I have some minor interference with the rear caliper. I tried to smooth off the cooling fins from the PBR calipers, but I'm still making contact in a couple of places. A 5mm spacer should lift it off the caliper just dandy. Can I do it and still be safe?

 

well, long as you have long enough studs. I dont see why you cant sand them down enough to clear though. I'll post a pic of my rear caliper. and of an LS1 caliper that I ground/sanded down too.

 

this is the LS1 rear caliper. they require LOTS more work then the LT1 or I believe the 3rd gen rear calipers. obviously this is before the paint. it looked like it came that way from the factory after it was painted.

 

Looks good Chris, but part of the equation is the spacers inbetween the axle flange and the disc brake mounting bracket. I think mine is spaced a little farther out than some, and even though I've ground off the fins from the caliper, I still touch the wheel in two or three spots when I rotate the wheel. That means there is only .010" or clearance or so in other places. Certainly not enough for when these wheels are rolling or getting subjected to side loads! I want .040 to .060 clearance for safety sake, and I dont think I can get that much more off the caliper and still trust it to do the hard braking I need when configuring for the road course.

There's plenty of stud on the Moser 12-bolt, so I think we'll be okay with the spacers, unless someone else has some convincing reason why NOT to run spacers. Maybe my interference comes from having a Moser 12-bolt fitted with GM calipers, who knows?? Whatever the reason, spacers seem to be the simplest solution.

 

I'm running 5/16" spacers with my Prostars Dan for the same reason. I ground the crap out of my calipers and they still hit so on went the spacers. I used them all last year with no problems. One word of warning though. When first running this combo tighten them often. We checked them after each pass and they were a little loose each time for 5 or 6 passes then were good to go and haven't been loose since.

 

I would also get ARP studs for safety.

 

yeah those LS1 rear took WAY too long to do. couldnt believe how much had to come off. but they didnt get thin in any areas. Im not sure about the spacers yours have due to the moser axle to adapt the GM rear brakes, but I did have to remove more then just the fins on both of those. LT1 and LS1. since yhou already have longer studs, Id say the spacer is the best way to go.

 

Yeah, I only had to smooth off a portion of the fins. As for the spacers, I'm using a 1/8 inch spacer. Group A wheels sells them that thin, and that's what was laying around in the garden shed full of spare parts. There appears to be about .060" of clearance between the caliper and the wheel now: That ought to be enough to account for any wobble that might show up under stress.

Chris, those LS1 calipers look like they were a PITA. Zounds, I get fearful of caliper spreading and fatigue. Probably not a problem for your application but I wouldn't run them on the road course for too many sessions.

 

(edit) I just got the 275-60-15 MT ET streets mounted on the wheels and I'm heading off to pick them up in an hour. Pictures should be posted tonight. I sure hope I wont have to roll the fenderwell lip, but what the heck, I've been sawing on body for the last few months anyway.

edit # 2: One of the wheels is mounted and wow, what a big tire! Huge. Definitely should've got the 26 incher but slightly used is used, and they were a deal at $100 ea. Now I need to pop out the springs and run the suspension through full travel and see what gets in the way.

 

damn dan, getting some serious tire under there now huh? Im goin to guess you got some aftermarket springs in the back, and that they lower the ride height some. next Im goin to tell you that Im pretty positive you HAVE to roll the fender lip. you should buy that tool they make for doin that. . then I'll rent it from you to do dads TA. how would that be? ok cool. let me know when I can come pick it up.
oh, and also, if you put air bags in the rear coils that will help a ton to keep from squatin and slicing into the tires. but if you ride around like that on the street, it'll be a stiff ride. seems on my Iroc it cut into the tires the worst while driving with passenger(s) before I put the air bags in the back. even 5psi helps alot to keep the car from squating over dips in the road.


:EDIT: put some fricken pics up here for us already :napoleon{{ GOSH!}} napoleon:

 

PICS!! I will probably run that size after my ET Streets are gone. 28" and 3.73's will give you plenty of room on the top end for a good sized nitrous jet.

I did the LS1 caliper/Weld Rim grinding mod... It had to be a 5lb weight reduction!

Chris there's no lip rolling with a 275 tire! HAHA!

 

liar liar pants on fire.

 

you need about a 3 inch stud (3.25) is what most use to be legal with welds and a spacer. Most use 5/16 spacers. I run 1/4

 

Here's the caliper and it's modification:


Here's the wheel after installation:



Here's the wheel sitting next to my street tire:


I wont be getting the car on it's tires until I finish contruction of the Y-pipe.
(Off-topic teaser for you)
Here's the first part of it, tucked nicely up there near the transmission!

 

Looks liek you have the same tranny crossmember I have. Not that I think about it, I got mine after seeing yours. Can't wait to see how your exhaust system looks, it'll help me make mine!