Clutch Preload 101 how-to
May 24, 2011, 06:06 PM
#17
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That's not exactly the same. Pre-loading will put a load against the motor and drivetrain. Results are more boost is built up since there is a load against the motor. Drivetrain is loaded up ready to rock and roll. All this without the car even moving. Slipping the clutch out slowly like you are describing does not pre-load the drivetrain until the car moves. And this will result in poor 60ft's from the slow clutch release. Effective sure, but not ideal for good 60ft's.
With twin disc clutches and triples it's a bit tougher to just "let the clutch out slow" like you say. They tend to grab extremely quick and hard. So there's not a whole lot of slipping going on. Pre-loading makes a world of difference when it comes to say a QM twin disc clutch..
I've cut 1.32 60ft's using the pre-load method in my talon using a CNC hand brake. With the CNC hand brake I can pre-load the clutch heavily on the line, so when I let go, it takes off like a automatic with a trans brake lol.
I will see if I can find a video of my talon using the CNC hand brake.
May 24, 2011, 06:16 PM
#19
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As I explained on page one to someone else, it's not dumping it if your already slipping the clutch when the e-brake is up. It's just somthing you will have to try and get a feel for it. But basicly you pre-load the clutch where it starts to grab, pull the e-brake up to hold the car from moving, then when your ready to go, let the e-brake down, car will start moving faster then you would think, by the time you let the clutch fully out, your already 20feet out. That's not considered "dumping the clutch" Dumping the clutch would be clutch all the way in, then just completely letting the clutch go when your ready. That's dumping it.
The 1st time people do it, it's one of those deals where after you do it you say to yourself "ahhhhhh I get it now!!" lol
Last edited by evodude32; May 24, 2011 at 06:18 PM.
May 24, 2011, 06:19 PM
#20
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Oh alright I got you, Ive been to the track twice and I preload using the same method but I try and slip the clutch because I was scared to go home with a broken tcase. But what your saying makes sense and now I c why I only got a 1.94 60 ft.
May 24, 2011, 06:22 PM
#22
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Ok, in this video you can hear my car how it leaves, it sounds close to an auto through 1st gear. You will see I start to bring the car up on the 2step in the pre-stage, then I hold the hand brake back, bring the clutch out to the point it starts to barely grab, then you can see I use the hand brake to bump into the full stage beam.. Once ready, I just let the hand brake go and walla, money shot!
http://www.youtube.com/watch?v=1CGEpRTA104
As soon as the car moved, my foot was completely off the clutch. The car left right at the 2step RPM and held that RPM 80% of 1st gear. If you pre-load correctly, the car will leave like an automatic transmission car does.
http://www.youtube.com/watch?v=1CGEpRTA104
As soon as the car moved, my foot was completely off the clutch. The car left right at the 2step RPM and held that RPM 80% of 1st gear. If you pre-load correctly, the car will leave like an automatic transmission car does.
Last edited by evodude32; May 24, 2011 at 06:27 PM.
May 24, 2011, 06:31 PM
#24
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I need to dig up the slip, but if I remember right, it was either a 1.32 60ft. or 1.38 60ft. I can't remember, that was 3 years ago lol. But my 60ft's were always consistent using the pre-load method. Not to mention I would kill people on a pro tree cause I was ready in the pre-stage since I was on the 2step while the other cars didn't get up on the 2step until they fully staged. So all I had to do is let go of the hand brake when I seen the light drop instead of fiddle farting around with the clutch and gas lol. Alot of my wins where done right there on the tree.
May 24, 2011, 07:08 PM
#25
That was a nice launch...wish i could do that..so i guess dont slip the clutch when it turns green just let go of the clutch....cnt wait to see the vid ur gonna do on the evo
May 25, 2011, 04:03 AM
#29
When you are about to pre-stage you pull up the e-break push down the clutch get to your 2-step is barely on. Bump the e-break down a little while slipping the clutch to get to the pre-stage light to come on. Now where you had the clutch at while staging kept it their while having the e-break all the way up. Everything is per-loaded and any ready to rock. Is this what you mean? I see where a CNC would be easier for this.
May 25, 2011, 04:50 AM
#30
My problem with saying I'm gonna practice this is, either do it right, or do it even slightly wrong and toast the clutch. So I'm afraid to even try to practice launching. But of course I'm still on stock clutch, so maybe I'll have more confidence in a beefier unit.