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I haven't had any issues with the diff - other than it being a crappy LSD - but I swapped the fluid out before the first event, so I don't have a reference for comparison. Although, I don't know how hot your track day was but at COTA I did 4x20 minute sessions in 104 degree heat, 120+ real feel, so humidity must have been 70% or so. Like I said, I still had power steering fluid leak, so it was well and truly hot, but no change in action in the diff or clutch at all.
What hot tire pressures are you running with the RE-71R's? I had 36 hot at COTA and that gave me a perfect temperature across the tire and it wore nicely, very little in fact, despite them getting very greasy at about the 12-15 minute mark. However, at the last autocross I didn't know where to start (I ran 38 cold, 40 hot on the stock tires and that was really nice) so I put 36 cold before the first 2 runs, which went to 40 hot and have destroyed the front right tire in the middle. The strip down the middle is worn on a sort of 45 degree angle! Rest of the tire is OK ish, so definitely too high pressure, but just wondering if perhaps 36 hot is still too much for the tire and car, I haven't experimented with lower pressures yet.
I have 245/40 front and 265/35 rear on stock rims, so it's certainly under tired which doesn't help.
That's good news on the diff, because my track day was a lot cooler temp, but I am 99.9% sure the fluid was stock. I was fine for the first four 25 minute sessions, but had the issue toward the end of the 5th session.
I think I was running 35 or 36 cold that day. I did not check the hot tire pressure. I even brought a laser temp gun to check the tire wear, but they were wearing really evenly at Road America. (I think I got most of the understeer out of the system at the last track day at a much tighter course.) Are you running the RE-71R's too? I am running 275's in back, but also 245's up front and I am on 19's.
Are you running the RE-71R's too? I am running 275's in back, but also 245's up front and I am on 19's.
Yeah I lashed out and went for them. I am on stock rims, so 8.5" front and 9" rear 19's. I would really like more front tire but $$$
My friend just bought a race MX-5 and is all in for less than $8k, which just makes me feel bad about spending money on this car, despite how nice it is. But, Porsche's must be beaten this weekend, so time to go flush brake fluid. Then obligatory wash and wax to fit in...
Front tires are getting destroyed, I think I'm going to try and find some 18x10 rims to install all around for the next set. These are about 50% worn in 1 track day and 3 autocrosses.
Front Right - Lots of wear from understeer.<br/>Hotchkis stabiliser and 3 degrees of camber with stock 8.5" wide rims, 245/40 tires.
What offset are you running in 10" to fit under the wheel arches? I was going to just go with the 370z offset, but I'm not sure that will work and don't want to get it wrong.
I haven't measured, but I don't rub ever. But I'm not running a lot of camber. Obvoiusly, if you camber in, you'll have more fender clearance, but less internally. Another thing to note is that I am on Koni/Swift suspension. If you are on a true coilover in the rear, it moves the spring placement, and you would have less inboard clearance against the spring. But full lock under compression (entering a driveway or something), it doesn't rub up front. I don't have any pics of the front, but here are some pics of the rear inboard. Notice how much closer the tire is against the shock. If there was a spring around that shock, there wouldn't be much clearance there.
What offset are you running in 10" to fit under the wheel arches? I was going to just go with the 370z offset, but I'm not sure that will work and don't want to get it wrong.
I'm not on 18x10 yet, on 18x9.5 +38 on a 265 tire up front.
I'm planning on running an 18x9.5 +25 up front soon, and I'll let you know how it clears everything. Mind you, my fenders are slightly rolled + pushed out slightly, but given that a +38 fits without problems and is tucked in, I think an 18x10 + 33ish with a 275 should fit perfectly. (.5 inch = ~12mm, so an increase in 6mm on either side.)
Front Right - Lots of wear from understeer.<br/>Hotchkis stabiliser and 3 degrees of camber with stock 8.5" wide rims, 245/40 tires.
Holy sh#t you are killing your fronts!! I think the autocrossing is not helping your tires. I noticed a similar problem on a very technical 1 mile track with 14 turns (kind of like autocross). I was doing the same thing on the first session until I adjusted my driving to trail brake a bit into the corner and steer out a little with the throttle. No wear problems at Road America where the corners are not nearly as tight. I run 245/275/19's.
After work today I spent some time prepping the car a little better to handle the heat of track days. I put in a Z1 insulated clutch cable, Redline 75W/90 Rear Diff fluid, Redline D4 ATF fluid for the power steering, Allstar Performance brake bleeder caps, and Motul RBF600 for the brakes and clutch.
Let us know how the ATF fluid goes. I am using the Redline Power Steering fluid because it came with the cooler from Z1, but I see most of the Zed folks recommending the ATF instead so I may swap over if it boils less easily than the standard stuff.
What's the deal with the brake bleeder caps? Did you lose one of the standard ones, or perhaps it tore with the heat of the brakes?
Let us know how the ATF fluid goes. I am using the Redline Power Steering fluid because it came with the cooler from Z1, but I see most of the Zed folks recommending the ATF instead so I may swap over if it boils less easily than the standard stuff.
What's the deal with the brake bleeder caps? Did you lose one of the standard ones, or perhaps it tore with the heat of the brakes?
How's the Z1 power steering cooler? Should be a fairly simple install, no? As for the brake bleeder caps, mine are pretty destroyed from the heat too so I might need another set eventually.
Also - got my car on some more appropriate trackday tires.
Just looking at the fitment on my car, with a pretty aggressive offset and flat rolled front fenders, it seems entirely likely you'd be able to fit an 18x10 with 285/35r18s in the front with a conservative offset. The 285/35 are shorter than the 265/40 that I currently have, on a 9.5in wheel, so that should help with clearance as well.
Keeping in mind that camber increases with compression, poking out a little should be okay if you have a high enough spring rate in front.
As an FYI, the tires I bought are Federal 595 RS-RR. I'll let you know how they fare as I am planning to bring it to a trackday in mid-December.
10-24-2016, 08:24 PM
