Lexdog

This is probably a silly question but I'll ask it anyway. How can you tell if you have 12 inch rotors or 13 inch rotors without taking the wheels off the car? Also I've read that the 13 inch rotors were Heavy Duty. If my car has 12 inchers can I upgrade to 13's? Also what aftermarket rotors would you suggest using. I would like more stopping power and I was looking at some slotted or drilled rotors. Do they make a difference? Any help would be greatly appreciated. :yesnod:

vader86

yes you can easily go up to bigger brakes, i know J55 was an option on LT1 corvettes or something similar because of the ZR1's brakes. But i dont know enough about your year, but you should have bigger brakes than i do anyway

If you go drilled or slotted, which i dont recommend, you better go all the way and get Baer brakes.

MarkBychowski

Without removing the wheel, easiest way is to look for the J55 option code on your sheet (I think it's in the storage bin or the center console).

If you're looking for upgrades, just go with the standard J55 componants ad some decent pads (I prefer PFC-Z pads, but they're a little dusty) . This can be done with all factory parts on your '91. Unless you're willing to shell out the cash for a high-end race brake kit. Drilled rotors will NOT help the car stop -- only thing they do is look cool and crack much more quickly than a normal rotor. Slots are OK, but don't do anything for improving brake performance in a street application.

ittlfly

I upgraded my 1992 12" LT-1 system to Mid - Americas 13"GT rotors, pads, calipars and mounting bracket kit....it's found on page 102 in their latest catalog. The rotors are "dimpled" and not drilled....they have been a real help in bring my beast to a firmer stop...the only thing missing are from the kit are the mounting bolts for the brackets. Chev. recommends that you use new ones if you remove the brackets from the backing plates....The kit is $799.99 + shipping and about $5.00 a bolt at GM for the mounting bolts if you buy new ones
Good Luck

91Vette

I bought the GS brake upgrade from Exotic Muscle. By far, it is the best modification I've done to my Vette so far. The stopping power is much better than stock.

Ramrod92

May like to take a look at this.... http://cgi.ebay.com/ebaymotors/aw-cg...tem=1805497830

PeteL

To find out if you have the 13" or the 12" front rotors, check the options list that is either under the lid of the center compartment or under the lid of one of the hatches in the rear. RPO code J55 means you have the 13" rotors in front.

If you have 12" rotors and want to change to the 13", page Jeff Koop (or somebody can post his websight with really great info on it) and he can set you up. Do not go and buy this upgrade on e-bay until you find out what it really costs. You do not need GS calipers. The GS brakes are just J55's with a pretty caliper that perhaps flexes a bit less, but that's it.

Pete

stroyer

I will have the following GM J55 upgrade parts for sale very soon, new, unused,
still in the boxes. I ordered the parts for this upgrade and then found out this
would be against the rules in SCCA Solo2 stock rules on my non Z07 car. Check
the part numbers and see if they would work for you on your '91.

Category: Vented HD Brake Rotors: GM Part #18028284 and GM Part #18028285
FRONT BRAKE CALIPER PLATES: GM Part #10181207 and GM Part #10181208
LEFT FRONT CALIPER: GM Part #12520231
RIGHT FRONT CALIPER: GM Part #12520232

I'll probably let the whole set go for about $470. (my cost)
Let me know if you are interested.

Scott


:spam


[Modified by stroyer, 7:01 PM 2/20/2002]

Lexdog

Thanks for all your help guys. Stroyer, I'm going to check into the parts you listed, but I'm almost 99% sure that if you want to sell them I'm willing to buy. Everything you listed should take care of any braking issues I have or will have in the future and that price is great! I don't intend on racing my car so I don't need anything too fancy or radical. :yesnod:

Lexdog

Oh one last question, are the stainless steel brake lines I see in all the magazines worth the price? Do they really make a difference? :yesnod:

stroyer

Oh yes, I certainly want to sell them since I can't use them. That was $470
out of my already thin racing budget. The reason I haven't listed them yet
is that they haven't arrived at my house yet. UPS has them scheduled for
arrival today (2/21/02). I'll reply to this thread again when I know I got
them.

About the stainless steel lines, yes they help, but I doubt you would notice
it unless you do a lot of prolonged heavy braking (like they do on road
courses). What they do is prevent the lines from expanding when under extreme
pressure. This keeps the peddle feeling firm. The more modern stock lines
don't expand too much. If yours are the original 1991 stock lines you may
want to consider replacing them. In that case, if the Stainless steel lines
aren't too much more I would go for them since they look pretty cool too.
Its up to you, but I think you would be fine either way.

To get more responce on this subject start a new thread.

thanks,

Scott

Lexdog

Stroyer, when you get your brake components please let me me know, I definitely want to buy them from you. Thanks in advance and keep me posted!! :yesnod:

stroyer

Lexdog, my parts came in yesterday. Sorry I didn't post sooner, but its been a
busy day at work. Lets take this offline to work out the details. Send me an
email to stroyer@micron.com (work) and stroyer1@mindspring.com (home) and we
can work out the details. Man, those 13" rotors sure look a lot bigger than
the 12"!

Scott

stroyer

Hey Lex, you still out there.....?

vette_tweak

http://forums.corvetteforum.com/zerothread?id=245280

stroyer

FYI- turns out Lexdog already had 13" brakes so I've listed my parts in
the C4 for sale section

thanks,

Scott