marcj1

Hi all:

Couple of basic questions about MT mechanics and operation.

Like many of you, my commute has its bottlenecks and I am trying to reduce wear and tear on my clutch/tranny to the extent possible. While it is probably impossible to never ever ride the clutch, I am trying to understand best practices.

Given that being in gear already allows me to get up and go when traffic moves ahead: Is there a mechanical difference between coasting in neutral with the clutch released and coasting in gear with the clutch fully depressed?

Does the clutch only get worn while traveling between being released and engaged?

In practice, I try to spend as little time with the clutch traveling, that is between engaged and released, to reduce wear. Is that the "correct" practice?

Many thanks,
Marc

Chrisbert

With the clutch depressed, you are placing the burden on the "throwout" bearing", or whatever they want to call it. When you press the clutch, a series of mechanical / hydraulic devices must hold the pressure plates apart.

The manual I think says not to coast long distances in neutral; not sure why.

w2aew

The throwout bearing (release bearing) is in use (wearing) whenever your foot is on the clutch. The clutch disk, pressure plate and flywheel are wearing whenever you are in the process of engaging/disengaging the clutch (i.e., not wearing when the pedal is fully depressed or fully released). Coasting with clutch depressed and in gear does cause the trans to "drive" the input shaft and clutch disk but they're under zero load so essentially no wear (except to the throwout bearing already mentioned. IMHO, I'd coast along in in neutral with clutch pedal released whenever possible.

Ned M

iTrader: (2)

What he said.

Even tho the 8 has very little low-end torque, it's possible to creep along in 1st at just a couple mph if you're in a slowly advancing line of traffic. Just back off a bit from the car in front of you and you can eat up quite a bit of distance with just one clutch / declutch rather than go forward 3 feet at a time and stop like most people with automatics do.

My last two MTX daily drivers, a Contour SVT and Eagle Talon AWD had 67,000 and 96,000 miles respectively on their original clutches with the balance of miles put on in-town driving.

marcj1

Many thanks for the info and advise!

Haze

Yup to all of the above. The car will idle forward in first at about 2 MPH or so, and that's fine for the car. The other thing is that if you are in accordianing traffic as it speeds up and slows down try to let the car in front of you slide out and come back when traffic slows so you don't have to change speeds that much. Also, when you have to speed up and you are pretty sure that it is just going to slow down again, I find that it is better just to rev the engine up instead of shifting. I've never had this heat the engine up in the 8, and it is better to rev the engine than overheat the clutch by constant shifts. Basically, the rule is just try to keep your foot off of the clutch.

As for the throwout bearing, I shift to neutral then let the pedal out to keep from running the throwout bearing any more than necessary. Some people say that a throwout bearing really won't get hurt by being run, but I don't see any reason to wear, and besides there is a tendancy to slightly release the clutch pedal over time if your foot is on it too long and that is bad for the clutch because you can let the pedal out enough to wear the clutch plates and the synchroes. General rule is to try to keep your foot off the clutch pedal as much as possible. All the best - H

Haze

Oh. I just noticed where your traffic problem is. The same Place as mine! If you look in the NE section of the forum, you will see a sticky thread for a Tri-State meet that we are having in Valley Forge park tomorrow, if you are interested in coming. It's just a bunch of people and their 8s, but we're always happy to see new faces. Just thought that I'd mention it. All the best - H

arattle

I was looking at coming to that, but I gotta go get my mirror fixed tomorrow. Hope to check it out next time though, whenever that is. How often do you guys hold these meets?

-arattle

Haze

The meets are every few months, but we aren't thinking of much for the Winter. The feeling is that people just won't be interested. We always post in the NE Section of this forum and the tristate club has its own site if you want to check that out.

www.rx8tristateclub.com

Definitely drop by some time.

-H

nchynk

Another clutch question: The position of the clutch where it engages the driveshaft in the RX8 is very close to the top (when its fully released). This is very different from my 2000 Celica where the clutch is very short and engages near the bottom (fully depressed).

I'm just wondering if you guys while changing gears fully press the clutch until it reaches the floor, or press it until is just passed the point of engagement? I do this in my Celica and everything seems fine, but when I do this in the RX8 it just sometimes doesn't feel right.

Haze

Always push the clutch all the way in.

Depressing the clutch just pulls apart two pressure plates . . . BUT if the plates aren't all the way apart things keep spinning (with force behind them) in the trans that really shouldn't be. The synchroes start to spin which speed up the lay shaft to engage the gears. If that lay shaft is spinning too fast (with too much engine power behind it) and you put the car into gear from neutral or quickly from gear to gear you can grind the gears or worse.

I had a girlfriend who decided to do this to my car when she was playing with "speed shifting". She engaged second from first hard with the clutch half way in. My Synchro on second quite literally exploded. O cpould hear the pieces being ground into the trans for about a thousand miles after that, and I spent the next 90,000 miles double clutching the car, which isn't what I bought a new car for. Even if you decide to not speed match and run the stick through the gears as fast as you can, make sure that the clutch hits the floor each time! You can still pretty much stick it in and dump it out, but with the clutch all the way in, it will permit the gears to match their speeds in the box, although it will be the hard way with alot of wear on the gears and synchroes. Have that clutch out too far, and bang goes the trans in one freaking shift. Also understand that your Celica is a detuned junk box compared to the complicated triple coned trans that's in your 8. Think of the 8 as precision and therefore it has to be handled in a precise way.

rxeightr

I read the manual & don't remember this being in there. I go down hills twice a day with the RX-8 in neutral.

RotorMotor04

if you let the clutch out doin lets say 8 MPH it will drop to 5 and stay there, the idle of the engine will keep the car moving without any "lugging."

Benthic

If you disengage the traction control, the clutch engages the drive shaft much sooner, and it feels more like a traditional manual.

w2aew

I find this extremely hard to believe, since the clutch is hydraulically actuated, and I don't believe there are any electronic values, etc. in-line that would alter the engagement point. The only "electrical" attachments are the starter interlock switch and the cruise-control sense switch. There are no electronic controls/connections to the clutch master cylinder or release cylinder.