Tony’s Garage: Readers' Tech Questions - June 2014

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Tony Huntimer Jun 20, 2014 0 Comment(s)
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Q. Hey guys,

I love Camaro Performers magazine and always get excited to see all the new cars and articles. I am trying to figure out what brake master cylinder these LS motor swap cars are using. I was interested in the one Larry Woo has in his car, which was featured in the February 2014 issue. It's a modern-looking plastic reservoir flat-top style that I really dig. I searched all over the web with no luck, so I figured I would ask the experts. I really appreciate any help you can give me.


Sean Kelley
Via email

Detroit Speed Master Cylinder Boost 2/4

Here’s the Detroit Speed Inc. master cylinder and booster setup that Larry Woo was running on his Camaro when it was featured on our pages last year.

A. Hey Sean,

I checked with Larry Woo. The master cylinder on his awesome Camaro was from Detroit Speed, Inc.

I'm not sure of the original application for the master cylinder sold by Detroit Speed. I'd ask them for you, but no company wants to divulge that kind of information. They've done all their homework on a combination of brake booster and master cylinder that works great for applications they sell it for.

The master itself looks like one out of a '96-and-up GM. The configuration of the reservoir definitely makes it a reservoir from a car, not from a truck.

The more important thing you should know is that the engine has no bearing on what master cylinder needs to be used. The overall physical size of an engine can limit the diameter of the brake booster, but that's a different topic all together.

The master cylinder used on a vehicle is based on the requirements of the wheel cylinders (if the car has drum brakes) and/or the brake calipers. A brake caliper or wheel cylinder that requires a large volume of fluid to move the pistons enough to stop a vehicle will require a master cylinder with an appropriately sized bore. Installing a master cylinder with a small bore on a system that requires a larger bore will keep the brakes from working adequately. Installing a master with a bore that's too large for a system will push too much fluid and cause the brakes to work too well—enough to be dangerous.

Another factor in designing a brake system is choosing the correct balance between the front and the rear brake circuit. Installing brakes in front that require very little volume of brake fluid compared to the requirements of the rear brakes will cause big problems because the brake system front-to-rear ratios are not balanced well. Properly balancing the front and rear brake circuits typically requires designing a system that needs more fluid volume to operate the front brake circuit than the rear brake circuit. A proportioning valve can be used to manually reduce the amount of fluid being pushed to the rear brakes.

Once the front and rear brake circuits are balanced, you'll need to choose a master cylinder with the correct size bore and piston combination. A master for a car with disc front and drum rear will not work correctly for a system that is disc front and disc rear. A drum brake circuit inside a master cylinder is designed to hold residual pressure on the brake shoes to keep them from expanded in the drum, thus reducing brake actuation time when stopping. Residual pressure valves for drum brake circuits can be purchased separately and installed inline. A disc brake doesn't require residual pressure to operate.

There are complete books on the subject of brake systems that will explain everything in finite detail. I suggest you do your homework or call the qualified technicians at Detroit Speed, Baer Brakes, Wilwood, CPP, etc. Let them help you get the correct parts for your brake system.

Q. Hey Tony,

I have a '67 Camaro convertible with a 383 making around 450 hp. I have a ProCharger on the shelf that I want to get installed soon. Here's the thing, my 7-year-old daughter loves to cruise with dad. When she's not with me, I like to have a little fun on the backroads. The current stock lap belts concern me. I don't want a big ol' rollbar in order to mount a shoulder harness, but I want more than a lap belt for my precious cargo. I also like the interior to be stock appearing. I like the harness setup in Jimmy Jackson's '68 convertible In the May 2012 issue of Camaro Performers. I can't find any information about the setup online. Where can I get more information or pictures?


John Chiolero
Via email

Chris Alston Removable Back Brace 3/4

Chris Alston’s Chassisworks 1 5⁄8-inch removable back-brace kit (PN 7041) would help do the trick.

A. John,

Jimmy Jackson's Camaro was built by the talented Jeff and Jesse Greening at Greening Auto Company. All the cars they build are beautiful pieces of art with function in mind. All of their work is one-off. The harness bar setup is a very nice concept. Obviously it doesn't function as rollover protection but is very effective as a harness bar.

Personally, if I were to ever build a convertible, this design is something that I would emulate. The toughest part to fabricate would be the quick-release part. Chris Alston's Chassisworks ( sells removable brace kits in different forms and would really cut down on fabrication time, whether or not you do the work yourself. The rest of the harness bar would need to be custom-made. Chassisworks also offers a full variety of fabrication components, including 6x6 floor plates to anchor the bars, but nothing that would be an easy slam-dunk for you to install.

The low-back seats in Jimmy's car look great, but they do not offer any support for the head in the case of an accident. To some enthusiasts, high-back bucket seats may detract from the clean lines of a convertible, but function should rule over form in cases of safety.

Got a burning tech question?

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