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Old 06-24-2001, 03:37 PM   #1
Mantis69
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Exclamation Double Clutch Method

Hey, I've just been reading up on double clutching and still have a few questions:

1) so you only double clutch when down shifting right? (that probly sounds stupid, but i just wanna clear things up)

2) I don't understand how this will save me time when racing, I mean wouldn't it be faster just to stick with the single clutch method? Or is it just to go easy on the transmission? which shouldn't really matter all that much while racing anyway....

3) when would you use the double clutch method? just whenever you down shift? it really doesn't make sense to use it while racing...hmm....

I'd say that's about it for now, any help is much appreciated.
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Old 06-24-2001, 04:38 PM   #2
blaznasn
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yea i would like to kno that too...
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Old 06-24-2001, 06:49 PM   #3
STiTuner
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This is what I understand form the concept.. correct me if I'm wrong anyone:

Double clutching will not make you shift any faster, infact it will make you shift slower when you're first starting out, you'll get quicker as you practice. What it does do it soften the load on the gearbox. It basically spins up the moving parts to get them all closer to the same speed so that when you disengage the clutch there isn't a harsh transition in the speed of the gears. when you try to change speeds of moving gears rapidly with a lot of torque you have a lot of problems.

Sooby's seem to have a problem with mass amounts of torque on the gearbox, especially 2nd gear (from what I've heard). If your just a lightly modded NA car you shouldn't have a probelm but when you start pushing around 250 HP in an RS is good to think about learning how to do it. After about 300 hp or so.. if you plan to use your Stock gearbox its really important.


Brad
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Old 06-25-2001, 12:02 AM   #4
blaznasn
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does double clutching wear out your gear box faster though since your doing it twice?
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Old 06-25-2001, 12:24 PM   #5
skywalker
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Double Clutching IMHO,

1.) It is a important thing to do while racing (but not necessary for poeple who go to just track days) because when you are coming into a corner hot you want to slow down as fast as possible right? Well the best way to do that is to use the breaks only. If you slow down fast by downshifting and use the engine, tranny and breaks you could cause the car to lose control. If you double clutch and break at the same time you are keeping the car at the correct speed throughout the corner. This is good because if you were to just cost around a corner that can also be bad, and cause you to slide.

When racing you are either on the gas 100% WOT or on the break.

2.) Double Clutching down properly can be done as fast as normal shifting. I can't do it quite yet but I learned from someone who could was quite fast at it. A great place to practice is during track days.

3.) I don't believe Double Clutching will wear out your gear box faster, if anything I coudl see it saving your transmission over time, because there will be less stress on it when racing.

This is what I learned from it, if anyone else has a better explanation I am all ears.
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Old 06-25-2001, 12:46 PM   #6
jeffg
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Just a point of clarity. double clutching is to aid in matching engine RPM to transmission rpm. This prevents grinding gears and helps keep the car settled. If you were to just downshift then slower engine speed would slow down the transmission (and wheels) too quickly.

Also, if you have a non-syncro transmission, this is the only way you are going to be able to shift. The purpose of syncromesh is to help match engine speed to transmission speed.
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Old 06-25-2001, 02:16 PM   #7
Clegg
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I have an automatic so it doesnt really apply to me, but I am just currious How do you double clutch a MT ? is it just pressing the clutch down twice?
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Old 06-25-2001, 02:49 PM   #8
Blindeye_03
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Well you brake before the corner and then go about 50% throttle through a turn (autocrossing is all I have done so far), once you hit the apex you go full throttle...So its not Full brakes OR WOT...


When you double clutch you save the life of the synchros...unless youre like me and you grind the poor bastards down ...
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Old 06-25-2001, 02:49 PM   #9
beethoven
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Steps to double-clutching (as I understand it) from 3rd to 2nd:

1) Push clutch in

2) Shift into N

3) Let clutch out

4) blip throttle

5) push clutch in

6) Shift into 2nd

7) Let clutch out

I believe the hole point of this is to make the shift from N to 2nd with the clutch in go smoother (less work for synchro's) and it won't slow the car down and lose as you go into a corner downshifting.

Heel and toe is basically doing this whole thing while breaking (you usually downshift while breaking), and it involves keeping your toe on the break and using your heel to blip the throttle.

Here's a question....couldn't you do this faster by leaving out steps 1 & 3?
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Old 06-25-2001, 03:54 PM   #10
yebokmj
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Default don't let the clutch out at all?

The way I generally shift is just to match the RPM's on the down shift by clutch in shift into lower gear and blipping the throttle till the RPM's match what they will be when I let the clutch out + about 200 RPM, and then let the clutch out. I don't see why you would need the extra step of letting the clutch in and out while going through netrual since when the clutch is in the car is in effect in netural.
Joshua
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Old 06-25-2001, 04:25 PM   #11
Mantis69
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You gotta be in neutral when u blip the throttle so it rev-matches the layshaft! The layshaft speed is equal to the engine speed when the clutch is engaged. The layshaft speed is related to the road speed when a gear is selected. Therefore, when the clutch is engaged AND a gear is selected, the engine speed is related rigidly to the road speed. (Nobody spins the wheels in this schematic outline!) When the clutch is disengaged AND the selector is in Neutral, the layshaft coasts down freely, regardless of either engine or road speed. So you have to be in neutral in order to effect the layshaft with the throttle. I know that's complicated as ****, but trust me it's the reason for lettingout the clutch in neutral.
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