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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.. http://i213.photobucket.com/albums/c...psw4wxjkrj.jpg http://i213.photobucket.com/albums/c...psdxiusxgq.jpg |
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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! |
pro-g braces
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
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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! |
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. http://i240.photobucket.com/albums/f...psodwmrxhx.jpg http://i240.photobucket.com/albums/f...psjgrgdr4x.jpg http://i240.photobucket.com/albums/f...psqb6z0bkf.jpg http://i240.photobucket.com/albums/f...ps3siwdgab.jpg |
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? |
WOW that would be awesome Trey! Going to go for it?
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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 http://i240.photobucket.com/albums/f...ps1fk3myfh.jpg http://i240.photobucket.com/albums/f...pso9fbsv5p.jpg http://i240.photobucket.com/albums/f...psnlzvpjs4.jpg http://i240.photobucket.com/albums/f...psgfkhhrpb.jpg 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 http://i240.photobucket.com/albums/f...psqjfxs3fn.jpg http://i240.photobucket.com/albums/f...psukt0dkgz.jpg http://i240.photobucket.com/albums/f...pshozi0tbe.jpg 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. |
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. |
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:
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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 |
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http://i240.photobucket.com/albums/f...psgfv5bcbd.jpg |
wow! That's pretty bad.
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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.
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Read through your whole thread tonight. Very nice work on the car. Since you are still running leaf springs on the rear, have you cut out the top of the front spring hanger brackets to allow you to raise the front spring eye holes to help add some anti-dive to the rear suspension? Herb Adams recommended this decades ago when he offered the firewall braces like you have now. You will need to reshim the pinion angle afterwards, but that is a minor thing compared to what you have already done. I didn't notice your having done this so far, but it made a noticeable difference in handling in my car back then( not the ones in my sig.).
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Thanks for the kind words, Ric. Yes, I did the Herb Adams mod. I actually did it long ago before this latest round of updates. I have no idea if it made an improvement, but I like the way the car handles currently. I've been busy in other areas of life and with working on a friend's 69 Mustang. I hope to be making updates and further advancement on this project soon.
Thank you |
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I've not heard of this mod and what I'm picturing in my head doesn't make any sense to me. Sorry for the high jack OP |
No worries, Greg. The mod is simple. You remove the front leaf spring pocket off the car or spring, then you drill a hole 3/4 inch higher, cut the top of the pocket so the spring will still fit, and then bolt everything back together. Some people, me included, also weld another width of metal over the top of the pocket to reinforce it since the top was cut out of it.
Here you go http://www.nastyz28.com/ubb/Forum10/HTML/007242.html |
Like Trey I was concerned about the strength with the window in the top. I made the window a bit larger on mine than most people need because I'm running spherical front spring eye bushings which allow more tip. In pics below you can see where I added metal to the sides etc. and the 3/4" difference in the higher hole. I panel bonded mine instead of welding, don't remember any particular reason why, might have been out of gas or something. Either way works fine to reinforce the pocket.
While on the spring pocket subject, try not to use the crappy china junk U nuts the restoration places sell under the OER or other house brand names when the pockets get reinstalled. If you can find CIP brand they're much better and you can identify them by the "CIP" stamped into them. http://i240.photobucket.com/albums/f...ps877bf3d2.jpg http://i240.photobucket.com/albums/f...psdb57b81c.jpg http://i240.photobucket.com/albums/f...ps69333bc9.jpg |
Ok, I have seen that mod before, perhaps from John. I feel like I've been on an island or something.... It seems like this would effect ride height slightly. What else does it do for the car?
Have you guys installed a track bar with your leaf springs? Do you have any details on the impact that made to the car handling and the installation? |
This is supposed to help plant the rear as you apply throttle.
I don't have track bars. i would think it would hurt articulation of the rear suspension. John may be able to explain better if he sees this. |
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It's referred to as the Adams mod but I believe Herbs chassis engineer Harry Quackenboss actually came up with it in the beginning. I've been aware of the mod since the 70's but never did it to any of my cars. Several years ago I had a conversation with Harry about it as well as the spherical front spring eye bushing mod and decided to try both on my car. |
John- what did you feel different once you did those mods? Did that mod improve corner entry, exit?
I believe the track bar helps keep the axle located in the center, although, I guess can't see where it would impede the articulation. With the track bar holding the axle in the center it would seem that the back would have more precision in following the front... Just a guess on my part |
When I was running my car one day at Sebring I had a instructor working with me and another guy in a Yellow Maserati taking turns playing lead/follow during a HPDE session. Instructor guy (BMW) said he could watch the rear of my car shift over the rear axle at turn in. If I hit the curbing hard at an apex the inside of the outside tire would slightly rub the inside of the inner fender. He suggested adding a locator such as a Panhard bar or Watts link to reduce the movement.
http://i240.photobucket.com/albums/f...ng10309033.jpg |
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Sorry, Greg. When you said track bar my brain thought traction bars like Cal-tracs. A panhard rod or watts link will help. You could also go with thicker shackles like I have from Custom Works to help keep lateral movement to a minimum. His pieces are towards the bottom of this page.
http://customworksperformance.net/suspension.html |
Trey, do you have the Delrin frame bushings in your car?
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Yes. I haven't begun to push my car hard enough to know if they help. I know Keith/Custom Works has a video on his site showing before and after he upgraded the shackles. However, he also did other changes at the same time. Those changes shouldn't have affected the lateral movement of the rear though.
Can't tell you about NHV transmission through the Delrin. The car has no interior so it's loud. I don't feel anything hash when I hit bumps. I'm running 200 lb springs in the back |
Haven't visited this thread (or forum) in a long time! Looking damn good! Our build styles are almost identical... (BTW I run a SPEC 3+ with my LT1 T56 and love love love it.)
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I got some info on PT that my front air dam should be lower for aerodynamic purposes, so I took some measurements and they are a fair amount higher than I realized. So I can go lower, but I wasn't expecting to see yours THAT low. I've seen 4.5 - 5" as the general consensus as far as a practical ground clearance number. I've got my exhaust tucked up nicely too, so I'm not as worried about that stuff as I am the front crossmember. You got that slammed! |
Thanks Woody. I appreciate the kid words. I need to take some more measurements now that it's been a while since I did all the work. Things settle and I'm not sure where I'm at now with ground clearance. I don't scrape or bottom out on anything so I'm good in that respect. Is it optimal for handling? I have no clue. I'm not at the stage where I can judge that. With the driving I have done, it ride and handles fine.
I'll look into that clutch too. I'll be needing to make that decision soon. |
Looking for opinions on how I should paint my engine since I'll be getting it built soon.
Here's what it looks like now http://i472.photobucket.com/albums/r...psv0ok9xnm.jpg With the shaker removed but the manifolds in place http://i472.photobucket.com/albums/r...psffc812d8.jpg I'm honestly not trying to build anything to show off. I just want it to be clean and hold up over time. I have a new billet throttle body that will go on the engine that's natural currently. I'm half way considering powder coating the intake black along with the block and leaving the ribs natural aluminum. How does that sound? Valve covers will remain unless I can find some C4 units. Those are black composite. What to do with the water pump? Silver or gray paint? Black? Thoughts? Suggestions? Thanks EDIT: I think I need to see about removing the oil fill extension. Looks out of place being that tall. |
Pretty Sweet! I have a soft spot for the later 2nd Gens.
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Thanks John! I appreciate the kind words.
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Trey,
Just my personal opinion but I like contrast, black and grey, or black and silver sound good. On my 68 the block is going to be gunmetal with black pulleys and the engine bay will be a black satin. I wish I would have painted the intake. I spend too much time on google images. Allot of nice engine bays on here too. You are making allot of progress! Joe |
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