Since we had so much fun with cam timing..how about Brakes

Here's a question. I'm having a b$%^h of a time keeping the tiny little pads, rotors and calipers on the front of my car cool. Ducting is free, right, as are modifications to the backing plate to allow air to reach the rotor, right?

So, I can I put on one of those "tophat" things I saw in Carrol Shelby's book on cooling solid discs that is basically an extension of the backing plate? It's basically a modification to the backing plate that directs air to both sides of the rotor....fire away guys, tell me what you think.

Jeff

I think that's legal and it's exactly what I'm going to do.

"Backing plates and dirt shields may be ventilated or removed. Air ducts may be fitted to the brakes, provided they extend in a forward direction only and that no changes are made in the body/structure for their use."

Of course in another part of the ITCS it specifically allows holes of certain dimensions to allow for brake duct hose.


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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

Ok...one down, one to go.

Next potential "solution" I have looked at is a fluid recirculator. It's basically a check valve in the brake line that allows fluid to flow out from the caliper when I use the brakes, to be replaced by other fluid in the line, using a line coming out of the bleeder nipple.

I was real iffy on this one to start, but then I looked at the GCR. Brake lines are free, and I've seen all kinds of crazy spirals and other things in the lines on other people's cars, so would "brake lines free" mean I can put this check valve in so that I can get the hot fluid out of the caliper before it melts my seals -- as it has been doing on a regular basis?

Is it brake fluid temp or rotor temp that is melting your seals?...the ducting should help with that....I'm wondering if blowers like sold at pe----- are legal??

[This message has been edited by m glassburner (edited September 21, 2004).]

Not sure. I don't think the fluid is boiling, but I can see the seals smearing across the piston. So, not sure what is getting "too" hot although I suspect the fluid is way above the melting point of the rubber seals.

I thought about the blowers but considered them definitely illegal -- nothing at all in the GCR about electric motors in your brake ducts. At least with the brake recirculator it is simply a check valve and additional brake pipes where brake lines are "free.' While I would like some that are more knowlegeable on these matters to weigh in, I think I at least have an argument here.

But we will see.

I don't see how a check valve can be construed as brake lines.


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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

Wheel fans are legal.

The seals should never touch the brake fluid, they are really 'dust boots'. (unless you mean the rubber brake pistion ring that some brakes have).

I am sure that the seals are burned up from the brake heat.

Alan

Don't know, but I'll make them for you. And, I'll put some peltier devices on there for you too, with big heat sinks. But what do I know, I've got adjustable cam gears I'll use too, so look out.

Have you used any of the temp-sensitive paint to see just how hot the components are getting?

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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608

Or stick a couple of thermocouples on there and we'll log the temp and figure out exactly what is going on. Might have to do that on a test day.

Alan, I don't use the dust boots, it is the rubber seal about 1/2 down the piston that is melting.

Ron, we'll take a look at it. Really annoying this problem.

George: just thinking out loud here, not really taking a position. How is the valve and additional lines any different from additional lines and a proportioning valve? Not sure that I see any real distinction.

Wheel fans are legal??

Per GCR 17.32 they are legal. Not sure how that affects the wheel width rule though....I'll stay out of that one.

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Daryl DeArman

Quote:

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Originally posted by JeffYoung:
George: just thinking out loud here, not really taking a position. How is the valve and additional lines any different from additional lines and a proportioning valve? Not sure that I see any real distinction.

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Proportioning valves are specified as legal.

A check valve for recirculating brake fluid cannot be confused with a proportioning valve. I don't see any other way to slide the valve under the rules. It's not a line which is free. There is just no provision for it.


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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

Jeff, I know where you're coming from...I've been there myself...but its a stretch at the very least. I gotta go with the guys here and say that adding check vlaves is beyod the scope of "brakelines are free".

The one phrase that caught my eye is the "brake circuitry may be revised", but adding lines and check valves is way more than revising.

And the proportioning valve sits in line..no added lines needed. The ITCS only allows pressure limiting P valves. (Which are limited in their use at the greater adjustment settings as they hinder the release of the brakes, making modulation difficult. (or so I read somewhere! )
Nice idea though!

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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

Wheel fans are just a different type of rim I thought ?? Designed to help move air ...

Wheel fans are sorta like hubcaps, and they extract air from the wheels.

They are specifically disallowed in the GCR for some classes (SS, SRF) if I remember correctly.

IT is not one of the restricted classes, again, as far as I can remember.

No opinion on whether or not checkvalves are permitted, but I think it should be possible to do fluid recirculation without any.

Idea #1: use a feed line with a larger diameter orifice at the master than at the caliper, and/or a return line with larger diameter orifice at the caliper than at the master.

Quote:

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Originally posted by Geo:
Proportioning valves are specified as legal.

A check valve for recirculating brake fluid cannot be confused with a proportioning valve. I don't see any other way to slide the valve under the rules. It's not a line which is free. There is just no provision for it.

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George,

How about if it's incorporated into the brake line? Brake lines are free, nothing says what you can or can't do w/ them.

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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608

That was sort of my thinking, coupled with Jake's reference to the brake circuitry (aren't lines and valves and such what they are referring to here?) being subject to revision, that lead to me concluding it was legal.

I might write Topeka on this. Sort of one of those things in the gray area that certainly moves IT farther away from stock cars with cages and suspension to true race cars........