Clutch and rotor question



I have a 2005 scion tc, i tend to drive…more aggressive than other drivers. my car needs new brakes and a new clutch pad. but while they have my clutch open i was thinking about upgrading my clutch for more aggressive driving. i wanted to get a sports clutch, but the guy im asking to install it for me says that instead of the sports clutch i should get a lightweight flywheel. please help me, i need to get the parts ordered soon. and for the brakes, i wanted to upgrade my rotors, should i get slotted or drilled rotors?


A lighter flywheel will allow the engine to rev a bit quicker but the downside is that you will lose some torque, or pull-power.

Can’t say on the rotors as that is too personal a choice. Either one will work. The drilled ones may have a tendency sometimes to develop a crack between some of the drilled holes; the slotted ones may have a tendency to run a bit cooler.
I would not expect a night and day difference between your stock rotors and any drilled/slotted ones though.


what exactly does losing torque mean? does it effect horse power at all?

what would i need to give my clutch a longer life span?


Torque is the twisting force that is exerted. I have no idea how much torque would be lost by a lighter flywheel, but it would show up when taking off from a dead stop, pulling hills, etc.
There may not be enough of a loss to worry too much about, but it would be more noticeable on an engine with a narrower powerband such as yours.

Probably one of the best ways to think of it would be in motorcycle terms. A Harley has gobs of torque. One of my antique Harleys will pull away from a stop light in 3rd gear without any hesitation at all. If you tried that with a high revving Kawasaki for instance, it might bog and fall flat. Hope that illustrates it a bit.

With aggressive driving, I don’t know about clutch longevity short of going to a heavy duty performance clutch.
I don’t know if you have a habit of resting your foot on the clutch pedal, but if you do, this is a habit to avoid. It brings a little pressure to bear on the throw out bearing and could possibly cause the clutch to slip a little bit, leading to shorter life of course.

Hope some of that helps anyway.


lighter flywheel will let your engine spin up(and down) faster. Less mass to spin. It’ll give a sportier feel going up the gears, with shorter transition time from gear to gear


HP is a function of torque.

HP = (Torque * RPM) / 5250.

So yes…if you loose Torque, you’ll loose HP. However the Torque you’ll loose with a ligher flywheel will only be in the Low RPM range.


thanks for all the help, it helped alot.

if anyone else has any suggestions, feel free to post them, i’ll be checking this until i buy the parts i need


A lighter flywheel will not affect torque but will, as was said, enhance acceleration as there is less weight within the engine to speed up. Your lower speed lugging point in each gear will increase, that is, the minimum RPM to keep the engine running smoothly will increase. Whether this will make a problem for you, I don’t know. Most motorcycles also have minimal engine rotational inertia (little flywheel effect) to maximize acceleration. A couple of exceptions are Harleys and very old BMWs which have/had plenty of flywheel. More flywheel makes a more calm engine at the expense of some acceleration.


I respectfully disagree with the statement that lightened flywheels do not affect torque.
Harleys are one of the best examples around as they are known for low end grunt.

Many guys who are into racing the old Harleys will lighten the flywheels as a first step. It allows the engine to rev faster but they all lose some of that low end grunt.

In fact, one of the big tricks on the old HDs being set up for racing was to replace the left side flywheel (the heavy drive side one) with another right side wheel.
The engine uses 2 right side flywheels and cuts a ton of weight off of the assembly. This also causes a loss of torque, but in HD racing torque was not the issue as much as faster revs.

Truett and Osborne pretty much wrote the book on aftermarket Harley flywheels (both stock and lightened) and that’s what they say also.