Jon, (of course), has it right.

My car is slightly front-biased on the brakes, but not by very much, and I can lock the rear brakes.

We tested / adjusted it on an empty, wet parking lot so we could observe the wheels under hard braking. We were somewhat conspicuous as we had a floor jack, and jack stands to make adjustments.

At one point a cop stopped to see what we were up to. While I was thinking about how I'd explain what we were doing, he just drove off...

My buddy, (who regularly races) had the same concern as Jon, and was surprised at how balanced the brakes felt. And then told me I have to get grip-pier tires...

Perhaps that slight front bias might seem worse at 120 mph... Good thing I'm not tracking the car, (though he keeps trying to get me to do it).

All-in-all, I prefer the more positive and easier to modulate pedal feel. I wouldn't go back. (And I have all the old parts to do it).

Again, just one guy's opinion.

Edited November 27, 201212 yr by Oiluj

If the brake balance is right, the 4x4 front caliper upgrade helps a little with increased heat capacity, mostly due to increase fluid capacity in the caliper and increased caliper mass. If you go the vented rotor S12W caliper you'll get a significant increase in heat capacity.

If the brake balance is right, the 4x4 front caliper upgrade helps a little with increased heat capacity, mostly due to increase fluid capacity in the caliper and increased caliper mass. If you go the vented rotor S12W caliper you'll get a significant increase in heat capacity.

And weight. 8(

Setting your brakes in the wet will get the proportioning right but only for wet conditions! In order to "set and forget" brake proportioning, it must be set in the highest grip scenario. Setting your brake distribution in the wet will cause the rears to lock-up prematurely in the dry. That is a dangerous setup.

The physics behind it have to do with decreased weight transfer in lower-grip situations. Less weight transfer means more weight on the rear axle, thus you need more rear bias in the wet. This extra rear bias then locks up the rears early in dry situations where there is more weight transfer to the front axle, leaving less weight on the rear.

Leon,

Nice explaination. I may have to look at re-adjusting. Given my set-up, at least I have the ability to reduce rear grip.

The parking lot was wet, but not "slippery", so my guess is that it may not be too far off.

Here is an example of what we are doing with 914 brakes. These are a reverse-engineered set of Porsche brakes. They weigh in at a whopping 3# each and shave 10# off the rear of a 911 or 914. They also happen to be the same brakes fitted to the Ferrari 308 series. Performance numbers are the same with the exception that they give up heat so much faster. We are thinking we might want to do the same with the Datsun Competition Sumitomo calipers if we can get our hands on a set. Pardon the Christmas marketing photo...

The thing I'd worry about with an Al caliper is deformation, especially with a large brake load applied at high temperatures. The dimensions of something like a Z-car Sumitomo caliper are based on the properties of steel. Was there any structural analysis done on the Al calipers? Any strenuous track testing?

Caliper flex is not a good thing.

We have engineers. 8) Flex apparently is a function of the fastener. The fastener in this case is more than adequate to prevent flex.

Oh, and to answer Leon, yes they are track tested.

The Wilwoods sound like a bargain.

Julio's 2nd rule of engineering is: "Don't build what you can buy".

I admit to sometimes violating that rule for "fun", but not with my employer's money.

(I have five rules of engineering)

The Wilwoods sound like a bargain.

Julio's 2nd rule of engineering is: "Don't build what you can buy".

I admit to sometimes violating that rule for "fun", but not with my employer's money.

(I have five rules of engineering)

Julio,

Are you thinking we are doing this at work? Nope...

No. No. No. I wasn't implying you use your employer's resources, nor did I intend it to be interpreted that way. Written communications can be poorly worded or mis-interpreted...

There were two messages in the last post:

1) My engineering rule above, which is self-explainatory. I literally had that conversation with someone at work today. Engineering time is expensive...

2) I wanted others to know that when I violate that rule, I don't do it at my employer's exspense.

i.e. When I used the model shop at my last job, I brought my own materials or paid the shop/company back in other ways. They didn't care, but I did. A "personal honor" kinda thing.

No negative reflection on you intended. We good?

Edited November 29, 201212 yr by Oiluj