Cooked clutch smell on hard accelerations, normal?

[Tommy]

Since I live in NYC I baby my clutch most of the time but on occasional hard starts going from 1-2-3 it smells like the clutch might be burning. I think this is the clutch b/c it definitely doesn't smell like tires. Is this normal or do I need to practice my fast speed shifting? If it is my shifting anyone have any tips, I just got a Ron Stygar clutch stop and it made a nice difference.

Tommy
'99 M3
Estoril/Blk

[Bob ///M3]

If you've ever smelled a burnt clutch, there's no mistaking it! Chances are, if you smell that smell, you will be in need of a new clutch soon.

As for tips, if you want your clutch to last as long as possible, keep in mind that the sooner the clutch and flywheel can "lock-up", the less friction (wear) there will be on it and the longer it will last. Speed-shifting (not lifting, just using the clutch) rarely helps gain anything compared to a quick, controlled shift. If the car was used for dedicated drag-racing, you probably would want to speed-shift it, but you would have a different type and/or style of clutch in it offering more clamping power.

When you think about it, during a launch (from a standstill) four things could happen; a.) you have traction and accelarate foward b.) you don't have traction and the tires spin c.) the engine is overcome by the demands of moving the car's weight and stalls or d.) the clutch slips. The only thing else that can happen would be for something to break such as the ring or pinion gear or driveshaft joint. When you already have some ground speed momentum, you can eliminate item b. but c. takes on a somewhat new definition...which is; the engine "will" produce all its available torque and horepower as it climbs in engine speed (rpms) while the clutch must remain locked-up in order for the car to increasingly gain speed. If there is a weak link, it "will be" the clutch.

When you see professional road racers shift, it is done quickly but concisely and controlled...not speed-shifting and never lifting. The reason is because there is so little to be gained by doing this (speed-shifting) and so much to be lost (clutch, transmission, more chance of a mis-shift, etc.). There is a tremendous amount of engine torque that must be coupled to the car's driveshaft with each upshift and this ALL happens through the clutch facing and the flywheel which happens to be the weakest link.

Also for your information, the higher the transmission gear ratio (higher gears), the more difficult it is on the clutch. The reason for this is because of the "load" (or burden) that is presented with the higher gears. In other words, the clutch doesn't see as much load in 1st gear as it does in say 3rd or 4th gear, because 1st gear's gearing is much lower. That's why most people who experience a worn clutch usually first feel it slipping when they accelerate while in a higher gear...because of the increased load or burden (because of the higher gearing).

Riding the clutch, feathering it, or allowing it to take an extra amount of time before the clutch locks-up with the flywheel will also cause added clutch wear. Again, the sooner the clutch and flywheel can "lock-up", the less friction (wear) there will be on it and the longer it will last.

Bob ///M3

[Tommy]

Thanks for the info Bob, I guess I need to be more gentle when driving. I'm used to sportbikes so I guess its a bad habit riding the clutch a little bit.

I'm going to try to be extra careful when I drive, especially when I want to go fast I will make my shifts slower.

Thanks,

Tommy