Can't Lower Car w/ G-Bar System

[DETON8R]

Originally Posted by Vegas69

That's not mine but a g link failure. Mine was just cracked around all three sides.

Todd, Thanks for your input and comments on the subject. I've read through your problem description and fix, and it looks like you have had a chance to beat it pretty hard since the repair. Is the fix holding up?

I'll fab up some supports and have the shop weld them in when I get my G-link welded in.

I've wondered what might happen by cutting the rear of the car to get the mini-tubs in. Looks like we can get a few things to bend and break that weren't supposed to.

And 2,500 posts on your build thread, you are the man!!

[frojoe]

Originally Posted by Vince@MSperfab

I'd get full weight and a few miles on them before you make the changes. But before switching to a shorter spring try a 150# or 175# 12" spring you should get a bit more compression out of it and still maintain a good ride.

I agree.. also measure the eye-to-eye of the shock when the springs have been broken in, or at least with some added weight in the trunk to simulate the sub box, full tank, etx. I believe the shocks are supposed to be 13.5" i2i at normal ride height leaving about 2.5" for bump travel and 2.5" for rebound travel.

If the spring is broken in and the i2i measurement is ~13.5" with normal weight on the 200lb/in springs, I don't think shorter springs or lighter weight springs would be the answer.

Lighter weight spring would be taking the same coilover but asking it to sit deeper into it's travel at regular ride height, so i might have 2" of bump travel and 4" of rebound travel, and on top of that the reduced stiffness of the spring will allow the shock to come that much closer & that much easier to bottoming out over a same bump for a heavier rate spring.

To use a shorter spring, the spring rate would have to go up (to keep same ride quality and 13.5" i2i) or else say a 10" or even 8" spring (to exaggerate) might coil-bind under full compression on the same 5"-travel shock body.

Really the ideal way to lower the rear end even more would be to get an overall-shorter-bodied coilover that maintains the same 5" travel (VariShock is 16.10", Koni is 16.10", Ridetech is ~15.9".. hard to find any shorter), to get a shorter-travel coilover with stiffer spring (due to reduced bump travel, at a sacrifice of ride quality), or to either lower the axle-side coilover mount or raise the framerail/body-side coilover mount.

[DETON8R]

Originally Posted by Vince@MSperfab

I'd get full weight and a few miles on them before you make the changes. But before switching to a shorter spring try a 150# or 175# 12" spring you should get a bit more compression out of it and still maintain a good ride.

Mike at CAC recommended and sold a set of 12" / 175 lb springs for the G-link rear. So that is the recommended set up from them. When I purchased they wanted to know how I planned to drive and what kind of power train package I was running. With a mild LS1/T56 and with my intended use of local grocery getter, summer time commuter up and down mountain roads in the Santa Cruz Mountains, and an auto cross/drag strip half a dozen times a year (fun not competition) that was the recommendation. They didn't recommend a stiffer spring unless it was really going to be used for competition.

And while the mountain roads are fun up here, this County and State are broke and the roads have their problems here and there. Having a stiff suspension would just result in my fillings popping out of my teeth if drive it too hard all the time.

Just my 2 cents....

[Vegas69]

Originally Posted by DETON8R

Todd, Thanks for your input and comments on the subject. I've read through your problem description and fix, and it looks like you have had a chance to beat it pretty hard since the repair. Is the fix holding up?

I'll fab up some supports and have the shop weld them in when I get my G-link welded in.

I've wondered what might happen by cutting the rear of the car to get the mini-tubs in. Looks like we can get a few things to bend and break that weren't supposed to.

And 2,500 posts on your build thread, you are the man!!

So far.... And my thread is at least half a bull **** fest.

[realcoray]

Just a FYI I just set my 72 Nova down with the G-Link on the lowest possible settings and it visually looks a lot better than the camaros here. The top edge of my rear wheels is tucked 1/4 of an inch or better and this is with an empty gas tank, no deck lid etc. I'm running 18 inch with 275/40 tires.

It's all just mocked up but I'm happy with the height.

[frojoe]

Mocked up on lowest possible setting combination. Here is full compression with an 18" rim and 275 tire...



1.75" clearance to framerail at full compression, with axle rotated forward a bit more than it would otherwise be if the upper link tabs were welded on, so figure actually 2.0" clearance...







2.0" rim tuck at full compression..



Recommended ride height for "race" of 50/50 bump travel (~2.5" bump, ~2.5" rebound, total 5.10 travel) equals ~13.5" eye-to-eye on the VariShock (full extended length is 16.10")...





At 2.5" of bump travel, 18" rim is hanging 0.5" below wheel lip.

[fillpot]

Guy's i'm also courious about this,i have a g-link installed in my 69 camaro mini tubed,etc,and was wondering what the ride height difference would be between the 12-200 and the 10-200 spring i have the 12-200 spring now.THANKS!

[dhutton]

Originally Posted by fillpot

Guy's i'm also courious about this,i have a g-link installed in my 69 camaro mini tubed,etc,and was wondering what the ride height difference would be between the 12-200 and the 10-200 spring i have the 12-200 spring now.THANKS!

Trouble is that you still want to be roughly centered in the travel of the shock. If you go too low you will not have any shock compression left and you will be bottoming out the shock. Centering the shock travel determines ride height. You can vary from that a little but not a whole lot.

Don

[frojoe]

Realistically for a 5" travel shock, you're not gonna want to lower it much more than to 2" bump/3"rebound for street driving. The absolute lowest I would ever let the shock "live" purely with a shorter spring would be with 1.5" bump/3.5" rebound, and that would have to be a lighter car and a very stiff spring, for racing conditions only. And that would only lower the rear end 1" past the max adjustment in ride height from suspension linkage. That's why I would recommend moving the upper shock mount higher or the lower shock mount lower, relative to the frame/rear axle

[Musclerodz]

reducing spring height will limit shock travel and will either coil bind or damage the shock for running it too low. if you want to lower the car you need to run a shorter shock and longest spring will give a softer ride.