Suspension upgrade questions

[jester911]

I am considering doing a few suspension upgrades but since the car is 18 years old I figure it best to start with replacing various bushings to start with.

I want to go to adjustable sway bars, turbo tie rods, and possible a strut tower brace.

A couple of questions I have are:

1. Do I need to do a bump steer kit if I go with turbo tie rods?

2.What size sway bars are the stock size on an 86 coupe?

3. What bushings are necessary to be changed ?

It sounds like the polybronze bushings are the best for me.
The car is mostly street but a little track time as well.

I have had this car going on 4 years now and I am trying to do a little at a time to restore and upgrade as I go.

[dd74]

Hi Jerry: you should decide what sort of driving you'll be doing, then go from there. Track vs. street is a strong consideration when setting up a suspension.

If at all, I would check out your bushings first to see if they really do need replacing. If so, just do those, drive it a good while, then see what else you need.

Shocks might be next. They're relatively inexpensive and provide good results. Then would be larger torsions, which gets into the realm of "what sort of driving you'll be doing." Swaybars would be last on my list.

The '86 came with 22mm front and read swaybars, I believe.

Others might think different thoughts about this, however, and they are not necessarily wrong...

[Zeke]

Others will have different thoughts. I read here that Mark Donohue preferred bigger sway bars to stiffer springs. Shocks are very important and must be matched to spring rate (t-bar size). I feel that sway bars must be matched to bigger t-bars as well.

No matter how you cut it, bushings and alignment are paramount. So, I would proceed with the bushings and shocks first if you need either or both. Then, decide on a ride height, which will determine if you need the bump steer kit. After that, corner balance and alignment. If you decide to add bigger sway bars later on, nothing will have to be reset. If you decide to add bigger t-bars later on, you start over at the very begining.

That makes David correct, even if I don't agree with putting in bigger t-bars before anything else.

[Randy Webb]

I think it would be helpful for people to post their setup but only for that year range and for mainly street driving. Earlier, lighter cars will use less strong bars of both types. Be sure to check these factors out when looking at old posts.

With the range of appropriate responses, you can think about how important comfort is to you, and go to one side of that range or the other.

[Az911]

I would start out with the turbo tie rods, a strut tower brace both are cheap and easy to install.

Leave the stock sways they are big enough unless you plan to auto x or do DEs even then they might be ok.

I would do bushings and tbars at the same time you do not have to do alot of work twice.

[911nut]

Originally posted by Zeke
I read here that Mark Donohue preferred bigger sway bars to stiffer springs.

Bigger sway bars will make for a choppy ride on the road.
Sway bars are incorrectly named. They tune handling by changing wheel loading during cornering. Bigger torsion bars are what will reduce body lean.

[Randy Webb]

Sway bars -- aka anti-roll bars -- connect the two wheels together and are particularly effective at reducing body lean (roll) when cornering. Because they tie together the wheels, the reduce the effect of an independent suspension, and could produce some negative effects if one wheel hits a bump but not the other. Big torsion bars will defintiely reduce body lean too, of course.

They need to be sized to everything else, so that may be where you got the idea that they cause a choppy ride. For a given wheelbase, "choppy" usually indicates mismatched springing and dampening rates (shocks). This is obvious if you lookat the portion of a physics text that discusses damped harmonic oscilators (which is what your suspension is). You don't have to work thru the equations -- just look at the diagrams.

[Zeke]

Originally posted by 911nut
Bigger sway bars will make for a choppy ride on the road.
Sway bars are incorrectly named. They tune handling by changing wheel loading during cornering. Bigger torsion bars are what will reduce body lean.

That's a new one. Could I read your sources?

[dd74]

Originally posted by 911nut
Bigger sway bars will make for a choppy ride on the road.
Sway bars are incorrectly named. They tune handling by changing wheel loading during cornering. Bigger torsion bars are what will reduce body lean.

I can't speak for sway bars creating a choppier ride. That would seem to come from a result from torsion bar/shock combinations which are either mismatched, or too heavy/strong for the car's weight. Either that, or driving on crappy roads.

As far as bigger torsion bars eliminating body lean (roll), I've heard about this. I've even heard of 911 race cars that do not run with sway bars (for weight reduction reasons), and use very large torsion bars to eliminate body roll. As far as the adjustability goes that can come with sway bars, well that's eliminated if one doesn't run them. I guess they'd have to rely on tire pressures at that rate.

All in all, Jester, you can see how complex and technical a suspension upgrade can become, right? It's not like shoving new cams in your engine or bolting on a muffler, eh?

[dickster]

hi jerry, i have the best year also - an '86!

i have been doin similar on mine.

i went with 22/31 t/bars - the supplier recommended. possibly too big for some for the street. the dury is out until i revalve the shocks.

did the bushes (rear) at the same time - neatrix, but would do polybronze now.

i have polybronze ready to go in the front.

i lowered mine to 24/24.5 - at this height you need drop links.

the turbo tie rods are a must upgrade.

i have bilstein sports shocks that i think are struggling with the t/bars - will get revlaved eventually.

i will go with larger ARB in the future as well. hopefully the smart racing ones!

not sure the strut brace is necessary for a street car/coupe.

good luck.

[jester911]

Thanks for the info so far guys. I put bilstein sports in the front and bilstein h/d shocks in back about a year ago. It made a world of difference.

Back to original questions. Do I need to use bump steer kit for turbo tie rods?

What other bushings should be replaced?

What size sway bars ( yes I know, anti-roll bars) are stock?

Mostly street driven but some track time as well

[dickster]

Back to original questions. Do I need to use bump steer kit for turbo tie rods?

i thought i had answered!

"i lowered mine to 24/24.5 - at this height you need drop links."

sorry should have been clearer - you only need to address bump steer if you lower the ride height. it doesnt matter whether you use turbo tie rods.