Front Brake Selection Help! 1970 Trans AM

[Ron Sutton]

Who Ron, every time I read one of your posts I realize how much I really don't know. Rather than add my 2 cents when you post should I just send you everything about my car or would you like to come over and tell me what I should be changing.
Haha

Sadly the old school of bigger is better type build is gone and I feel way out of touch on what the hell I'm doing. I've only been out of the loop a couple decades but man has a lot ever changed.
I've been in racing for 35 years and the last 20 years has advanced a TON in technology & set-up models.

On a serious note, I really never realized that over building the braking system could lead to issues.
Yup! Been there & done that. Even on race cars.

On the NASCAR Modifieds I designed in 2010 that debuted in 2011 ... I initially designed in too much braking force for the tires we were running. The cars were fine ... and fast ... in pre-season testing when the drivers could brake earlier & softer. But when the green flag flew at the first race we realized we had a problem. If the drivers braked early, they'd get passed on corner entry. If they drove in deeper (requiring harder braking) to protect the spot ... it just locked up the tires.

It wasn't a front to rear bias issue. It simply had too much total braking force. The next week we spent two days testing combinations with less total braking force ... and got the cars back up front & winning races.

I've started down a path with Wilwood so am I right to assume that if I contact them and go through what the hell I'm building they can make proper recommendations?
I can't say that for sure. I know a lot of good guys at Wilwood that REALLY know their stuff & I like their product. I have raced on Wilwood brakes since 1979 back when you could call Bill Wood or Mark Woods. I have also raced with 10 other brands of brakes and like a lot of them too.

But I feel Wilwood's off-the-shelf pro touring street brake packages can be misunderstood. The typical 6 piston Superlite caliper based kits increase braking force only a little & require aggressive pads for serious increases. These pads cost more & wear out quicker. In fairness to them, they're responding to market demand for cool looking, big, red or black, billet, 6 piston calipers & large 13" to 14" rotors from the Pro Touring market. If they put too much brake force in the package, people might get themselves in trouble (wrecks) from tire lock up.

Or, are you going to be in the Vancouver, BC anytime soon?

No ... not planning on it.
But we can discuss your project right here on PT.com. I'm helping a few guys improve their stuff this way & I'd be happy to look at what your doing, discuss your goals & offer some advice.

[NOT A TA]

John, how did you like the Porterfield pads?

They worked very well for what I needed and could afford at the time. I had been trying various brands and compounds of shoes and pads but most barely lasted a weekend. The pads/shoes Porterfield sent allowed me to continue to improve as a driver without forcing me to upgrade wheels/tires before I was ready in order to fit bigger brakes. If I had continued to use them on track I would have started using higher quality rotors because the heat was crystallizing the rotors.

I did not have the brake ducts hooked up at the time and the wheels themselves got so hot the plastic emblems in the center caps were melting and distorting. The pic below is what a new set of most brands of shoes looked like after a weekend of HPDE at places like Sebring that are tough on brakes. The Porterfield supplied pads & shoes held up much, much better but at the expense of the OTC rotors. On the street I use a dedicated set of pads/shoes, rotors/drums, that work without the heat needed to get the performance of track pads and swap for track weekends.

[Ron Sutton]

John,

Thanks for sharing your experience. Another PT.com member, Lance Hamilton, Autox's his '85 Monte Carlo SS on Porterfield pads & really likes them. Of course in AutoX he is NOT achieving anywhere near the heat saturation that happens in road racing.

As you know, increasing braking power is a lot like increasing engine power ... you need to increase cooling to go along with it. Building more HP in the engine requires bigger radiators, better fans, better ducting or some combination of methods to cool that extra go power. A lot of guys don't know brakes are the same. If you increase stopping power ... the heat generated went up ... and you need to cool it with ducting, wider rotors, better vanes, external fans, heavier rotors or some combination.

If you don't manage that heat, the heat saturation kills the brakes ... pads, fluid, rotors & sometimes even calipers ... but also hurts the tires, wheel bearings, etc.

What kind of pads are you running now with your Baer brakes?

[Ron Sutton]

I came back at looked at this thread ... and John's Post #22 ... with my headline question ... and the photo of burnt up pads ... may at first glance make it look like the Porterfield brake pads failed. But that's not the case. Please read the details, as I wouldn't want this discussion to give anyone the wrong impression.

So far, John & most guys running Porterfield pads and/or shoes have liked them.

[jtwoods4]

Hey Ron,

Can you run the calculations with the following setup? I just want to see how your suggested setup differs from what my vendor originally wanted to sell me.

1 inch bore master
Smaller 2 Piston D154 on rear with 12.19 Rotors (wildwood kit http://www.wilwood.com/BrakeKits/Bra...emno=140-13025 )
13 inch rotors on front with the Wilwood SL4 Caliper ( caliper link: http://www.wilwood.com/Calipers/Cali...emno=120-11136 )

By the way, HPDE events are exactly what I am running now. Working up to time trails

[NOT A TA]

Thanks for sharing your experience.

What kind of pads are you running now with your Baer brakes?

I'm in the middle of a big upgrade project now that includes the brake installation so the stock pads will stay on for initial street driving. I may try the pads at a one day event at my local track (Palm Beach International) which is not tough on pads. I'm changing so many things at the same time I expect there will be a learning curve and would like to do that nearby before travelling. Project thread here https://www.pro-touring.com/showthre...hamas-and-more

[jtwoods4]

By the way.... here is the link to the 70 TA Project Thread

https://www.pro-touring.com/showthre...40#post1012440

[jtwoods4]

I'm in the middle of a big upgrade project now that includes the brake installation so the stock pads will stay on for initial street driving. I may try the pads at a one day event at my local track (Palm Beach International) which is not tough on pads. I'm changing so many things at the same time I expect there will be a learning curve and would like to do that nearby before travelling. Project thread here https://www.pro-touring.com/showthre...hamas-and-more

Nice TA Build

[Skip Fix]

Ron nice spread sheets-the TA setup with the 1LE rotor doesn't actually look too bad. Thanks for all the posting.

I'm still trying to figure out why Wilwood's standard 10.75 rotor and Dynalite caliper is an "upgrade" over stock discs other than lighter as it has been advertised over the years.

I've got them on the 79 Camaro drag car with 2.5 metrics on the rear with the TA rear discs BP-10s on the front and some Bedix FE organics on the rear but it has skinnies on the front and bigger slicks on the rear. 1.032 Strange MC.

Late model asphalt car I picked up to make a road track car has GM calipers(class spec at the time) all 4 wheels but some pretty big rotors on the wide 5's.Dry sump, fire system,dual MSDs nice 355 SBC 180 degree headers(sounds liek a giant Kawa ninja cycle) for $5000! Just needs the rear section/fuel cell area rebuilt where it bumped the wall before I got it! So even the old GM calipers can slow a big asphalt car down.

[chocthunder]

WOW!!! What great information from Ron Sutton. I just recently upgraded the front brakes on my 69 camaro with the D52's. I feel a lot better about the decision after reading Ron's post. I wanted to get bigger calibers but if I am reading the chart correctly I might not need to. For my use it looks like the
D52's will work great, I will upgrade the rear with D154's in the future.
Again, thanks's Ron for the information.

[Henesian]

Is a 6.25:1 pedal ratio with Aftermarket pedals? Also, I assume that the .750" M/C with no booster = manual disc brakes?

[Ron Sutton]

Is a 6.25:1 pedal ratio with Aftermarket pedals? Also, I assume that the .750" M/C with no booster = manual disc brakes?

If you are referring to the sample brake charts ... then yes on both questions.

But the charts are just for reference to compare caliper clamping force with all other things being equal. Many of the calipers have too large of piston area for a 3/4" M/C & the clamping force would be WAY too much.

[Henesian]

If you are referring to the sample brake charts ... then yes on both questions.

But the charts are just for reference to compare caliper clamping force with all other things being equal. Many of the calipers have too large of piston area for a 3/4" M/C & the clamping force would be WAY too much.

Ah okay. How do you know when it's too much and what kind of numbers you should be aiming for front to back? Also, how do you factor in other ideas like caliper strength? Because, all that clamping force on a D52 is not good for it compared to a big 6 piston caliper in an hour long road race or something. How do you really factor in all the information to make an actual brake system choice on an application like this, which alot of us have?

[Ron Sutton]

Ah okay. How do you know when it's too much and what kind of numbers you should be aiming for front to back?
The answer to figuring out most things in cars in a combination of formulas & experience. You can find & buy the formulas out there. But, I think formulas are dangerous without experience. For someone with experience, formulas just help us be accurate & measure what we're doing.

The first thing to know ... is almost every part of the system plays a key role to braking force: piston area, brake pad CoF, pedal ratio, M/C size, rotor size. You've probably heard it a hundred times in many "car" areas ... it's the "total package or combination" that matters. Brake systems are the same. I'd be happy to help you work out a system for your car. If you want to learn how to do systems yourself, I'd suggest you buy a brake book get the formula & start testing.

Also, how do you factor in other ideas like caliper strength?
I'm sure there are engineering formulas, but again, you still need to know what numbers you're looking for. Here, experience is everything. You can reach out to guys with knowledge & experience in the area you need, or simply tap into the experts at brake companies.

Because, all that clamping force on a D52 is not good for it compared to a big 6 piston caliper in an hour long road race or something.
If you're referring to the Wilwood D52, it's stronger than you think it is. It is a beefy caliper with massive aluminum crossover bridges held together by four 3/8" bolts, where most of the 6-piston calipers are held together with four 5/16" bolts. The stiffness of the 3/8" bolts in the D52 caliper is 51.7% stiffer than the 5/16" bolts in most other Wilwood calipers.

I'm not saying the D52 is a better road race caliper. It is just better than you may think it is. A a well designed two or four piston caliper will typically flex less for a given clamping force than a six piston caliper ... due to length.

But if we were building a serious road race car in the 3000-3400# range with wide slicks, some aero & maximum mechanical grip, we would wouldn't want to run any of these calipers. We'd be deciding between Brembo, AP & Alcon monoblock racing calipers.

How do you really factor in all the information to make an actual brake system choice on an application like this, which alot of us have?

I use formulas & experience. But I have to ask a lot of questions to get clarity of the application, purpose & goals. Again, I'd be happy to help you work out a system for your car.

[Skip Fix]

Ron can you run the drag car's system through your spread sheet? I think they are the 1.75 pistons in the front Dynalites.

[Ron Sutton]

Ron can you run the drag car's system through your spread sheet? I think they are the 1.75 pistons in the front Dynalites.

Sure, but I think the drag kits use smaller rotors. Get me the rotor size, pedal ratio, pad compound & M/C size

.

[Skip Fix]

"I'm still trying to figure out why Wilwood's standard 10.75 rotor and Dynalite caliper is an "upgrade" over stock discs other than lighter as it has been advertised over the years.

I've got them on the 79 Camaro drag car with 2.5 metrics on the rear with the TA rear discs BP-10s on the front and some Bendix FE organics on the rear but it has skinnies on the front and bigger slicks on the rear. 1.032 Strange MC."

Manual MC, pedal ratio 6:1 -or whatever exact the upperhole gives you on the pedal. Wilwood 1.75 four piston Dynalite calipers.

A factory 11" with the big single 2 15/16" floater is probably a better brake other than the weight difference. Not sure the 12.19 Wilwood rotor will fit the 15x5 ProStars.

[Ron Sutton]

"I'm still trying to figure out why Wilwood's standard 10.75 rotor and Dynalite caliper is an "upgrade" over stock discs other than lighter as it has been advertised over the years.
This drag race front set-up doesn't offer more braking than the stock set-up, just lighter rotational weight & lighter overall weight.

I've got them on the 79 Camaro drag car with 2.5 metrics on the rear with the TA rear discs BP-10s on the front and some Bendix FE organics on the rear but it has skinnies on the front and bigger slicks on the rear. 1.032 Strange MC."
OK, I worked up a brake calc sheet below.

Manual MC, pedal ratio 6:1 -or whatever exact the upperhole gives you on the pedal.
I won't know what your brake pedal ratio is. So the calculations are only as good as the information input. If you want to know for sure, go measure your pedal.

Wilwood 1.75 four piston Dynalite calipers.

A factory 11" with the big single 2 15/16" floater is probably a better brake other than the weight difference.
Sure it is. The drag race front set-up doesn't offer more braking than the stock set-up, just lighter. Besides, it's hard to use all the braking force possible in the front with skinnys.

Not sure the 12.19 Wilwood rotor will fit the 15x5 ProStars.
I have no idea on fit. Not my area.

Here is the chart.

[Skip Fix]

Thanks Ron!! I guess a little better than drum but less than the stock power disc setup. Maybe a little better bias towards rear with the bigger tires there.

[Ron Sutton]

Thanks Ron!! I guess a little better than drum but less than the stock power disc setup. Maybe a little better bias towards rear with the bigger tires there.

No worries. Glad to help. How quick is the Camaro?