Need new clutch

[sha1234]

well she has finally given in to spirited driving... its still origonal from 160,000 clicks or at least thats what i belive.... needless to say the plan for the car is to at some point get some power out of it... IE. turbo, or stroker, or supercharge.... who knows none the less i would like something that would be fine to clamp nice and hard for maybe 200+ HP or so...
SO what would be a recomendation... other than the M20 flywheel and clutch swap... any help would be good

[kowalski]

hahaha i was going to say m20 flywheel conversion. why wouldn't you want to do this?

[Boyracer]

I have been wondering about the clutches too lately.

Does one need upgraded clutch instead of stock in NA tuned engine? As stock my engine has 175 Nm of torque that is transferred to gearbox trough clutch.

If I tune the engine in NA configuration, it is unlikely that the torque will be more than 190 Nm. BMW Motorsport manages 114 Nm / liter on S54 but it is very advanced engine. That torque / liter output would mean 205 Nm in 1.8 liter M42

So torque might go up only 8% but power can increase from 140 -> 180 hp which is 28%.

Because the amount of torque transferred is not that different, standard clutch should be able to cope with it easily, no?

To transfer larger amount of power you just spin the engine and clutch faster but that does not require any more clamping force from clutch I think because the torque will not be more than maybe 190 Nm.

On supercharged engine, you can easily increase the torque some 100% so in M42 case from 175 Nm -> 300-350 Nm. So in that case you definitely need clutch with more torque capability! :eek:

So I have concluded that I should plan clutch upgrade mainly with torque in mind, not power. And since the increase is so small, stock clutch could work.

I think there could be problem if the clutch is allowed to slip too much :confused:

Can anyone share their thoughts on this matter?

[Wise Old Dog]

A stock clutch can handle the moderately tuned NA engine just fine. If you are doing some sort of drag racing, with fat tires in the rear, you will want a stronger clutch. Either way, the M20 clutch can handle whatever you throw at it. As far as a turbocharged engine goes, I don't think there is that much more of an initial power jolt than a NA engine. It needs to spool up for the max power output. Again, the M20 clutch would be plenty strong. Take a look at the Metric Mechanic web site. Look at the high output M42 engines they make. And they recommend the M20 clutch for every one of their engines that can fit a 228mm clutch (e30) If you have an e36, then you can go to the M3 clutch which is a 240mm disc.