The panty dropper

[Doug1]

Have you considered a hydraulic setup like this...


http://americanpowertrain.com/c-3205...-lt-1-t56.html


I have a factory setup sent to me by mistake. Here is pic of that deal..

[Centerforce]

Originally Posted by WSSix

Will do. Thank you.I hope to be putting in the throwout bearing that I got from you guys in tomorrow or Sunday.

Great! Let us know how it works for you!

[WSSix]

Interesting, Doug. I had no idea a hydraulic setup similar to the LS T56 was available for the LT T56s. I'm going to stick with the factory style for now because aside from this issue, I've not had a problem with it. We'll see what tomorrow holds.

Thanks!

[allenm]

could you give me your opinion of the pro-g braces in your car. impact on handling improvements. has the braces created any structural problems at the contact points on the firewall. did you brace behind the firewall at the contact points. great read on your project and thumbs up for constantly making improvements to this great marque...allen

[WSSix]

Hi Allen. The braces work very well at stiffening the car. I can't comment on any impact on handling as I didn't push the car hard with the braces on and I did the subframe connectors shortly there after. I'm very pleased with the overall combination of the g braces and the subframe connectors. Rattles and creeks have been minimized. The car doesn't feel as loose and flexible as it was prior to their installation. I can put a finger between the t top and the windshield cowl and not be pinched going around corners or hitting bumps like I used to.

I did not reinforce any part of the car for the g braces. I may in the future when I do body work. I know that's topic of discussion with these parts. I also know a lot of people have used these type braces for years without issues to the firewall and didn't reinforce anything.

I say do it for sure. Good luck and thanks!

[NOT A TA]

During the past couple years I've been designing, testing, and producing various parts for 2nd gens including reinforcements for sub frames and use with the PTFB G-braces. I've been selling them to members on the various forums and decided earlier this year to form a company called Laboratory Fourteen "Lab-14".

While folks have used various triangulation braces to the upper cowl on the street for many years without any noticeable detrimental effects to the cowl there have been people who use their cars for auto sports who have experienced damage from constant flexing and the shear forces.

The pinch welded sheet metal where they attach at the top of the firewall flexes pretty easily and you can literally bend it with your hands if you grab the ledge and apply pressure like you are trying to break a pencil with your thumbs. I've tested several configurations for cowl support in conjunction with the use of the PTFB Pro G-braces.

Trey, Doug has a bunch of my products and will probably show them in his project thread here when he gets to it.

Shown below in the first pic is the kit I sell for upper cowl reinforcement when installing Pro G-Braces without any other upper lateral triangulation. The larger plates sandwich the pinch weld ledge on the drivers side and narrower ones on the passengers. The different sizes are necessary because of the recess for the wiper motor which allows more leverage for the G-Brace to flex that area. The reason the plates are wide is because the G-Braces mount almost centered on the large openings on the top of the cowl which allows more flex of the vertical part of the firewall. With the wide plates forces are spread out to the horizontal sheet metal on the top of the cowl.

I also have upper and lower control arm mount reinforcements, UCA mounting studs by ARP, sway bar mounts, and adjustable UCA mounting stud supports as well as various other structural reinforcements for both the early and later style stock 2nd gen sub frames.

The lower pics were taken during sub frame deflection testing of various combinations of Pro G-Braces and reinforcements.

[WSSix]

That's awesome, John! Thanks for replying with the information. Do you have a website? I see the adjustable UCA supports. I'm interested in the other supports for the control arms both upper and lower. Can you share the results of your deflection testing?

I agree that a more race oriented car would flex the upper cowl from the triangulation bars. The forces put on a car during hard driving with sticky tires etc is so much greater than what a normal street car experiences. When I go to do my body, I was planning to make changes and add more support just because. I doubt I'd ever need it but while the body is in pieces, why not?

[jarhead]

WOW that would be awesome Trey! Going to go for it?

[NOT A TA]

Originally Posted by WSSix

That's awesome, John! Thanks for replying with the information. Do you have a website? I see the adjustable UCA supports. I'm interested in the other supports for the control arms both upper and lower. Can you share the results of your deflection testing?

I agree that a more race oriented car would flex the upper cowl from the triangulation bars. The forces put on a car during hard driving with sticky tires etc is so much greater than what a normal street car experiences. When I go to do my body, I was planning to make changes and add more support just because. I doubt I'd ever need it but while the body is in pieces, why not?

Thanks!

I don't have a website yet. When I figure out how to create one it'll be at lab-14.com and until then I'll continue to take orders through PMs etc. or by phone and take paypal or checks for payments. Hopefully I'll find the time to learn website set up soon.

The deflection testing I did can't really be compared to anything because I have a unique setup and the testing method can only be used to compare changes under the same conditions. So I'll give a bit of background and then discuss the tests I made. I am not done and will test other things as well.

1st, I'm using a modified 80 sub frame in my 70 bird. To do so required relocating the rear body mounts and I decided to strengthen the rear section of the sub frame by boxing it at the same time. In addition to boxing the outside, small plates were welded to the inside so that solid body mounts would sit flat further strengthening it. So deformation of the section of the frame at the rear body mount has been minimized. The cowl area body mounts on the sub frame were also reinforced with thick metal plates to reduce flex and distortion. I sell the cowl body mount reinforcements also. pics below









In addition to the body mount modifications the upper control arm mounts have been modified with an additional steel plate welded on as well as using ARP studs with a wider splined area to keep the stud more stable. While the UCA modifications don't change the subframe deflection without the G-Braces they could (or do) affect the results when the G-Braces are in place. Plates are made for right/left UCA mounts and come with hardware to align for welding etc. as well as optional ARP studs. pics below







My deflection test was conducted under static conditions without the engine, front suspension, steering, etc in place and no sheet metal as seen in the previous post pics. The cowl and front section of the passengers compartment was filled with 400-500 lbs of weight. A piece of right angle stock was bolted to the body pinch weld at the lower cowl extending forward to the frame horns where an indicator was bolted to the front of the frame horn as seen in the pic in my previous post. PTFB solid body mount bushings were used torqued to 100 lbs and no frame connectors were used. A floor jack was used to lift the frame at the front of the frame rails with a 4 X 4 across the horns.

Without G-Braces the frame deflected over 3/4" before the body lifted off of the cribs I had holding it up.

With Pro G-Braces which were not preloaded (and no additional braces or reinforcements other than the ARP studs and welded UCA plates) deflection was reduced almost 1/2".

Adding upper cowl reinforcement plates sandwiching the ledge reduced deflection another 1/8"+.

Adding the adjustable lower braces for the upper control arm cross shaft mounting bolt/stud did not change anything. I really didn't expect them to because their job is to prevent wobble of the UCA mounting stud during high loads when the shocks are compressed or when on the throttle lifting the front end.

I did not test the additional triangulation braces that mount to the upper cowl because they're one of's and not something I'm currently selling. Also they're main functional is to reduce twisting during lateral loads which I'll be testing later on.

So the results were that the G-Braces combined with my reinforcements reduced the deflection (under the given conditions) to about 1/16- 3 /32. Using a couple tram gauges I determined that the deflection remaining wasn't forward of the cowl body mounts but was the floor of the body deflecting down at the rear body mounts.

Things to consider:

The testing I did was only to test vertical deflection. I did not test for reductions in the twist of the sub frame, maybe next time.

Vertical deflection of the sub frame occurs both upward and downward so my measured deflection and reductions may actually only be 1/2 (+ or -) of the total movement possible. Without putting the body on a frame rack I don't know if the same force up or down flexes the frame an equal amount in each direction.

The front end sheet metal provides additional support that was not there during my test. The upper inner fender of a 2nd gen is made like a frame rail and probably reduces deflection to some degree through the core support when solid body mounts are used.

I will conduct more tests when the car is assembled and frame connectors are installed. Also I'm sure I'm forgetting something as I did the tests a while back so if there's any questions fire away!

Long post and time for me to sleep. I'll write a post about lower control arm mount reinforcements tomorrow.

[Doug1]

I plan on getting to some of this starting this weekend. Haven't been able to touch the car for weeks due to work so I finally have 2 days off in a row!

I'll post up some of the pics.