Ok so I have a 92 coupe with base suspension/brakes.

I can upgrade to the 13" rotors and larger calipers or the GS ones.
I could also get C5 conversion brackets and use C5 and/or Z06 brakes.
Then there are the very pricey Baer, Wilwood etc... upgrades.

Does anyone have any benchmarks showing quantitative proof of how much stopping distance improvement each or any of the above do?

I'm not looking for "butt dyno" or "yeah they feel better".

Thanks

 

C5 brakes are better than the 13" C4 J55 brakes. C5 brakes won't work with stock sawblade wheels. If you want to run C5 brakes, you need A-molds or C5 wheels (or aftermarket). Lowest cost upgrade is C4 13" J55.

Oh, yea, you can always run with spacers...but if I was upgrading my Vette, I wouldn't use spacers on my wheels.

 

Do you track the car?

Is it just a sunday driver/cruiser/daily driver?

Can you currently lock the tires up before ABS kicks in?

Do you experience fade/soft pedal?

 

Check out "road test results" from people like road & track

I found the C5 had superior braking over any C4 including the 13' j55

So I did the C5 conversion on my 88. No need to do the back brakes since C4 and C5 rear are basically the same.

But I did add the DRM proportioning spring!

I can tell you the published test results weren't wrong!

C5 with standard roters and stock pads are awesome. Upgrade to hawk pads if you want more.

There have ben magazine tests of baer and others compared to stock C5 and it looks like for about $ 4,000 more, you can shave about 6 feet off your 60 to 0 mph braking distance. $4000 for six feet is....?

You may be able to get the C5 behind the sawblades without spacers

Jack

 

Jack, that's for one time, 60mph-0mph. Try it 6 times in 2 minutes or once from 120mph and you'll see what the extra dough gets ya.

IMHO, 60mph-0mph is a magazine test, it doesn't reflect real world braking, but all the advertisers (auto companies) have decent results.

 

Thanks guys keep it coming.

To answer your questions and some of my comments.

It is my daily driver for work.

It is also my autocross car. And it may make it to a couple of HPDEs.
It's an A4 so it won't see much track time. Works just fine for autox.

I have come very close to locking them up before ABS kicks in but not usually. And only since I went to the HP+ pads.

No soft pedal or fade doing autox.

I did take off the PFC carbon metallics I had and put on Hawk HP+ pads.
That made a big difference. They even grab quite well on the 1st pass and don't seem to need a lot of heat. But they are dusty little buggers and will no doubt eat my rotors up.

I've looked at the J55 conversion as a good inexpensive upgrade but I wasn't sure it would improve stopping distance. I get the impression that they will only improve fade since the rotors are 13". More surface area... Fade isn't really an issue in autox.

Doing the C5 upgrade might be a problem. I run C5 wagon wheels with my street tires and run 18x9.5 all around. I had them black powder coated so they give the car a different look. My autox wheels are my original sawblades. Using spacers for autox only wouldn't be terrible but a 1/2" spacer sounds pretty thick to me. Especially in the front. I assume I would want to put spacers on all 4 wheels.

Are those fair assumptions?

Graham

 

Don't even waste your breath. I think Jack would recomend the C5 brakes to the C5R team. That's why one of the most imprtant questions is what does the owner use his car for.

 

Graham, one thing to consider is, will the upgrade bump your class in the autocross? If it's going to put you in the prepared class, you had better get your check book back out and get ready for the other mods to become competetive once again.


At this point and time I don't think a upgrade is needed. Depending upon which track you hit for your HPDE, you may eventually need some type of upgrade after getting cooling to the brakes and decent fluid and pad compound.

 

Thanks Jeff. Yeah I'm aware it would bump me from AS to BSP. I was trying to gauge what the braking improvement would be worth as I was considering moving into BSP. I've been tinkering with the idea of coil overs for a while

I've read the posts on the home made brake duct cooling and that is on my list of things to do over the winter. I can use it for HPDE then block them off for autox so I don't get bumped. A friend has done it so I can look at his car for reference. He tapes over the openings for autox so they are defeated. No one has complained about it.

Graham

 

not if you're going to C5 brakes. C4 and C5 are two different platforms, so no updating/backdating between them. C5 brakes will bump you all the way to BP. (or maybe SM2, i think they might be open on brakes.)

(coilovers aren't legal in SP, either, for a car that doesn't have the springs over the shocks/struts from the factory. so it's straight to BP with coilovers, too.)

fwiw, for auto-x there's not much difference even between the 12" brakes and J55 brakes. in fact, some of the competitive BSP cars go back to the 12" brakes so they get up to temp quicker, and weigh less.

-michael

 

Well then, you came to the wrong place unfortunately.

 

Jack, your maximum braking ability is only as good as your tires are sticky. If you can lock up the tires, you're not getting any more out of your brakes.

My stock 85 brakes stop 60 to 0 in 127 feet. But after 2 hours of hard driving, they've nearly taken me 1500 feet down the cliffside. twice. Now I've got more spent on brakes then the rest of the car.

High performance brakes will actually INCREASE your stopping distance in city driving, because the pads won't be in their temperature range.

 

I am running new Kumho's stick like glue!

I run the "tail of the dragon" and similar roads for 350 miles per day at fairly high speeds and very aggressively and the stock C5 brakes don't fade and don't seeem to loose efficiency.

I am probably "hitting" the brakes a little about 15 to 20 times per mile. to scrub off ten to twenty miles per hour through a turn.

Jack

 

Here's a thought: Are your existing brakes working like they did from the factory.

I had a bad master cylinder and couldn't even get the ABS to activate. Changed it, put in the bias spring and bled new fluid. The difference is remarkable.

That's with the same old pads and rotors. 12" fronts.

The C5 thing is nice, but far from free. Cheaper than BAER and Wilwood, but still expensive.

note: I don't autocross or race. I want emergency braking first and hot braking second.