Non vented rear discs?

[Eric Howell]

How bad are they from a performance standpoint?
The brakes in question are from an Exploder 8.8. It's fairly common to swap these rears in to S-10's but I'm not sure about the brakes.

[silver69camaro]

What kind of performance are you talking about?

I wouldn't use solid rotors, but if the diameter is big enough, the heat can still be shed off fairly well.

[Eric Howell]

I would like to start auto-crossing and maybe go to the Year One Experience once the truck is done. It will definitely get beat on.

The rotors are 11.25 and 12.1mm (0.476) thick.

[Apogee]

In short auto-x type events, they should be fine with some decent pads. Any HPDE track days will probably push them to their limits and beyond...it just depends on how and where you drive it. My friends S2000 has solid rear discs and they're definitely the weak link in the brakes. Ducts help, but the only way to actually get them to work like they should for a full 20-30 minute session has been to run aggressive track pads like the Hawk 9012 Blues and consume rotors. The stickier the tire you run, the harder you can be on the brakes.

Tobin
KORE3

[NOGO]

I run stock Explorer discs on my Nova and they are fine for autocross. You dont build very much heat on autocross compared to road racing, and the rear brakes dont build the heat up nearly like the fronts. There are aftermarket companies that sell drilled and slotted rotors for Explorer brakes if you want to go that direction.

[Eric Howell]

Thanks guys. Think I'll go ahead and get the rear end. If it ever does see track time then rotors will just be an additional cost.

[jknight16]

I believe more people have had issues with getting these brakes to balance out well with a set of fronts than they have with them being solid rotors.

Marcus at SC&C and I were discussing this when I was shopping for brakes and this was the concern he mentioned. So make sure your fronts are going to play well with these rears, or your truck may have brake bias issues that are beyond what an adjustable prop valve can tune out.

[Eric Howell]

Never even crossed my mind. The truck is going to have C6 up front. I have been trying to find the bore size of the ford calipers but no luck yet.

Is the problem due to the size of the rotor or the caliper?

[jknight16]

Most people don't think of it and it ends up causing them to buy things twice. Ask me how I know...( I have a lincoln versailles rear disc setup if anyone needs them:machine:)

It is the size of the caliper that creates the balance issues. Tobin is your man if you're doing C6 calipers in the front. He knows what works well with those brakes.

[Eric Howell]

After a bunch of searching I came up with 1.88 caliper bore for the Explorer if that will help.

[Apogee]

Eric, you are correct that the Explorer rear caliper piston diameter is 1.88" [47.8mm], which actually compares fairly favorably to the C5/C6 counterparts which have 1.77" [45mm] pistons. This means that you have about an 11% larger piston area and a 7% smaller rotor diameter (11.22" versus 12.0"), almost negating the difference. We've got plenty of customers running C5/C6 fronts with the larger C6 Z51 rears with excellent results.

The wheel pattern for the Explorer is 5x4.5 with a 2.78" center bore, so that will probably need to be addressed as it won't match the GM standard 5x4.75x2.78. Lug-centric rotors are not a good solution for a performance application IMHO.

Tobin
KORE3

[Eric Howell]

Thank you again Tobin.
The rotors and axles will end up getting re-drilled unless it needs spacer/ adapters to run the wheels I want. Didn't know the rotors are lug centric but that should be easily solved with a spacer ring.