Increasing torque at high revs

13th December 2011, 19:30

I've had my car rolling roaded the other week, where my torque peaked at 5250 revs, but then afterwards had a major decrease...

I've got a decat and a cold air intake at the moment, produced 128.5bhp but I was curious how I would increase that high end torque

13th December 2011, 19:46

You cant.

13th December 2011, 20:01

The only way of moving your torque higher is to rev it more.. High lift cams and high compression. Look at the civic type r's they produce their peak torque very high

13th December 2011, 22:03

5250 is normal speed for peak torque on that engine. As said the only way to significantly move the peak torque further up the speed range is to change the valve lift profile and timing (unless your budget is high, in which case there are many other options)

14th December 2011, 08:58

Quote:

Originally Posted by dannygti

The only way of moving your torque higher is to rev it more.. High lift cams and high compression. Look at the civic type r's they produce their peak torque very high

type r is not a good comparison and a bit misleading as it has variable valve lift + variable valve timing .neither of which is possible with the tu engine .
it does however show that it is not possible to have a fixed camshaft profile that can work perfectly across a very wide range of rpms, which is why vvt +vvl is so popular with modern engines.
Its not a new idea but it has only been possible to get it right with the coming of the engine managment systems std cars now have
you can only move the max torque peak up the rpm by increasing bhp at same time and making that max bhp figure at higher rpm as well ,which on n/a and no variable timing means it will be less at lower rpms .
but the car should not feel like it has stopped accelerating even after max torque is reached because bhp will rise with rpm although torque number is dropping ,
if it does feel that way then something is wrong with set-up
your only option to increase torque significantly without increasing rpm is boost ..
you can have double the power(torque) at same rpm with boost

having said that when fitting a s/c to a honda typr first thing is to alter the vvl point right down and then redajust the vvt side of it to match becasue once you are pushing air in then you do not need the same sort of duration you would with n/a tuning

14th December 2011, 17:04

Sometimes you don't half go on John...

My example weren't supposed to be in depth or indeed perfectly accurate just a quick example for the op

14th December 2011, 17:32

You retard both the intake cam and exhaust cam keeping overlap the same, moves torque up the rev range, but you lose more low down torque than you gain at the top

Along with that, you can change your exhaust manifold for a 4-1 rather than 4-2-1 system

21st December 2011, 14:21

fitting a 421 manifold would free up some more revs

21st December 2011, 14:38

Quote:

Originally Posted by luthor1

Along with that, you can change your exhaust manifold for a 4-1 rather than 4-2-1 system

On a near standard car there really won't be a difference.

21st December 2011, 14:56

Fitting a 4-2-1 definitely wont move torque up the rev range, that's my point, 4-1 is higher rev orientated, 4-2-1 is lower rev orientated. Not massive difference, but it's all part of the ingredients list. Add higher lift cams with longer duration, fit iTB's with short trumpets, fit a supercharger (not a turbocharger) all these things move torque up the rev range as opposed to down, that's my point really