dizwiz24

I'm an engineer for a major tire company and know that - for straightline traction, a 315/35R17 is going to provide more contact patch (contact width is the same, but front to rear contact patch is more) vs. a 315/30R18.

So I dont consider the 18's or 19's as a trade up. Unless you count the looks. However, being an engineer I am more concerned with function than vanity for the street/strip type driving I do.

Now, if I had a dedicated road racer, the decrease in sidewall height might increase responsiveness to a point where Id notice an improvement.

Of course, dedicated road racers are also concerned with unsprung weight too, and the larger 18 or 19" diameter wheels adds mass in that category.

What will probably push me (unwillingly) into the direction of 18's or 19's is a phase out of the 17" based tires that I rely on as tire manufacturers shift attention away from those UHP lines. Even my buddy at GDYR, a fellow corvette owner/buff, couldnt get GDYR to keep making Eagle F1 Supercar in the 315/35R17 size. They discontinued that line and I hope they continue to at least provide the Eagle F1 GS-D3.

At that point, I will go to the 18's & 19's I need to support these great Z06 brakes !

Thanks for the adapation of these to C4s !

87L98Z52

Yea,how are the brakes man??

drmrman

So far they are great! Made a couple high speed pulls and slowed to a crawl multiple times to bed the brakes (on a closed course) and they felt GREAT! Because the rears take up more stopping power the nose barely dives anymore and the fronts have less tendency to lock up! Which is great because the ABS comes on much deeper on the pedal.

87L98Z52

SWEET!!
Im looking to do this,i shot an email over to Jeff about the front brackets but havent heard from him yet.
Dont know if he has them for an 87.

856SPEED

Great write up....very informative......

lt1396corvette

This looks like something I'm gonna do.I like the fact that you did the rear with the front.

Charleston2012

Looks great. One question though. WIth all that rotor real estate, is it really worth it as it doesnt use all the rotor for pad contact. Look at the wear marks and you can see allot isnt even being touched by brake pads.
Seems a waste of rotor.

gkrynick22

great writeup! This is coming up on my list of things to do soon. I will definitely save this thread and use it for my install. I have factory z06 wheels, so clearance shouldn't be a problem. I have an 85 so my install is probably a little different. Thanks for taking the time to take pictures and detail this out!

drmrman

Your going to have to take that up with GM I didnt engineer the pad and rotor set up

drmrman

Im not sure if the C5Z06 rims will clear the C6Z06 brakes?

Charleston2012

I understand that. But, will it stop you in a shorter distance than the factory J55 brakes, if using the same compound pad. More than likely it will , and look better to boot.

gkrynick22

Crap, never thought of that. Might have to go with C5 Z06 brakes then.

Aardwolf

Doubt it, but would like to see it tested. Could be worse actually. Lots of articles at Stop Tech.

http://www.stoptech.com/tech_info/wp...upgrades.shtml

Kubs

All of the wear is toward the outside of the rotor where reducing reducing the torque is most effective. Hes not giving anything up by not using the whole rotor.

The increase is braking force will be a little bit better, but it is not worth the cost of Z06 brakes. They are not all that great, and a BBK would be similar money and more effective. Even C6Z owners ditch the stock brakes for a BBK. If looks are all its about then yes they do look killer on a C4, but I wouldnt think of it as a braking upgrade.

87L98Z52

Well this wld be lightyears ahead of my 87 brakes!!!
Still cant find someone that makes the front adapter bracket to put these brakes on 85-87 vettes though!!

People he used for back brakes make same setup for the 85-87,its jst fronts that are the problem.

drmrman

I wouldnt go that far... ANY brake swap is an upgrade for the C4! You should know that!

And if you are talking about track performance then the C6Z06 brakes are not ideal. There have been TONS of threads on this forum about how there are many upgrades from the Z06 brakes and if your budget allows for it then I would sudgest streching your dollar and going for an aftermarket companys. But this is a street car thats driven hard. It works for my set up just perfect. If you want to talk about cost... I paid a fraction of what it would cost to do a stoptech or other company. Also I feel that these brakes are great for the C4 platform being that the C4 weighs almost the same exact amount as the C6Z!

Kubs your a cool dude so If you want to talk numbers you can send me a PM But I had NO plans on upgrading from the C5 brakes until I got this deal on the Z06's!

drmrman

I had them and I loved them! Great upgrade for the C4 brake system! I had the C5 brakes with stoptech rotors and HAWK pads!

grantar2

The price for the Z06 calipers isn't that bad refurbished.

My question is more about wheels, since that is what is going to cost me the most (I have 3 sets and would need a min 2 sets). Are C6 Z06 wheels the right offset for a late model C4 (in my case 1990), or do you have to go repro and specifiy an offset. What size tires are you running? Any rub issues. If I upgrade would expect to run 315/35/18?

neat

What shim are you talking about behind the axle nut? All I remember being behind the axle nut was a large washer. There is a wear shim between the bearing and the outer stub axle, but I've never heard of needing to stack them on top of one another.

For those of us who are less knowledgeable, can you expand on that issue some?

drmrman

You are 100% Correct it is not dirrectly behind the axle nut it was in between the axle and the bearing capsule. I had to add 2 shims to the drivers side because I was experiencing binding as I would torque down on the axle nut. I BELIEVE I have some videos of it binding still. If I remember correctly I took them with my cell phone and the quality was not that good. When I spoke to SSI about why I needed to shim one side and NOT the other, they said it could have been due to a few things, Temp... worn tooling... Ect...

Like I said Ill try and find the vids later tonight when I get home from work.