Matt87GTA

Steve? Alloy? Anybody?

Matthew91-Z28

Hey guy...I remember being in the spring/summer discussion about the C4 brake upgrade. I recall you fabbed that bracket and had them on your car and you saying that (at first) did not notice a huge diff b/c you said you had your brakes tuned up stock disc/disc set up already tuned up a bit. And then there was soem debate over your brake booster not being the J65(?). I see that you sold the set-up, I guess to slap on the new wilwood design we're discussing here. Great job by the way. My question is, what is your final opinion on that set-up? After having them on your ride for a while before you sold them, how would you rate their performance?

I am still looking into the 2-piston set-up and have a line on some C4 calipers/baskets. Would you still recommend them?


-Matt

alloy

iTrader: (16)

They are the new forged Superlite series calipers.

alloy

iTrader: (16)

You remember correctly in that I wasn't all that impressed with the C4 setup. But my stock brakes were in incredible shape, so that may be one of the reasons I didn't see that much of a difference. Maybe I just expected too much out of the C4 setup. Dewey really likes the C4 setup, but when we changed his brakes out for the C4's, his stock pads were into the rivets. So he probably experienced more of a difference than I did with them.

Yes the C4 setup is better than stock, no question of that. But it was not the "eye opening difference" I was looking for. I didn't like the harder pedal effort with the decreased piston area of the C4 calipers over the stock pedal effort. I really had to jump on the brakes to make them perform like I wanted. I needed something that would live under 2 drivers autocrossing the car during back to back runs, and also live and perform during our local track days at Portland Int. Raceway for 1/2 hour all out blasts around the road course. The C4 setup just wasn't enough.

Knowing that the C5 setup wouldn't fit under my stock wheels, and with my other requirements in mind, that's how the wilwood 13" kit was born. And let me tell you the wilwoods were definitely "eye opening" over the C4 setup. The rotor is only 1" larger in diameter than the C4's, but the difference was unbelievable. It would have been even more dramatic going from the stock setup to the wilwoods.

Anyway I guess it all depends on how fast you want to go, or stop for that matter as to which setup you go with. Both setups are better than the stock 10.5 brakes. I just needed more on my car than a 1LE or C4 setup could offer.

Justins86bird

Alloy - What's the piston area of the Wilwoods? And what rear brakes are you running now?

alloy

iTrader: (16)

The piston area is 9.62. I don't recall the area of a stock piston, or the C4's right now. It's in a post here somewhere.

The piston size of these calipers is perfect for the 15/16" dia. stock master cylinder. It's exactly the size that wilwood recomends.

My rears are stock drums for the moment. I'm trying to decide what rear disk setup to go with. But I can tell you it won't be anything that came stock on these cars.

Justins86bird

Found it

formul8!!

Hats off to you guys. Very few companies even want anything to do with thridgens anymore. (SLP...*cough-cough*)

And here you are coming out with new products for them. And listening for more.

The Thirdgen market is just getting ripe. Figure there were at least three times more thirdgens manufactured than 4th gens. The market is that big, just no one wants to recoginze it.

This winter, you will have an order from me for the brakes shown here and Alloy's strut mounts.

Keep the good stuff coming!


My thirdgen wishlist:

-Street worthy front tubular A-arms
-rack and pinion steering conversion
-tune on the fly ECM (the Prominator is coming soon!)
-lightweight bumper supports

Dewey316

1. I know someone working on them

2. No news there, but i hear spohn my have something in the works.

3. Its already out

4. PM me, i may be able to help you there.

formul8!!

1) Cool! (I know who too)

2) That would sweet. A PITA, but sweet!

3) It is? I thought they are still Beta testing?

4) Will do.

Dewey316

just re-read your post, the Prominator is the moates peice isn't it? if so it is still in beta.

Colt

This might help people become a little more informed about the Wilwood caliper.



I can assure anyone that this is top quality stuff. I like how Wilwood designed this cliper with spring loaded pad retention plates. This makes the caliper more streetable. I own the old Superlite IIA's that didn't have positive pad retention to keep the pads from rattling.

Alloy,
I have a few questions.

1) What is the rotor offset?
2) Are the hubs steel or aluminum?
3) What size Timken bearings are used?

Hey ebmiller88,
Doesn't this bring my old Wilwood rear brake project into a new light? This kit from Spohn would be a great match for the rears I have.

Tom

alloy

iTrader: (16)

The hubs are cut down stock rotors and use standard size wheel bearings.

Zac's92

How would someone go about buying replacement rotors when the time comes? are they willwood's? Is there a reason that a 1.25" thick rotor wasn't used? seems that it would have better heat disapation. How about two piece rotors? is there a possiblilty of getting those as an option? If 13"x1.25" two piece rotors we're avalible I just might have to order a kit!


Zac

89_3rd_gen

Good question Zac's92. I wasn't going to say anything. I was just going to measure the discs in the kit and replace them with some colemen or sierra hats and discs, haven't decided floating hats or discs want to look at mounted hubs and calipers first. I not much of a fan of single piece discs that are drilled, especially on a nonfloating system. I don't have a problem paying the $1600 for hubs, brackets and calipers. Because I belive I'm buying all the time these guys spent coming up with this.
I was going to do the C5 kit and up grade to a C5 big brake kit (like a stoptech/brembo $3K) intergrate both bracket holes dimensions into a custom bracket. Or one of the Baer GT kits.
Now these guys come along and answer my prayers, thank you again. The way I look at it your saving me about $2000 even counting the disc swap. And being able to use off the shelf circle track stuff is always nice (so many choices).

alloy

iTrader: (16)

The replacement rotors are available through Spohn or myself.

2 piece 13" x 1.25" rotors are definately available, but will add $300 to the price of the kit.

The disks we supply with the kit can either be drilled and slotted, or non drilled and slotted. That option is availaible at the time you place your order.

91Z28-350

yum, 2-piece rotors....damn, up to $2k now so it's going to be summer before I get brakes.

AGood2.8

Alloy, Are these true 13" rotors or are they for instance 12.65's or 12.187's? Before I buy a 13" kit, I want to be certain its 13". I have seen many times that if the rotor dia. is just larger than 12" they will call it 13.
Thanks, Dean

alloy

iTrader: (16)

Dean,

Here ya go.

AGood2.8

Thank you sir. I'm impressed- A true 13" setup that will fit under an Iroc rim. You definately have my interest. I will be waiting patiently for the rear setup you say you are possibly developing for a balanced setup. I am a loyal Spohn customer- I like the best availible products.

Colt

Alloy,

Just wondering who is the manufacturer of the rotors? Is it GM, Wilwood, Brembo...?

I'm not sure if you saw question #1 in my previous post?

Tom

alloy

iTrader: (16)

The rotors are either american made (drilled and slotted-see pic above) or made in Canada. They are high quality rotors we purchase.

The part#, manufacture, and offset info we are not disclosing.

formul8!!

We just want to make sure that they are not Taiwanese basement cast rotors.

All I care about is:

1) They are high quality
2) will push my RONAL's out so I do not need a spacer anymore
3) they will pull my eyeballs out of the sockets when I hit the pedal hard

Colt

Thanks for answering my questions Alloy. I understand why you're not willing to disclose certain information.

alloy

iTrader: (16)

#1. the rotors are very high quality. Neither myself or Steve would offer any cheap parts under any circumstances. Especially not on a brake kit.

#2. The kit will push your wheels out .300 I'm not sure how much the Ronal's need, but this is the amount they will widen your front track.

#3. YES they will pop your eyeballs out. You better be wearing glasses to catch those eyeballs or they may hit the windshield!!

Matt_91RSTPI

I currently have a '91 RS with the single piston cast iron front disk setup and rear drum brakes.

I have aquired most of the parts for the 1LE front conversion and was going to go that route along with a rear disk upgrade until I saw this new Wilwood kit. Now I'm very interested in this front kit as well as a companion drum to disk rear upgrade.

My only question is how can you be selling this without a new proportioning valve or master cylinder given all of the various combos installed in 3rd gens?

Even the parts list for the 1LE conversion would require me to buy a new GM proportioning valve although I belive my master cylinder is the proper one for a 1LE front/rear disk car.

Nice looking kit for sure. As soon as I gather a little more info. I'll make my final decision as to which route I will go.

alloy

iTrader: (16)

As I stated in a previous post, the stock 15/16" master cylinder is the perfect size for these calipers. So no replacement of the M/C is necessary if yours is in perfect working condition.

I've not heard that a new prop valve is needed to change front brakes. If you go from drum rears to disk rears, then yes by all means you have to change the prop valve. But on the front you are just swapping disk to disk, so no change is necessary. And if I'm incorrect about this. I'm sure someone will definately let me know. But from my experience a new prop isn't needed for a big front brake swap.

When I had the C4 brakes on the front of my car (basically 1LE clone setup) before the wilwood setup I also stayed with the stock prop valve, and they worked just fine. Now those same brakes reside on Dewey's car with the stock M/C and prop valve and are also working very well.

On my car I just swapped on the front brakes with no other changes and they work quite well. I put 125 miles on them today as a matter of fact. Every time I drive the car with these brakes I really enjoy how well it stops. It doesn't take much pedal pressure at all to slow me down.

If you have any other questions, just let me know.

Dan

Tibey

Would this kit improve even further with the use of a hydraulic assist booster?

alloy

iTrader: (16)

Can you explain exactly what you mean by an hydraulic assist booster? I'm assuming you are referring to a power brake booster.

toddlsf

http://www.stu-offroad.com/brakeconv/bc-7.htm

I know, this is a jeep page, but it gives you an idea.

alloy

iTrader: (16)

Ok, now I understand what it is.

I really can't see any benefit of this system over the stock power brake booster. If you have a big cam then you might need a vacum pump to work the power brakes, but it seems like installing a small vac pump would be much easier than trying to plumb both high and low pressure hoses for the hydro boost.

alloy

iTrader: (16)

I finally found the info to calculate brake torque for different sized rotors, so I thought I'd post a quick example here using 10.5" and 13" rotors.

In this example I'm using the same pad coefficient of friction, and piston area. All this is meant to do is to illustrate the difference between stock 10.5" rotors, and 13" rotors. Nothing more. There are a lot more variables such as pressure differences, piston area differences, fixed verses floating calipers, different pad compounds, etc. But again, this is only to illustrate the torque increase going to a larger rotor gives you.

10.5" rotor

5602 pounds of clamping force x .65 (pad coefficient of friction) x 4.81 (torque arm length)=17514 in. pounds divided by 12 = 1459 ft. pounds of torque.

13" rotor

5602 pounds of clamping force x.65 (pad coefficient of friction) x 6.06 (torque arm length)=22066 in. pounds divided by 12=1838 ft. pounds of torque.

So 1838 - 1459 = 379 ft pounds of torque increase per rotor, x 2 (2 rotors) = 758 ft. pounds of increased braking torque with 13" rotors over 10.5 rotors.

I hope this helps everyone understand the reasoning behind using larger brake rotors.

BretD 88GTA

It has long been perpetuated on this board that when upgrading to the 1LE brakes you may need to change the prop. valve regardless if you have a disc/drum car OR a disc/disc car. The idea being that the 1LE cars got a specific prop. valve unique to them.

Here's and old thread on this. Note item #2 on the list:
https://www.thirdgen.org/techbb2/sho...threadid=59878
I even questioned Andy Z28 directly on this regarding my car via e-mail and he emphasized that the prop. valve must be changed since I have an '88.

I will soon be installing the 1LE front brakes on my '88 disc/disc car and have a new "1LE" prop valve to compare to my factory installed one and will confirm if there is a difference. I was also told that my car should have a J65 MC and that I needed a J50 MC. I went ahead and bought a new GM J50 MC only to learn upon comparison that my car already has a J50 MC on it.

This may be due to a dealership repair since starting in 1990 all F-bodies got the J50 MC and this is what the standard replacement MC is. It may also be due to the fact that my car was actually built in '87 and the J50 MC may have carried over in early production. The J65 may have come into use later in the production run.

So, based on what I have been able to gather so far, some models will need a new prop. valve, while other models may not depending on when they were built. It doesn't help that GM wasn't always consistent in how they built these cars.

SLP IROC-Z

iTrader: (1)

i really dont really think this is the thread to discuss this but. IF you are only upgrading the FRONT brakes to 1LEs the stock MC and PV will work no matter what car. when u get into changing the REARS to 1LE setup then u must change the MC and MC IF your car A) wasnt equipped with drums to begin with B) ur car has the 88 and OLDER rear disc brake setup. thers even an alternative to that, u can do away with the stock PV all together and install a wilwood adjustable one, this is what im doing.

alloy

iTrader: (16)

I agree, this thread should be kept to questions relating to the 13" brake kit.

But as one last thought on this, in the thread "BretD 88GTA" linked to, Andy wrote regarding the prop valve needing to be changed:

"After you have done your 1LE front brake upgrade, a quick test drive will verify this".

I've got over 3500 miles on my 13" front brakes now, and I'm not sure how many miles Dewey has on his car with the C4 brakes we installed on his car, but I'd guess it's more than just a "quick test drive". And both of our cars seems to be working perfectly with the stock disk/drum prop valve with upgraded front brakes.


SLP IROC-Z, I would be interested in seeing how you plumb the two front brake lines into an adjustable prop valve with one inlet line, and one outlet line.

Dewey316

mine are working flawlessly, since i commute with my car, i have over 5k miles on them now. and we did not change the prop valve.

BretD 88GTA

I agree we shouldn't go off on a tangent and turn this into a prop. valve discussion, but I do feel that covering it in some fashion is pertinent since I suspect many people are wondering about it with the 13" upgrade.

It's good information to know some of you guys are running the 1LE, or better, front brakes and did not change your prop. valve. It would also help to know what year your cars are.

It seems the 82 - early 89 cars MAY require the new prop valve. The late 89 to 92's will not.

SLP IROC-Z

iTrader: (1)

the wilwood proportioning valve the i have will be used to meter line pressure for the REAR brakes not the fronts. so basically im doing away totally with the stock PV. the front will have full unmetered line pressure. when i looked for line locks i decided on the hurst line lock solenoid because it has 1 inlet and 2 outlets. so the line for each front caliper will come right off that.

the reason why i said in my original thread that the stock PV can be replaced with an adjustable wilwood one is because i was under the impression that the front brakes on all the thirdgens receive the same line pressure, i am aware however that the rears got different pressure depending upon the style IE; 88 and older disc share differnt pressure then the 89 and newer disc/all drums and thats why the master cylinders vary. so it would then make sense if someone were to install PBR rear disc brakes on their 88 and older disc equipped car they could use a wilwood adjus. prop valve instead of replacing their original with the 89 and newer disc/all drum PV.

alloy

iTrader: (16)

My car is an 87, Dewey's car is a 90 I believe. Both are disk/drum cars.

Jim85IROC

iTrader: (2)

I have a question about offset. Both the Baer kit and the C5 swap cause the front wheels to have a slightly different final offset. How does this kit effect offset if at all?

My apologies if this has been addressed already. The longer the soap opera between Steve and 383 played on, the faster I scrolled.

91Z28-350

It's on the first page. 3/16" per wheel (0.1875"), which means it's 6/16" (0.375") wider from wheel to wheel.

Matt_91RSTPI

So you've both chosen to upgrade the front brakes and leave the rear drum setup?

I just want to confirm as I still have rear drums and have been of the mindset that I should upgrade them to disks as well if I'm going to do the fronts with such a massive improvement.

Leaving them would certainly be more financially appealing.

SLP IROC-Z

iTrader: (1)

wouldnt that be 3/8s wider from wheel to wheel?

91Z28-350

Yes, 6/16 == 3/8 == 12/32 == 24/64.

SLP IROC-Z

iTrader: (1)

lol just puttin my math skill to use with reducin fractions

alloy

iTrader: (16)

Ok, the offset is increased .300 per side. I mis spoke myself early in this thread saying it was .187 like the C4 setup offset, but stated the correct offset later on. My apoligies for this. I thought everyone would read my last reply about the offset for the Ronal wheels. But this thread is getting long, so I suppose not many people will read every post.

The front brake upgrade came first for me because the C4's weren't enough, and you couldn't use stock IROC wheels with the C5 setup. Not to mention the front brakes do 60% or more of the braking, so naturally they were my first priority.

I will be upgrading the rear drums on my car to disks, and I am working on a rear disk upgrade as I mentioned earlier in this thread. But for now I'm running the big front setup until I get something worked out for the rears.

I'm not sure what Dewey's plans are for his rear brakes, so he will have to tell you himself what upgrades he is or isn't planning. I only know about some engine upgrades he is working on at the moment.

ebmiller88

iTrader: (7)

Me too...disc/drum MASTER cylinder with C4s...it works great.

Ed

Camaro_nut

To Steve Spohn ( or anyone that can answer this!),

Can I leave the rear drum brakes alone if I just upgrade
my front disc setup to the Willwood 13" that you offer?
Does it matter much if I do leave the rear as stock drum?

When will the rear disc version be available to
compliment the front version?

What other suspension goodies are in the works???

z28cdoyle

Steve, Alloy,

It looks like you guys did a wonderful job on this kit and I like the fact that you guys are developing this kind of stuff for our cars. It seems like a lot of the aftermarket is concentrating on stuff for Hondas and other FWD cars.

By the way, how the *%&^ did you guys get jobs where you can work on cars and fab parts for a living? I would love to get paid to work on developing stuff for cars. Instead, my job is just a way to get money to pay for what I really like to do...work on my car and go to the race track.

Keep up the good work.

CrazyHawaiian

Use the search button Jim!! LOL!! Just messn with you bro!!