1991 brake upgrade
Thread Starter
Racer
Joined: May 2007
Posts: 424
Likes: 0
1991 brake upgrade
Currently looking to upgrade my braking system and would prefer to keep my 17" grand sport replica wheels if possible. What have you guys run that will clear the 17" brakes? The car will mostly be street driven. I have read all sorts of threads with c5 conversions, c6 conversions, Wilwood brakes Keep the stock brakes etc.etc. Also where have you located stock brake line replacement kits? Everywhere I look they seem to be discontinued or out of stock.
At a minimum I would like to replace the lines with a new pre-bent kit - need to locate
Replace the caliper lines with stainless lines - not sure what lines are best
I have read about the DRM brake bias spring but can't seem to locate that either.
I'm interested in seeing if the wilwood kit is worth it or is it better to just get some new pads and keep the factory brakes? Are there any brembo brake kits available if in the future I went this route and upgraded wheels etc.
With the new build the car made 526hp so I would like to stop a little faster if needed. I also have a vacuum pump for the cam that I have yet to install.
new engine specs:
396 stroker (526HP on engine dyno)
10.5:1 compression
com cam hydraulic roller cam - duration 242/248 lift 585/580
aft heads 195cc ported eliminator 75cc double valve springs, hardened retainers and locks, 1.6 comp cams rocker arms, 2.05" stainless intake valves, 1.6" exhaust valves
holley sniper efi system
Any Info would be great! Like I said at a minimum I would like to replace the 30yr old lines, caliber lines and maybe install the DRM spring
At a minimum I would like to replace the lines with a new pre-bent kit - need to locate
Replace the caliper lines with stainless lines - not sure what lines are best
I have read about the DRM brake bias spring but can't seem to locate that either.
I'm interested in seeing if the wilwood kit is worth it or is it better to just get some new pads and keep the factory brakes? Are there any brembo brake kits available if in the future I went this route and upgraded wheels etc.
With the new build the car made 526hp so I would like to stop a little faster if needed. I also have a vacuum pump for the cam that I have yet to install.
new engine specs:
396 stroker (526HP on engine dyno)
10.5:1 compression
com cam hydraulic roller cam - duration 242/248 lift 585/580
aft heads 195cc ported eliminator 75cc double valve springs, hardened retainers and locks, 1.6 comp cams rocker arms, 2.05" stainless intake valves, 1.6" exhaust valves
holley sniper efi system
Any Info would be great! Like I said at a minimum I would like to replace the 30yr old lines, caliber lines and maybe install the DRM spring
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
How much are you willing to spend? Will you be racing? That will determine how fast you stop and how much heat you need to dissipate while stopping.
The options are endless, but keeping the OEM 17" wheels will limit your choices.
The options are endless, but keeping the OEM 17" wheels will limit your choices.
Racer
Joined: Feb 2005
Posts: 338
Likes: 49
From: Quincy,Illinois
If you apply the brakes as hard as you can now, does the abs kick in? If so then bigger brakes will not stop you any quicker, just kick in the abs sooner. You can only stop as quick as the tire grip will allow. Bigger brakes are better at dissipating heat, but unless you track the car for long runs you won’t build up that much heat. If I was you I would replace any lines you think might be bad. Install the stainless braided lines. If you want the cool look factor, then either paint or powder coat the calipers. Put some cadmium plated slotted rotors on it and some decent pads. If it’s not already J55 you could ad that very easily. The DRM bias spring will put a little more rear brake in it, so that could help you some too.
Thread Starter
Racer
Joined: May 2007
Posts: 424
Likes: 0
mostly street driven but with the big cam I feel like the brakes are just junk. Still need to hook the larger vac pump up so hopefully that helps me. I would prefer to keep my grand sport wheels. Not sure if the wilwood vs regular brakes are a huge difference or not being roughly the same rotor size?
Thread Starter
Racer
Joined: May 2007
Posts: 424
Likes: 0
If you apply the brakes as hard as you can now, does the abs kick in? If so then bigger brakes will not stop you any quicker, just kick in the abs sooner. You can only stop as quick as the tire grip will allow. Bigger brakes are better at dissipating heat, but unless you track the car for long runs you won’t build up that much heat. If I was you I would replace any lines you think might be bad. Install the stainless braided lines. If you want the cool look factor, then either paint or powder coat the calipers. Put some cadmium plated slotted rotors on it and some decent pads. If it’s not already J55 you could ad that very easily. The DRM bias spring will put a little more rear brake in it, so that could help you some too.
are the j55 brakes just larger rotors or calipers as well? Any idea where I could buy the spring?
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
mostly street driven but with the big cam I feel like the brakes are just junk. Still need to hook the larger vac pump up so hopefully that helps me. I would prefer to keep my grand sport wheels. Not sure if the wilwood vs regular brakes are a huge difference or not being roughly the same rotor size?
Do you have the base JL9 braking option? Was that still available in a '91? Going to J55's will improve that some if you don't have them already. Going further to a C5 front setup will be better still and those bigger/stiffer C5 calipers (should??) fit under your Grand Sport wheels? If you have a true Grand Sport depending on what model year I think it came with a J55 brake option that has bigger calipers than a regular J55 setup.
DRM lists this bias spring;
http://www.dougrippie.com/brake-bias-spring
Check out these threads;
https://www.corvetteforum.com/forums...the-j55-s.html
https://www.corvetteforum.com/forums...ne-pics-2.html
https://www.corvetteforum.com/forums...with-pics.html
Last edited by mako41; Jul 10, 2020 at 08:35 PM.
Racer
Joined: Feb 2005
Posts: 338
Likes: 49
From: Quincy,Illinois
If you have a big cam, then you are probably low on vacuum and the booster is not working fully. I would suggest adding a vacuum reservoir to keep the booster working .
Thread Starter
Racer
Joined: May 2007
Posts: 424
Likes: 0
A full wilwood setup will fit under those OEM wheels, improve braking considerably, but cost you big $$. What exactly do you have now?
Do you have the base JL9 braking option? Was that still available in a '91? Going to J55's will improve that some if you don't have them already. Going further to a C5 front setup will be better still and those bigger/stiffer C5 calipers (should??) fit under your Grand Sport wheels? If you have a true Grand Sport depending on what model year I think it came with a J55 brake option that has bigger calipers than a regular J55 setup.
DRM lists this bias spring;
http://www.dougrippie.com/brake-bias-spring
Check out these threads;
https://www.corvetteforum.com/forums...the-j55-s.html
https://www.corvetteforum.com/forums...ne-pics-2.html
https://www.corvetteforum.com/forums...with-pics.html
Do you have the base JL9 braking option? Was that still available in a '91? Going to J55's will improve that some if you don't have them already. Going further to a C5 front setup will be better still and those bigger/stiffer C5 calipers (should??) fit under your Grand Sport wheels? If you have a true Grand Sport depending on what model year I think it came with a J55 brake option that has bigger calipers than a regular J55 setup.
DRM lists this bias spring;
http://www.dougrippie.com/brake-bias-spring
Check out these threads;
https://www.corvetteforum.com/forums...the-j55-s.html
https://www.corvetteforum.com/forums...ne-pics-2.html
https://www.corvetteforum.com/forums...with-pics.html
Thanks!
Yea I have the JL9 option now. Any idea if grand sport calipers and the j55 rotor combo would work together?
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Thread Starter
Racer
Joined: May 2007
Posts: 424
Likes: 0
I believe Doug Rippie still sells that spring. The J55 is bigger calipers and rotors. I switched to J55 on my 86 with the DRM bias spring.
If you have a big cam, then you are probably low on vacuum and the booster is not working fully. I would suggest adding a vacuum reservoir to keep the booster working .
If you have a big cam, then you are probably low on vacuum and the booster is not working fully. I would suggest adding a vacuum reservoir to keep the booster working .
Yea I ended up finding the drm spring and ordered it. In the process of adding a larger vacuum pump as well right now.
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
The C5 pads have more surface area, the C5 calipers have larger pistons.
The C5 calipers dissipate heat better since they are vented. They're also a superior casting.
The C5 rotors are wider than the J55 by more than 1/8".
The C5 calipers are so much larger than the J55 that a J55 caliper can fit inside a stock non A-mold 17" wheel, while a C5 will not, despite the J55 rotors being a larger diameter.
Also, if you swap to C5 brakes, you can use C6 calipers instead which are yet another step above.
Not to mention C5 rotors/calipers/pads are readily available at lots of local parts stores and are half the cost of the J55 stuff.
The only reason not to spend the money on the C5 vs the J55 stuff, is that you already have the J55 on your car.
Thread Starter
Racer
Joined: May 2007
Posts: 424
Likes: 0
The C5s are absolutely an improvement over the J55. Rotor diameter is barely a piece of the equation on that one.
The C5 pads have more surface area, the C5 calipers have larger pistons.
The C5 calipers dissipate heat better since they are vented. They're also a superior casting.
The C5 rotors are wider than the J55 by more than 1/8".
The C5 calipers are so much larger than the J55 that a J55 caliper can fit inside a stock non A-mold 17" wheel, while a C5 will not, despite the J55 rotors being a larger diameter.
Also, if you swap to C5 brakes, you can use C6 calipers instead which are yet another step above.
Not to mention C5 rotors/calipers/pads are readily available at lots of local parts stores and are half the cost of the J55 stuff.
The only reason not to spend the money on the C5 vs the J55 stuff, is that you already have the J55 on your car.
The C5 pads have more surface area, the C5 calipers have larger pistons.
The C5 calipers dissipate heat better since they are vented. They're also a superior casting.
The C5 rotors are wider than the J55 by more than 1/8".
The C5 calipers are so much larger than the J55 that a J55 caliper can fit inside a stock non A-mold 17" wheel, while a C5 will not, despite the J55 rotors being a larger diameter.
Also, if you swap to C5 brakes, you can use C6 calipers instead which are yet another step above.
Not to mention C5 rotors/calipers/pads are readily available at lots of local parts stores and are half the cost of the J55 stuff.
The only reason not to spend the money on the C5 vs the J55 stuff, is that you already have the J55 on your car.
yea I’m just looking to keep the wheels I currently have that’s my only issue and why I was looking into the j55 option along with grandsport calipers
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
The C5s are absolutely an improvement over the J55. Rotor diameter is barely a piece of the equation on that one.
The C5 pads have more surface area, the C5 calipers have larger pistons.
The C5 calipers dissipate heat better since they are vented. They're also a superior casting.
The C5 rotors are wider than the J55 by more than 1/8".
The C5 calipers are so much larger than the J55 that a J55 caliper can fit inside a stock non A-mold 17" wheel, while a C5 will not, despite the J55 rotors being a larger diameter.
Also, if you swap to C5 brakes, you can use C6 calipers instead which are yet another step above.
Not to mention C5 rotors/calipers/pads are readily available at lots of local parts stores and are half the cost of the J55 stuff.
The only reason not to spend the money on the C5 vs the J55 stuff, is that you already have the J55 on your car.
The C5 pads have more surface area, the C5 calipers have larger pistons.
The C5 calipers dissipate heat better since they are vented. They're also a superior casting.
The C5 rotors are wider than the J55 by more than 1/8".
The C5 calipers are so much larger than the J55 that a J55 caliper can fit inside a stock non A-mold 17" wheel, while a C5 will not, despite the J55 rotors being a larger diameter.
Also, if you swap to C5 brakes, you can use C6 calipers instead which are yet another step above.
Not to mention C5 rotors/calipers/pads are readily available at lots of local parts stores and are half the cost of the J55 stuff.
The only reason not to spend the money on the C5 vs the J55 stuff, is that you already have the J55 on your car.
The C5 calipers stronger castings will reduce flex and spreading much better than J55 pieces and don't discount the fact that C5 parts are more readily available and cheaper than J55 stuff.
Last edited by mako41; Jul 16, 2020 at 12:16 PM.
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
Safety Car
Joined: Jun 2010
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Thread Starter
Racer
Joined: May 2007
Posts: 424
Likes: 0
Looking into another option now ...you can get a c5 willwood kit front and rear for $1600? Could these go on a c4 with the c4 to c5 brake adapter? Seems to good to be true considering the c4 willwood fronts are $1600 or so alone and you could get a complete c5 setup for roughly the same cost plus the brackets? Has anyone done this?
Pro
Joined: Oct 2017
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Thread Starter
Racer
Joined: May 2007
Posts: 424
Likes: 0