Z06-HEC*

Ok so i assume i need a new clutch....
Stock clutch right now and car is putting down about 540 to the wheels.
Been to a few races and it was fine.
After race events i took car to city and got caught in stand still traffic for over an hour. So as car heated the clutch was getting harder to shift...
Eventually it was almost forcing it into gear.
I pulled over and let it cool off for an hour, checked the clutch fluid and it was fine. Once cool i was back on the road driving normal.
Since then i take it out just for short runs but no racing or long drives.

Need an upgrade right?
So suggestions ?

Hopefully i can get some quick answers so i can get something purchased asap.

cv67

If its not slipping then-
Sounds like its not disengaging a slave issue perhaps?

Z06-HEC*

so at the races it was fine...

One day took it to work and got stuck in traffic and car heated up. So getting into gear was the issue, really hard, but once in it was driving... eventually since traffic was slow i pulled over and let it cool down for an hour, then back to normal....

Z06-HEC*

Also i spoke to a shop over the phone and they mentioned all or most twin disc setups will make noise....
Is that accurate?

AzDave47

I just did a strong HCIE install that included the McLeod RXT 1000 dual disk clutch. It is very user friendly, light pedal, easy to intentionally slip and I have not noticed any extra noise from it. I haven't done any drag race starts on it yet, but then I need to learn how to do them properly as my background is road racing and I have no experience with drag race starts.

If you do a clutch, do a new slave cylinder (I went OEM) and install a remote bleeder while in there.

phipp85

Based off your sequence of events you just need some quality high temp fluid in your system. Heat builds and allows the fluid to be slightly compressed. The hotter it gets the worse the problem becomes. I use Castrol SRF in mine but others work too, just look for a high wet boiling point around 500 degrees.

Lack of marcel and hub springs is what makes for a noisy drivetrain. Nothing to do with the number of disc. That's a false blanket statement since many people upgrading to twins or triples are looking for performance first, street-ability second. I'm sure there are plenty of street friendly twin disc clutches out there.
I'd change that fluid before replacing the clutch, unless you are just looking for a reason to buy a new clutch.

AzDave47

You didn't narrow the choice too much by saying that, did you? Choice of one!

https://www.lelandwest.com/brake-flu...ow=1&SF=4&ST=2

Any of the ones with a wet boiling point over 400* should work fine, too, at 1/4th the price of SRF. I'm not saying SRF isn't the best because it probably is.

phipp85

You could say I was trying to point the OP in a particular direction.

Unreal

Aftermarket clutches, and lighter clutches may allow you hear the transmission/torque tube noise. It isn't the clutch making the noise, so it just depends on what you mean by twin disc make noise. The clutch maybe quiet, but the car does get new noises.

Z06-HEC*

So now that you are mentioning that, before the races i did change my fluid and went with some off the shelf dot3/4 fluid..... I used the granger method on changing it so i cycled about 4 times until it was fully clean and kept checking it every few days before the race...

during the races it remained clean through out the day with no issues. I think i missed 1 or shifts into 3rd gear towards the end of the day because it wouldnt go into the gear... (I shift at red line during race)

So i kept checking the fluid the days after and making sure it was clean but then i got stuck in the city traffic... and no shifting at all...
I'm wondering if thats all i need... change to a high boiling fluid.
Afraid i do that, spend a few hundred for the next race event and get stuck or worst brake something. I guess i could just take the car to work again and see what happens with long running time...

Z06-HEC*

So I went to Autozone to look for their best option. The crap I had was Valvolene DOT3/4 and i believe the boiling point was 311F. The most expensive stuff they had at autozone and the best from what they claim was Pentosin Super DOT4. They claimed all the German cars use it and same claim on the label with boiling point of over 500.....
I used the Granger method and got it looking clear with about 3 cycles of pumping.
So i havent used the car yet but plan on driving to the city at some point and putting it through some traffic...

AzDave47

Here are a list of specs on brake fluids. Yours is half way down the list:

https://www.lelandwest.com/brake-flu...ow=1&SF=4&ST=2

Z06-HEC*

Thanks man, I may just shop around for some of those top ones and keep it handy. I will keep flushing this Valvolene crap out and try to get the car hot to test it out.
I dont see the GM brand in that list so not sure what the stock fluid boils at. I assume better than this crappy Valvolene...

Josh B.

Hopefully the better fluid will fix the issue. Do you have headers installed? It sounds like you are heating your fluid quite a bit, It might be worth inspecting your clutch line and ensuring that it is a safe distance from the header tube. Mine comes close naturally. Big zip tie holds it back a little bit more. I never have any issues like you describe.

Good luck with it.

0Anthony @ LGMotorsports

I would agree with that statement too. It is easy enough to flush the system with some good fluid before pulling the drivetrain out of the car for a clutch replacement that may or may not be the answer but to me it sounds like you are not getting full travel of the slave cylinder which could be a result of water contamination and boiling of the fluid.

Z06-HEC*

just decided to go ahead and order some Torque RT700 from amazon...
not even going to give this pentosin a valid try. 311 to 329 is not much a change IMO
thanks for the help guys

rpmextra

I use the wilwood EXP 600 fluid. It's easy to find at summit, jegs etc and not too expensive