It honestly might because of the way bigger and stickier tires that you are using. I can't imagine any more lock on street tires though. Even 60% is quite aggressive. I have heard good thing about the motul fluid in the cusco diff. I use the motul 0w40 in my engine...

i have my Cusco RS also on 80% lock, but with mild ramp up settings, also my clutch plates are WPC friction treated so they engaged smoother. With the narrow tires you run mike and the lower speeds i can see the 60% being ideal. Im a road course guy on 275-285 tires and 10.5 rims so the 80% is pretty damn good. I also use the Motul 75w140 Gear competition fluid

He isn't kidding. I'm a track guy, and it always happened around 7/8 of a tank. At Road America at 15/16ths in the carousel.

20 minutes was the longest session I could ever run before phunk's fuel system upgrade. Now I have taken it down to fumes.

Like Mike said about fuel starve. It happened to alot of us. :mad: phunk has a kit to fix this problem. :tup: It's a second pump inside the tank, on the left side. You can look all you want. You can't see it. I have have one myself. Better contact phunk quickly. His second batch maybe sold out.

Well, that sucks. A second pump or anything in the gas tank is not a legal modification for my class.

Oh well. I have to raise my weight target by 60lbs... I still should be able to get the car down to 3075 with a full tank of gas.

:(

jesus really? some Auto-x rules are just too nazi

SPC front arm legal? Bushings can't have more metal than stock?

Ideas on improvements. Rather than getting bigger tires why not raise redline to 8000 rpm? You can still grab power up there and gives you a little more top end while keeping low end responsiveness.

Aluminum hat rotors? Huge rotating weight reduction.

^aint that the truth, the stock rotors are 30lbs O_O

Guys with blown oil pumps then motors would probably advise against that.

id accusump for consistant 8k rpm work, more then that id do a better crank and dry sump knowing the stock crank's weakness at such rpms

As for the SPC arms, I believe the rule is something like... "the ratio of metal to rubber cannot be greater than stock." The stock arms bushings look like they're the same ratio... although, I haven't done the actual math.

I do plan on getting the Z1 aluminum hat rotors. Those save 10lbs a corner.

I did think about raising the redline. Thoughts on what would be safe? **EDIT** I just read some of the other comments... I'd probably rather not raise the cars redline....

What about the weakness in the VVEL at 8K... Can you swap to the HR heads in STR?

265/40/18 AD08Rs sounds like a better solution and give you about 3mph more than you get now.

255's are the limit in STR. I'm thinking about the 255/40/18 AD08's.

Doh got the tires sizes for STX and STR mixed up. I did recall the 9" width max.