Author Topic: DIY: Make your own tunnel brace (Read 71461 times)

Sly Bob · « **Reply #75 on:** February 19, 2009, 09:20:05 AM »

I used 1/4". Didn't want to the extra weight of 3/8" when the 1/4" is the one that makes the biggest difference. Next is the DDM rear suspension brace.

As for lubricant, the package that the blades came in suggested Varsol or mineral spirits but WD40 is convenient and everyone has a can. Don't need much of it.

Sly Bob · « **Reply #76 on:** February 19, 2009, 05:57:59 PM »

Got the brace back from powder coat today. All I can say is WOW!

The sad part of all of this is that no one is going to see this after I install it on the car.

When I dropped it off this morning Mike at the shop said that it probably wouldn't be ready until next Tuesday. A few hours later he called me and said that it was ready.

He did an awesome job (don't mind the fingerprints) and I may not ever buy another can of paint again!

Maybe powder coated brake calipers next...

[attachment=2]

Sol Asylum · « **Reply #77 on:** February 20, 2009, 12:48:24 AM »

Quote from: DeepBlueGXP on February 19, 2009, 09:14:22 AM

Why, so when it heats up you can use the flame as a light?

I would recommend using a magnesium alloy in place of the aluminum. It will save weight and the light from the flame will be blinding!

lil goat · « **Reply #78 on:** February 20, 2009, 03:06:44 AM »

Quote from: Sly Bob on February 19, 2009, 09:20:05 AM

I used 1/4". Didn't want to the extra weight of 3/8" when the 1/4" is the one that makes the biggest difference. Next is the DDM rear suspension brace.

As for lubricant, the package that the blades came in suggested Varsol or mineral spirits but WD40 is convenient and everyone has a can. Don't need much of it.

I hope you aren't serious about the weight saving, you are talking about a weight difference equal to your cell phone and wallet between, 1/4" and 3/8", I think the 1/4' will be more than adequate any thinner than that I think is to thin even in 6061, mine is 3/8 6061 in a lovely shade of pink, but it was a prototype the very first one on a GXP and the first race version for DDM. I love PINK

Sly Bob · « **Reply #79 on:** February 20, 2009, 08:25:15 AM »

Quote from: lil goat on February 20, 2009, 03:06:44 AM

I hope you aren't serious about the weight saving, you are talking about a weight difference equal to your cell phone and wallet between, 1/4" and 3/8", I think the 1/4' will be more than adequate any thinner than that I think is to thin even in 6061

Yeah I was serious but it was more a matter of me justifying to myself why I didn't want to spend 50% more on the material when the difference in performance of the final product was negligible.

What I can't figure out is what that extra hole is for down the one side of the brace? I drilled it out anyway as does DDM but there isn't a bolt there.

lil goat · « **Reply #80 on:** February 22, 2009, 12:30:03 PM »

It's to reduce weight of course!

BLK GXP · « **Reply #81 on:** February 25, 2009, 12:04:27 AM »

I found a piece of 1/4 inch 7475 online for about 70 bucks, shipped. They have more. It might be big enough to make two braces. When it gets here, I'll get started on it. I have access to a plasma cutter at work, so I should be able to cut it out fairly easily. I'll post how it goes.

Dave@DDMworks · « **Reply #82 on:** February 25, 2009, 08:08:52 PM »

I know why ours has the hole in it

DeepBlueGXP · « **Reply #83 on:** February 25, 2009, 08:22:35 PM »

Quote from: Dave@DDMworks on February 25, 2009, 08:08:52 PM

I know why ours has the hole in it

I guess you're not tellin?

Sly Bob · « **Reply #84 on:** February 25, 2009, 10:52:47 PM »

Mine has the extra hole drilled as does the stock one. Ya' want to share the secret Dave?

And what torque is everyone torquing their tunnel brace to.

lil goat · « **Reply #85 on:** February 26, 2009, 02:05:28 AM »

I think 35 ft/lbs or something like that is correct, I just squezzed the trigger on my impact gun until it went click click click, it's adjustable and was not on max.

DeepBlueGXP · « **Reply #86 on:** February 26, 2009, 09:30:08 AM »

I did 35lbs on mine, I got the spec from my general structural repair manual which gives torque specs for all hardware based on size and thread. (it's something I obtained during my aviation mechanic career)

Dave@DDMworks · « **Reply #87 on:** February 26, 2009, 11:46:21 AM »

The shop manual calls out for 11 ft/lbs for the torque on the bolts. We usually put Randy's in and out with a impact wrench when working on his car, but then again we have to always test worse case scenario over here. I would think the 30-35 ft/lbs area would be more appropriate for these bolts, although I have not taken a look to see what grade they are.

Cheers · « **Reply #88 on:** February 27, 2009, 10:56:44 PM »

If you do 30 ft\lb do not ever try to take them out. You will have problems.....

I went to change them back to 11 ft\lb, per Dave, and not a good thing

Sly Bob · « **Reply #89 on:** February 28, 2009, 07:01:59 AM »

The reason that I am asking about the toque is this. When I installed the tunnel brace I jacked up the front of the car and slid under it to work. I did the install without problems and torqued the bolts to 11 foot pounds or 135 inch pounds. When I went to put the car back down again, of course I lifted it from the front corners to get the jack stands out and I heard a pop that sounded like the brace moving as the body flexed.

For that reason, I was wondering if the torque was correct. Cheers, if you had problems with ripping the heads off of the bolts that had been torqued to 35 lbs, maybe I should leave it alone. Maybe go to around 20 lbs?

SolNut · « **Reply #90 on:** February 28, 2009, 05:40:56 PM »

OK, DUMB Question

Where are you guys & gals getting the correct length bolts for this Mod?

(Adding 3/16" to 3/8" thickness has to change the length required)

Steve

Chemist · « **Reply #91 on:** February 28, 2009, 05:43:47 PM »

Quote from: 2091351 on February 28, 2009, 05:40:56 PM

OK, DUMB Question

Where are you guys & gals getting the correct length bolts for this Mod?

(Adding 3/16" to 3/8" thickness has to change the length required)

Steve

Steve, the stock bolts are fine for this.

SolNut · « **Reply #92 on:** February 28, 2009, 05:47:25 PM »

Then GM made them TOO long just for this?

Hard to believe they would have Spec'ed a bolt longer than was required for the original pan.

Steve

BLK GXP · « **Reply #93 on:** March 01, 2009, 12:24:12 PM »

I finished making mine last night. The small plasma cutter I borrowed would not cut it, so I cut the entire thing out with a jig saw. It took a while, but the end result is great. I just bolted it up under the car with the stock piece over it. You can't even see it . I did not put any paint or other coating on it. I figure the aluminum should be fine on its own.

Sol Asylum · « **Reply #94 on:** March 01, 2009, 06:07:17 PM »

Quote from: BLK GXP on March 01, 2009, 12:24:12 PM

I finished making mine last night. The small plasma cutter I borrowed would not cut it, so I cut the entire thing out with a jig saw. It took a while, but the end result is great. I just bolted it up under the car with the stock piece over it. You can't even see it . I did not put any paint or other coating on it. I figure the aluminum should be fine on its own.

As long as they don't use road salt near you or you don't drive it when salt is used you probably won't have much of a problem with uncoated aluminum. However aluminum will corrode for a whole list of reasons so you might want to paint it anyway.

Lucy'sDaddy · « **Reply #95 on:** March 01, 2009, 10:06:53 PM »

I haven't made mine yet, but will go with 3/8" 6061-T6 BECAUSE of the corrosion reststance. PLUS powdercoating

2kwk4u · « **Reply #96 on:** March 02, 2009, 11:47:23 AM »

Quote from: BLK GXP on March 01, 2009, 12:24:12 PM

I finished making mine last night. The small plasma cutter I borrowed would not cut it, so I cut the entire thing out with a jig saw. It took a while, but the end result is great. I just bolted it up under the car with the stock piece over it. You can't even see it . I did not put any paint or other coating on it. I figure the aluminum should be fine on its own.

One other concern with this is that you're butting two different metals against one another. If/when the aluminum does begin to corrode, it will be accelerated b/c it is in contact with the steel. Eventually, they might just glom together in a giant mess of corrosion.

I just changed out the front hubs on my '03 VUE a couple weeks ago. The steel hub assembly is a tapered fit into the aluminum steering knuckle on that car. I couldn't make any progress with a cold chisel or by whaling on the hub with a mini sldege. After an hour, I decided to remove the whole assembly on both sides and knock the hubs out with a press (barely able to do it that way even) because the corrosion had more or less cemented the two parts together!

baconbits · « **Reply #97 on:** March 02, 2009, 12:28:25 PM »

I was just reading an engineering book on metals in contact.. one thing it did mention was not to use stainless steel bolts on the aluminum that is subject to weather as they will definitely corrode the Aluminum..Plated or galvanised bolts are said to be OK..
Bacon

Hal 9000 · « **Reply #98 on:** March 02, 2009, 02:50:47 PM »

I'm in construction, and can tell you from experience if you use a hardened steel self tapping screw to hold aluminum plate to something, then expose it to "salt air", like a coastal environment, The hardened steel screws will become brittle and shatter after a short time.

(not a good thing when you're talking about security ceilings at Rikers' Island) ..

SolNut · « **Reply #99 on:** March 02, 2009, 03:01:04 PM »

I am not a ME, before going Digital in ’67, I was civil. My dad was an A&P Licensee after #2 who retired from an Aircraft Manufacturer. My early learning curve was punctuated with the fact that his Reed & Prince had a tan handle and the Phillips did not.

My question about bolt length for the Backbone was because my dad always said ‘that all fasteners have specifications’ (inees and outees). His legacy about this has provided me with drawers of fasteners that he sorted from the 5 gal buckets of sweepings that the surplus store sold. The cardinal rule of the assembly line being ‘if you drop something, do not pick it up, it could be the wrong fastener’.

I haven’t been able to find a consensus on the Torque for attachment and still have a gut feel that the bolts would be too short if you hang a 3/8” thick plate.

Just being a jarhead again, I guess.

Steve

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Author Topic: DIY: Make your own tunnel brace (Read 71461 times)

lil goat

lil goat

lil goat