'J' compound from Wilwood

[rdorman]

Any one running the 'J' pymatrix compound from Wilwood? If so, what is your experience with them? Dust, noise, Rotor wear, temperature?
Thanks
Rick

[rdorman]

ttt

[Roscoe]

Rick,
I guess no body is running them. For what it's worth I use the Porterfield carbon kevlar pads R4-S. They are great for street and track, rotor friendly, low dust, no noise and nice and grabby.
Roscoe

[rdorman]

I have heard a number of people mention the R4-S pad. But with the balance, peddle effort, etc that I am trying to accomplish I am in need of a higher CF pad. The R4-S is .4, similar to the EBC Kevlar pads I have run, where the J compound is .58.

I have completely 'reversed' engineered the system that was on my car from a performance for intended use and 'feel' standpoint. The system is getting very close to where I want it to be. The J compound, larger front master cylinder, made to fit pushrods and a freshen of the other master cylinder should complete it.

Lets just see how good my math is!

So no J compound user eh!?

Rick

[rdorman]

Good news and bad news.

Before I get to the details, I post this because I know that many of you have fought with brakes that you consider to be inadequate. So, learn from my work, trial and error and expense. I tried to keep things generic so you can adapt them to your application.

The good news is they work great! Very smooth engaging and disengaging. Very high coeficient of friction and have to even hint at fade (good past 1300 F. but I don't do any long track stuff so not a real good test!). Car has NEVER stopped better. Very easy to modulate and greatly reduced peddle effort.

Bad news. The dustiest pad that I have ever seen in my life. If you where at DVSFIII, then you probably saw the mess they make. These are race pads, pure and simple. HIGH rate of wear unless they are HOT. When they are hot they last virtually forever (so I am told).

Where am I now. I went back and did the math. I can get nearly the same balance and brake torque from the low dust 'T' compound if I go to the 12.19 rotor over the 10.75 one that I have now, so that is where I am going next. Unless there is something else I missed, this should be it.

This the final setup that works very well (for track time you will want a higher temp pad, fine for autocross but not Mid-Ohio!).

- 2740 lbs. with me and half a tank of gas running hoosier TD's (street tire won't come near this grip, generally, so this might be a bit much for a brake setup). 45/55 weight distribution.
- 5 to 1 peddle assembly. Mine is from Neal, doesn't really matter
- 5/8 rear master cylinder, 7/8 front. Balance bar is almost perfectly centered.
- Two pot 1.625 rear calipers (mine are jag/girling) clamping a stock sized jag rotor (I have to double check but seems to me the rotor is about 9.75 inches in diameter. Using a .46 CF pad (mine are EBC Greenstuff pads, they work very well. You could go to Yellow or Red for racing but I don't recall the CF).
- Four pot 1.75 inch front caliper (mine are wilwood billet dynalites) clamping a 12.19 rotor with about a .42 CF pad (mine are wilwood 'tan' pads, Q for a bit more torque and heat range ). All fits inside a 15" rim (check your rims first! you need at least 14 inches. Another eighth or two would be good.

What you get is a car that will stop very well. Peddle is high and hard as a rock with minimum travel. Peddle effort for a maximum stop is a reasonable 85 pounds. I can stop at a pretty good rate with out even having to get my leg into the game.

If you stick to a 10.75 inch rotor, all else being equal, your peddle effort will climb to about 103 pounds.

Once I have finished I will let you know. So far the math has been pretty much right on the money. Now if I can just borrow a G meter or make up some 'toppling' blocks, I can get some real numbers. More to come!

Rick

[750hp]

Rick, where did you find the Wilwood CF values? For what it's worth, I have the D compound Wilwood pads, and I can't believe how "normal" my braking system feels. Here's my combination : http://www.home.gil.com.au/~marsh/brakes.html

Here's what Wilwood say about their "D" pads.

PolyMatrix “D” compound pads have one of the highest cold friction torque values of any race pad material with strong resistance to fade or glaze during periodic sharp rises in rotor temperature. This makes it an excellent choice for light to moderate braking dirt tracks, drag racing and performance street category competition. "D" compound has a flat torque curve that provides immediate, predictable pedal response and superior modulation characteristics throughout the entire temperature range. Dirt track racers enjoy the positive response and smooth engagement qualities that won't upset the car during light braking on dry-slick race tracks. Drag racers can hold the car steady in the water and during staging, and benefit from the powerful feel of positive braking past the finish lights. Club sports racers experience the powerful stopping torque without excessive squeal and rotor wear.

[rdorman]

That is quite a nice set up you have there! With my 15" wheels there is now way I can fit those brakes!

If you go out to wilwood's site under products/brake pads you will find a pdf that has great charts of the pads CF and temp ranges.

My problem is that I can not run the big rotors, 12.19 is my max and I am going to them, so I need to relie on other factors such as pad CF. Plus since I drive on track tires, all the time, my maximum stoping force needs to be a bit higher than most.

Is dust an issue with the D compound?

Thanks
Rick

[terry lee]

I HAVE THE "DL POLYMATRIX" PADS ON MY CAR WITH 15"WHEELS STOPS GREAT, BUT LOTS OF DUST. The good news is it washes right off.
I ALSO RUN THE SUPER HI-TEMP BRAKE FLUID.

TL

[rdorman]

Seems the only polymatrix pads that are not dusty are the T and Q pads.
Rick

[Randy Rosenberg]

Hi Guys,

I could use a bit a help here on this subject...

I've got Dynalites with bridge bolts front & rear on my SPF with Trigo 15" wheels. And I've got 2 sets of brake pads:

1. Tan colored pads that I use with street tires.
2. Black colored pad that I use with slicks on the track.

I've got no clue how else to describe these pads... What "letter" code are these?

From my observations, the black pads grab like no tomorrow - they are unbelievable, yet really dusty and really squeaky when cold. The tan pads are quite and not very dusty at all, yet I'd like to find a pad that is 1/2 between these two, as I'd like a bit more "grab" with my street tires, yet I don't want all of the dust and squeal of my black pads.

So, 2 questions from what I've described:

1. What are the letter codes to the pads that I have?
2. Is there a recommended pad that 1/2 way between these two, and if so, then what is it's letter code?

Thanks,
Randy R...

[rdorman]

.. I can't help you based on the Color. Plus I don't recall if they have part numbers stamped on the back of the pad or not.

Follow this link to the pad catalog and everything you ever wanted to know about Wilwood pads!

http://www.wilwood.org/PolyMatrix%20Catalog.pdf

Rick

[Cal Metal]

Rick:

Could you provide some data on what the lettering designates. I had a discussion with an engineer at CarboTech--pads I use on my Plymouth Neon ACR--and he was discussing the lettering system to me but didn't have any specific info to send me. He did mention a site that dealt with material and coefficients of friction but I couldn't locate it on the web.

Any info would be appreciated.

[rdorman]

The letter is the different compound. The link I have above lists them all.
Thanks
Rick

[terry lee]

Originally posted by rdorman


The letter is the different compound. The link I have above lists them all.
Thanks
Rick

After double checking the above link and my invoice; the part number for the pads I am using is "7112E," with the compound being "E". I have no idea what the "DL" stated in the invoice is for. So far, they work really good for my type of track driving.
Sorry for the confusion.
TL

[rdorman]

I think the DL is for dynalight or the type of caliper. Just a guess! The Q compound has a similar CF with a slightly reduced tempature range and are the low dust variety. If you are looking to cut down on the dust you might give them a shot! Take a look at the chart on page seven and you can see the difference in CF vs. temperature.
Thanks
Rick

[750hp]

Rick - I had a look at the pdf Wilwood file that you mentioned. Very interesting. I wish I had seen that before I ordered my pads. I think I might have gone for a slightly higher heat range. I was at a local racetrack, and doing sustained stops from 150+mph. I hope the pads don't glaze or otherwise fail as a result of operating above their nominated heat range!?!?

Randy - my pads had the part number stamped onto the backing plate, and printed onto the top of the actual pad material.

[Randy Rosenberg]

Thanks guys... I feel like a schmuck. I wrote my post (question) from work, and when I got home I found my brake pad boxes with the part numbers on them.

My street pads are: 15T-5912K
My track pads are: 15B-3999K

Reading thru the Wilwood catalog (Thanks Rick), I'm wondering if "Q" or "E" pads would provide me with a bit more brake grip on the street without being noisy or dust. I'm leaning towards the "Q" pad from what I've read.

Any suggestions or recommendations?

Thanks,
Randy R...

[rdorman]

It is a great catalog isn't it? I have not found any other company that releases the kind of great information that wilwood does.

My impression about the dust issue is that if it doesn't say low dust, then it is high dust! That leaves us with Q and T compounds (unless I missed one). Look at the CF graph for the Q pad and you will see that they work better (higher CF) as they get hot.

I just took off the J pads this weekend and put the T back on. I could not live with the amount of dust from the J pads on a day to day basis. In order to come close to the brake torque produced by the J pad with the T pad I have to increase my rotor size from 10.75 to 12.19 and STILL the peddle effort will be slightly higher(all else remaining equal). The Q pad would make up the difference. I think that shows just how much higher friction in a real world, quantitative way, the J pad grip is above the T.

Big brakes make the whole equation easier to solve for a street car, but remember, F1 runs 13" rims! They also have a billion dollar a year budget!

Rick