Plymouth GTX. New suspension. Any recommendations?

[PlymouthGTX]

So the GTX has had an enormous amount of work done through the winter. Over £10,000 spent.


Now we are looking to improve the suspension set up.

Everything seems functional although one of the leaves in the near side rear leaf spring is cracked.

Is there a preferred set up to replace everything or is it best to just stick to the original set up but with new parts?

Thanks for any input

[morgan]

I hotchkiss'd mine all round. Not cheap but really tightened up the car. Torsion bars were the best bit.
Shipped them from jegs i think - springs and torsion for $100 ( which seemed wayyyy to cheap for the weight)
You can always get them to one of ron fentons crates ( search) for big stuff.

[raven68]

Depends how much you drive it. Ive uprated 'old suspension' with stiffer lower springs, polybushes, uprated shocks, etc and the car ain't a pleasure to drive anymore as its so stiff it bumps and bangs over our crappy potholed roads. Stick to standard set up is what I have done with the Charger as just replacing all the worn steering joints, ball joints, rubbers and rear springs/shocks made a huge difference for not a lot of money. Its fine for weekend cruising and days out.

[PlymouthGTX]

I hotchkiss'd mine all round. Not cheap but really tightened up the car. Torsion bars were the best bit.
Shipped them from jegs i think - springs and torsion for $100 ( which seemed wayyyy to cheap for the weight)
You can always get them to one of ron fentons crates ( search) for big stuff.

Can you tell me more about specific parts ordered and replaced please. Thank you

[PlymouthGTX]

https://www.hotchkis.net/product/1970-m ... 2312&sm=20

I found this. Would this be a good package or best to stay standard ?

Thank you

[PlymouthGTX]

I gave them a call and "rob" said the shocks needed are Fox valved at $145 a piece and a 1.1 torsion bar for $350 plus new ball joints for the TCA and
B Body Pivot Shaft and Bushing Kit from Hotchkis Sport Suspension at $129.

[Dave999]

chart of bars below

make sure you buy your bars off a manufacturer with decent reputation.
the hex end is set at a specific angle that differs for each bar thickness because each thickness twists a different amount under load.
if the offset and thickness are mismatched you can't adjust the suspension properly
the subtleties of this is lost on some manufacturers

hotchkiss, firm feel and mopar get it right

for rear springs i'd be inclined to find a uk manufacturer or reconditioner. they can re arch and re temper the springs in your spring pack and replace or repair any broken ones

what you spend on a custom job here you would be spending on shipping, and you have some come back if they droop in 3 years. you have no rights on anything exported outside of US territory regardless of how crap it is.

http://arengineering.com/tech/torsion-bar-tango/

stuff on spring rate with input from a guy at hotchkiss

http://www.protouringmopar.com/showthre ... ng-weights.


front
upper control arm bushes or new control arms (ask morgan his are great)
lower control arm bushes
plate the lower control arm bases (ask Anton at APD)
use moog bushes in both places
strut rod bushes 3 types get moog improved and follow the instructions in the package not the manual
idler arm replace the rubber with a urethane bush or a ball bearing conversion
front end set up
lots of views....
but standard ride height is best
positive castor (some for manual, as much as possible for power steering)
some toe in so the wheels run straight ahead when loaded up
neutral or a smidge negative camber

fit anti-roll bar

rear
re build springs with new plastic sliders and zinc plate interleaves (make your own)
get them re arched for proper height and re tempered to provide a spring rate that compliments the front. if done right you probably don't need anti roll bar at the back. if you get one get the one that bolts to the body not axle tubes pointless adding the full weight of the bar to the axle.

urethane bush front eyes and shackles

i use KYB gas adjust. they are dirt cheap and a a slight upgrade. i'd suggest if you do all this work you should probably invest in something better

keep in mind that what is good for drag racing is particularly crap for everything else. so establish in the first instance what the retailer of the parts means by "racing" drag or road and track (circuit)

big stiff springs will make it handle like a modern car ONLY if the shocks are matched to the install based on chassis dyno suspension testing.

i didn't have the time or money for that so i made sure i set everything back to standard. ride height spring rate etc and used a slightly stiffer shock wch gets a little bit harder when worked.

its easy to end up with something that handles like a milkfloat on rubber cone suspension if you just go mad on the stiffest springs you can get

mine drives alright
rolls a little but that just gives a better indicator of when it will let go. stops better and i don't loose bits of exhaust on speed bumps

Anton at APD did my rear springs and i rebuilt the front end with a 16:1 manual box. it works quite well
16:1 manual in an A body is ok power steering is 14:1 anyway
i used NOS upper ball joints and japanese Three 555 lowers (4x4 off roaders rate them) and TRW track rod ends (three 555 make stock for MOOG)

try to get ball joints and track rod ends with the proper plastic edged push fit seal as used by mopar not rubber boots with wire clips as used by everyone else.

but keep in mind that ball joints are robust and you probably don't need em. and each pair of upper arms can only manage 2 or 3 ball joint replacements before they are scrap, each install cuts a new thread and any mis alignment stretches the hole in the arm.
although i guess you could press the holes back to size ..... mebee

Dave

[DaveB]

GTXs and R/Ts drive great compared with lesser models,not a bit better,loads better.
new moog bushes and ball joints on front,HD leafs on rear,front anti-roll bar,good set up,job done