mm86911

Planning for upcoming track event and inquiring if anyone has experience with mixing brake pad compounds (different material front and rear).

Will be testing following setup:

(F) Hawk Blue
(R) Hawk HP Plus

Taking the spare HP Plus pads for the front in case the results are undesirable. I am aware of the need to get some heat into the Blues before they start to grip (compared to the HP Plus). Primary concern is car balance coming off 140 mph straight.

Done several DEs with both stock pads (fade far too quickly at Road Atlanta) and Hawk HP Plus. Last August with 95 ambient and 135 track temps I was experiencing alot of fade in the front with the HP Plus pads. Had to bleed the front calipers at end of each day.

From what I from remember in August seemed that the rears were dusting MORE than the fronts.

BTW - Calipers are fresh rebuilt stock, fresh rotors, dust shields removed and running ATE Blue fluid.

Ted Drake

I have always used same brand pads front and rear.
Imho run the same but superior pads front and rear.

If the front brakes are still over heating consider front brake ducts.

If you plan to race at high speeds maybe you need bigger brakes?

If the the brakes are working correctly but you dont like the bias then install a brake bias control.

Your concept may work though consider this on your test session.

What if your front brakes take longer to heat up, are you going to be locking up the rears during your first laps? Careful braking on cold race tires in corners, might be like pulling up your E brake on a curving wet off ramp.

Then for a couple laps they may be balanced?

Then towards the end of the session will the fronts be locking up as the stock rear pads may not be as grabby at racing temprature?
Flat spotted front tires?

ninefiveone

I run different compounds front and rear at every event. I'm running Pagid blacks in the front and street metalmasters in the rear. For my usage, this nets me very even braking.

Bill Gregory

Mike,

To expand on what Ted said, what brake cooling do you have today? You've got several good choices for your 86 911, whether it's an under a-arm scoop and hose to a fitting which feeds air to the center of the rotor (Weltmeister [available thru several sources, I like Paragon Products], OG Racing, AJ-USA all carry these), or if you have a hole in your front valance you can run a hose to a cannister feeding the center of the rotor. You would also want to get an additional piece to close off the hub, so the air goes out the rotor vanes and not out the hub center. Smart Racing has a stainless piece for around $35/set which work well. OG Racing's kit comes with them. This type of cooling makes a huge difference.

Another option you have is to put titanium shields in between the pads and caliper pistons, to slow the flow of heat to the pistons and brake fluid. Seine Systems sells these for $120 per axle set. (www.seinesystems.com) I used these on my 964, and when combined with brake cooling (if you can call it that on a 964), helped to contribute to going longer times between brake bleedings.

mm86911

Thanks for the feedback all. No brake cooling system in place currently but have researched and will likely do that in the spring. Mike F on PP board (see post there) will be at same event in January so we'll compare notes on titanium shields.

James-man

Any additional information on titanium shields?

I checked out www.seinesystems.com and the price is lower now, but they are only available in limited sizes. It looks like I can only get them for rears.

While I plan to increase my front brake duct capabilities but would like to get ti shields to replace the anti-squeal shims that I warped last year.

Perhaps a job for a local machine shop? Is DIY out of the question?

Thanks.

JCP911S

In theory, mixing pads is a way to compensate for F/R bias.... PCA CR does not allow bias control, so if you have an issue, that is one way to deal with it.

However, it needs to be carefully worked out as pointed out above different compounds have different heat characteristics torque characteristics etc, etc... if the compounds are not complimentary, you could cause the system to be very inefficient.

A930Rocket

Not to hijack, but I just replaced my rotors and noticed that the outside of the rotors were showing a lot more stress than the insides (radial cracks from holes to edge on outside of rotor). I have the brake cooling ductwork going from the hats to the air dam. Any way to even the cooling out?

KOAN

I have balanced my brakes successfully on my Audi by using different pads F/R. The balance is better, and the pads/rotors have lasted longer, with no lock-up. I do have aftermarket brakes, though, and my efforts may be compensating for unbalanced braking F/R. Don't be afraid to experiment, but realize that you are experimenting, and drive accordingly.

SundayDriver

I would start by calling Hawk or other pad mfgs. They should have a very good starting point for pad mix to balance a car and will know which compounds have similar characterisics where it counts. Many of the mfgs web sites list suggested mixed - I don't recall if Hawk does that.

Bull

I work closely with a Hawk Distributor (as a sub-distributor), and haven't seen a suggested "mix" chart. They do often have customers mix the Hawk blacks (front) with the Hawk Blue 9012s (rear). I find that the same compound front and rear works best for my car.

SundayDriver

Here is one example I quickly found on the Hawk website. If you dig, you may find others...

DTC-70 Extremely high torque with aggressive controllable initial bite. Superior release and torque control characteristics. Brake pads designed for cars with high deceleration rates with or without down force.

DTC-60 High torque with less initial bite than DTC 70. Superior release and torque control characteristics. Brake pads designed for cars with high deceleration rates with or without down force. Recommended for use with DTC-70 when split friction between front and rear axle is desired.

ceboyd

I happen to run EBC Yellowstuff in front and Pagid BLACK RS14 in back on my TT setup on my 993 (nice for 'cheating' on brake bias too)

Bull

Yes, there is "if you were to want/need this" type info on some mixing. I was responding to the request for a definitive chart for mixing compounds. Obviously, any compounds CAN be mixed and it depends on the needs of your car/application.

bgiere

i used different compounds of Performance Friction pads when i DE'd the 1987 911,,,PFC 97 on the rear...can't remember what on the front...I think the 01...was very nice...a little hint...use Motul RBF 600 and the AJ USA Brake cooling kit...it really worked for me at Mid-ohio's long straights...ATE Super Blue would always boil for me for some reason...never had a problem after i made the changes...good luck to you... i am confident you can find a combo that will work...the SC/Carrera brakes are great once they get setup for your driving style.