Suspension Upgrades For '73 911

[356KarmannSUPER]

I'm interested in hearing what people have to say about suspension upgrades for a '73 911. I would like to lower it, and it has 7" Fuchs.
-What kind of:
-struts?
-spring plates?
-torsion bars?
-swaybars?
-brakes?
-Anything else?

The car probably needs some suspension freshening, so what maintenance should be done there? The car is an all-stock 911T which will be used for hard street driving and a little track. I don't mind a car that is stiff, but I do not want one that is jarringly so. Opinions?

[marcesq]

FWIW here goes:

-struts?
If you have the choice - Bilstein, sport if want it firmer

-spring plates?
You can pick up OEM adjustable spring plates for 100, gives you about 1/2" in each direction. Years are '77-'83. Replace bushings with Neatrix

-torsion bars?
21/26

-swaybars?
I'm using stock right now, so no comment

-brakes
Not sure what you mean here. You can do a very simple upgrade to Carrera ('84-'89) front and rear rotors and calipers. Although you will have to add an apportioning valve of the same vintage.

If you are talking about pads, there are many opinions there. I am using Hawk HPs and am happy with them.

Most people are of the opinion that the stock brakes are more than sufficient as long as no big increases in hp have occured.

Just my 3 cents

[addictionMS]

I am running a full 1985 suspension on my 1970, added hard bushings every where, bilstein HDs, and Sway a Way spring plates ( I prefer these because it is much easier to change the torsion bars, four cover bolts, and the bar pulls out, you don't need to pull the whole spring plate out.)

Carrera brakes and Pagid Orange ( would not suggest the orange actually)

This is a stiff riding car, hard to drink a coffee while driving kind of stiff

car is very low, pictures can be seen at my website

Jim

[Neilk]

Change the trailing arm bushing with OEM ones. Mine were pretty worn.

[dd74]

All this is good advice. Hard street driving and some track events might not necessitate new brakes - 911 brakes are some of the best in their stock form - I'd just make sure that everything brake-wise is in top condition. OEM pads seem to work fine, too.

My thoughts on suspension are pretty much the same. The Bilstein suggestion is very good as is the torsion bar increase.
Bushings - by far I think this would be the first area to address given the age of your car. Install new bushings everywhere, and see from there how your car handles.

Sway bars - if needed, you could go with Carrera bars ('87-89) and save yourself some cash over the adjustable types. Though the more you track the car, the more likely you should get something adjustable.

Springplates - like Marc said, you could pick up a pair of SC springplates for a Ben; Ebay is a good source.

I also suggest a strut tower bar. Now opinions will be mixed as to the effectiveness of such a bar, but after I installed one, my car became less indecisive at the front end and handled much more sharply.

Look, also into turbo tie rods, particularly if you lower your car, because the steering geometry will be off.

Get some good tires on those 7-inch Fuchs (Bridgestone, Yokohamas, Michelin) without a lot of sidewall flex, and you'll be in very nice shape.

[Randy Webb]

Much depends on street vs. track. You want to replace ALL the rubber in the suspension - including the top shock mounts (camber plates). It is 30 years old. Is it a "T"? If so, you might swap in a complete Carrera Fr suspension -- the cross arm is a bit lighter and you have a good choice of calipers. Also get the AL Rear banana arms -- saves about 11 lbs in this vital area. I prefer the OEM late model spring plates over the aftermarket ones. If racing on an unlimited budget, get the ERP 935 Fr arm setup with coilovers. Get Sander hollow trosion bars and the Smart Racing sway bars. turbo tie rod ends. Read the Exl. article on Jim Calzia's light wt racer and check out his web page table on the Early 911S web site. Get a quality wt. balance, and don't go too low. Don't go too stiff on the street. Nobody really knows what type of strut brace is best -- or at least no one has posted or published verifiable tests. You could put 911R wheels on the rear. If you have another $10,000 to spend, I'm sure we can get you started on a high (carbon) fiber diet. If this first $10,000 seems a bit much post specific queries and folks will help you do it on the cheap, as some posted above.

[logician]

Hi,

I really like the Sway-Away adjustable spring plates vs. the OEM plates. The height adjustment is made by simply turning an allen screw. You get about 0.2" per turn. This makes height adjustment and corner balancing very accurate and easy. It's also very handy for tweeking the ride height at the track if you need to, as I did at my last event to cure some tire rubbing problems. When I first decided to use the SAW plates, I was concerned about the possibility of squeeking due to the plastic bushings. But turns out this was not a problem at all.

Regarding other upgrades, I really like my relatively stock '73 911s suspension for mixed street/track. The only two changes I've made are the spring plates, and Bilstein Sport shocks. The spring rate might be a bit soft for track, but it's reasonable, and a pretty nice firm ride on the street. I run 205/60-15 tires on 6" Fuchs for street, and 205/50-15 on 7" rims for track. You might have a problem with 206/60-15 tires on 7" rims.

Regarding ride height, I set my suspension to a little lower than the Bruce Anderson "Euro spec. Be careful not to lower the car too much, as Bruce Anderson warns that the suspension will not work correctly -- read his book. The really low suspensions that you see for 911 race cars works on track because of the very stiff spring rates, but won't work with softer suspensions. Actually, I believe my previous '85 911 was lowered too much, and did not handle as well as it could have for it.

-Juan

[viejopatron]

Replace every bushing. It's a dirty nasty job [the way I do it], however it's mandatory. You wouldn't believe the compression set on old rubber.

[addictionMS]

Juan,

wait a minute, your previous 85 911 "IS" my current 70 911, and you did a great job setting that car up :-)

All I added was the bushings , sway-a-way spring plates, and tub, well I guess a 1970 is lighter than a 1985 by quite a bit, so your off the hook.

Can't wait until we meet again at a track event, love to see your new ride.


Jim

[logician]

Hi Jim,

> wait a minute, your previous 85 911 "IS" my current 70 911,
> and you did a great job setting that car up :-)

It's funny, I keep seeing references to my old car in your posts. My favorite is the oil tank that you cut in half. It's like I donated my organs to science, and get to watch what comes of it! My second favorite post is "Saws-All time for the Targa".

> All I added was the bushings , sway-a-way spring plates, and
> tub, well I guess a 1970 is lighter than a 1985 by quite a bit,
> so your off the hook.

I've learned a few things since -- ride height and SAW spring plates are two. And I've now experienced the difference 500 lbs can make. My '73 is only 2330 lbs, stock and with some gas! This weekend I swapped out the relatively heavy stock seat for a Recaro SPG, so I'm guessing the car is now below 2300 lbs.

> Can't wait until we meet again at a track event, love to see
> your new ride.

I'll be at Laguna Seca this weekend, Friday through Sunday. I'm being optimistic about the weather... Will you be attending also?

-Juan

[skinnerd]

I'm in accordance with most everyone before me:
Bilstein sport or Koni shocks
21mm front, 27mm rear torsion bars (hollow not necessary)
Keep the suspension rubber bushed (replace with new if existing is worn) to keep ride comfortable
Good aftermarket anti-sway bars (Weltmeister which are fine or better)
Adjustable spring plates are nice, but not necessary
"Performance" lowering and corner balancing by "competant" shop
Brakes: forced air scoops, hi temp ATE fluid, track pads that don't require a lot of heat to work (so you can auto-x them or use on the street)

I had this set-up for years on my 73 RS replica, and it worked well on the track, autocrossing and on the street.

[addictionMS]

Juan,

Visiting on Sunday, not driving on the track. I will look for you, what color is your new car? Do you have a car number yet?


Jim

[logician]

Hi Jim,

My new car is black, car #911, see tiny picture in my icon. Here's a larger picture from NCRC web site:

> http://www.ncracing.org/images/rides/jpineda.jpg

The numbers are magnetic.

356KarmannSUPER, regarding suspension, I believe the following are the stock specs for '73 911s -- my car:

Torsion bars 19/23mm front/rear
Sway bars 15/15mm front/rear

I believe your 911T has same torsion bars, but does not have sway bars at all. One thing that is nice about the stock bars is that you don't have to tune them at all, and that they are set up reasonably well. I found that I spent a lot of time trying to figure out the right setting for the adjustable rear sway bars that I had in my old '85 Targa.

Brakes on the 911s are improved too -- aluminum S calipers front, and M calipers in back. I think your 911T has M calipers all round. I use Pagid Orange race pads essentially all the time. They aren't optimal for AX, and squeek on the street, so I really should swap them out when not at the track.

One improvement that I have not figured out yet is what to do about a roll bar. I think that is an important feature for the track, and I also like the way the belts attach directly to the roll bar compared to getting routed to the rear seat belt points when using a harness bar. In my '85, I had a DAS bolt in roll bar, but they don't make those for the early body. I'm considering a TRE or OG Racing roll bar. I like the way that the mount to the sill, rather than the floor -- seems stronger.

Finally, an important improvement for track is a racing shell to repace the stock seats -- especially those in the older cars. It's also better for safety. I bought a used Recaro SPG seat that fits like a glove. I made sure to get the slider kit so that I can fine tune the position, and also move the chair forward to access the rear.

-Juan