Updated TCP G-Bar triangulated 4-link...

Discussion in 'Classic Mustang Specific Tech' started by reenmachine, Nov 17, 2007.

  1. Would it be possible to weld the control arm/shock mount directly to the axle or the leaf spring pad be possible? It would make the installation even cleaner (not that the one you showed is ugly by any means...)
  2. You mean like this? :D

    This is the one I'm using in the '68 Bullitt. You can get the end pieces that they would use to weld to a FAB9 housing. You have to be a lot more careful positioning everything, but it does indeed come out looking really clean.




    Attached Files:

  3. Yeah, like that :nice:
  4. Pete thanks for the pictures. It doesn't take up as much space as I envisioned and certantly not as much as much of the competions 3 links and such. You mentioned it looks like there is space for 2 1/4" exhaust but what is your thought on 2 1/2"?

  5. +1, An excellent question!
  6. Well, what's another 1/8" on either side! :)

    Lemme get the car on the ground and get under there before I answer. I'm sure it's one of those things that will be doable by the right exhaust guy. Eyeballing it, it's tight but there is space there.

    I think I actually have a minute now to write more about the install so I'm going to get to it. The phone's been ringing all day though so if I flake again I'll get to it ASAP.
  7. So like I said before everything was pretty straightforward with the exception of the vent/brake line thing. Yes, you could probably get away without welding the hats on, but you've already got the welder out so why not zap it up. Of course, do little bits at a time to minimize the chance of distorting the housing.

    I won't bother going into the step-by-step since you can download the instructions from TCP's website and they very clearly walk you through it.

    There are three phases to the assembly (besides taking all of the old stuff out): positioning the cradle, assembling the parts, and adjusting everything. It's the first and third parts where you spend all the time.

    There is adequate adjustability in the cradle mounting points to account for the chassis irregularities we all know and love. There are six points of attachment: L&R frame rail just aft of the snubber, the 2 old upper shock mounting points, and the 2 pinion snubber bolts. I spent a couple hours getting the cradle positioned just so, which was probably overkill, but I'm weird that way. When you tighten one part down another moves, but through a sequence of jumping around and tightening fasteners in steps you can get it where you want it to be. They also provide shims to place between the cradle and the old upper shock mounts to get that interface to sit flush and I used 2 per side.

    Once you weld the frame brackets into place the cradle is captured and can't be removed. At first I was bothered by this but when I thought about it I couldn't figure out why. If the whole thing had been weld-in I never would have thought twice about it so why do I care now?

    To go off on a brief tangent, the frame brackets could be designed to be completely bolt-in. DVS's Cobra IRS installation kit places a bracket in the same location, and it's bolted in in a very secure manner, complete with anti-crush spacers inside the frame rail. It carries basically the same load as well. I guess my thinking is that then the typical person could bolt the entire kit into the car and take the housing to a local driveline shop to get welded up. It would be more of a garage-friendly installation. It would come down to cost -- would you be willing to pay an extra 50 or 100 bucks to not have to weld to your car?

    The other thing about the cradle installation is that they have you basically mock the whole thing up into place, get it all aligned perfectly, then take it back out to grind a couple of holes and prep the frame rail metal for welding. Then you have to get the thing back into place again. Next time I'm going to do it all in one step. You know within about 1/4" where the brackets will end up, so do the frame rail prep ahead of time with a little extra space. You can also make the oval holes with the bracket in place.

    So then you have to assemble everything. Lower links, upper links, and coilovers. It was hard to get the springs onto the shocks, but I was doing it by myself. If you had someone helping you it would be easier. I took the adjustment knob off of the shock so I could thread the lower perch just a little lower to squeeze the spring on. A 1" shorter spring would have been ideal.

    So here's what I think is the useful observation out of this whole process:

    The g-Link kit would be a lot faster and easier to install and adjust than the g-Bar kit.

    As has been discussed ad nauseam in this and other threads, systems with polyurethane bushings require those bushings to deflect (people often mistakenly call this "bind") as the linkage moves. As a result, each bushing has a neutral position in its mounting location where there's no resistance and it can move in and out of place freely. In any other position there is resistance to motion. This resistance is negligible with the weight of the car acting on it, but when you're trying to move things by hand to get them to line up it can be a bear. So, when you're removing, adjusting, and replacing the links to adjust pinion angle for example, if everything's not lined up just so it's not easy to get them out of and into place. You run into the same problem when installing the coilovers and adjusting ride height. Do not interpret this as a shortcoming of the system, it's just the nature of the beast if you want the ride quality (and lower price) the bushings provide. That ride quality was the goal with this particular car, so I think it'll be well worth the effort.

    With the g-Link pivot ball system, you'd be able to remove, adjust, and replace links much more easily regardless of the position of the suspension. Over the course of the install this probably would have saved me 2 hours and some knuckle skin.

    Overall, the kit looks awesome in the car and the quality of the hardware is outstanding. Nothing I encountered would lead me to discourage anyone from going for it.

    The car won't be on the road for another couple of days until I sort out some other unrelated stuff but as soon as I drive it I'll post my impressions of ride and handling.
  8. Are you going to run the tailpipes through the space between the coilovers and gas tank (over top of the upper links), or are you going to run them on the outside of the coilovers, in the area of the bumpstops?

    Attached Files:

  9. The pipes will go inside the coilovers, but they won't exactly go over the upper links though. It's hard to get a feel for the space in a photo.

    These mufflers have to outlets to the outboard side.
  10. I cut 1/2 a coil off of the front springs and the car sits just awesome now. That's just a temporary fix until we do a bunch of front end work in a couple of months, but it came out great.


    Attached Files:

  11. That is a great looking set-up. I'm looking forward to the next installment when you get behind the wheel.

    Now those pics that you posted of the stock 9" housing using the FAB 9 weld on brackets (as opposed to the U bolts), is that something TCP offers as an option or extra? I think I'd rather go down that path than the U bolt set-up.

    I was thinking using one of the new Currie crate diffs but they only use the 9 plus housing so the webbing is much wider. Presumably this will impede the installation of the upper link brackets but at the end of the day that's just another mod which needs to be made.

    Cheers, Mike B.
  12. Excellent write-up.
    I'm saving some $$$ and will get myself one.

    Nice Stang by the way :)
  13. Yes, there is the option to order the brackets "loose" so that you can weld them on to your existing housing instead of using U-Bolts. You will need to order the locating fixture with your kit. It helps you mount the upper arms in the correct position, you can then set your pinion angle and weld the lower brackets into place. You can then send the fixture back to us, and get some of your money back. (It kind of works like a rental) Doing it this way, as Pete did, will really give you the best, most finished looking appearance, short of ordering a bolt-in FAB9.
    This is the best option for early 8" rears that neck down at the ends. Our U-Bolts are designed to go on a larger tube diameter, and require fabricating a spacer to take up the space.
  14. Tim, I take it you work for TCP? I din't get much joy when I contacted them recently. A monosyllabic response to my request for a price and second tech request email hasn't been responded to as yet. Anyway, let's move on...........

    I'm getting Currie to build a rear end for me. I've decided to go with their 9+ hot rod housing primarily because the upper link brackets can be welded to the tubes as opposed to the webbing of the wider 9+ track carrier housing. Do you think it would be a problem being welded to the webbing? I would prefer the wider oval style carrier housing. Both have 3" tube axles. Currie can give me whatever I want so they can delete the leaf spring pads.

    I'm thinking I would like to go with the Fab 9 lower brackets to delete the U Bolt adaptor kit, however I'm located in Oz, so it makes it impractical to send the brackets back. Whats the extra cost for Fab 9 lower brackets?

    For my application, I'm thinking the G-Bar with pivot links, single adjustable shocks and the sliding link anti-roll bar.

    Cheers, Mike B.

  15. hi Tim, have you finished the G-Bar install in the cougar yet? still anxiously awaiting pics from that, thanks
  16. I would like to go all the way back to the begining of this thread and have a little more discussion on the 3-link vs G-bar. I have seen and read enough about the G-bar in this thread but not on the 3-llink. I had dicided to go with the RRS 3-link as it would compliment the RRS front struts I have on the car now but after reading this thread I'm not so sure. Someone at the beginning of this said the RRS was not a very well designed system. Can anyone explain in more detail? My car is a street/road race car. Performance is the goal over ride quaility. I drive 8/10th at the track to keep the car out of the grass.
  17. There's nothing wrong with the RRS 3-link design. It appears that they initially made the decision to use a big bushing at the front of the torque arm that would have to compress as the suspension travels due to the different arcs the trailing arms and torque arm want to travel. This isn't the best solution for a system touted as an "all-out performance" system, so they switched to using a dogbone pivot up front basically identical to that on the TCP 3-link.
  18. I'm using RRS struts on GW lower control arms and had always intended using their complementing 3 link set-up for the rear. I never liked their torque arm arrangement for the same reasons bnickel describes earlier in the thread. As a result I canned that idea and started looking for something new and this is where I've ended up. I still plan on using the RRS Phase 3 rear brakes though, to match the front combo.
  19. OK -- the owner picked up the car today. Among many little things inconsequential to this topic, I installed the g-Bar and the TCP Manual rack & pinion steering kit (stock column).

    My driving impression of the g-Bar was great. It was taut without being harsh, there was no noise from the bushings (they're all greaseable) and the damping felt great on the street at about 1/3 of the way up from the softest setting. This is a daily driver and we wanted to err on the ride quality side, hence the decision to get the g-Bar vs. the g-Link. The adjusting knob is simple to reach when the car is on the ground so changing the setting would take seconds anyway.

    One of the more noticeable changes is how confidently the car plants itself when you get on it. It really hooks.

    I waited to post this until today since I wanted to see what the owner thought first. After all, he drives the car every day vs. my few miles of "before" experience. He came back from a trip just around the block to say that it was absolutely a "night and day" improvement. He then drove it a bit more, including around some cloverleafs and down the freeway at speed. Again, "night and day" in his opinion.

    It's hard to quantify -- it's not like we ran laps or took it to the skidpad or anything, but the "butt dyno" results were overwhelmingly positive.

    I'll post again after he takes the car to the exhaust shop.
  20. I'm interested to see the result with the exhaust.
    Thanks for the update.