Rear suspension upgrade advice

B

buzz77

Master Mechanic
Jun 11, 2013
287
39
28
#1
Hey guys time to replace the 40 year old coil springs and air shocks on my 79 GP. Was looking at the UMI rear coil over shock kit.
I'm only looking to improve the handling and cornering in spirited street driving and improve the rake and stance on my car. Would you say these pricey rear coil overs are over kill and I can get almost the same performance from a set of new moog coil springs and a set of bilstein shocks?

It currently has the 7/8th thick rear sway bar will going to a 1 inch make a noticeable difference? Thanks guys!
 
G

Gremlinsteve

Greasemonkey
Mar 6, 2018
243
189
43
#2
Ugns will chime I I'm betting
Take his advice

I used moog 5660 fronts
Bilstein shocks
36mm f body sway bar
Drop spindle from a s10
C5 brakes

Drop spring from bmr
Air shock
F41 sway bar
C5 brakes

Jeep steering shaft
F41 steering box

17x7 front
225/50

17x9 rear
275/45


It's awesome now
 

Attachments

06 dodge cr

06 dodge cr

Greasemonkey
Jul 15, 2013
247
48
28
Franklin, PA
#3
Here is my input on this, If your not out thrashing your car on autocross tracks or on the back roads then coilovers are over kill. I would suggest UMI 1 inch drop springs with bilsteins all on four corners. Is your car a F41 package car? I'd assume since it has the rear bar already.. but going to a 1 inch from 7/8 might help a tad, what will make a big difference is the adjustable frame and rear axle mounted sway bar. The list could go on and on... it all depends what your plans are with your car.. Good luck it gets very pricey quick!!
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
22,899
3,877
113
Kitchener, Ontario
#4
whatever you decide to do with the rear you need to set up the front as well so the car is balanced
 
565bbchevy

565bbchevy

Geezer
Aug 8, 2011
5,362
2,113
113
Michigan
#5
While coil overs would be nice there are plenty of affordable upgrades that will make a big improvement on handling for a fun street car.
 
UNGN

UNGN

Comic Book Super Hero
Sep 6, 2016
2,597
1,048
113
Southlake, TX
#6
If you want the car to "handle" better in the real world, ditch the stock location bar in favor of a "pro touring" style rear bar. A larger stock location bar is better at the drag strip or on a smooth parking lot autocross, but can get you in trouble if there is a bump in the middle of that high speed turn or onramp.

The pro touring style rear bar will free up the rear suspension to take bumps with less potential for bind that can pick up the rear suspension and throw the back of the car off the road, in bumpy, lower traction situations.

My T-type is set up for dragstrips and table top smooth surfaces, so I have a big 1.3" ATR rear bar (and the stronger LCA's that are required when using a bigger stock location bar). Massive tail out oversteer when hitting bumps at high G's is something you have to be ready for and you learn to drive just below the limit and not try to get that little extra out of it.

My 2+2 is more confidence inspiring with the same tires as my T-type. I used to have a Large stock location rear bar on the 2+2, but after sliding through the grass @ 110 mph after hitting a bump at the apex of a turn convinced us to go another way. It was probably faster with the large stock location bar, as you could steer the car with the throttle in a turn (letting off turned the car in more, let off too much and the back end could break loose), the problem was it was much, much easier to crash.

Bilstein shocks are an excellent choice for street shocks if you go with lowered springs.
 
Daca214

Daca214

Master Mechanic
Dec 1, 2017
257
180
43
Jupiter, FL
#7
Hey guys time to replace the 40 year old coil springs and air shocks on my 79 GP. Was looking at the UMI rear coil over shock kit.
I'm only looking to improve the handling and cornering in spirited street driving and improve the rake and stance on my car. Would you say these pricey rear coil overs are over kill and I can get almost the same performance from a set of new moog coil springs and a set of bilstein shocks?

It currently has the 7/8th thick rear sway bar will going to a 1 inch make a noticeable difference? Thanks guys!
I went moog and bilstein and its a nice tight stiff ride. I have boxed rear control arms also
I will not be racing just a DD
 
B

buzz77

Master Mechanic
Jun 11, 2013
287
39
28
#8
If you want the car to "handle" better in the real world, ditch the stock location bar in favor of a "pro touring" style rear bar. A larger stock location bar is better at the drag strip or on a smooth parking lot autocross, but can get you in trouble if there is a bump in the middle of that high speed turn or onramp.

The pro touring style rear bar will free up the rear suspension to take bumps with less potential for bind that can pick up the rear suspension and throw the back of the car off the road, in bumpy, lower traction situations.

My T-type is set up for dragstrips and table top smooth surfaces, so I have a big 1.3" ATR rear bar (and the stronger LCA's that are required when using a bigger stock location bar). Massive tail out oversteer when hitting bumps at high G's is something you have to be ready for and you learn to drive just below the limit and not try to get that little extra out of it.

My 2+2 is more confidence inspiring with the same tires as my T-type. I used to have a Large stock location rear bar on the 2+2, but after sliding through the grass @ 110 mph after hitting a bump at the apex of a turn convinced us to go another way. It was probably faster with the large stock location bar, as you could steer the car with the throttle in a turn (letting off turned the car in more, let off too much and the back end could break loose), the problem was it was much, much easier to crash.

Bilstein shocks are an excellent choice for street shocks if you go with lowered springs.
Thanks Ungn. I didn't realize the stock mounting location creates what your describing. I bought the umi tubular lowers and will get the upper ca's with the rotojoints. I have a t-top car and was also thinking of getting that stiffening bar that goes across the shock towers.
 
B

buzz77

Master Mechanic
Jun 11, 2013
287
39
28
#9
I went moog and bilstein and its a nice tight stiff ride. I have boxed rear control arms also
I will not be racing just a DD
Which moog springs are you running? Is it stock height?
 
B

buzz77

Master Mechanic
Jun 11, 2013
287
39
28
#10
whatever you decide to do with the rear you need to set up the front as well so the car is balanced
In the front I have bilstein shocks and the 36mm hollow sway bar. Rest is stock. Last night driving in light drizzle, the rear was all over the place fishtailing, going sideways, felt too bouncy as well. I have a pontiac 400 with the 200 4r. The front of the car seemed planted to the ground but damn that torque was making the back end twist all over.
 

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