Explain exactly what your are doing when you rev match.

 

i'll super simplify the concept.... at 60mph you are in 5th gear at 2.7k RPM... but you do know if you stay in 4th gear and hit 60mph you'll be closer to 3.5k rpms... so when you are cruising at 60mph but want to downshift to 4th gear to accelerate, your engine is puffing at 2.7k but your tranny is now wanting to move at 3.5krpms.... if you do not rev match, the synchros have to work to bring the engine revs to match the 3.5k rpms, which will bring excessive wear to the synchro gears... now if you rev up your engine to 3.5k rpms before you downshift to 4th, then synchros work has its work cut out and minimize the stress on the tranny.. theres more details but hope you get the gist of it

 

Sup,

I rev match ALL THE TIME and my clutch is going strong at 9200 mile (even though I burned the **** out of it on sunday). I'm not sure why yours is going down so early I mean I've had 300 plus whp and have been ripping my car for about 3k (anyone whos know me knows this). My stock clutch still grabs like a champ. The only problem I'm experience is when I hold a high RPM like 4K I hear a really weird rattling and I'm not sure what that is :shrug:

 

my car rattled to, thats why i brought it in... they said the rattling was from chunks of third gear floating around the rest of the gears....

i bought my car with a 150 miles on it..
it grinded 3rd gear from day one... so who knows the condition of the tranny before i got the car...

btw- the clutch never felt weird,... it make a slight hum, but it engaged and disengaged without a hitch

 

My 3rd gear grinds sometimes, but I think it's more or less the way I shift sometimes without knowing. It's not exactly a "grind" persay, it's more or less just a notch I guess.

Was your third gear giving you any problems? Grind on acceleration or anything?

 

notch is how i would describe my third gear... u dont hear a grind but u can definitly feel a quick notch..

 

budlong,

My friendly advice for you is to find a lawyer and stop talking to them without your lawyer -- in other words, let the lawyer do the talking. If the service techs are dumb enough to continue to claim that "rev matching" when done properly destroyed the clutch and or transmission, any decent lawyer will eat them alive. Keep complete records of all costs you incur while the car is unavailable -- rental cars, time off work, mileage, etc.

But most importantly, listen to what your lawyer tells you -- not me or anyone else. In my opinion $4K is worth fighting for.

Good luck.

 

more like 5k.. but i totally understand...i;ve called some lawyers but im waiting for them to get back to me... in the meantime im going back to the dealer to take pictures of my trans.

 

That is some great advice. Totally ridiculous that you should have to fork out that type of cash.

 

good luck bro.. let us know every detail how it went its good to know for the future.

 

Just to clear up a misconception which has been repeated here a few times...

Rev matching as most of you are describing it does absolutely nothing to decrease wear or stress on the synchros.

The engine is connected to the layshaft through the clutch, and the layshaft is connected to the driveshaft through the gears. The synchros are part of the gearing assembly, and they work to synchronize the layshaft speed to the driveshaft speed. If you have the clutch pedal depressed, the layshaft is disconnected from the engine and you can vary the engine speed all you want -- the layshaft doesn't know the difference.

An example:

1) Cruising in 3nd gear, you let off the gas and press in the clutch pedal. Since the gear lever is still in 3rd, the layshaft is driven by the driveshaft (which is driven by the wheels rolling on the road), and is perfectly synchronized.

2) Accelerate the engine to the perfect speed required for a downshift to 2nd gear. Since the engine is disconnected from the transmission, this doesn't affect the layshaft at all.

3) Move the gear lever from 3rd to neutral. This disconnects the layshaft from the driveshaft. The layshaft immediately begins to decelerate.

4) Move the gear lever from neutral to 2nd. The synchros have to work to accelerate the layshaft to a higher speed.

5) Release the clutch pedal while holding the engine RPMs steady with the throttle. The clutch engages without even a hint of slip.


If you want to eliminate wear on the synchros, or if your synchros are worn out and non functional, you need to start doing double-clutching. To do double clutching, after step 3 above, you release the clutch pedal, blip the throttle to get the engine RPMs (and the layshaft speed!) just a tad over the desired engine speed for 2nd gear, press the clutch in again, and continue with step 4.

 

there is no such thing as rev-matching. It's correctly called "double clutching." One can do it "heal toeing" or without the brake simply using the gas and the clutch.

 

budlong,

Which Mitsubishi dealer did you take your car to? I don't have an Evo (I have a S2000), but a good friend has an Evo (which I'm actually driving around for a few days). Anyway, his 3rd gear synchro failed a while ago, and the dealer initially tried to deny him warranty coverage. After a great deal of complaining, they gave in and covered the repairs for him. Your situation sounds similar...hopefully you can get it covered as well.

 

So in other words, heel and toe shifting (i.e. rev matching to avoid clutch slip) is bad for your syncro's? If so that would explain worn syncro's, but not bent teeth on the gear itself. If the heel and toe does in fact wear on the syncro's then that just sucks for performance driving. Please tell me the syncro's are tough enough to put up with this.

 

Rev matching does exist. It serves to reduce clutch slippage while shifting.

Double clutching serves to reduce synchro stress while shifting -- or in the case of a "dogbox" transmission (one with no synchros), double clutching allows you to shift without making horrible gear grinding noises.

Heel-and-toeing simply refers to rev matching while simultaneously braking, and may or may not involve double clutching.