Clutch and Launching
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Newbie
Joined: Feb 2007
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Clutch and Launching
Ok most of us are to afraid to launch our evo's because we don't want to break anything on a $30,000 car. So with an aftermarket clutch how abusive can we be then? Instead of getting 30 launches or whatever out of the stock clutch. How many can you roughly get out of an aftermarket clutch? Just wondering .....
If you have a good understanding of the clutch system on the Evo, you can make good use of it ... even with the stock disc.
The stock clutch line has a restrictor built in that exists to protect the drivetrain from excessive shock. this is the reason a lot of people claim that the stock clutch sucks. What happens is that if you slip the clutch like you are used to doing in other vehicles, this restrictor slips the clutch even more and the result is excessive wear.
To "fix" this issues, many people remove the stock restrictor which allows the clutch to act more like the clutch we are all used to. However, this is technically removing a safety fallback that is protecting your drivetrain components.
My solution is to adjust your launch technique to compensate for the additional slip given by the restrictor. You can launch HARD on the stock clutch. I have about 35 launches on my stock clutch so far ... all at around 10-13 psi. My clutch does not slip, even at 26 psi peak boost. I have pulled off a 1.62 60' and consistently pull 1.7x 60' times.
the thing is that if you try to launch while afraid of breaking something, you will over slip the clutch and kill it very quickly. Drivetrain damage is usually caused by the initial shock of a launch when there is a little slack in the drivetrain components. The slack is all let out at once and the gears slam in to each other. When launching, ease out until the slack is gone and then drop the pedal FAST and let the restrictor slip for you.
The stock clutch line has a restrictor built in that exists to protect the drivetrain from excessive shock. this is the reason a lot of people claim that the stock clutch sucks. What happens is that if you slip the clutch like you are used to doing in other vehicles, this restrictor slips the clutch even more and the result is excessive wear.
To "fix" this issues, many people remove the stock restrictor which allows the clutch to act more like the clutch we are all used to. However, this is technically removing a safety fallback that is protecting your drivetrain components.
My solution is to adjust your launch technique to compensate for the additional slip given by the restrictor. You can launch HARD on the stock clutch. I have about 35 launches on my stock clutch so far ... all at around 10-13 psi. My clutch does not slip, even at 26 psi peak boost. I have pulled off a 1.62 60' and consistently pull 1.7x 60' times.
the thing is that if you try to launch while afraid of breaking something, you will over slip the clutch and kill it very quickly. Drivetrain damage is usually caused by the initial shock of a launch when there is a little slack in the drivetrain components. The slack is all let out at once and the gears slam in to each other. When launching, ease out until the slack is gone and then drop the pedal FAST and let the restrictor slip for you.
Evolving Member
Joined: Oct 2006
Posts: 227
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From: MA
I still haven't fully tested out the stock clutch, I haven't launched hard yet. So far I've just babied it off the line and have most of my fun in 2nd and 3rd. I can barely afford the car right now so I'm desperately trying not to break anything yet. I think that the stock clutch is fine so far, I guess I'll really find out once I try a hard launch and can afford any repairs. 
If you have a good understanding of the clutch system on the Evo, you can make good use of it ... even with the stock disc.
The stock clutch line has a restrictor built in that exists to protect the drivetrain from excessive shock. this is the reason a lot of people claim that the stock clutch sucks. What happens is that if you slip the clutch like you are used to doing in other vehicles, this restrictor slips the clutch even more and the result is excessive wear.
To "fix" this issues, many people remove the stock restrictor which allows the clutch to act more like the clutch we are all used to. However, this is technically removing a safety fallback that is protecting your drivetrain components.
My solution is to adjust your launch technique to compensate for the additional slip given by the restrictor. You can launch HARD on the stock clutch. I have about 35 launches on my stock clutch so far ... all at around 10-13 psi. My clutch does not slip, even at 26 psi peak boost. I have pulled off a 1.62 60' and consistently pull 1.7x 60' times.
the thing is that if you try to launch while afraid of breaking something, you will over slip the clutch and kill it very quickly. Drivetrain damage is usually caused by the initial shock of a launch when there is a little slack in the drivetrain components. The slack is all let out at once and the gears slam in to each other. When launching, ease out until the slack is gone and then drop the pedal FAST and let the restrictor slip for you.
The stock clutch line has a restrictor built in that exists to protect the drivetrain from excessive shock. this is the reason a lot of people claim that the stock clutch sucks. What happens is that if you slip the clutch like you are used to doing in other vehicles, this restrictor slips the clutch even more and the result is excessive wear.
To "fix" this issues, many people remove the stock restrictor which allows the clutch to act more like the clutch we are all used to. However, this is technically removing a safety fallback that is protecting your drivetrain components.
My solution is to adjust your launch technique to compensate for the additional slip given by the restrictor. You can launch HARD on the stock clutch. I have about 35 launches on my stock clutch so far ... all at around 10-13 psi. My clutch does not slip, even at 26 psi peak boost. I have pulled off a 1.62 60' and consistently pull 1.7x 60' times.
the thing is that if you try to launch while afraid of breaking something, you will over slip the clutch and kill it very quickly. Drivetrain damage is usually caused by the initial shock of a launch when there is a little slack in the drivetrain components. The slack is all let out at once and the gears slam in to each other. When launching, ease out until the slack is gone and then drop the pedal FAST and let the restrictor slip for you.
Newbie
Joined: Aug 2004
Posts: 37
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From: Socal
really? what are you using for boost control?
I have my standing rev limit set at 59XX rpm and it holds at 6k even and it builds and holds 10psi of boost... I control everything with ecuflash and tuning with evoscan and an safcII
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5750 RPM. I've dropped the timing to 6º in the 120% load column and 7º in the 140% and 160% load columns (5500 and 6000 RPM rows). I control boost with the ECU and the stock BCS.
+1 on what TouringBubble said. Nick @ DTM taught me this method and I watched him pull a 1.59 and a 1.61 in my car on stock clutch/tires/pressure. I've et to try it on the track but I did it twice on the street and didn't smell clutch at all.
You've brought up a good point ... if you smell the clutch, you are doing something wrong! I know it's hard with all of the horror stories out there, but you have to be aggressive when launching. Don't just slide your foot off the side of the pedal, but move quick.
well i have ecuflash, a tune by mellon on just the fuel maps and timing, nothing was changed in the two step "controls" persay...but i'm only gettin 5 - 7 boost on the two step. at 5500
Yeah, I don't think Chris usually changes the timing for the limiter for his basic tunes. I'm sure you could request it though. You could also check the post I linked above and do it yourself.
Evolving Member
Joined: May 2007
Posts: 123
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From: Sacramento
You've brought up a good point ... if you smell the clutch, you are doing something wrong! I know it's hard with all of the horror stories out there, but you have to be aggressive when launching. Don't just slide your foot off the side of the pedal, but move quick.
- When we use the launch limiter, are we full throttling the gas pedal?
- When you say dont just slide your foot off the side of the pedal, are you referring to dropping the clutch completely? So once we feel the clutch grabbing, then can we drop the clutch?
Thanks!
By the way.. What the hell does clutch smell like? My friend says he can smell clutch, but none of us do these hard launches..
Last edited by MaxKanisha; Sep 6, 2007 at 10:22 AM.