I have no STU experience yet, but I would get the widest possible tire I could get - mainly because that is the most limiting factor in how fast you can carry all of that weight around.

 

 

^ i feel like my 17x9.5 set up was noticeably nimbler - i think it almost cancels out, honestly. i only swapped to run evo x brakes

 

Considering the Evos short gearing, I would def go for the slight hit in accel for a slight increase in 2nd MPH. We use to hit mid 60s on every course. Longer courses had us sitting on rev limiter 1-2 sec in multiple places, if not longer. Granted we aren't hurting for power, but low to mid 70s have become the new norm for national courses.

Edit: Just looked up the measurements for both and its only a 0.3in height difference which is pretty insignificant. That's about 1%. But the size difference in width is more than the 10mm would suggest. 0.5" in section width and 0.8" in tread width. That's a pretty big jump, I would absolutely go that direction.

 

Going from 245/40R17 to 265/35R18 was a small, but noticeable, difference in acceleration.

255/40R17 vs 265/35R18 is a much smaller difference. I feel like I hit the rev limiter more on the 255s than the 265s, but that could have just been course dependence and placebo effect.

 

That would be fantastic. Keep me in mind or send me a FB msg on what you need to make this work.

 

In my experience... more grip has a larger affect on times vs more mph. You'll go through every section quicker with more grip (wider tires) vs the few straightaways on an autocross course.

 

Will do

 

What offset rims are you using on the 18x10s? Also, what needs to be massaged in the fender wells to make those fit?

 

I have RPF1 in 18x10 +38. 18mm spacer up front, 5mm spacer in the rear.

Fender lip rolling is required, but no pulling is required. STU doesn't allow pulling, so I spent some extra time during the fender rolling process to keep the fender shape unchanged. The trick is to park near the wall of the garage and then very carefully wedge some precisely cut 2x4s between the wall and the fender with some generous microfiber cloth padding on the car side, of course. This allows you to get aggressive with the lip rolling without excessively pulling the fender in the process.

The 5mm spacer in the rear is just barely thick enough that I installed extended rear studs to be safe. Racing Brake has nice some extended studs that aren't as excessively long as the ARP studs.

Proper camber is required to help tuck the tires. I'm currently around -3.4 up front and -1.9 in the rear.

18x10 is a close fit and requires some precision with the spacers and fender rolling, but it does work. I can't find any evidence of rubbing anywhere.

 

/\ This is what we did as well.
18x10 +38 with 19mm~ front spacers and 4mm rear. Added extended rear studs.
Rolled the rear aggressively using a scissor jack, blocks of wood and padding, from the wall to the fender (and a lot of patience).
We didn’t need to run as much rear camber but that will depend some on your ride height, just keep an eye on the trailing arms.

I’ll also add that with this combo we were able to fit 285/30’s, the fronts will hit the rear portion of the fender and side skirt, fairly significantly, so we installed some STU legal SuperPro Front lower control arm rear bushing - DURO3741K, this moved the assembly forward enough to fit (minus a little “self-clearing” on the fender liners).

 

Good point, I forgot about the front lower control arm bushing. I also had to install the SuperPro DURO3741K up front to make this work.

I have the Ciro top plates at maximum caster up front and the front tire still catches the front of the side skirt at the back of the wheel well at certain steering angles. Only really noticeable when backing up.

 

My intake hose at the throttle body is popping off more often lately . The rubber is hard as hell and no matter how hard I tighten the hose clamps (it's had three so far), I believe it is only a matter of time before it pops off once again. I've read the rules for STU (section 14.10-C) where it says "The air intake system up to, but not including, the engine inlet may be modified or replaced. The engine inlet is the throttle body, carburetor, compressor inlet, or intake manifold, whichever comes first." Since this problematic hose of mine is after the compressor inlet, my question is, may I replace this one hose with a non-OEM hose? The Mitsu hose is $86 (MR993868), whereas an entire silicone hose set is only $65. For anyone wondering how many years and miles it takes for a hose to quit, I've got 218,000 miles on my Evo 8.

 

It's after the compressor intlet, so, I'd say it needs to be OEM.

 

I'm trying to get my old Evo back into STU spec, and one of the things it is missing is the front under tray. It was destroyed by a truck tire carcass many years ago. I've been hunting through https://www.mitsubishipartswarehouse.com/ looking for the three main pieces to it, but haven't found them. eBay wasn't helpful either. Does anyone know those part numbers?