Double clutching feels weird. I have done it just out of curiosity. I haven't found a good use for it yet. I know that the older cars needed that to lighten the load on the synchros. Nowadays, it's almost obsolete.

 

The only detail left out of the double-clutch sequence above is that when you release the clutch in neutral, you simultaneously blip the throttle to get the rpm's to just a shade above the rpm that you'll be at in the newly selected gear. The idea is to get the clutch disk and input shaft running at the exact speed required to mesh the gears w/o synchros.

I still remember doing that on the old Ford F-800 commercial truck that I drove during one summer job many years ago.

An excellent application for double clutching the 8 is when you are downshifting while slowing down. Clutch and come out of your high gear to neutral, release the clutch and begin to brake with your right foot. Tilt you foot sideways and blip the throttle with the side of your foot while still braking, then depress clutch and select lower gear.

With practice, you'll be able to match the revs to get an easy downshift while slowing down without asking the synchros to work very much, and you'll be ready in the lower gear to take off again...

Perfected this in my old MG, and works very well in the 8 (at least with my feet).

 

So will I save my synchros some wear by revving the engine a little before engaging my clutch during a downshift?

 

No, but it will save you clutch wear if you match rpms before re-engaging the clutch (and is much smoother in general). The syncros are internal to your gear box and are worn while you are selecting the new gear (N->gear) when the layshaft is speed matched with the drive shaft so that the new gear set can engage.

 

i only do release the clutch when i need 2 downshift more then 1 gear.....if its only 1 gear i need 2 go down i juss don't realse the clutch....is that good or no?? i've only been driving stick for like year and half......wanna learn more! got heel-toe perfect....but still confused bout double-clutching....

 

Double clutching I think is only needed when racing, and redlining while downshifting. The purpous it to syncronise the speed of the engine with the transmission with as little clutch use as possible. This way you don't get the sudden shock from the two trying to match speed causing the rear tires to skid, and sending you into a slide. If you get good enough at matching speeds you can actually shift with no clutch... I could do this well in my truck, but don't want to try it in my 8 yet. Sure helps to learn if you ever lose a slave cylinder.
As far as beating on my 8, I feel it is something I do not do. I drive it aggressively, but I do plan to get good life out of it. I have always had a habit of replacing a broken part with something stronger, and I would like to SCCA race my 8 once the warrenty is up. I'd like to see 300k miles, but I highly doubt it'll make it close if I start to race. BTW outside of warranty, I always do my own work on all my vehicles.

 

Rotarian, did you get your transmission checked out yet?

 

Nope, not quite yet, but really soon, maybe next week. I am due for the 7500mi service.

 

I double clutch 6 -> 3 shifts.. very smooth, then the car takes off like a rocket!

 

It is strange but I don't use 5th gear for just about anything.

I drive about 80 MPH to work everyday and it is always 1,2,3,4 then 6.

When I want to pass someone I go back to 4th.

Personally I would have preferred a 5 speed transmission over the 6 speed we have with gear. Probably could have been beefier and I could go from 5th to 4th with a lot more ease.

Warning about RX-8's transmission: unlike every transmission I've ever owned, it will let you go into any gear at any speed. It went effortlessly into 2nd one time when I was trying to find 4th.

Ouch...

-Mr. Wigggles

 

You are not the only one to have done this. I have heard it in other threads. When you do it at 70 and the rear wheels start to drift it can be scary though. Not to mention how the guy behind you reacts. "Oops, no brake lights."

 

yep, been there, done that, this is where double clutching comes into play. 3rd gear @ 85 rpm, clutch in, heal toe break blip the throtle, down shift about 70 and engine break instead of rear wheel lock up. This also ligns you up in second for coming out of the turn. Watch GT or Formula racing, and listen carefully. You hear them enter truns and double clutching to downshift.

 

I was refering to the drop to 4th from 6th at 70 mph getting missed when down shifting for a pass and into 2nd by mistake. I only made it once myself when I wasn't real familiar with the 8's shifter and the spring loading that gently forces it into a 3-4 position.

The 6-4 downshift doesn't need to be double clutched, but I would definitly double clutch a 6-3 unless I was going to make a 180 and needed to drift around a cone as I have done in autox.

 

I generally do the heel-and-toe part but without the double-clutching. Is double clutching always advisable when matching revs by heel-and-toeing? [N4BBS but not on the air lately.]

 

What type of shifting behavior will wear out a synchro?

My 1 - 2 synchro was worn out on my last car when turned it in for the 8. I used to do alot of hard downshifting.....

 

Did I kill this thread?

 

I know the feeling :D. Sometimes I wonder if I'm using invisible font . I'm sorry I don't know they answer to your synchro question.

 

the much too hard kind of shifting will wear out a synchro. they're like brass clutches, they don't see a lot of wear with normal easy and gentle shifting, but if you're a ham-fisted mAd kWiCk shifting ricer, then you could torch them easily.

what was the car you were driving before?? was it known to have crappy lower gear synchros?? it's usually the case that, especially when slowing to a stop and cycling downward through the gears (a habit i try to discourage in all my stick-driving friends) that 2nd and 1st can be tricky to snick into.

 

I had a 2000 Mitsubishi Eclipse RS. Pretty basic 4 cylinder.

Here's what I think it was. I downshifted alot with this car and when I first got it - it wouldn't let me downshift from 2 to 1 until the car was almost stopped. Well, I forced it a couple of times until it let me do it everytime.

I was just worred that I have some bad habit with normal everyday shifting that was wearing the synchros out.

I had the clutch replaced at 60K miles and I asked the guy to replace the front brakes while he was doing the work. He did, but said the front breaks were in great shape. After 60K miles!
Before I get flamed..... I don't drive like that anymore (and I'm not a ricer)......

 

Fonzie - I had the same 1-2 shift feeling notchy. The service rep placed synthetic in the tranny - made a big difference.

He also mentioned 2 other 8's that got completely stuck in 6th gear also.