The ideal Torque Curve

[obi_waynne]

What would you say the ideal torque curve is for a car? Too many people focus on peak power and the torque curve is far more important.

Personally I think a car that delivers peak torque from 2000 to 6000 rpm is pretty good. I can't see the point of having lots of torque below this or a sudden peak at say 4000 rpm.

Diesels seem so quick because they have relatively flat torque curves.

What are your preferences when it comes to power delivery and are you into NASP or Turbo engines?

 

[HDi fun]

The flatter the better really.

Saabs HoT petrol turbos are superb examples. I know the peak torque figure is not as high as a diesel but you get great response from 1500rpm all the way to 6500rpm.

Diesel turbos are spent by 4000rpm really, although the shove up that point is enormous.

 

[pgarner]

yeah low down torque from just under 2000 rpm right up to around 5500 rpm
no point in having lots of torque below 2000 for traction issues.

nasp do give nice flat curves but they need the cc to get anything
but prefer the turbo - i get between 170 and 185 ftlb between 1900 and 6000 rpm.

 

[HDi fun]

Turbocharging is the best way to get a flat curve. NATASPS are very peaky unless the tuner decides to flatten the curve by detuning the peaks. This is kind of counter productive.

Diesel and petrol are converging all the time. Petrol engines are getting more economical and diesels are getting revvier (and thirstier)

It's time for something new now I think.

 

[pgarner]

how are you getting on with the tattie powered engine ?

 

[thexav]

Electric motors are near linear torque curves. Lets get a Prius and replace the motors with something more substantial.

 

[HDi fun]

DC motors do have linear torque characteristics. Unfortunately it's a inversely proportional to rpm. So at 0rpm they have peak torque. At peak RPM (say, 20,000) they have 0 torque.

At 10,000 rpm they'll have 1/2 of peak torque.

 

[davevm]

should be flat between 2500-4000 rpm

 

[HDi fun]

flat between 0 and 19,000 RPM would be better.

 

[pgarner]

flat for as long as possible 4000 is too low for it to drop off

 

[MasterAuron]

The flatter the better really.

Saabs HoT petrol turbos are superb examples. I know the peak torque figure is not as high as a diesel but you get great response from 1500rpm all the way to 6500rpm.

Booooooring Sod all until 26psi at 5000 rpm and BAM!!! Much much more fun and you can always change down a gear!

 

[obi_waynne]

There are two types of drivers, those that love turbos and those that don't!

 

[BAD63R]

My max torque curve as far as the power goes is 3000rpms to 6200rpms, but thats the remap that helping it do that other wisee it would max out at 6000.

 

[turbonutter69]

There are two types of drivers, those that love turbos and those that don't!

I like turbo's........

 

[HDi fun]

Booooooring Sod all until 26psi at 5000 rpm and BAM!!! Much much more fun and you can always change down a gear!

Nope sorry, not for me. I like linear torque delivery.

Lots of it, mind you.

And over the entire usable rev range.

My ideal car would not need more than one gear.

That way we can dispense with gearboxes completely, auto and manual - they just get in the way of driving the car.

 

[turbonutter69]

No you can't do that. You need a manual for when you go into a bend too hot so you can dump it down a gear to aid slowing down.

 

[HDi fun]

I do not understand that statement at all.

Whether you use engine braking directly by lifting off or enhance it with a down-change you are still de-stabilising the car. The service brake (foot-brake) is no more or less likely to destabilise the car. The service brake is regulated by the stability control system (ABS or more) - a sudden downchange cannot be over-ridden (some auto's will do this, though)

Anyway, what are you doing if you need to suddenly alter speed though a bend?

Why not try separating inputs: braking, steering and changing are best not done simultaneously.

If you separate these you can drive far more quickly.

 

[turbonutter69]

What I mean is I use the engine for braking just as much as I use the brakes. ie Late on the brakes and down shifting quick to utilise the engine braking power.

 

[HDi fun]

Try early braking and use 1st as a hill descent control mechanism.

Uphill you might well need your driven wheels to be turning very very slightly more quickly than the surface is passing beneath them.

 

[turbonutter69]

Late braking FTW. Nothing like booting it down a country lane and slamming the brakes on and using the engine to slow down.

 

[HDi fun]

Late braking FTW. Nothing like booting it down a country lane and slamming the brakes on and using the engine to slow down.

Downchanging whilst using the brakes is fine under hard driving conditions but it's better to choose the gear you want earlier rather than later. Don't swap cogs to assist slowing. Swap 'em to maximse your exit speed. It's quite reasonable to go down the box and brake right into the apex. Just make sure you're in the right gear for maximum pull out of the bend.

Minimal steering until you are confident you need no more braking will increase your exit speed.

 

[turbonutter69]

Thats more or less exactly what I do. I do all my braking in a straight line but just after the last change down to what ever gear I need I turn in hit the apex then power out.