Smooth gear changes

Author
Discussion

baboon

Original Poster:

40 posts

223 months

Thursday 29th September 2005
quotequote all
During relatively enthusiastic in my porsche 996tt driving i find the gear change between 1st and 2nd very jerky when letting off the throttle fully before disengaging the clutch because the enginge slows too much too fast. I have now started keeping a light throttle on to maintain enough revs to keep the change smooth.
Usually i change at about 3500-4000RPM but will usually use the throttle to keep the engine at about 2500RPM during the gear change to try and match the wheel speed in 2nd gear.
Is this technique ok for the engine and clutch because i have read many conflicting articles on the web, some saying you HAVE to take off the gas completely and others saying you can keep it on.
What is the best method for preserving the clutch?
Thanks for the help, i'm very scared of hurting my car and really appreciate any advise!!!!!

r988

7,495 posts

229 months

Thursday 29th September 2005
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I'd stay off the gas to save your clutch. Try pulling the gear out, getting off the gas, then dipping the clutch slightly, it should all happen in roughly that order and almost simultaneously, I used to use this technique for fast/smooth changes when I had a car, worked well enough.

As a side note a lot of newish cars actually have a throttle delay thing that keeps the revs up for a moment when changing gears, I actually find that feature incredibly annoying though.

There are loads of more knowable 996 Turbo drivers on the M5 forum who can probably help with the specifics of your type of car though, might be worth taking a look round.
www.m5board.com/vbulletin/forumdisplay.php?f=26

Don

28,377 posts

284 months

Thursday 29th September 2005
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The very best method of preserving your clutch is to use it as little as possible!

1) When in queues try to get into first quickly and stay in first as long as possible. Leave a big gap in front so you can "soak up" stop start.

2) Don't do tyre smoking getaways.

3) Minimise the number of gear changes by block shifting, particularly on downshifts.

4) Match revs on upshifts and downshifts.

i.e. In a mate's Cerbera I found the revs would fall to tickover the moment your foot went on the clutch if you didn't maintain those revs with the accelerator. So - on upshifts - I would dip the clutch, immediately adjust my accelerator foot to the desired revs for the new gear given the current road speed, pop it into the new gear and then lift the clutch.

Which, it sounds to me, is exactly what you are doing!

You'll KNOW if you are getting it right. If the gear change is silky smooth with no perceptible "drag" or "push" to the car as the clutch comes up then you got the rev matching right and will have done the least possible wear to the clutch plate.

And its comfortable!

Don't forget to be doing the same on downshifts. In your 996 its beautifully set up for heel and toe - so you can match revs whilst braking. If the one-foot-two-pedals dance isn't something you can or want to do you can do the same thing IAM stylee by braking first, getting off the brakes and onto the accelerator, dipping the clutch, matching revs and getting the new gear and then lifting the clutch.

The principle of what you are doing sounds right to me!

Fat Audi 80

2,403 posts

251 months

Friday 30th September 2005
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If it feels smooth then it is!

Mechanical sympathy is all about being smooth. If you are coming off the clutch quickly with no discernable jerk or drag than it sounds spot on to me.

Clutch slippage is what will quickly destroy the clutch friction surface whether going up or down gears and especially if slipped a lot pulling away.

I always make sure the clutch is fully disengaged before applying full throttle. (Unless I am planning a really swift getaway... )

andy_s

19,400 posts

259 months

Tuesday 4th October 2005
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..and of course, a sustained gear change keeps the car stable and neutral, just how you want it.....

(lol - just read this back and sound like an ar*e - you know what I mean !)

carl_w

9,180 posts

258 months

Wednesday 5th October 2005
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Don said:
i.e. In a mate's Cerbera I found the revs would fall to tickover the moment your foot went on the clutch if you didn't maintain those revs with the accelerator.
Shift up quicker then!