Wilwood stopping power

[Ron Sutton]

Hi Ron,

Sorry for the hijack, but does the extra thickness of the FLSI or FSL4R/FSL6R (... assume the FSL4R/6R have better stiffness than FSLI) give noticeably less deflection than the FNSL4R/FNSL6R (narrow Superlites are in most kits ... assume to more easily fit stock wheels)?

Also, how would you rate a GN6R vs. the narrow-body Aero calipers in most kits? Been considering a GN6R front / FSLI rear combo.

Thanks.

Hi Duane,

Good questions. I can not answer either one with data to back it up, as I have not tested the calipers you're asking about on a brake dyno with measurement equipment. All I can give you is my opinion. An educated opinion, but still an opinion.

I think the Forged Superlites are a smidge stronger (more rigid/less caliper flex) than the Forged Narrow Superlites.
* If you were running them in the front, like we do on our Track Toy 11.75" & 12.19" brakes (see HERE) ... I'd only run the standard width Superlites.
* If you're running them in the rear ... with piston area of 2"-3" ... I don't think it matters. We still use the regular width Superlites in our rear kits HERE & HERE.

I am certain the Aerolite calipers are stronger (more rigid/less flex) than the Wilwood Grand National 6P caliper. I can't quantify how much, as I have not tested the GN6P on a brake dyno with measurement equipment, like I have with the Aerolite 6. My guess, is the GN6P has about 30-35% more flex at 1000 psi, compared to the Aerolite 6. I like the GN6P for race applications where I can run an aggressive race pad. I wouldn't use it on the street. Stick with the Aerolite 6.
You can see our 11.75" & 12.19" GN6P Track packages HERE, 13" & 14" Aerolite Track packages HERE & Pro-Touring packages HERE.
* You'll notice an absence of Superlite caliper front packages. There is just no comparison to the Aerolites.

Even though I couldn't provide you with hard data, I hope I was of help.

[65 drop top]

I agree with you. This package has too small of piston area for a manual system. FYI ... I didn't design nor sell this system. What he needs is more piston area front & rear. The issue is the Superlite caliper isn't rigid enough to handle more clamping force. The calipers will simply flex. Frankly I don't sell Superlite caliper front brake systems anymore. The Wilwood Aerolite 6 calipers are much better, much more rigid calipers. For manual systems, we increase the piston area to 5.40" with the Aerolite 6. In the rear, we run Superlites with either 2.46" or 3.00" piston area & balance the system with proportioning valve or bias bar. *The Superlite caliper works well with smaller piston areas. It's when it get up around 5" is where we start to see clam shelling of the caliper & mushy pedal.

Now for this particular application, a Aerolite brake kit may not be available from Wilwood. In that case, each of his options comes with negatives:
* Higher CoF brake pads, like BP20s, Hawk HP+, etc will create more braking force, but cost more, wear out quicker, wear rotors quicker, squeal & dust the wheels
* Switching to a power booster will create more braking force, but the calipers will flex & pads will wear uneven.
* A smaller master cylinder will create additional hydraulic force & more braking force, but will make the calipers flex the same as if they had larger pistons.
* With a power booster, the driver probably won't feel the caliper flex & the pedal will feel firm. Not so with smaller master cylinders.

Just my 2¢.

When I bought this kit I was working with Wilwood on the combination. At the time, about 2 years ago or so, this was the biggest, baddest kit they made for my application. I understand the physics now, but I guess I'm just a little disappointed with the final product. Wilwood knew I wanted a manual system. Had they told me I needed a booster to get them to work properly I may have looked at other options. I previously had Baers on the car and they worked great. I had to change because I got new wheels and they didn't clear the Baer hubs.

Hi Ron, is been a couple years now, but you helped my with the brake system for my '55 Chevy. I'm finally getting close to having it on the road. I went with the Aero6 5.40 15" front and Aero4 14" 3.56 rear. Your calc's put me at close to 4000 #'s with a 15/16" manual. Would a hydroboost be overkill? I like the feeling of tapping the brakes and getting a good response, but I also don't want to lock them up just by looking at them.

[dontlifttoshift]

A hydroboost on the 55? That's not going to work very well with those calipers.

On your Chevelle it will work great. We did a 69 with the same brake kits you have and a vacuum booster and it was OK but the 540 didn't make a ton of vacuum. Installed Hydroboost and the car will suck the eyeballs out of your head now....same thing, billet wheels, didn't want dust.

[Ron Sutton]

When I bought this kit I was working with Wilwood on the combination. At the time, about 2 years ago or so, this was the biggest, baddest kit they made for my application. I understand the physics now, but I guess I'm just a little disappointed with the final product. Wilwood knew I wanted a manual system. Had they told me I needed a booster to get them to work properly I may have looked at other options. I previously had Baers on the car and they worked great. I had to change because I got new wheels and they didn't clear the Baer hubs.

Hi Ron, is been a couple years now, but you helped my with the brake system for my '55 Chevy. I'm finally getting close to having it on the road. I went with the Aero6 5.40 15" front and Aero4 14" 3.56 rear. Your calc's put me at close to 4000 #'s with a 15/16" manual. Would a hydroboost be overkill? I like the feeling of tapping the brakes and getting a good response, but I also don't want to lock them up just by looking at them.

Howdy !

I'm on the same page as Donny. You & I configured your '55 Chevy brake package for a manual system. To add a power booster to it would be more than overkill. It would be dangerous to the point of undrivable.

Even though you didn't plan to, you & Wilwood ending up with a system for your '65 Chevelle that really needs to be boosted. This car would benefit from going with a hydroboost, as Donny suggested.

On a different note, not specific to your cars, but applicable anyway ...
I don't think enough car guys are clear on how different manual & power boosted systems should be configured. Back in the 60's the car manufacturers like GM made the front calipers with over 6" of piston area. Combine that with a 6-1 pedal ratio and M/C around 15/16" & you had good passenger brakes producing around 2500# of braking force. When they sold them as power boosted brakes ... with the single, low efficiency boosters of that era ... all that was required was to change the pedal ratio to around 4-1 & they worked good as well. At least for the standards of the 60's.

Today, with modern car designs, the boosters are much more efficient & effective. So they design front calipers with around 4" of piston area & they work good. Producing around 2700-2800# of braking force ... except in Performance cars like Camaros, Mustangs, Vipers & Corvettes ... where they increase the CoF of the pads & engineer the systems to produce around 3000-3200# of total braking force. These modern cars are ALL POWER BOOSTED, typically with a dual vacuum booster or hydroboost.

For autocross & track, I am not a fan of boosted systems for how they affect the quality of braking. Vacuum systems are not consistent. When you brake into turn 6 of WeBeFast Autocross Emporium at point X one lap ... with 14" of vacuum in that instant ... and get X amount of braking force. The next lap you make, for whatever slight difference you did with the throttle, now you have 9" of vacuum and don't have as much brake. Then the next lap you may have 15", etc, etc. In short, vacuum boosted brakes are not consistent on track ... where you the driver need them to be if you 're going to drive at the limits.

Hydroboost brakes are more consistent, but they take away brake pedal feel. Driver's can't modulate the brakes very well with a hydrobooster. They act almost like an on/off switch. Not 100%, but almost. For these reasons, you don't find boosted brakes on professional race cars where the brake systems are $50,000+ & engineered to the nth degree. IMHO, boosted brakes are a luxury item for street cars. They make the car/truck easier to drive on a daily basis. A slight push on the pedal & we're stopping easily at a stoplight. I wouldn't want manual brakes in my daily driver. But manual brakes are the best for our triple duty Pro-Touring cars that see Street, AX & Track.

My suggestion is this:
* Every person should decide for themselves if they want power or manual brakes on their Pro-Touring car .... based on their usage & preferences.
* If it's going to be a manual system, the piston area needs to be around 5.5" or greater, combined with the proper ratio pedal, rotor, M/C size & Pad CoF.
* If it's going to be a boosted system, the piston area needs to be around 4"+/- combined with the proper ratio pedal, rotor, M/C size & Pad CoF.

[65 drop top]

Thanks Donny and Ron. That's what I thought for my '55, I'll stick with the manual system. I just wanted to double check so I don't run into the same problems as the Chevelle.

Again, the Chevelle brakes aren't horrible, they just aren't overly impressive. Is there a way to actually document how well they perform on the car, something like measuring a 60-0 stop? Then I can evaluate how the overall package works. How many feet would be considered a good stop? I was also considering doing a side by side stop vs my moms new Mercedes. If the Chevelle was even close to it, I'd assume the brakes are fairly safe for street duty. Although her Mercedes has massive AMG brakes, I don't think I have a chance.

[dontlifttoshift]

Here is what some really fast cars do 60-0. http://www.motortrend.com/news/20-be...nces-recorded/

A stock big block 69 camaro went 60-0 in 143 feet.....A 69 GT500 took 164 feet......

[Ron Sutton]

Thanks Donny and Ron. That's what I thought for my '55, I'll stick with the manual system. I just wanted to double check so I don't run into the same problems as the Chevelle.

Again, the Chevelle brakes aren't horrible, they just aren't overly impressive. Is there a way to actually document how well they perform on the car, something like measuring a 60-0 stop? Then I can evaluate how the overall package works. How many feet would be considered a good stop? I was also considering doing a side by side stop vs my moms new Mercedes. If the Chevelle was even close to it, I'd assume the brakes are fairly safe for street duty. Although her Mercedes has massive AMG brakes, I don't think I have a chance.

You're welcome. Glad Donny posted a link. I didn't have that kind of info.
Looks like 100' is a good baseline & C6 is King of the production cars at 90'

[RSX302]

Boy does this thread bring back sore memories. I went through the same pain 10yrs ago. I tried many manual brake combos and the only one that worked to my liking was twin 3/4" masters on a bias bar system with Wilwood H race pads. (13" rotor with Superlite 4"area) Where was Ron Sutton 10yrs ago..lol

Since I couldn't continue to run this system on the street, I switch over to a hydroboost system, 1.12 master and BP20's.

Since you already have your system and you say that it's ok, I would try the BP20's before doing anything else. I don't have any squealing and doesn't seem to wear my rotors any more then the BP10's. It may feel the same as the BP10's when cold, but as soon as you get heat into them, they should be a little better. My 2 pennies

[Ron Sutton]

Boy does this thread bring back sore memories. I went through the same pain 10yrs ago. I tried many manual brake combos and the only one that worked to my liking was twin 3/4" masters on a bias bar system with Wilwood H race pads. (13" rotor with Superlite 4"area)

Where was Ron Sutton 10yrs ago..lol
Running 9 race teams. Haha

Since I couldn't continue to run this system on the street, I switch over to a hydroboost system, 1.12 master and BP20's.

Since you already have your system and you say that it's ok, I would try the BP20's before doing anything else. I don't have any squealing and doesn't seem to wear my rotors any more then the BP10's. It may feel the same as the BP10's when cold, but as soon as you get heat into them, they should be a little better. My 2 pennies