Morris's heat shield idea was a great suggestion and I think that definitely would work for anyone since it worked for him. We went with the easiest and quickest idea by placing a short length of brake ducting hose connected to the sub frame with the intake dipping just below the rear plastic cover under the car into the air flow and the other end right on the slave cylinder. Just finished an 85 degree track day with a mid-afternoon run of 35 minutes with no issues.

 

Do you have any images?

 

My '05 had this problem, during hot summer days in stop-and-go traffic. Had the slave cylinder replaced last year, was doing it again this year, and my tech installed the slave cylinder heat shield from the G35. Cost me $90, but so far so good. I'll let you know if it seems to be working next really hot stretch of weather we get.

 

Jason- I need to get the car on a buddy's lift today, I'll shoot some pics of the duct then.
Also, LeMans, do you have a link to a photo of what that G heat shield looks like? Googling didn't produce anything for me yesterday...

 

Here ya go, Jason.

 

Thanks for the pics....cant believe that worked that well. I guess I am going to have to try it.

 

Yeah, I know what you mean. It's not like it's a big ol' naca duct in the grill or something but so far so good. I'm interested in this heat shield that apparently is made for the slave in the G35, but not so interested in spending $90 if $5 of ducting continues to work.

 

Hope I am not being Capt. Obvious, but you have replaced the fluid with hi-temp, correct? As mentioned before Motul 600 or something similar? That cleared up the exact same problem I had after header install. Since then I installed the stainless steel line after the original line developed a crack.

 

Capt. Perf-
Yeah it was changed to Motul probably since I got it home from the dealer. Also just installed stainless lines and have ordered some Hawk DTC-60 pads for the next track day. My last track day absolutely destroyed a new set of HP + and they left a ton of deposits on the rotors. Since the Pluses aren't a true race pad I guess it's time to start using one. It's interesting what you learn about a car's strong and weak points after driving it a few years on track. I've never used anything but HP Pluses and now they've become a problem. I guess next year it'll be time to upgrade to a solid BBK.

 

Changed out slave/master/ and fluid and no issues.

I think what was really going on was air in my line and low temp fluid.

When we were bleeding the new system, it had the same characteristics as the problem setup due to air.

 

I (DE with Stillen headers/ HF cats) have the exact same problem along with my friend (stock HR) during the a hot day at Willow Springs, we bled the clutch fluid on site with Super blue racing brake fluid and problem solved. And I actually heat warped the clutch fluid hard line just in case at the same time.

 

Haven't had this problem in the HR yet.. I'm running SS clutch line, RBF600 and wrapped HFC's with stock headers/shields. I would imagine the ducting might help a bit, but I having a hard time with low velocity air flow protecting more than good shield/wrap. By nature, there should be a vacuum created under the car, so you might be pulling down more than you would actually push up there... just a thought.