z28cdoyle

I took my car to the race track yesterday to test out the LS1 brakes. I have an 85 IROC witht he LS1 brakes on the front and J65 rear disc (with recall kit installed). This was a road race track (Nelson Ledges in Ohio) so the brakes were worked much harder than in street driving. Here's the lowdown and some problems to watch out for if you are doing this swap.

The nice thing was that nothing broke. The brakes definitely had more bite than the stock system. I was running Carbotech Panther Plus 1109 compound pads up front and Performance Friction street pads on the rear. I was able to brake later for corners than I ever could before. When I mashed the brake pedal hard it felt like my head was going to fly off.

The stock 85 master cylinder and J65 rear discs seemed to work very well with the LS1s in the front. I did not have the rear wheel hop under heavy braking that I was getting with the stock front brakes.

Now for the problems. My wheel studs are loosening. I have the NAPA 641-1581 studs (same as Dorman 610-323). This is not a problem with the studs just holes in the hub that are too big. I will almost certainly have to switch to the slightly larger knurl ARP studs.

The wider track caused by the hub/rotor combination cost me a tire after it rubbed on the fender. Luckily the "racing gods" looked down upon me and smiled as I came in to check things over and found the cut tire before it blew out. I run Toyo Proxes RA-1 race tires in 255 width on the 5 spoke IROC wheels. Anyone running 255s and doing extremely hard cornering on the track or highway on/off ramps should watch out for this. Make sure the mounting tabs for the inner fender liner are bent in away from the tire. This never happened to me before so I'm sure it was due to the wheel/tire being pushed slightly farther outboard with the LS1 setup.

I am a litle disappojnted that I have some stress cracks in the outboard side of the rotor after only 100 miles on the track. Of course this is not a shortcoming of the LS1 brakes but I was hoping to get better rotor life sice the bigger brakes should run cooler than the stock ones. This may also be caused by poor quality rotors. I have slotted rotors I bought off Ebay for about $50 each.

Oh well, the next stop is Watkins Glen in a few weeks which is harder on brakes the Nelson Ledges. Stay tuned.

ebmiller88

iTrader: (7)

Did you drill the hub holes out at all? That's odd that the studs loosened up on ya like that. Have you thought about doing the front/rear wheel swap? The stock offset is 4.75" front and 5.25" rear, so if you put the rear wheel on the front it will negate the added offset of the brake kit. Mongoose did this and he runs all 4 rear wheels with a 1/4" spacer on the rear and he's happy with it. No issues that way, and you're running a 255 on the front too.

Too bad on the rotors too, I'd just go with some good quality Raybestos rotors or something, not too expensive to replace either.

But overall, glad to hear they are performing well.

Ed

z28cdoyle

No, I did not drill the holes in the hubs. The holes in these hubs are already at about .490" measured with my calipers. I measured the knurl on the NAPA/Dorman studs at .498". I will call around tomorrow to get some of the ARP studs which should solve my problem.

I don't think I can run rear wheels on the front of my car. When I put my wheels on for the first time with the LS1s, I put a rear wheel on the front by mistake (stock 5 spoke IROC wheels). The spokes banged into the caliper and the wheel would not even turn.

ebmiller88

iTrader: (7)

Hmmm...OK, I still haven't tested the front/rear swap thing yet since I still haven't put my C4 HDs on yet....

I used the ARPs on my RS and drilled a .484" hole for them, just a little info you may like to have, but I haven't had any problems with the Motormite/Dorman studs being loose, they've all been good for me.


Ed

z28cdoyle

I ordered the ARP studs from Summit yesterday. They should arrive tomorrow. I only had the studs loosen on the left front hub. That was not a real huge suprise though. The track I drove at a few weeks ago is notoriously hard on left side parts. I would often break left rear wheel studs off after a day at that track (my record is 3 in one day). I have broken 2 hubs there (stock brake rotors) over the years and I saw a guy with a Toyota Supra break the center right out of a ForgeLine wheel (left front). The track is bumpy with very fast right hand sweeping turns. If you want to expose all the weaknesses in your car; take it to the race track. The weak parts on your car will definitely break.

I will be going to Watkins Glen next weekend with it's long, fast straights, wicked downhill braking zones, and seriously fast cars (Porsches, BMWs, Ferraris, and ex Winston Cup cars). This will be a real test of the LS1 stopping power. With the stock brakes I had to brake much earlier than other guys to get slowed down for corners.

Eightyninef

your problems in order:

don't run 255's no matter what your neighbor says.
run 245-45's. dump the toyo's in favor of kumho's.

max out the neg camber, and you shouldn't rub, although your rubbing is the 255's, but adjusting the camber can only benifit you.

don't run slotted - drill rotors. they cost too much, and they spider crack to fast.
get cheap rotors from rockauto.com
the raybestos pro grade are good and cheap. they have cheaper rotors as well. rotors are disposable and are cheaper than pads, and the cheap ones seem to work better. and if they crack, thick disposable.

and if all else fails, blow the bus stop !!!!

askulte

z28cdoyle,
Which club are you running with at WGI? Adding a single 3" duct to the center of each brake rotor helped me tremendously. That, along with competition pads (PFC 97's up front) and a fresh bleed of ATE Super Blue held up pretty well. The bus stop is the hardest braking section by far, but I love that track! There's also a PDA track day at Pocono on May 8th, and an EMRA time trial at Pocono on May 9th...

Larry - I haven't had problems with rubbing the 275's up front, or heard of folks rubbing the 265 kumho's. Where was it rubbing for you?

Andris, 2:13 on the WGI long course...

RegaPlanet

I agree the life you got out of your LS1 rotors is about avg especially since they're slotted. And also as stated adding some ducting will help immensely with life of stopping power and actual wear. My suggestion there would be to mount the brake duct intakes right beside the radiator. Every inch you move out decreases air flow through them quite significantly. The only rotors I know of out there that will last you several RR weekends are Porsche rotors. A couple guys over at FRRAX have switched over to them and have had very good results.

Good luck at the Glen!!!

z28cdoyle

Hey guys it is nice to chat with some guys who don't automatically assume "track" means the drag strip.

I am still rather suprised my Toyos rubbed. I have been running the 255s for years and never had any trouble. I could see the rubber marks under the fender so I know where the tires were rubbing. Last weekend I bent and pounded everything under the fenders away from the tires. I should be OK now.

I actually have two 3" brake ducts going to each rotor from where the turn signals used to be. It seems to work rather well. I have run Hawk Blue pads for a few years. They stop well but are hard on rotors. I just switched to Carbotech Panther XP 1109 with the LS1 brakes.

I will be running at WGI with Trackmasters. They have a great format for open track with a lot of seat time. I have blown thru the bus stop more times than I care to admit because I could not get slowed down with the stock brakes. By the way, that was braking at the 600 sign. I guess I'm going to have to find some speed. My best time on the long course is a 2:19.

RegaPlanet

There are a bunch of other Fbody guys heading to the glen on the 3rd and 4th I believe it is. Guess that wont be you but thought I'd let ya know...

Anyone going to the Glen on may 3rd and 4th?

So I take it this is your track only car or are you just taking out your turn signals at the track? I'm currently doing the AX(ESS) thing north of the border but the car is mostly prepped for RR minus the fact I'm still on stock brakes and without a cage. Just giving myself more experience before I get it on with the big boys.

2:19 eh... not to shabby at all!

Have any pics or videos from your days at the track?

slow305

iTrader: (2)

Why? Kumhos may be faster but the Toyos last longer and are more durable. Hardly a problem.

Pat

Souseless

I was just at Summit Point with Trackmasters. I am driving in the intermediate student class. I have the 93-97 pbrs in the back and 10.5 stockers in front with no vents. I tore through a brand new set of Hawk HP+ pads, ruined 2 rotors, overheated my brake fluid, and cooked the rubber boots off of my front calipers. I am definetly looking at putting in some vents. I have an 89 ta and I was looking at the fog lights as a possible inlet for air. How, and to what did you secure the vent hose by the caliper? Are you directing the air into the center? I was on frrax.com and that is what was being recomended there. Will you be at the WGI trackmasters event in June? That is the one that has the kids day event tied into it. I have been reading up on the LS1 brake swap for a couple of weeks now and would love to get a look at a car that has the swap completed. Also I have been thinking about going to Nelson Ledges for one of their friday open track days, do you attend those?

slow305

iTrader: (2)

What type of fluid? Did you bleed it between sessions? Good brakes aren't just about the pads -- it's about the entire system. And knowing what the limits are. Also, don't forget tires play in important role in braking.

I ran an event in October at Summit in my '90 WS6 and trashed a set of Raybestos Brute Stop pads, but the rotors ($25 O'Reillys specials) are still fine, and I never boiled the fluid (off the shelf stuff, nothing fancy). I think I bled the brakes after each session (or close to it). Never did but maybe 3-4 hard laps before I felt the brakes starting to feel spongey, then I'd do 1-2 easy laps before going at it again. Proof that you can get away with "OK" pads, "OK" fluid and not burn stuff.

I also ran my old '00 Lightning at Summit and VIR and never had problems with brakes. Close to 5,000 pounds with driver, stock rotors (that were still on the truck when I sold it in March), stock lines, Porterfield R4S pads, ATE fluid (bled often), Kumho Ecsta V700s.

Pat

z28cdoyle

I know all too well how hard Summit is on brakes. I run their Seat Time events. I also incinerated a set of brakes there before I had my ducts perfected. A set of new Hawk Blue pads wore down to the backing plates causing the piston on one of the calipers to push out of the bore. The brake fluid caught fire when it hit the rotors which were both cracked beyond belief. All that was after about 100 miles.

I run Ford brake fluid (570 deg dry boiling point, a lot cheaper than the racing stuff with the same boiling point).

I have the dust shields removed from the inboard side of the rotors to allow more air flow from the brake ducts. I use long nylon cable ties to hold the hoses to the steering knuckle. Believe it or not I use a soup can at the end of the hoses to run the cable ties thru (punch holes in the sides of the can). This keeps the cable ties from ripping up the hoses. You want the hoses to blow air into the center of the rotor. I built this funky looking manifold to try sealing the hoses to the hubs better like some of the Nextel Cup guys use. It was a complete flop. It is still a good idea though if you could find something to work.

I take my car to the track on a trailer so the turn signals are semi-permanently replaced by the brake ducts. I carefully cut a piece off the side of the nose piece to make room for the twin 3" hoses while still allowing the turn signals to be reinstalled if I want to drive the car on the street.

I run at Nelson a lot (I was just there about 3 weeks ago for their first Fundayz). Not sure when I'll be back there again with my car. The next time I go will probably be as an instructor. In that case I won't have my Camaro there. The Nelson Fundayz are a great deal. $120 for more seat time than you're likely to get at any other track. The pavement is a little rough though.