Requesting guidance on a suspension refresh/upgrade project

[zevenbergena]

Finally getting around to addressing suspension on my '80 SC.
Everything is stock and original except for what looks like KYB's in the rear.

Just ordered Bilstein Sports for all 4 corners, Turbo tie rods, poly-graphite upper strut mounts and a strut brace, ball joints, and all associated hardware for the initial refresh.

I auto-x when I can and would like to eventually track the car for fun, but I'm honestly looking at a 98% street car. I'd like to lower the car to euro spec heights. Should I even look into altering torsion bars/sways? Will the struts help cut down on excessive body roll (see pictures below)? I don't mind a slightly stiffer ride but I do use the car for occassional longer trips and getting up to the windy roads, but I don't want to be miserable while driving around town either.

I know it's a slippery slope, I know I'm not looking for fully adjustable coilovers or anything super fancy. Appreciate recommendations and tips.
TIA
Aaron Z.

[zevenbergena]

There's a video of another event here:
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and you can see just how mushy it currently is.

[Flat Six]

". . . while you're in there . . ."

As long as your replacing tie rods and ball joints, consider replacing A-arm bushings. Many choices from stock rubber to solid, nearly all available from our host. Would seem a shame to tighten up the front end without also addressing A-arm bushings.

Just my $.02.

Dale

[Trog]

What's your budget?

[Zeke]

I'll bet there are a 1000 threads about upgrading suspension and I'm sure it's a chapter in Wayne's book "101 Project for Your 911."

Over the years it has boiled down to a few rules:

Don't over dampen your spring rate (or under dampen).

Selection of shock absorbers is dependent on several factors. These include tire track, weight and of course, what torsion bars are in the car. For stock bars, a lot of people have chosen Bilstein HD's for the front and Sports for the rear.

Heavier torsion bars or sway bars.

Mark Donohue apparently once said that there were two schools of thought on this. The wheels on the car have to be able to follow the road or track surface. And the car needs to stay as level as possible to preserve tire camber. A car with stock torsion bars and not very aggressive shocks will benefit from some stiffer sway bars. Combinations vary, but 911's like it set heavier in the front.

Free up the suspension while tightening it.

New performance bushings will help the suspension to travel more freely while keeping alignment settings in closer tolerance. You can imagine what the rear trailing arms are doing with those big worn out spring plate bushings under hard acceleration and braking. Dynamic rear toe changes can make a car squirrelly.

Alter ride height

This subject has to be approached carefully. Given all stock components, every inch a car is lowered is an inch lost in suspension travel. That is to say "jounce" travel. And the camber variables are changed. The latter usually being for the better. But, you can't over do it with stock struts and stock length shocks or you will be bottomed out under hard cornering or on bumpy surfaces, both of which can make car control difficult.

Improve tires and wheels

Enough said.

Finally, tightening up the body.

A simple strut brace between the strut towers is a beginning. A triangulated one is a step up indexing the top of the towers to each other and the tub in general. A weld in roll cage (not just a hoop behind the seats) will secure the center of the tub from flex. The ultimate stiffening uses even more bars to tie the suspension mounting points to each other and the tub. This is an extreme set up that would be called for if all the other parameters were maxed out.

[zevenbergena]

Thanks Dale, gottem added.
Trog, I don't have a set number for a budget. I'm trying to keep it reasonable but I definitely want to do it right. The only thing I hate more than cutting corners or trying to stay tight is having to go back and fix or replace things again soon.
Milt, I tried searching the forums for basic 911 suspension theory and worked through the Suspension Wizard and got such a wide variety of things I thought I might 'need' that I wasn't able to come up with a solid plan yet. I do also own '101 Projects' and will be using that in conjunction with the Bentley's and the forum to do the work. I'll have to dig through again for recommendations in the book...

[HarryD]

Find the local suspension wizard in your area and spend some quality time with him outlining your desired outcome. That is what I did here in Oregon with Jeff Gamroth and Steve Weiner (pelican aka steve@rennsport). The time will be well spent.

If you learn by reading, check Steve's Website for some info as well (www.rennsportsystems.com; http://www.rennsportsystems.com/2b.html; http://www.rennsportsystems.com/1-e.html)

[RWebb]

nice summary, milt!

you can search up my yet another Rgruppe threads for the suspension to see how to evaluate what you want

there is no perfect suspension

[911st]

The classic step up for a trackable street SC is 22/28mm torsion bars. Later if you want it stiffer you can up grade the sway bars. However, new sway bars are a good idea as they have adjustable drop lengths that make it easier to corner balance your car.

This is very compatable with your Sport shocks. Some recomend HD's front and Sports rear.

Do all the bushings with replacement rubber or hard style. Sport alignment and good corner balance with your weight in the drivers seat.

Most opt for a steering rack spacer kit to improve bump steer and turbo steering tie rod ends.

No need to go lower than 25.5" / 25" fender height for a street car.

Most report this as a very streetable set up and a lot more controllable, safe, and fun on the track.

One option up from this would be mono-ball front strut tops that let you dial in more neg camber up front. My current favorite is the Camber King from Smart Racing Products. If you leave your shock hat off you can almost get up to -3 deg camber.

This is a pretty proven set up and used by a lot of owners over the years.

[michael pagano]

Not to butt in but im doing the same thing so no need to start another thread...

For a 76 911 what T-bars should I run with stock sways and bilstien HD's for 98% very sporty street driving? Im guessing the 22/28 for the SC might be a tad different

Also what will sports in the rear change vs HD's? arent they shorter so you will get more travel or something?

[Zeke]

Originally Posted by michael pagano

Not to butt in but im doing the same thing so no need to start another thread...

For a 76 911 what T-bars should I run with stock sways and bilstien HD's for 98% very sporty street driving? Im guessing the 22/28 for the SC might be a tad different

Also what will sports in the rear change vs HD's? arent they shorter so you will get more travel or something?

The narrow cars with 7's on the back and lighter weight don't need 28's IMHO. HD's are hard riding shocks that can be felt in the seat more than Sports. But mind you, I/we said heavier shocks when you up the bars.

People who have done this more than once will usually send specs to their shock provider and have the shocks valved accordingly.

It is a fact that mated heavier shocks and bars to a particular car will ride softer than if only one of the two have been replaced. This is how is should be.

[RWebb]

yup - I run 6's & 7's with 21/27 t-bars -- my '73 is unusually light for a street car tho.

[michael pagano]

They are hd's that re getting refreshened by bilstien(from like 1988 or something) so ill get them to valve accordingly. So like 22/27(bc rwebbs is ligheter)?

[zevenbergena]

Thank you Milt for the summary and everyone else for the input. I know it's one of the topics we see a ton of in the forums and probably isn't even hardly fun to add to, but I really appreciate it.

Doing upper mount bushings and the strut inserts this weekend and, taking a look at things, I was wondering: has anyone just pulled the entire insert out through the top? Seems like it would be a lot easier than removing the entire strut assembly and based on the diameter of the bushing vs. the insert, it looks like it would fit. Curious if this seems too convenient to be true.