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Discussion Starter · #1 ·

I tried screwing around and doing some burnouts with my 8.1/6spd and was shocked that it would slip the clutch instead of burn tires! I've towed 14k no issues, so I was not expecting clutch problems.

However, I did smoke a Beretta clutch in one day at the drag strip before - because of the GM engineered restriction in the slave line (to put a band aid on weak axles). I read that GM did the same with LS1/6spd Camaros too and their wimpy 7.5 10-bolts. I replaced the stock slave line from my Beretta with -3AN hose and never had a single problem pounding the snot out of it in the following 10 years.

So rather than dive in to a clutch replacement job, I figured I'd investigate the hydraulic system of the truck. I did a quick road test and punched the throttle from a slow roll while in gear...and it blasted the tires off as it should.

And I found that the quick connect design creates a fluid restriction that does the same thing - slowing clutch engagement rather than snapping the pressure plate on the disc. So I eliminated the quick connect by running the slave hose straight to the master cylinder. I had to scooch it up the frame brackets a little bit, but it reached fine.


Great success! Happy burnouts all day. And it was free and easy. I'm happy with that.
 

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So if those two little inserts are slowing down engagement, are they slowing down the equalization between the fluid in the lines that are on both sides of them? Would that would mean that:
  • Clutch engagement would be quicker. - At high rpms, your rear end would lock, and engagement would be a pretty harder jolt on the driveline.
  • Clutch release would be quicker - resulting in a firmer pedal "feel". - In GM's "wisdom", I wonder if this is the reason because it was a problem for some people.




Is this more or less the same thing as the "drill mod" they have for the LS1? (I couldn't find a link, but) I remember it being where they drill into a metal, (I think) connector or restriction valve to improve the flow rate. This looks like we have the plastic component version of that.
Here's something I found "During rapid shifting in short periods of time, such as drag racing, the fluid from the master, through that line, down to the slave cylinder due to that restriction impedes flow BACK to the master between shifts. It usually rears it's ugly head in the 2-3 shift but more likely your 3-4 shift due to lack of hydraulic pressure from the fluid being trapped in the line."
I have had that problem before, and think that's why my trans has had trouble.



I think I'm going to do this as soon as I get a chance.
 

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Discussion Starter · #3 ·
It's essentially the same thing as the "drill mod".

Yes, it makes the clutch engage quicker. It wouldn't make any difference with like a G80 rear locker, but it will shock the driveline more now...but only if you dump the clutch. Regular driving I see no difference.

Fluid is returned to the master cylinder by the pressure from the pressure plate. So this restriction keeps pressure in the slave hose longer because the fluid can't flow fast enough.

In my Beretta the clutch pedal was actually noticeably lighter after the mod. I didn't notice much of a difference with the truck. And with the Beretta I had to kinda re-learn how to drive it smooth cause it could be jerky on quick shifts. But that becomes muscle memory after a while and I absolutely pounded on that thing for 10 years with zero clutch trouble - even on drag slicks at the track.

It's well worth the minimal effort.
 
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