Exactly. You guys don't even list if your wilwood setup was designed around the single piston front non brembo's, dual caliper front non brembo's, or OEM brembo's. They all have different rear setups so the brake bias is going to be different on all of them

 

I'm not interested in playing this game guys I simply don't have time. A couple of us have had an enjoyable and intersting conversation about the business in general. I'm good with that.

If you want to crunch numbers all day and tell me why you feel that one design or another is better be my guest. I've even provided the interactive on line calculator to do so.

http://www.tceperformanceproducts.co...alculator.html

I'd suggest however that before you make too many statements you might want to explore both what bias is and how it's measured. Then evaluate how that interacts with both the dynamic needs of the vehicle as wel as proportioning issues. Post up your findings of the stock set ups first and if I have time we'll go from there.

 

gotta love the 1 trader rating

 

Last I knew, Wilwood doesn't actually make kits for certain cars. It's the vendors that put the gets together. I am almost positive TCE put the kit together for you and it's not an actual kit from Wilwood.

Edit: Nevermind I see they make kits now. Back a few years ago they really didn't do that.

 

Differences in even the oem systems: Front rotor size went up 1.06" and it went from 1 piston to 2. (don't have the piston areas though).
That resulted in the rears going up 1.18" even though the pistons went to 2

'05+ Sedan and Coupe, '06 Sedan X
Front: 12.6-inch X 1.1-inch power-assisted vented disc - 2 pistons
Rear: 12.1-inch X .63-inch power-assisted vented disc - 1 piston

'03 and '04 Sedan, '04 and '05 Sedan X
Front: 11.7-inch X 0.9-inch power-assisted vented disc - 1 piston
Rear: 11.5-inch X 0.6-inch power-assisted vented disc - 1 piston

'03 and '04 Coupe Brembos
Brembo® brakes
Front: 12.76-inch x 1.18-inch power-assisted - 4 pistons
Rear: 12.68-inch x 0.87-inch power-assisted - 2 pistons



One of your kits for the 03/04, increases the pistons from 1 to 4 and increases the front rotor sizes from 1.5". Yet there is no rear kit offered or suggested.

 

I have one because I put the ads up as a tester. I've only put up two ads. Both of them sold (although ebay didn't get their cut on one)

I understand you guys are skeptical, you're supposed to be. I'll let the products speak for themselves. Do your research, know what you're buying, and make an informed decision.

 

I don't understand why WE have to do our research. How come you can't show us YOUR research? YOUR test results? YOUR front/rear bias caclulations?

 

I think regardless this kit will help a fair amount over the non-brembo kit. It may not be the perfect solution or have the perfect bias but it would help.
It's not priced like a stoptech kit for that reason...

 

I suspect my reply wil have some natives restless. Why not post the bias of a Wilwood kit. (clearly no other supplier does but pay no mind to that either) So I did some quick calcluations for those who want them.

Keep in mind that brake bias is not the sole component of or bench mark of brake system performance. It's simply a numerical ratio of static values put into a formula. Is 80/20 better than 70/30 or 60/40? There's no direct answer to that.

So assuming a front and rear factory Wilwood kit here are your bias ratios:
72/28
78/22
68/32
75/25
76/24
69/31
81/19
80/20
74/26

Q: Ok, so which one is it?
A: All of the above.

Which one would you like it to be? While I mentioned that bias can be swayed by 5% very easily you can see that in fact you can alter bias by well over 10% with some foolishness on pad selection alone depending upon which form of from kit you were working from; 13" or 14".

Which one is right for you? Again there's no easy answer. While some values maybe better suited for the street, others are superior on the track. What's best for a car of four around town is not going to be best on the front straight at Road America.

Moving one step further however it gets even messier. With many pads having varying torque curves what starts out as one ratio can easily become another. For the better or worse.

What's often overlooked in the great debate of "proper bias" is that you're often (as in this list) only reflecting upon static numbers. Putting these values into service may or may not net you the final results you have simply by the numbers. Why not? Because vehicle dynamics, tire adhesion, surface conditions and line pressures vary. The first are easy. Line pressure becomes more important howevrer. Pickng a value you like above might seem good at lower pressures, but when pushed if your chosen bias value elevates rear line pressure too much too quickly you'll hit the knee point before maximum rear rotor torque can be achieved. With static values you only assum constanat pressure. A street car doesn't work that way.

I'm not talking down the value of the question, I'm only telling those who don't understand all this that theere's no "magic number" that's going to be ideal for all occasions. While some companies tell you their kits maintain proper or stock bias as soon as you make the required pad change to do a track day you've changed that value. Same is true of the stock parts; if you feel that your stock system is best and put in a set of Brand X track pads up front and Brand Y pads out back because "that's what worked best for me" then you've altered the bias.

I'm rambling....sorry. Bottom line is that bias remains only a numeric value and can be easily altered to meet anyones desired spec.

 

The friction coefficient depends on the exact pad and rotor film temperature PLUS it changes as the rotational speed changes so the FUNCTIONAL bias changes independently and during an application.
Best one can do is calculate the changes in static weigh [based on wheel base] under one set of deceleration [0.95G] and at one speed..........in every other speed situation it will be wrong.

Why engineers data log pad temperatures thru out the race eventually they tweek it right.

 

Todd, why did you use a front AND rear Wilwood kit as your bias example?

Don't you think the Nissan/Infininti/Mercedes/Bmw engineers go though the same calculations as you + 10x more? Yet when they increase the front bias, they also address the rear bias. Even for a modest front bias increase.

I'm not sure why you use brake pad selection as part of your argument. No one ever specifically requires a specific brake pad when they offer their kits. So IMHO, it's a variable that can't be pinned down.

 

I'm not down on your thoughts here. But I don't see what your trying to achieve. One one hand your asking for further information and data but discounting a pad change as being of any importance when in fact we both know they are one of the main things buyers look to change on stock brakes. For the most part folks are looking to go from a 70/30 split to a 75/25 (example) if they install "track pads" on the front. Short of installing some monster pad on the rear nobody is shifting anything to the rear. And any gains from it would be questionable depending upon use.

The average consumer is not going to know or understand values less than 5% change. I grant you that extensive testing may reveal something there but we're talking real world not a lab. And with any decent kit (front only or front and rear) you sill have the same ability (or easier) means of tuning to your needs as you do on oem parts.

 

I appreciate your comments. My replies:

1) Most of my issues is with the front only kit being "acceptable". I have no issues with a front AND rear kit. That's actually my preference to keep the oem designed bias in place. Just found it odd that you replied to me using a front and rear kit when that was my contention all along. The kit in question here is a front kit only.

2) Yes makers "might" tune conservatively. Do you have data that proves Infiniti/Nissan tuned their systems conservatively?

3) Proof of Nissan/Infiniti increasing their bias for the rear when they increase the front brake power?? I thought the hard data from the specs I just posted proves just that?? If they could increase the front only and ignore the back, why woudln't they? Clearly they do not. The reason why I tend to think they are using performance as their engineering criteria is because braking dist is a very important aspect of their design goals. Remember, they have to go up against BMW/Mercedes/Audi. Their design needs to perform well in the 100-0 - 60-0 tests. Proper bias is very important in getting the shortest brake dist performance. Changing that bias with a made up kit is more likely to DECREASE this performance aspect than it is to improve. Unless you have the data to show otherwise of course. But I'd suspect you would have provided this by now though.

4) Another reason why I think bias wasn't calculated or considered carefully is that the same kit offered as a front only (actually 2 kits) aren't backed up with a rear kit. And they are offered on the contention that the rears aren't needed. On the other hand, these same kits WILL be offered with a rear kit. The same exact kits. Now depending on the spec, the bias will be either altered in a negative way or the bias will be restored to where they should be. Either way, one or both of these kits will not have the proper bias specs in at least one of the kit's offerings. ie.. front only or front and rear. Unless they offer different specifications for each option. Which it looks like they won't.

5) IMHO, if the bias is "only" changed by 5%, how is that determined? How is that determined that's benefical? Going from a 11.5" rotor to a 13" unit and the use of 4 piston calipers vs 1, seems like the bias would be changed more than just 5%. Unless the area of the 4 pistons in that caliper add up to something less than the area of the 1 in the oem unit.

6) Pads. I see you work with the customer in pad selection on the basis of their application. ie.. street/track/sport etc. Which is fine. But you wanted to say you can alter the front/rear bias via different pad selection. How do you juggle getting the right pad for the customer's application while changing the front/rear bias to the right amount all at the same time?

 

Jeff,

You're missing some terribly important information here and making some assumptions on the data you posted. No harm, no foul if you don't know or understand I'd not fully expect you to.

First there's no real measure of "brake power" and what one might consider rotor torque is again only one aspect of what you're trying to put your finger on. Some of this I'll keep short, much of the info is on my bias page.

Your on car stats leave out one of the most important element: PISTON AREA! There's no way you can really evaluate what is there or not without that information.

Rotor size goes up or down on the models. Rotor width changes but so what? Width has nothing to do with brake torque or bias. Not in a static measurement anyhow. One might argue heat management effecting pad Cf at a given temp etc. but let's keep it simple.

Piston quantity is NO measure of what the function of the caliper is. I can show you four pot calipers from as little as 1.5sq" to over 5sq". To say one is different than the other is an understatement. Looking to some other cars I am more familiar with, the WRX and Eclipse come to mind. Both were available with single pot floaters, a two pot floater and later a four pot on the WRX. They all have nearly identical piston area!

Larger two pot floaters simply spread the same load (area being equal) over a wider foot print for better wear. A four pot simply squeezes the same pressure from a fixed mount vs a floater (again piston area being equal)

I think now I better see your issue with why or how a six pot can or cannot have the same impact as a single pot or two pot factory. But we are missing some of the most critical info to truly review it.

So more piston means better, must; it squeezes hard? No necessarily. The four pot factory kit may also come with a larger mc which lowers line pressure. Again, we need more info. Maximum rotor tq is the point the tire no longer turns and is skidding. How you get to that value can be many ways.
For the most part the more effective means is a larger rotor- it gets you more mass, swept area and better thermal capacity. (see you own notes) But for drag racing where weight is an issue a change in caliper to more piston area able to clamp the rotor harder and faster might be the ticket to save weight. Loss of pedal feel for a road racer however could hamper those who like a firm pedal.

The pad selection is based on the parts used to build the kit, my knowledge of the pad compounds and the customer being honest in what they do with the car. No you won't have a pad suggested that is right in all use. I never promote that and challenge any supplier who does. Somewhere there is a compromise. I know that I can elevate rear brake torque in an Impala SS for example for street use but also know how far to take the same customer for track use and a four wheel pad change. Moving from a general street pad on both ends to all out race pads on both ends won't work. Sometimes you havt to trust your supplier or do some trial and error to hit the sweet spot. I confess that I'm usually pretty close but it also reflects 15yrs and customer feedback.

BTW, all that is something you don't get in a "point and click" order or the lowest price....

 

1) I do believe I've addressed the piston area already. I know about total piston are. Thanks

2) I don't know why you are talking about rotor WIDTH. I've never even mentioned it. Only rotor diameter as it pertains to greater torque arm advantage.

3) Pads. I KNOW you choose pads based on usage. BUT you claim to use pads to change brake BIAS. How do you choose pads based on application (street/track) AND JUGGLE BIAS CONCERNS at the same time?

I still haven't seen what any of your kits do to maintain the oem brake bias. I trust they do, just that I haven't seen any simple data that supports it.