Front brake backing plates

N61WP · 03-19-2002

I've heard different opinions on removing the front disc backing plate (splash shield). An old trick I was always told was to remove them to get more air flow and cooling around the disc. Now, I've been told that the disc cools better with the plate as it directs air around the disc better. How about some opinions?
Thanks,
James

opelmark · 03-20-2002

Opinions? We got 'em, James. Leave the backing plates ON. Besides the cooling effect, they deflect rocks, road debris, all that kind of thing. Those engineers in Germany knew what they were doing.

RallyBob · 03-20-2002

I've always cut down the backing plates. I leave the area that protects the hub grease seal, cutting the rest of the sheet metal away. I've found the rotors run cooler on the track (pyrometer testing). Another side benefit has been reduced brake dust buildup on the wheels for the street. The down side....on dirt roads anyway, I've picked up some rocks before between the caliper body and rotor. NASTY noise, and they must be removed to prevent the rotor from becoming grooved. For me, this possibility is acceptable.

Bob

TGSI Racing · 03-20-2002

From a cooling standpoint (and the Opel brakes need cooling), the backing plates HURT. I do as Rally Bob suggested, and cut down the plates so that only the bearing/seal protection remains. Then as much air as possible will go by the disk.

The next thing to do is duct some air. But you can't just blow air on one side. Since the disk is solid, if one side has cool air and the other does not, then the disk will warp

. So the way to duct air is to make a duct that wraps around the disk and puts air on both sides of the disk. You have to be sure everything clears the wheel, so the duct has to be the same short of shape as the caliper.

When Gary gets the "picture-in-post" function working again, I'll put up a picture of what we do.

Gary · 03-20-2002

Originally posted by TGSI Racing
When Gary gets the "picture-in-post" function working again, I'll put up a picture of what we do.

The picture posting is working. use the "Attach File" box at the bottom of the new post screen. I need to figure out how to get the picture posts from the old board over with the threads.

N61WP · 03-20-2002

Thanks for the advice guys. I'll be pulling them apart and cutting them down soon. Nothing like help from my 2 favorite "BOBS".
James

TGSI Racing · 03-30-2002

As promised, here is a picture (finally got my digital camera back from my kids) of the RIGHT way to do brake ducts for solid disks. Note that there is a splitter in the inlet. The splitter is NECESSARY so that air goes to both sides of the disk.

TGSI Racing · 03-30-2002

Here's a picture of left & right side ducts.

TGSI Racing · 03-30-2002

Here is the duct mounted. Notice again that the splitter directs about half of the air over the top and to the outside of the disk.

This is actually the first prototype for a 240Z that we are building. (This was easier to get pictures of since everything is apart). Anyway... ducts for the Opel are essentially the same.

TGSI Racing · 03-30-2002

This picture shows how the duct fits inside the wheel. You've got to be sure the duct doesn't rub or interfere with anything... or all your work will become junk the first time out.

TGSI Racing · 03-30-2002

For those who are wondering why I'm so "anal" about brakes... In 1995 TGSI Racing went to a 24hr race in Ohio. This is what the car started out looking like. Those who were there with us remember what happened when the brakes went away about 12 hours into the race...

TGSI Racing · 03-30-2002

When the brakes "went away" there was a Car & Driver magazine sponsored Ford Contour SHO in the corner in front of the Opel... that's not how we wanted to meet the Car & Driver folks. Needless to say, what they wrote about us in the magazine was not flattering.

A sawsall was used at the track to clear away sheet metal that was crushed into the wheels. We rebuilt the brake system and after about 2 hours we got back in the race. Amazingly, we finished the race.

When we got back home and surveyed the damage, this picture shows what was left after we cut out all of the stuff that "wasted"... and you can't see the stuff that's "gone" on the other side.

Rather than trying to fix the car, the shell now serves us as a platform to "mock up" custom stuff.

By the way, this is the second car that I've "bent" beyond repair because the brakes went away.

RallyBob · 04-01-2002

This is how I cut away the backing plates for my own cars. Notice this is from a Manta/Ascona, so the area holding the brake line clip would not be there on a GT

Bob

03-19-2002	#1 (permalink)
N61WP Member Join Date: Mar 2002 Location: New Orleans, La Posts: 533 Classified Rating: 0% (0)	Unanswered: Front brake backing plates I've heard different opinions on removing the front disc backing plate (splash shield). An old trick I was always told was to remove them to get more air flow and cooling around the disc. Now, I've been told that the disc cools better with the plate as it directs air around the disc better. How about some opinions? Thanks, James

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03-20-2002	#2 (permalink)
opelmark Opeler Join Date: Mar 2002 Posts: 100 Classified Rating: 0% (0)	Opinions? We got 'em, James. Leave the backing plates ON. Besides the cooling effect, they deflect rocks, road debris, all that kind of thing. Those engineers in Germany knew what they were doing.

03-20-2002	#3 (permalink)
RallyBob Project 1450 supporter... Join Date: Mar 2002 Location: Pleasant Valley, CT Posts: 6,656 Classified Rating: 0% (0) Provided Answers: 4	I've always cut down the backing plates. I leave the area that protects the hub grease seal, cutting the rest of the sheet metal away. I've found the rotors run cooler on the track (pyrometer testing). Another side benefit has been reduced brake dust buildup on the wheels for the street. The down side....on dirt roads anyway, I've picked up some rocks before between the caliper body and rotor. NASTY noise, and they must be removed to prevent the rotor from becoming grooved. For me, this possibility is acceptable. Bob

03-20-2002	#4 (permalink)
TGSI Racing Member Join Date: Mar 2002 Location: California Posts: 286 Classified Rating: 0% (0)	From a cooling standpoint (and the Opel brakes need cooling), the backing plates HURT. I do as Rally Bob suggested, and cut down the plates so that only the bearing/seal protection remains. Then as much air as possible will go by the disk. The next thing to do is duct some air. But you can't just blow air on one side. Since the disk is solid, if one side has cool air and the other does not, then the disk will warp . So the way to duct air is to make a duct that wraps around the disk and puts air on both sides of the disk. You have to be sure everything clears the wheel, so the duct has to be the same short of shape as the caliper. When Gary gets the "picture-in-post" function working again, I'll put up a picture of what we do.

03-20-2002	#6 (permalink)
N61WP Member Join Date: Mar 2002 Location: New Orleans, La Posts: 533 Classified Rating: 0% (0)	Thanks for the advice guys. I'll be pulling them apart and cutting them down soon. Nothing like help from my 2 favorite "BOBS". James

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