Best torque curve for track and drags etc

[TRDmod]

Ok

what type of torque curves are more suited for a sustained track pukekohe type style of track?
how would that differ to a drag racing power curve? or a slower track such as the old taupo track or manfield?

heres my theory and interpretation of it:

If its a fast track like puke, then your rev range is always high and you are opens on top end power which means that top end is more important than low end power and torque.

Slower circuits need you to have more low end power because when you corner to drop revs and speed and need to pull out asap..... so top end poewr isnt as important in this case as you would probably never use the most of it.

drag racing is jsut all out power, across the band, the more power the better everywhere.

Is this correct? any feed back?

because my aim is to tune my car for circuit, mainly fast circuit like puke, so i want to know what is best.

thanks

[Dell'Orto]

Nah, drags you can have a fairly topendy narrow powerband and do well, cause you're at WOT the entire run.
Somewhere like Puke you'd want good midrange and top end, mostly mid range power.

[Mr Revhead]

mid to top for track racing, no matter what the track.
main thing to make sure of is the powerband matches the gear ratios

[TRDmod]

i just dont understand, i have been to puke a few times
and all that time, when coming out of the corners, apart from the hairpin, you dont really have a point in time where your rev is lower than 5. its always higher, so i dont see where in puke i can use mid range.

jsut a question, what is your definition of low end, mid and top range?

lets asy my car a 205 you guys know redlines at 7k rpm

just so i know where we are all at
thanks
:d

[RomanV]

There's no real answer to your question.....

A torquey engine that only revs to 5000rpm can do well on a track, and so can a peaky engine that never drops below 6000rpm the whole time.

What makes all of the difference? Gear ratios and final drive ratio....

If you want an easy way to get a rough idea what differences things like altered gear ratios etc make to your time, I reccomend that you download the dos version of 'cartest', and have a play with that....

Not 100% accurate obviously, but interesting none the less.

[2jayzgte]

Mate if your driving a road car on the track short shifting is the way to go just keep the car in the right rpms where your car is making its most Torque for get about revving it to the red-line your car probably stops making power after 6400 rpm anyways.Just check your dyno sheet if you have one and where its making its max Torque try and drive it in that rev range..

[Mr Revhead]

says the man with an auto and 2jzgte

but hes right

[pc]

mid to top for track racing, no matter what the track.
main thing to make sure of is the powerband matches the gear ratios

What he said. It really doesn't matter where your torque curve is, as long as your gear ratios work with it.

[strx7]

main thing to make sure of is the powerband matches the gear ratios

that there is the key

a car with alot less power but perfect gearing for a track/circut will slap something with more power but shitty ratio's EVERY time.

[strx7]

its like a phrase that used to do the rounds of the US rx7 forum, your car has gears so use them.

[fivebob]

Mate if your driving a road car on the track short shifting is the way to go just keep the car in the right rpms where your car is making its most Torque for get about revving it to the red-line your car probably stops making power after 6400 rpm anyways.Just check your dyno sheet if you have one and where its making its max Torque try and drive it in that rev range..

Not so, you need to take into account the gear ratios. It's torque at the wheels that counts not torque at the crankshaft. In most cases you will be producing more torque at the wheels in a lower gear at redline than you will in a next higher gear at the same speed. Therefore you will be accelerating faster in the lower gear.

This is most definitely the case for the 3S-GTE and the E15x series gearboxes. For all except 4th->5th, shifting at, or very close to redline produces more torque at the wheels than short shifting.

[2jayzgte]

Well there are some absolute knowledgeable quotes going down here but I showed my dyno sheet to a ex-Nz rally champion and Targa champ Joe McAndrew and he gave me this advice while it may differ from car to car I certainly just do what he said and it has paid dividends for me on the track so while people here are having differing opinion's I definitely no for sure this works..

[TRDmod]

fair enough
i guess i was asking what kinda torque curve is best
it comes down to changing at the right times and the cars characteristics in the end of the day.

[fivebob]

Well there are some absolute knowledgeable quotes going down here but I showed my dyno sheet to a ex-Nz rally champion and Targa champ Joe McAndrew and he gave me this advice while it may differ from car to car I certainly just do what he said and it has paid dividends for me on the track so while people here are having differing opinion's I definitely no for sure this works..

Dyno graph is useless without knowing the gear ratios, so how can you know it works without hard data. SOTP dynos are about as useful as the eyechrometer for accuracy. A stopwatch, or better still datalogging, is the only true way to tell which shift point is best

To do this properly you need to sit down with a calculator, or better still put it into a spreadsheet and work out what rpm you will be in the next higher gear at various shift points, then you calculate the available torque by multiplying the torque at the crank at that rpm by the gear ratios and compare. Conversely you can take peak torque and multiply that by the gear ratio, then calculate what the RPM in the lower gear would be at that point, then multiply the torque at that RPM by the gear ratio and compare.

However all this is academic in TRDMod's case. By looking at his dyno plot you can see that peak torque is at approx 6200rpm. As shifting at redline will drop you below that in all gears, you can never shift into the peak torque of the engine without upping the redline to 8000 rpm, even then it's only the 4th-5th shift that will put it close to peak torque.

In saying that, there may be some occasions where having less torque at the wheels is desirable, like exits from low speed corners, but for all other times when you want max acceleration then you need to make sure that maximum torque is available at the wheels, and lower gears and higher rpm are usually better, especially if peak torque is higher up the rev range.