[Z06] Why double clutching saves the Syncros
01-01-2008, 07:10 PM
#1
Drifting
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St. Jude Donor '08-'09
Why double clutching saves the Syncros
I ran across this article on double clutching. I'm glad I double clutch, even though the transmission is fully syncronized.
augydog
Double Clutching, or how to not wear out your syncros.
I seem to have run into quite a few people who are not too clear on the method of double clutching, nor the reasons.
Well the reasons are simple, double clutching will greatly reduce your syncro wear, in fact if you could do it perfectly all the time it would totaly eliminate all syncro wear. In many transaxle cars with worn syncros, double clutching is the only way you can downshift at speed without grinding the gears, and in some really worn out gear boxes it may be the only way you can shift period.
Before we get started lets have a basic review of what goes on in your gearbox. Inside there are two main shafts, lets call them the INPUT shaft and the OUTPUT shaft. The Input shaft spins at the same speed as the engine when the clutch is engaged (that means pedal up). The output shaft is connected solidly to the wheels via some other gears, half shafts, etc. so it spins at what we can call road speed. Get it so far? Input shaft spins at engine speed, output shaft at road speed.
Now when your car is in neutral these two shafts are not connected which is why you can rev the engine up in neutral with the clutch engaged and the car does not go anywhere. In order to make the car move we need to connect these two shafts together, we do that with one of the gears. Lets do that with first gear. With the car at a stop, first gear selected and the clutch DISengaged (pedal down) the shafts are connected but not turning. Remember they can't be turning because the output shaft spins at road speed and the car is stopped. The input shaft is not connected to the engine because the clutch is disengaged.
Now, we will let the clutch out and the car will start moving because the clutch by definition engages and CONNECTS the engine to the Input shaft of the transaxle (via the driveshaft of course. Now the Input shaft is turning at engine RPM and the Output shaft is also turning but a whole lot slower due to the 3.5:1 first gear. That means that when in first the input shaft spins 3.5 times for every one time the output shaft spins.
Now the fun part. We rev our already warmed up car up to 6300 RPM in first and shift into second (just a normal shift, we are not double clutching yet). Now what happens? As we all know this will result in a big drop in engine RPM. However the output shaft continues to spin at the about the same speed because road speed has not changed much during the shift. However what is the input shaft doing? Well, it's spinning a whole lot slower, it just dropped from 6300 rpm to 3600 rpm. So, what caused it to slow down while the clutch was in during the shift? If you guessed SYNCROs your right! The syncro is simply a metal ring that uses friction, like a break to slow down the input shaft to match the speed of the output shaft so the two shafts can be connected by the gear. Every time you shift up a gear the syncro slows the input shaft enabling it to be reconnected to the output shaft. If the syncro is worn and it can't get the shafts to the same speed you will hear that horrible crunch and grinding sound.
Now the more the syncro has to slow down the input shaft the harder its job is. A shift at max RPM causes a much bigger RPM change then a shift into second at 3000 rpm. That means that the syncro will have a much easier time dealing with a 3000 RPM shift then a redline shift. So your car is much less likely to grind with a low RPM shift and will have much less wear on the syncros. Of course it's not fun to drive around at low RPM all the time so we need another way to reduce the load on the syncros, and I am getting to that.
Now lets consider a downshift. A downshift is just the opposite of an upshift meaning engine RPM and Input shaft speed will increase. That means the syncro will need to speed up the input shaft which is a whole lot harder then slowing it down on an upshift. On an up shift the input shaft slows down on its own and the syncro just helps it along but on a down shift the syncro has to speed that shaft up a couple thousand RPM and that's very hard on it. Again a key to minimizing the wear is to shift at the lowest speed possible and only go down one gear at a time. A shift from 5th into second at 40 mph will require the syncro to speed that shaft up a whole lot more then a shift from fourth to third at twenty for example. In fact even if your syncros are new they may give trouble in that 5th to second scenario and won't last long if you do that.
Understand that that was just a very basic non tech description of how the transaxle works but should give enough info to understand double clutching.
Double clutching is a method of reducing the load on the syncros by matching the speed of the input shaft to the output shaft manually during shifts. During an upshift it will be neccesary to manually slow down the input shaft and during a down shift you will need to speed it up.
How do we do this? It's easy, at least in theory although it will take a little practice. First of all lets sit in the car, start the engine and rev the motor with the clutch engaged (pedal up) and the car in neutral. Right now you are speeding up and slowing down the input shaft. Whatever speed the engine is spinning, thats the speed of the input shaft. As soon as you depress the clutch pedal the input shaft will start to slow to a stop since it is no longer connected to the engine. After you depress the pedal wait a moment for the shaft to slow down to make things easier on the first gear syncro which will need to stop the input shaft. Now lets get the car rolling by letting the clutch out and run the car up to max RPM in first. Now we are going to DOUBLE CLUTCH into second gear. First let off of the accelerator press the clutch pedal in and move the shifter to neutral. Let the clutch pedal out and wait a moment. Now engine RPM and consequently Input shaft RPM will begin to drop. Thats exactly what we need. Once the engine is approaching to desired rpm (it's better to do this too early then too late) press in the clutch pedal and select second gear. If you time it right the syncro will only have to slow down the input shaft a couple hundred RPM instead of the 3500 it needs to slow during a normal shift. Even the worst syncro can handle this job so you can understand why this method reduces wear and enables shifting with really worn syncros.
Practice upshifting this way and soon it will be second nature and you will be able to do it really fast with no wear or damage to your transaxle. You will soon learn just how long you have to pause with the clutch out in neutral for the RPM to drop the right amount. It's a little different in each gear about a two second pause for the first to second shift and about one second in all the others except fifth. Shifting into fifth the RPM drop is so minor that double clutching is not needed but if you want too, make the pause as short as you can and it will be about right.
OK, now the hard part the double clutching down shift! This is what separates the amatures from the experts.
Really it's not that bad Lets start with a fifth to third shift at around 60 mph. This is the typical passing scenario. First of all the car at 60 will be at about 3000 rpm in fifth. In third gear it will be turning around 4000rpm at 60, that means we will need a 1000 rpm INCREASE.
We start out by pushing in the clutch pedal, putting the car in neutral and letting the pedal out. Now we can speed up the input shaft to 4000 RPM with the accelerator pedal. Once it is at the required RPM or close enough push the clutch pedal in and select third gear, then let the pedal back out. This really takes a lot of practice but once you get it you can downshift to second or third from and other gear smoothly with no gear crunching or grinding. When practicing this don't get too hung up trying to look at the the tach and match rpm, you just need to blip the throttle to an RPM higher tnen needed and let it settle into the desired range and then select the gear before the input shaft slows down too much.
Good luck and lets preserve those syncros.
augydog
Double Clutching, or how to not wear out your syncros.
I seem to have run into quite a few people who are not too clear on the method of double clutching, nor the reasons.
Well the reasons are simple, double clutching will greatly reduce your syncro wear, in fact if you could do it perfectly all the time it would totaly eliminate all syncro wear. In many transaxle cars with worn syncros, double clutching is the only way you can downshift at speed without grinding the gears, and in some really worn out gear boxes it may be the only way you can shift period.
Before we get started lets have a basic review of what goes on in your gearbox. Inside there are two main shafts, lets call them the INPUT shaft and the OUTPUT shaft. The Input shaft spins at the same speed as the engine when the clutch is engaged (that means pedal up). The output shaft is connected solidly to the wheels via some other gears, half shafts, etc. so it spins at what we can call road speed. Get it so far? Input shaft spins at engine speed, output shaft at road speed.
Now when your car is in neutral these two shafts are not connected which is why you can rev the engine up in neutral with the clutch engaged and the car does not go anywhere. In order to make the car move we need to connect these two shafts together, we do that with one of the gears. Lets do that with first gear. With the car at a stop, first gear selected and the clutch DISengaged (pedal down) the shafts are connected but not turning. Remember they can't be turning because the output shaft spins at road speed and the car is stopped. The input shaft is not connected to the engine because the clutch is disengaged.
Now, we will let the clutch out and the car will start moving because the clutch by definition engages and CONNECTS the engine to the Input shaft of the transaxle (via the driveshaft of course. Now the Input shaft is turning at engine RPM and the Output shaft is also turning but a whole lot slower due to the 3.5:1 first gear. That means that when in first the input shaft spins 3.5 times for every one time the output shaft spins.
Now the fun part. We rev our already warmed up car up to 6300 RPM in first and shift into second (just a normal shift, we are not double clutching yet). Now what happens? As we all know this will result in a big drop in engine RPM. However the output shaft continues to spin at the about the same speed because road speed has not changed much during the shift. However what is the input shaft doing? Well, it's spinning a whole lot slower, it just dropped from 6300 rpm to 3600 rpm. So, what caused it to slow down while the clutch was in during the shift? If you guessed SYNCROs your right! The syncro is simply a metal ring that uses friction, like a break to slow down the input shaft to match the speed of the output shaft so the two shafts can be connected by the gear. Every time you shift up a gear the syncro slows the input shaft enabling it to be reconnected to the output shaft. If the syncro is worn and it can't get the shafts to the same speed you will hear that horrible crunch and grinding sound.
Now the more the syncro has to slow down the input shaft the harder its job is. A shift at max RPM causes a much bigger RPM change then a shift into second at 3000 rpm. That means that the syncro will have a much easier time dealing with a 3000 RPM shift then a redline shift. So your car is much less likely to grind with a low RPM shift and will have much less wear on the syncros. Of course it's not fun to drive around at low RPM all the time so we need another way to reduce the load on the syncros, and I am getting to that.
Now lets consider a downshift. A downshift is just the opposite of an upshift meaning engine RPM and Input shaft speed will increase. That means the syncro will need to speed up the input shaft which is a whole lot harder then slowing it down on an upshift. On an up shift the input shaft slows down on its own and the syncro just helps it along but on a down shift the syncro has to speed that shaft up a couple thousand RPM and that's very hard on it. Again a key to minimizing the wear is to shift at the lowest speed possible and only go down one gear at a time. A shift from 5th into second at 40 mph will require the syncro to speed that shaft up a whole lot more then a shift from fourth to third at twenty for example. In fact even if your syncros are new they may give trouble in that 5th to second scenario and won't last long if you do that.
Understand that that was just a very basic non tech description of how the transaxle works but should give enough info to understand double clutching.
Double clutching is a method of reducing the load on the syncros by matching the speed of the input shaft to the output shaft manually during shifts. During an upshift it will be neccesary to manually slow down the input shaft and during a down shift you will need to speed it up.
How do we do this? It's easy, at least in theory although it will take a little practice. First of all lets sit in the car, start the engine and rev the motor with the clutch engaged (pedal up) and the car in neutral. Right now you are speeding up and slowing down the input shaft. Whatever speed the engine is spinning, thats the speed of the input shaft. As soon as you depress the clutch pedal the input shaft will start to slow to a stop since it is no longer connected to the engine. After you depress the pedal wait a moment for the shaft to slow down to make things easier on the first gear syncro which will need to stop the input shaft. Now lets get the car rolling by letting the clutch out and run the car up to max RPM in first. Now we are going to DOUBLE CLUTCH into second gear. First let off of the accelerator press the clutch pedal in and move the shifter to neutral. Let the clutch pedal out and wait a moment. Now engine RPM and consequently Input shaft RPM will begin to drop. Thats exactly what we need. Once the engine is approaching to desired rpm (it's better to do this too early then too late) press in the clutch pedal and select second gear. If you time it right the syncro will only have to slow down the input shaft a couple hundred RPM instead of the 3500 it needs to slow during a normal shift. Even the worst syncro can handle this job so you can understand why this method reduces wear and enables shifting with really worn syncros.
Practice upshifting this way and soon it will be second nature and you will be able to do it really fast with no wear or damage to your transaxle. You will soon learn just how long you have to pause with the clutch out in neutral for the RPM to drop the right amount. It's a little different in each gear about a two second pause for the first to second shift and about one second in all the others except fifth. Shifting into fifth the RPM drop is so minor that double clutching is not needed but if you want too, make the pause as short as you can and it will be about right.
OK, now the hard part the double clutching down shift! This is what separates the amatures from the experts.
Really it's not that bad Lets start with a fifth to third shift at around 60 mph. This is the typical passing scenario. First of all the car at 60 will be at about 3000 rpm in fifth. In third gear it will be turning around 4000rpm at 60, that means we will need a 1000 rpm INCREASE.
We start out by pushing in the clutch pedal, putting the car in neutral and letting the pedal out. Now we can speed up the input shaft to 4000 RPM with the accelerator pedal. Once it is at the required RPM or close enough push the clutch pedal in and select third gear, then let the pedal back out. This really takes a lot of practice but once you get it you can downshift to second or third from and other gear smoothly with no gear crunching or grinding. When practicing this don't get too hung up trying to look at the the tach and match rpm, you just need to blip the throttle to an RPM higher tnen needed and let it settle into the desired range and then select the gear before the input shaft slows down too much.
Good luck and lets preserve those syncros.
If you have ever driven a trans. with no synchros, this will be second nature.
01-01-2008, 11:17 PM
#3
Safety Car
Old school, and it works.
Grant
01-02-2008, 12:21 AM
#5
but, whats the difference between a fully depressed clutch, and putting the gear in N, aren't both disengaging the gine from the wheels? I mean keep your leg on the clutch until the RPM drops on upshifts and reach the desired speed to match road/engine speeds together, and the opposite for downshifts, which is when you need to blip the throttle.
To answer my question, whats the difference between having a fully depressed clutch at 1st gear, and a having the gear at Neutral, sounds the same to me.
To answer my question, whats the difference between having a fully depressed clutch at 1st gear, and a having the gear at Neutral, sounds the same to me.
01-02-2008, 02:43 AM
#7
Melting Slicks
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having the clutch disengaged and the trans in first gear means that the input shaft is spinning at "road speed" x first gear ratio. having the clutch engaged and the trans in neutral means that the input shaft is spinning at engine rpm. the syncros still have to do work when you shift into gear.
if you only single clutch on downshift, you are "only" matching engine rpm to road speed, to avoid "locking up" the rear wheels when you engage the clutch. the synchros still have to match input shaft speed to output shaft speed (when you engage the gear). when you double clutch you are bringing up the input shaft speed so that the synchro has less work to do.
if you only single clutch on downshift, you are "only" matching engine rpm to road speed, to avoid "locking up" the rear wheels when you engage the clutch. the synchros still have to match input shaft speed to output shaft speed (when you engage the gear). when you double clutch you are bringing up the input shaft speed so that the synchro has less work to do.
01-02-2008, 02:45 AM
#8
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but, whats the difference between a fully depressed clutch, and putting the gear in N, aren't both disengaging the gine from the wheels? I mean keep your leg on the clutch until the RPM drops on upshifts and reach the desired speed to match road/engine speeds together, and the opposite for downshifts, which is when you need to blip the throttle.
To answer my question, whats the difference between having a fully depressed clutch at 1st gear, and a having the gear at Neutral, sounds the same to me.
To answer my question, whats the difference between having a fully depressed clutch at 1st gear, and a having the gear at Neutral, sounds the same to me.
Last edited by O7zeeO6; 01-02-2008 at 02:48 AM.
01-02-2008, 02:46 AM
#9
OK, here are my 3 scenarios, and well need a data-log tool to verify this, how can the syncros be slowing the car down while the clutch is STILL fully depressed, engine is disconnected from the wheels?!?
1- you depress the clutch and downshift from 5th to 2nd, keep the clutch depressed, and measure deceleration rate.
2- You depress the Clutch and leave the gear in 5th, and calculate the deceleration rate.
3- You depress the clutch, move the gear into Neutral, and measure deceleration rate.
Since the engine is diconnected from the wheels, all three scenarios should lead to the same deceleration rate.
Edit: I dont even know what I am saying, as I am not familiar with double clutching.
1- you depress the clutch and downshift from 5th to 2nd, keep the clutch depressed, and measure deceleration rate.
2- You depress the Clutch and leave the gear in 5th, and calculate the deceleration rate.
3- You depress the clutch, move the gear into Neutral, and measure deceleration rate.
Since the engine is diconnected from the wheels, all three scenarios should lead to the same deceleration rate.
Edit: I dont even know what I am saying, as I am not familiar with double clutching.
Last edited by ayousef; 01-02-2008 at 02:51 AM.
01-02-2008, 03:02 AM
#10
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OK, here are my 3 scenarios, and well need a data-log tool to verify this, how can the syncros be slowing the car down while the clutch is STILL fully depressed, engine is disconnected from the wheels?!?
1- you depress the clutch and downshift from 5th to 2nd, keep the clutch depressed, and measure deceleration rate.
2- You depress the Clutch and leave the gear in 5th, and calculate the deceleration rate.
3- You depress the clutch, move the gear into Neutral, and measure deceleration rate.
Since the engine is diconnected from the wheels, all three scenarios should lead to the same deceleration rate.
Edit: I dont even know what I am saying, as I am not familiar with double clutching.
1- you depress the clutch and downshift from 5th to 2nd, keep the clutch depressed, and measure deceleration rate.
2- You depress the Clutch and leave the gear in 5th, and calculate the deceleration rate.
3- You depress the clutch, move the gear into Neutral, and measure deceleration rate.
Since the engine is diconnected from the wheels, all three scenarios should lead to the same deceleration rate.
Edit: I dont even know what I am saying, as I am not familiar with double clutching.
In the scenario you mentioned above, the input shaft needs to be sped up not slowed down to match the higher speed of the output shaft.
I think a diagram might help in understanding this. I don't fully understand the physics of the entire thing either.
01-02-2008, 05:21 AM
#11
Melting Slicks
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it helps to understand it if you know how a manual trans is put together mechanically.
there is an input shaft with gears on it. those gears have external "teeth" and internal teeth. the external teeth (of all gears) mesh with the external teeth of the gears on the output shaft. ie, all input and output gears are always meshed, and all input gears always spin at output shaft speed x gear ratio. but the input shaft gears are not fixed to the input shaft itself. that is where the internal teeth come into play.
the shifter moves a fork which is connected to the input shaft, and engages the internal teeth on the selected gear. this locks the selected gear to the input shaft and now the input shaft is spinning at output shaft speed x gear ratio. in order to engage the teeth without grinding, the input shaft must already be spinning at output speed x gear ratio. the synchros do this job by having a friction surface.
when you double clutch, the first blip is with the clutch engaged and the trans in neutral. since the clutch is engaged the input shaft is spinning at engine speed (but since no input gears are engaged you are not affecting the output shaft). blipping then raises the speed of the input shaft which is also the job of the synchros but you can see since the synchro is a friction component it must wear so using the blip to do this yourself saves wear. now when you select a gear the synchro will just slow the input shaft down (instead of speeding it up) which is apparently much less work. plus you'll (supposed to) be closer to the final input shaft speed as well, again less work for the synchros.
the second blip is with the clutch disengaged and after you have selected a gear. this blip is to bring the engine speed up to the input shaft speed, to avoid rear wheel lockup.
http://en.wikipedia.org/wiki/Manual_transmission
http://en.wikipedia.org/wiki/Double_clutch
i don't really see the point of double clutching with a synchro transmission. unless someone can present quantitative info on synchro wear ...
01-02-2008, 06:51 AM
#12
your reasoning is correct. the synchros are not slowing the car down!
it helps to understand it if you know how a manual trans is put together mechanically.
there is an input shaft with gears on it. those gears have external "teeth" and internal teeth. the external teeth (of all gears) mesh with the external teeth of the gears on the output shaft. ie, all input and output gears are always meshed, and all input gears always spin at output shaft speed x gear ratio. but the input shaft gears are not fixed to the input shaft itself. that is where the internal teeth come into play.
the shifter moves a fork which is connected to the input shaft, and engages the internal teeth on the selected gear. this locks the selected gear to the input shaft and now the input shaft is spinning at output shaft speed x gear ratio. in order to engage the teeth without grinding, the input shaft must already be spinning at output speed x gear ratio. the synchros do this job by having a friction surface.
when you double clutch, the first blip is with the clutch engaged and the trans in neutral. since the clutch is engaged the input shaft is spinning at engine speed (but since no input gears are engaged you are not affecting the output shaft). blipping then raises the speed of the input shaft which is also the job of the synchros but you can see since the synchro is a friction component it must wear so using the blip to do this yourself saves wear. now when you select a gear the synchro will just slow the input shaft down (instead of speeding it up) which is apparently much less work. plus you'll (supposed to) be closer to the final input shaft speed as well, again less work for the synchros.
the second blip is with the clutch disengaged and after you have selected a gear. this blip is to bring the engine speed up to the input shaft speed, to avoid rear wheel lockup.
http://en.wikipedia.org/wiki/Manual_transmission
http://en.wikipedia.org/wiki/Double_clutch
i don't really see the point of double clutching with a synchro transmission. unless someone can present quantitative info on synchro wear ...
it helps to understand it if you know how a manual trans is put together mechanically.
there is an input shaft with gears on it. those gears have external "teeth" and internal teeth. the external teeth (of all gears) mesh with the external teeth of the gears on the output shaft. ie, all input and output gears are always meshed, and all input gears always spin at output shaft speed x gear ratio. but the input shaft gears are not fixed to the input shaft itself. that is where the internal teeth come into play.
the shifter moves a fork which is connected to the input shaft, and engages the internal teeth on the selected gear. this locks the selected gear to the input shaft and now the input shaft is spinning at output shaft speed x gear ratio. in order to engage the teeth without grinding, the input shaft must already be spinning at output speed x gear ratio. the synchros do this job by having a friction surface.
when you double clutch, the first blip is with the clutch engaged and the trans in neutral. since the clutch is engaged the input shaft is spinning at engine speed (but since no input gears are engaged you are not affecting the output shaft). blipping then raises the speed of the input shaft which is also the job of the synchros but you can see since the synchro is a friction component it must wear so using the blip to do this yourself saves wear. now when you select a gear the synchro will just slow the input shaft down (instead of speeding it up) which is apparently much less work. plus you'll (supposed to) be closer to the final input shaft speed as well, again less work for the synchros.
the second blip is with the clutch disengaged and after you have selected a gear. this blip is to bring the engine speed up to the input shaft speed, to avoid rear wheel lockup.
http://en.wikipedia.org/wiki/Manual_transmission
http://en.wikipedia.org/wiki/Double_clutch
i don't really see the point of double clutching with a synchro transmission. unless someone can present quantitative info on synchro wear ...
01-02-2008, 07:55 AM
#13
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Unless you are doing some very hard racing one does not need to double clutch.
Here is a heel-n-toe double clutch video in a Speed World Touring car on the Long Beach circuit Heel-N--Tie_ Double Clutch Video
Here is a heel-n-toe double clutch video in a Speed World Touring car on the Long Beach circuit Heel-N--Tie_ Double Clutch Video
01-02-2008, 08:07 AM
#14
Melting Slicks
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Wow..I understand the importance of rev matching on downshifting, but this just seems a bit too extreme on a modern day manual tranny on a performance supercar.
Also the new TR-6060 tranny on the 08 C6/Z06 have double the amount of syncros as the T-56.
Double clutching would just loose too much time if your trying to drive in a performance manner.
Also the new TR-6060 tranny on the 08 C6/Z06 have double the amount of syncros as the T-56.
Double clutching would just loose too much time if your trying to drive in a performance manner.
01-02-2008, 08:11 AM
#15
Melting Slicks
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Unless you are doing some very hard racing one does not need to double clutch.
Here is a heel-n-toe double clutch video in a Speed World Touring car on the Long Beach circuit Heel-N--Tie_ Double Clutch Video
Here is a heel-n-toe double clutch video in a Speed World Touring car on the Long Beach circuit Heel-N--Tie_ Double Clutch Video
01-02-2008, 08:19 AM
#16
Unless you are doing some very hard racing one does not need to double clutch.
Here is a heel-n-toe double clutch video in a Speed World Touring car on the Long Beach circuit Heel-N--Tie_ Double Clutch Video
Here is a heel-n-toe double clutch video in a Speed World Touring car on the Long Beach circuit Heel-N--Tie_ Double Clutch Video
01-02-2008, 08:30 AM
#19
Burning Brakes
That guy's double clutching on the down shifts only.
Not needed on our modern transmissions. I do it from time to time for practice more than anything but to double clutch to "save your syncros" is ridiculous. Seriously, unless you do something seriously wrong those syncros will easily last 100K miles. What's the chances you'll have drive your car 100K miles? Worst case they wear out and you replace the syncros. They're a maintenance part in my opinion.
You can down shift more to save your brakes, never rev over 4,000 RPMs to save your valve train... never take the car out of the garage to save your tires. What's the point? Do it for practice if anything.
Not needed on our modern transmissions. I do it from time to time for practice more than anything but to double clutch to "save your syncros" is ridiculous. Seriously, unless you do something seriously wrong those syncros will easily last 100K miles. What's the chances you'll have drive your car 100K miles? Worst case they wear out and you replace the syncros. They're a maintenance part in my opinion.
You can down shift more to save your brakes, never rev over 4,000 RPMs to save your valve train... never take the car out of the garage to save your tires. What's the point? Do it for practice if anything.
01-02-2008, 08:55 AM
#20
Melting Slicks
waste of time in our z06's...or any modern trans....thats why sychro's came about in the first place...to eliminate double clutching...so why go backwards?...