

[rhys86]

Power is a mathematical calculation, without torque and revs, you have no power gain.

Thanks thought as much

[turbotom]

Power is a mathematical calculation, without torque and revs, you have no power gain.

Now hold on just a minute.....The original poster's question is a little ambiguous....

Whilst it is a fact that power and torque are a mathematical calculation.... and tied together with an expression....

peak values of power and torque do NOT occur at the same rpm.

So you CAN tune to limit peak torque output whilst still increasing peak power output!

working in the old system of units..... Horsepower = (Torque(lb-ft) * rpm) / 5252

and inversely

Torque (lb-ft) = (Horsepower * 5252) / rpm

I'm assuming this question was raised due to a necessity to retain some reliability?

Else why else would you want to reduce peak torque?

To give an example......

I was having gearbox issues because of the very high peak torque outputs generated by pushing for ever more grunt....

With our turbo charged motors, it is very easy to get ridiculously high peak torque output by getting the boost up high very early in the rpm band.

15 psi at 3000 rpm generated around 250 rwkw ( about 590 lb-ft torque at the rear wheels! ) in my ute, and I fried my modded gearbox. Twice!

I then asked the boys at HPF to limit the peak torque...... whilst still aiming for maximum peak power.

The boost was reduced slightly below 4000 rpm, and the tune was adjusted, and I now have approx 500 lb-ft peak torque at the wheels, whilst still getting over 400 horses at the rear wheels.

And the gearbox has been good for 2 years now.

So in fact the answer to your your question...

"Are tuners able to tune a car to get more power and not as much torque??"

is actually YES they can!

tom

Edited 05/09/08 07:50 AM by turbotom

[TOM1111]

limiting torque is how nizpro has made the high 300rwkw BA's not explode with stock internals

is there any point in having a higher peak power with limited torque???

[ETM]

is there any point in having a higher peak power with limited torque???

exactly, when you take away torque all you have is a dyno sheet, whats the point in having the worlds slowest 300kw car?

Edited 05/09/08 08:53 AM by ETM

[turbotom]

limiting torque is how nizpro has made the high 300rwkw BA's not explode with stock internals

is there any point in having a higher peak power with limited torque???

Well, yes again.

For exactly the reason I did it.

To have reliability.

You won't get a decent ET if you

1/ sit on the line burning rubber rather than getting traction

2/ spin sideways into second gear 50 metres from the tree

3/ twist a tailshaft or snap a half shaft(sedans) due to excessive torque

4/ shatter the internals of your gearbox

5/ crack the diff mounts

6/ do I go on?

So yes, there is a point in having a peak power with limited torque.

The hard part is establishing what that peak torque IS.... for reliability!

Don't forget, it's torque that applies the strain on all the components, be they in the motor or the gearbox or driveline or tyres. Every component has a yield point, so if you want reliability you need to ensure the yield point is NOT exceeded.

I've found a combination that meets my needs..... and it's been going well for two years without issues.

[FPV TRANNY]

Makes sense to me.

[antigravity]

I was always of the understanding that power = torque x rpm.

So you can have extremely high pulling power down low, but not necessarily have a lot of power, because the revs are low.

And that's why you can have your torque fall away high, but still have your power band increase because the RPM's are increasing...

Power is a mathematical equation derived from Torque. SO you can have torque without power, but not power without torque...

So when your vehicle is getting tuned, your tuner is playing with the torque output at different revs to provide the best power output. The longer and flatter the torque band is at a low RPM, the more drivable a vehicle is (ie. no need to keep the car high in the power band to move).

[Craig.]

I was always of the understanding that power = torque x rpm.

Can you use this simple formula to explain why some XR6Ts which make 300KW only make 700NM of torque while others with 300KW make over 900NM?

If power and torque are related I cant see how.