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Joined: Jan 2016
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Has anyone installed a suspension upgrade? i just want to improve the ride on our car. Thinking sway bar upgrade, frame connectors, springs
changes etc.. How about lowering kits, anyone? Don't need a stiff ride. Thanks all.

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Its your car of course, but I like to experience the machine the way the Pontiac engineers designed it.

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Equipped my ‘68 with stock front suspension with shortened springs, fat sway bar, KYB gas shocks, subframe connectors, polyurethane body mounts, Hotchkiss 1 1/2”
lowering leaf springs. Relatively inexpensive compared to high end pieces in the aftermarket and dramatically more
fun to drive. PM for details.


Thanks,
Dennis
Joined: Jun 2003
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-Factory front springs
-Rear 5 leafs with 1" lowering block in rear and no spring isolators.
-1 1/4" front sway bar.
-Guldstrand mod.
-Aluminum body mounts.
-QA1 single adjustable shocks.
-Upper/Lower tubular controls arms with delrin bushings and built in positive caster.
-245/45R17 front and 275/40R17 rear.

Rides really smooth and handles great.

Next mods will be subframe connectors and pro-forged 0.5" taller upper balljoints to further improve camber gain. Plus Baer Tracker adjustable tie-rods to correct bump steer. Moving up to 18s in rim size.

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I’m thinking my next upgrade is better shocks and tubular control arms. Who is the control arm manufacturer you are
using? Are they equipped with steering stops? Do the Delrin bushings transmit road harshness to the car. (Roads here are very bad)


Thanks,
Dennis
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I have DSE upper control arms and SpeedTech lower control arms (I did mine so long ago DSE's LCAs were still in development). I don't recall if my STs have steering stops. I think they come that way now, but not way back when I bought them. Don't think they have added built in caster either like DSE's.

The delrin bushings are are virtually friction-free, so if anything they improved the ride. I even went up in spring rate and sway bar size at the same time and it felt smoother (same shocks before and after swapping the arms).

Last edited by FirebirdMike; 03/25/21 07:37 PM.
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Thanks. Didn’t realize that about the delrin bushings. I’ve seen the DSC control arms in person. Nice pieces.


Thanks,
Dennis
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If you think Indiana's roads are bad...I lived in Detroit at the time I did my suspension upgrades. So I understand your concerns and can speak from experience.

With rubber or polyurethane, the arms will have stiction and deflection as the loads are put on the wheels. The control arm is not following it's intended arc in a smooth fashion. This makes everything feel stiffer and affects the suspension geometry. Whereas delrin bushings have virtually no friction and no deflection. Now the arm can move only in the intended arc and smoothly, transferring all the loads to the springs and shocks letting them do all the work. This is ideal for both ride quality and handling.

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Since your asking about upgrades to handling without affecting ride, let me give you another piece of advice... solid body mounts. Huge difference in how the car feels.

When I did mine, wasn't sure exactly what to expect. Lot of conflicting information. The funny thing is, the people swore by them actually put them on their vehicle. The people that warned against, thinking it would affect the ride, of course never actually tried them. So I figured worst case maybe I'd sacrifice a little bit of ride quality to take out some body lean. But all this talk did make me curious, and since it was the only modification planned, I figured I'd do a good before/after comparison.

In the morning I setup everything to do the job. But before I actually swapped them, I took the car out. I had a habit of resting my hand on the pillar and would notice it would shake, so I did that on the before ride. I also drove it over many, many pot holes (in Detroit it's easier than trying to avoid them anyway smile.). We had railroad tracks nearby, so it it over those as well. And finally, did a couple circles in both direction at higher than normal speeds to feel the handling.

Then I swapped them, and repeated. I was pleasantly surprised that it actually felt smoother over bumps and tracks. I think because it didn't have the flex happening between the subframe and the body causing more motion. Plus now instead of the flex, the force inputs all went to moving the wheel, making the shocks do the absorbing as they're meant to. But the body lean... wow what an improvement! And the pillar was much more stable.

Make sure you hit them with a lot of penetrating oil (a lot). I sprayed mine from all angles several days before I actually did the swap. Too many first hand stories of "I broke the but welded to the floor pan, now what do I do?" Use a breaker bar for leverage if you must, but gradually increase the pressure, never jerk or hit the ratchet.

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Thanks for the information on Delrin bushings. Will change my direction on control arms.
I couldn’t agree more on the huge improvement body bushings make. Years ago I machined solid aluminum bushings for the rear mounts to better tie in the subframe connectors. Fearing harshness, I installed polyurethane body bushings in the other two locations and the core support. With no other changes at the time, truly amazing improvement in how tight the car drove.
Sage advice on penetrating oil. Through the years I’ve used a lot of different products but found PB Blaster works great. When tearing into an old assembly I’ll spray everything down a or two ahead of time.


Thanks,
Dennis

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