Blitz Active twin disc slipping!!!!

[JN1AS4]

I have a mildly built sr20det with basic bolt-ons(gt2871r, 600cc, HKS 272, z32 maf, Enthalpy ecu, FMIC, etc.) mated with a Blitz Active twin disc clutch. I took a trip to the drag strip over the weekend on street tires. When launching it I had to slip the clutch to help with wheel spin. My very first pass went flawlessly. But during my second pass I noticed my rpms slightly fluctuating in 3rd gear, so I got out of it and just coasted the rest of the track. I then parked it for 1.5hr to allow it to cool down. Then I went for my third pass of the day. After slipping the clutch out of the hole once again it decided to start slipping in 3rd gear again. So I parked the car for about another hour to allow some cool down time before heading home which was a 2hr drive from the track. The clutch has survived hundreds of hwy pulls/donuts over the past 4 years but for some reason it can't take drag racing. I've clutch kicked and everything else since this weekend and its been performing as it should. I understand that launching a car creates more drivetrain shock than anything else but i figured that a clutch that's so overrated for my setup shouldn't be an issue, especially on street tires. I had this same issue with the car last year this time. So I replaced the oem slave cylinder with a aftermarket(local parts store) slave cylinder thinking that was my problem. But the same problem has returned. I was wondering if a Nismo slave cylinder is needed or am I potentially suffering from worn disc and need to rebuild my clutch. The system was properly bled and I've checked the fluid level so that isn't the problem. Any advice on this subject would be greatly appreciated.

[koukistylejdm]

looks like its on its way. and correct me if iam wrong but let slip that kind of clutch to launch sound like a real bad idea

[Mikester]

^^Yes...

I don't have experience with Blitz clutches, but even my OS Giken twin plate will get pissed at me for trying to slip it into a launch... It's dampened for daily driving purposes; but is supposed to be treated like a whore otherwise.

This will help you on the strip:

1. Reach launch rpm

2. Drop clutch

3. Remove foot from clutch pedal completely

4. FEATHER THROTTLE (not clutch lol) to get wheels to hook up

5. Enjoy fun ride down the track ;)

[jr_ss]

Time to replace the clutch man. You said it yourself, you've beat the piss out of it for over 4yrs, it's near dead.

[JN1AS4]

Time to replace the clutch man. You said it yourself, you've beat the piss out of it for over 4yrs, it's near dead.

I haven't totally beat the hell out of it for the past 4yrs. It has 12k miles on it max. And those weren't ALL hard miles. I've learned my lesson with trying to slip it while launching. I'm going to proceed with dumping it like stated above.

[cotbu]

4 years on a clutch in my sr20 powered 240sx? I can only dream of it!

[Mikester]

I haven't totally beat the hell out of it for the past 4yrs. It has 12k miles on it max. And those weren't ALL hard miles. I've learned my lesson with trying to slip it while launching. I'm going to proceed with dumping it like stated above.

Just remember... 3rd & 4th are where you are really going to start making torque & feel the clutch slipping... If you dump the clutch on the launch; and still experience slippage, jr_ss's comment applies (rebuild clutch).

4 years on a clutch in my sr20 powered 240sx? I can only dream of it!

HAHAHAHA took me a minute-

I see what you did there :bowrofl:

[05subysti]

uh 4 years on any aftermarket clutch especially a twin disc is amazing! just rebuild the thing :)

[JN1AS4]

4yrs is a long time. But the car spent years in storage. Hence the 4yr/12k miles. That's only technically 3-4 oil changes. Of course I've done 15+ oil changes over the 4yr duration. But 12k on a $2k clutch doesn't sound good at all. Especially when you break down 12k miles equal roughly 3-4 oil changes typically.

[Mikester]

uh 4 years on any aftermarket clutch especially a twin disc is amazing! just rebuild the thing :)

Dude- a twin plate will last just as long as any other aftermarket clutch depending on how you treat it.

Mine lasted forever DD-ing all week and drag racing the fuck out of it on weekends for 2yrs... the guy I bought it from drifted it for 2yrs before that... and it's still kicking ass in my 240 on the same discs/PP/TOB. Of course 8-10K miles will take me about a decade to accumulate these days; but that is a different story hahaha.

[JN1AS4]

Dude- a twin plate will last just as long as any other aftermarket clutch depending on how you treat it.

Mine lasted forever DD-ing all week and drag racing the fuck out of it on weekends for 2yrs... the guy I bought it from drifted it for 2yrs before that... and it's still kicking ass in my 240 on the same discs/PP/TOB. Of course 8-10K miles will take me about a decade to accumulate these days; but that is a different story hahaha.

When drag racing were you slipping the clutch while launching or dumping the clutch and feathering that gas pedal. Have your clutch ever slipped while drag racing?

[koukistylejdm]

lol just never do that again it looks like ur mom is driving on top of burning ur clutch

[jr_ss]

You don't feather the clutch... If you slip it at the start(more common on single disc) it'll slip to an extent and then grab. Did it hundreds of times on my RPS Max street. There comes a point when the clutch has had enough, be it from excessive slipping, heat or wear. Heat kills clutches that aren't designed for it. I've never known a twin disc clutch to slip like youre trying to do. You can slip to get it moving, but once it bites, theres no more slipping.

[Mikester]

When drag racing were you slipping the clutch while launching or dumping the clutch and feathering that gas pedal. Have your clutch ever slipped while drag racing?

When I launch, I LAUNCH... I want every ounce of power possible at the wheels... I hit launch RPM, dump it & use the throttle from there on out.

If you are having trouble getting your rear tires to hook up, switch your rear suspension either back to OEM-style shocks; or get some drag radials... you could also pay for a full drag rear suspension setup- but that wouldn't really be practical unless the car was a dedicated drag machine..

In my GT-R, drag racing was even MORE fun (ORC unsprung twin)- literally just wait for 8,000rpm, slide my foot to the slide & let the clutch pedal fly up... AWD launch = awesomeness~

You don't feather the clutch... If you slip it at the start(more common on single disc) it'll slip to an extent and then grab. Did it hundreds of times on my RPS Max street. There comes a point when the clutch has had enough, be it from excessive slipping, heat or wear. Heat kills clutches that aren't designed for it. I've never known a twin disc clutch to slip like youre trying to do. You can slip to get it moving, but once it bites, theres no more slipping.

On a dampened twin you can slip 'a little'; but yeah... Sounds to me what he was doing was literally either riding the slippy spot or feathering the pedal in & out of it during the launch. Either way HORRIBLE for any clutch... let alone a twin that costs a billion dollars to rebuild lol. WOnder what the flywheel looks like?

[JN1AS4]

You don't feather the clutch... If you slip it at the start(more common on single disc) it'll slip to an extent and then grab. Did it hundreds of times on my RPS Max street. There comes a point when the clutch has had enough, be it from excessive slipping, heat or wear. Heat kills clutches that aren't designed for it. I've never known a twin disc clutch to slip like youre trying to do. You can slip to get it moving, but once it bites, theres no more slipping.

I never said anything about feathering the clutch. I'm not an idiot. I only slipped the clutch while launching to disturb the power and allow time for it to hook.

[JN1AS4]

When I launch, I LAUNCH... I want every ounce of power possible at the wheels... I hit launch RPM, dump it & use the throttle from there on out.

If you are having trouble getting your rear tires to hook up, switch your rear suspension either back to OEM-style shocks; or get some drag radials... you could also pay for a full drag rear suspension setup- but that wouldn't really be practical unless the car was a dedicated drag machine..

In my GT-R, drag racing was even MORE fun (ORC unsprung twin)- literally just wait for 8,000rpm, slide my foot to the slide & let the clutch pedal fly up... AWD launch = awesomeness~



On a dampened twin you can slip 'a little'; but yeah... Sounds to me what he was doing was literally either riding the slippy spot or feathering the pedal in & out of it during the launch. Either way HORRIBLE for any clutch... let alone a twin that costs a billion dollars to rebuild lol. WOnder what the flywheel looks like?

I won't bother slipping it ever again. I'll just go for the dump while feathering the gas. And I'm curious to what my flywheel/clutch look like as well. But I won't know unless I'm either rebuilding this clutch or switching my clutch setup entirely. I won't be pulling the tranny off just out of curiosity though...lol

[whitey240]

your clutch is fine you just need to practice driving on the strip. Slip the clutch to roll you forward then drop and go. Feather throttle as needed. My OS Giken reacted exactly as you are describing when I would ride it out a little long coming off the line. it just takes practice

[JN1AS4]

your clutch is fine you just need to practice driving on the strip. Slip the clutch to roll you forward then drop and go. Feather throttle as needed. My OS Giken reacted exactly as you are describing when I would ride it out a little long coming off the line. it just takes practice

Appreciate the advice. My first launch was the best by far and it didn't slip. But further in the day my launches became a little sloppy and my clutch wasn't happy one bit. I will continue to practice though. Thanks.

[jr_ss]

I never said anything about feathering the clutch. I'm not an idiot. I only slipped the clutch while launching to disturb the power and allow time for it to hook.

No one said you were? But feathering the clutch is the same thing you just described above...