Panty Dropper
 

So I see the upper control arm supports that weld in
but do not see the pieces that are running forward to the frame
Been running the g-braces for a few years and like the idea of going
farther down to the frame.. is that something you also sell lab 14?

Also interested in the lower supports.. look forward to your next post
as I have been told they really flex by a few others

G-braces seem to be one of the most noticeable thing I ever did
to bracing my car.... even more than the subframe connectors
They seem to make the front end more precise to me

Bob

Thanks for the excellent write up John. I appreciate your efforts and responses. I wish I had done some of the simple things you did to your subframe before I welded my connectors into the car. I believe there are a lot of little things that can be done to these cars to really make them better street cars without going to a full race cage.

Bob, more precise a good way to put it. I agree with that assessment. I feel like the car actually turns immediately when I turn the wheel. That I did notice before I did the suspension on the car. Also, if you look in pictures three and four you can see the UCA braces. Look at picture four especially. Look at the Gen II sticker on the UCA, right to the left is a turn buckle. That's the UCA support that run forward to the frame.

Joe, I'm not following. Are you referring to the additional supports? If so, then eventually, yes. My body needs attending to. It's in very good condition for the year considering just how bad these cars can get easily. However, I still have plenty to do. I have to find a balance between enjoying the car and working on it. Right now, I'm trying to tip the scales more to enjoying the car. That means I'll do the body work some day but not any time soon. Eventually, I'll also do a transmission brace that goes through the body like my subframe connectors do. That's how DSE does it and I think it creates a good look even if mainly hidden.

Good luck, Doug.

Gotcha :thumbsup:

I believe part of the "more precise" feel after G-Brace install is due to the braces limiting twisting of the sub frame. I haven't tested that aspect yet but will eventually. Just need to decide on a good method of quantifying changes.

The plates that get welded to the upper control arm mount are for guys sticking with traditional coil spring/shock set ups. Those switching over to coilovers usually don't need the plates because they're welding supports on the outside. The plates provide a thicker section for a larger splined section for the upper control arm cross shaft studs or bolts.

The original upper control arm cross shaft mounting studs were only receiving compression and tension forces the way the factory engineers designed them. The addition of G-Brace type products forces the mounting stud to accept shear forces that try to wiggle the stud. With todays aftermarket suspensions and agressive -camber settings for auto-X and track use the point where the G-Brace attaches is spaced away from the UCA mount with shims and the cross shaft giving the shear forces leverage. The G-brace is exerting lot of side force when hitting bumps and standing on the throttle. The original design wasn't made to withstand the constant attempts to wiggle the cross shaft mounting stud.

So with the base of the cross shaft mounting stud more solid I designed adjustable supports for the stud that mount to the inside angled down to the frame horns on the same angle that force from the G-Brace is either pushing or pulling the stud. So the G-Brace is sandwiched between the immovable UCA mount and a preloaded adjustable support greatly reducing the possibility of the UCA shaft mounting stud or bolt from being able to flex or wiggle due to the shear forces.

Top pic below is a pair of the adjustable supports from the current batch. They're a bit different than the ones on my car shown in the other pics to make installation easier, allow clearance for more applications of aftermarket control arms, and to be prettier on the side that can be seen when looking under the hood. Functionally they perform the same.

http://i240.photobucket.com/albums/f...psmd2nxial.jpg

http://i240.photobucket.com/albums/f...pshgfkewep.jpg

http://i240.photobucket.com/albums/f...pstdzwljrw.jpg

So, moving on to the lower control arm mounts.

The GM engineers really dropped the ball. They must have known about the issues that affected the 1st gens yet they continued to use the poor design another 11 years through the 2nd gen run. The lateral forces affecting the lower control arm were transferred to the edge of the sheet metal frame. That's a lot of force on the thin edge. Compounding that, while one side had the support offered by the shoulder of the bolt that actually fit the hole the other side had the threads of the bolt contacting the edge of the frame. So the forces were transmitted through the tip of the threads to the thin edge of the frame, not good.

So even on a daily driver that got bumped into parking blocks on a regular basis the force ovals the holes in the frame where the LCA attached. The rear most hole in the brackets welded to the frame is usually the worst. I've repaired lots of these.

You can see in the pic below the poor design.

http://i240.photobucket.com/albums/f...pscfb6fda1.jpg

Early 2nd gens used the smaller 1/2" bolt shown below while the late 2nd gens used the 14mm shown next to it. Mid 73-78 used 9/16" and most aftermarket stuff I've dealt with is 9/16".

http://i240.photobucket.com/albums/f...ps35680ae1.jpg

I put together kits with various modified washers and bolts that get welded to the frame. This spreads the load, reduces frame flex and allows transfer of the forces through the shouldered section of the bolt on both sides of each mounting point to a wider edge than the original frame. The kits are kind of on a case by case basis depending on welder available, which version of sub frame, what aftermarket equipment is being used etc.

Ya I know what you're thinking. You could hunt around for the correct bolts, distorted thread locking nuts, and other hardware and then make patterns, cut, grind, drill, etc. but it's easier and cheaper to just buy a kit from me. Yes, it's cheaper. You can't get everything from one place that I'm aware of and you can't get some of the items in the quantities you want. When you figure the items purchased you don't need, shipping for items you can't find locally, gas to drive around to local places searching, and so on, it ends up costing more than I sell the stuff for. AND, I've already modified things to match certain frames and fit snug on quality hardware. I know this because that's what I went through trying to do my car in the beginning and I'm thinking your time is free, if you put a value on your time it's even more of a deal to just buy a kit.

Here's some of the types of hardware that come in a LCA mount reinforcement kit.

http://i240.photobucket.com/albums/f...psgvduko5a.jpg

Once the pieces are welded to the frame they look like this.

http://i240.photobucket.com/albums/f...pstmkhizah.jpg

http://i240.photobucket.com/albums/f...pspn78b2na.jpg

Panty Dropper
 

John,
Pm sent wanting some of your items
Don't make the car too pretty.. you may
never want to race it again :)

Bob

Good talking to ya Bob. Here's the pic I said I'd put up of the worst LCA mount I've had to fix so far that wasn't caused by rust.

http://i240.photobucket.com/albums/f...psgfv5bcbd.jpg

wow! That's pretty bad.

Aggressive driving with 275 40 17 300 tread wear front tires. Gotta remember when the frame and suspension for these cars was designed in the late 60's radial tires weren't even offered yet. The tires we're running now offer sooo much more grip than the standard 6" wide or optional 7" bias ply tires offered in the early 70's. My 70 bird left the factory with 6" wide E78 14 bias ply tires with a fairly hard rubber compound and 45 years later I'm running 18" 285/295 DOT R radials almost a foot wide with a 40 tread wear. That puts a lot more force into the LCA mount cornering above the point the original tires would have lost grip and started sliding.

When Pontiac started putting the "radial tuned suspension" badge on the gauge panel they hadn't changed the basic suspension geometry, just altered spring and sway bar specs a bit to work better with 7" radial tires.

Increased braking ability with our combined aftermarket brakes and tires also far exceeds the original cars capabilities before skidding and puts force on the LCA mounts in the same manner as bumping into parking blocks.

Very true and something for people to remember as the push the performance of these cars further and further.