Torsion Bar Help

[4kidsno911]

Hi Pelicans,

Need some advice on torsion bars. I am refreshing the front end on my 1986 3.2 carrera. Doing pretty much everything from bushings to turbo tie rods, ball joints, etc. I did not contemplate replacing the torsion bars but when I got one of them out I noticed some rust and a worn out spot causing a the squeaking more than likely. First question is opinions on replacing this torsion bar and the other side with the stock 19mm or go to 20 or 21mm to make stiffer? I also ordered Bilstein HD strut inserts to go in the Boge Struts that came on my car so not sure how this would match up with the stiffer front torsion bars? If I went up in size on the front would I need to go up in diameter in the back as well and replace? This is a street car that I plan to take on some spirited drives and maybe up to VIR once in a while if I can get it back together! Thanks!

[Bill Verburg]

Originally Posted by 4kidsno911

Hi Pelicans,

Need some advice on torsion bars. I am refreshing the front end on my 1986 3.2 carrera. Doing pretty much everything from bushings to turbo tie rods, ball joints, etc. I did not contemplate replacing the torsion bars but when I got one of them out I noticed some rust and a worn out spot causing a the squeaking more than likely. First question is opinions on replacing this torsion bar and the other side with the stock 19mm or go to 20 or 21mm to make stiffer? I also ordered Bilstein HD strut inserts to go in the Boge Struts that came on my car so not sure how this would match up with the stiffer front torsion bars? If I went up in size on the front would I need to go up in diameter in the back as well and replace? This is a street car that I plan to take on some spirited drives and maybe up to VIR once in a while if I can get it back together! Thanks!

do both w/ hollow Sanders bars + bushes

if you just do the front it increases oversteer, some want that others don't , wheel/tire selection also affects this as does alignment specs

These shows the effects of different t-bar sets

[donbecker1234]

To add:

Sanders bars might be hard to find as IIRC they are out of business and supply is drying up. Sway Away still makes bars.

Regarding replacing bars, maybe yours are fine but I would say that springs aren't meant to last forever. Search on the forum and you'll find past posts from people who have had a torsion bar fail. Could be bad at speed.

Regarding the bar change/upgrade, newer cars use much higher spring rates, but they also have much better shocks/struts than the old linears that most use on these cars. They also have different geometry which I'm sure plays a part.

There are many people here on the forum that feel their car "handles great" with the standard/stock bars and shocks.

Then there are those that upgrade to the "sport" shocks and say those are better.

Myself (and some others) have upgraded to digressive KW's that are 2 way adjustable for compression and rebound and are happy with that combined with upgraded torsion bars.

At the much further end you see people switching to coil overs and 3 way shocks.

You're likely to get a ton of opinions on what you should do, if you can ride/drive another car with upgrades that might help.

One other significant point is the amount of rubber used in the bushings and other areas of a stock suspension.

I switched to monoballs front and rear and solid bushings from Rebel Racing, as well as upgraded torsion bars. The KW's allowed the car to be dialed in to still comfortably ride well, despite the many warnings I had here on the forum that the car would be too stiff.

My 2 cents: the stock and "sport" shocks/struts are needlessly obsolete technology. I'm very happy I spent the coin to redo the suspension fully and with newer technology.

[Bill Verburg]

Originally Posted by donbecker1234

To add:

Sanders bars might be hard to find as IIRC they are out of business and supply is drying up. Sway Away still makes bars.

Regarding replacing bars, maybe yours are fine but I would say that springs aren't meant to last forever. Search on the forum and you'll find past posts from people who have had a torsion bar fail. Could be bad at speed.

Regarding the bar change/upgrade, newer cars use much higher spring rates, but they also have much better shocks/struts than the old linears that most use on these cars. They also have different geometry which I'm sure plays a part.

There are many people here on the forum that feel their car "handles great" with the standard/stock bars and shocks.

Then there are those that upgrade to the "sport" shocks and say those are better.

Myself (and some others) have upgraded to digressive KW's that are 2 way adjustable for compression and rebound and are happy with that combined with upgraded torsion bars.

At the much further end you see people switching to coil overs and 3 way shocks.

You're likely to get a ton of opinions on what you should do, if you can ride/drive another car with upgrades that might help.

One other significant point is the amount of rubber used in the bushings and other areas of a stock suspension.

I switched to monoballs front and rear and solid bushings from Rebel Racing, as well as upgraded torsion bars. The KW's allowed the car to be dialed in to still comfortably ride well, despite the many warnings I had here on the forum that the car would be too stiff.

My 2 cents: the stock and "sport" shocks/struts are needlessly obsolete technology. I'm very happy I spent the coin to redo the suspension fully and with newer technology.

Don makes some very good points that I agree w/

I have full mono-balls on mt 993 w/ custom digressive Billsteins, it's a track car w/ spring rates never seen on a t-bar 911(you'd have to go to coils to get rates that large) but is still acceptable for street use, The best street suspension was much softer springs, digressive Billsteins and RS sport rubber bushes

acceptable and great are worlds apart, my street t-bar 911, w/ old fashioned linear HD/Sport Billsteins and sport rubber bushes is great for street use and ok for track use, digressives could only be an improvement

that said I've driven dozens of t-bat cars admittedly few if any have digressive shocks, it's really easy to go too far w/ t-bars, for mostly street use I draw my personal line at 21/26

Hadn't heard that Sanders was out of business, very sad to hear that, they made a fantastic product for our cars

[wjdunham]

Not directly related to the bars, but if you go with the new Bilstein HD inserts into the Boge struts (assuming you have the struts with the threads for the gland nut on the OUTSIDE), make sure you have about 5mm of the green part of the insert sticking above the strut body. If you don't, the gland nut will not fully clamp the insert into the strut body and you will get some clunking and play in the wheel. Drop one or more large washers into the bottom of the strut to compensate for the insert being slightly too short.

I wouldn't say this is a "common" problem, but I have had the issue with a pair of later Boge struts I upgraded to in my '69 and one stock '85 without the issue, and seen a few threads where others have had the same issue.

As far as the torsion bar sizes go, there definitely is no single right answer, and unless you are racing and can measure the changes in lap times on a specific course, it's all just "feel" in my opinion. I stayed with the stock sizes on my '85 and went with larger 21 front 27 rear on my '69 hot rod build. Both cars have full Elephant Racing polybronze bushings and adjustable front and rear sway bars, Bilstein sport inserts. I don't drive at the limit of traction so I don't have any objective measure of the over/understeer characteristics, but both are joys to drive and don't feel that much different from each other and are both far better than before the upgrades.

Good luck with your refresh.

[David Inc.]

Originally Posted by 4kidsno911

Hi Pelicans,

Need some advice on torsion bars. I am refreshing the front end on my 1986 3.2 carrera. Doing pretty much everything from bushings to turbo tie rods, ball joints, etc. I did not contemplate replacing the torsion bars but when I got one of them out I noticed some rust and a worn out spot causing a the squeaking more than likely. First question is opinions on replacing this torsion bar and the other side with the stock 19mm or go to 20 or 21mm to make stiffer? I also ordered Bilstein HD strut inserts to go in the Boge Struts that came on my car so not sure how this would match up with the stiffer front torsion bars? If I went up in size on the front would I need to go up in diameter in the back as well and replace? This is a street car that I plan to take on some spirited drives and maybe up to VIR once in a while if I can get it back together! Thanks!

I wouldn't stiffen just the fronts without doing the rear. The car will be more prone to understeer, and you'll get a rougher ride without a real increase in agility.

[GH85Carrera]

I have a 85 911. I did my front bushings and full front end suspension refresh. The bushings were shot, and rubbing the t-bars like yours. I went to Bilstien HD shocks, 21mm front and 27 rear for the t-bars. I think it is perfect. My wife will still ride in the car, and it handles great. In the rear, all I did was replace the shocks and the rear bushings, and the torsion bars of course. If your front bushings are shot, the rears will be just as worn and in need of replacement.

The rear is a real pain in the buss compared to the front. Then I had the car corner balanced, and alignment.

Good luck, there are a ton of choices and tons of threads on the board on what is ideal. I drive my car on long road trips, with my wife on the passenger seat, and I do the occasional track day for fun, and autocross and curvy fun roads in Arkansas. I believe it is the perfect setup for my needs.

[Shaun @ Tru6]

I am putting a new suspension on my M491 over the winter. Lightly used Fox front struts and rear shocks. Rebel Racing bushings front and rear. Stock sway bars. 16" E50s with new 205/245 A008s.

I prefer a stiffer suspension. Car as stock is very soft.

Any recommendations on torsion bar sizes?

My 84 Targa had 22/29s with Sports and was great though I feel the softness/twistyness of the Targa unibody aided in making the ride both comfortable and sports purpose.

[David Inc.]

Originally Posted by Shaun @ Tru6

I am putting a new suspension on my M491 over the winter. Lightly used Fox front struts and rear shocks. Rebel Racing bushings front and rear. Stock sway bars. 16" E50s with new 205/245 A008s.

I prefer a stiffer suspension. Car as stock is very soft.

Any recommendations on torsion bar sizes?

My 84 Targa had 22/29s with Sports and was great though I feel the softness/twistyness of the Targa unibody aided in making the ride both comfortable and sports purpose.

I'm using 22/28 in my '82 with Bilstein sports in my '82 SC. I kind of wish I had gone with 21/28 as the front feels too stiff in relation to the rear more situations than not. I only really get oversteer in high speed sustained corners or when I trail-brake way too much on track. On the road the front end feels like it's getting pounded over bumps that the rear absorbs without complaint, and it's pretty susceptible to front lock-up under braking.

Even with the car as stiff as it is I still deal with a lot of body roll to the point that 200 treadwear and below tires will be too grippy and just scrub the shoulders even at max front camber (with de-cambered ball joints) The rears have more adjustability so can still handle it. I just haven't bitten the bullet of upgrading the swaybars on the car, but it definitely needs it.

[donbecker1234]

Here's my list:
Car: '87 M491 (turbolook) Carerra Coupe w/G50 transmission
Engine: 78-79 930 turbo
Note that the turbo look had turbo brakes, as well as the wider rear suspension/trailing arms.
G50 means the trailing arm attachment point in the rear is different as well.

Rear Torsion bars: Sanders/Elephant Quick change 30mm ($515)
Rear Trailing Arm Monoballs (Tarett) ($200)
Rear Adjustable Spring Plates (Rebel Racing) ($500)
Rear Solid Spring Plate Bushings (Rebel Racing) ($460)

Front Monoball Adjustable Strut mounts (Tarett) ($450)
Front Solid Control Arm Bushing (Tarett / Rebel Racing) ($400)
Front Strut Brace (Tarett) ($200)
Front Torsion bars: SwayAway 22mm ($325)
Turbo Tie Rods ($185)
Front Adjustable Bumpsteer (RebelRacing) ($380)
Ball Joints ($215)

Eibach Adjustable Front & Rear Swaybar kit ($590)
KW 2 Way V3 Front & Rear Dampers, Front spindle raised 19mm ($3400)

Front Wheels are 7x16 Fuchs
Rear Wheels are 9x16 Fuchs
Tires are Yokohama A-008P: 205/55 and 245/45 ($1200)

Total for parts: $9020.

I did the install myself which wasn't too hard, the alignment, corner balancing and bumpsteer adjustment I had a local Porsche race shop complete.

To add, if you're shopping for suspension parts, IMHO you have to take any recommendation in context of everything on the above list, as they all impact and work with each other.

So asking about torsion bars, you are inevitably going to need to understand the condition of all of the rest of the suspension to anticipate the effect of changing one item.

I originally started with a car that I knew needed rear bushings, and by the time I researched it, decided to just replace all these parts in one shot to not be chasing issues, incompatibility etc etc.

Buy once, cry once.

[Bill Verburg]

Originally Posted by Shaun @ Tru6

I am putting a new suspension on my M491 over the winter. Lightly used Fox front struts and rear shocks. Rebel Racing bushings front and rear. Stock sway bars. 16" E50s with new 205/245 A008s.

I prefer a stiffer suspension. Car as stock is very soft.

Any recommendations on torsion bar sizes?

My 84 Targa had 22/29s with Sports and was great though I feel the softness/twistyness of the Targa unibody aided in making the ride both comfortable and sports purpose.

If you liked 22/29 then you do indeed prefer a stiffer ride, that would rattle the fillings out of my mouth

205/245 besides a tooth ralling ride 22/29 induced less understeer than stock in your '84 so why not use it in the M491, to undo that and perhaps go a little the other way

21/28 would go a little further

20/27 even a bit further w/ a less jarring ride

The other thing is that wider wheel track by itself reduces the wheel rates, the factor here is ~ 13.8% reduction in wheel rate per inch per wheel in front and ~2.9% per inch per wheel in back

[4kidsno911]

Thank you everyone for the advise and sharing your experiences! I am leaning toward 21MM and 27 and going ahead and tearing into the rear as well this winter. I only want to pay for one alignment and balancing. Going to lower the car as well. Thanks again

[Locker537]

The good news is torsion bars are not too expensive. Mine had similar wear so I replaced them this year.

[Shaun @ Tru6]

Thank you Don and Bill, great specs. I have a set of 22/28 bars already. I got the 28s because (and I hope this was good logic, please let me know otherwise) I have taken a lot of weight out of the back of the car. The whole thing weighs in at 2550 lb. Total AC delete including brackets, hoses, etc., George's headers, a tube of stainless steel masquerading as a muffler and no heater blower. That and a '75 915 that has to be a solid 20 lb less than the 915/72 original to the car that I need to rebuild some day. Also just one a fixed back Momo driver seat for the interior. The gearing and the lightness and the exhaust with a chip makes it an extremely fun car to drive. It just feels really soft compared to my old 84 Targa and my 2175 lb '73 with a 3.2 and 19/26 bars. That car is the most fun 911 I've ever driven. I know the wide body won't let the car ever feel like the 73 but I want it to feel crisper and more direct.

[4kidsno911]

Originally Posted by wjdunham

Not directly related to the bars, but if you go with the new Bilstein HD inserts into the Boge struts (assuming you have the struts with the threads for the gland nut on the OUTSIDE), make sure you have about 5mm of the green part of the insert sticking above the strut body. If you don't, the gland nut will not fully clamp the insert into the strut body and you will get some clunking and play in the wheel. Drop one or more large washers into the bottom of the strut to compensate for the insert being slightly too short.

I wouldn't say this is a "common" problem, but I have had the issue with a pair of later Boge struts I upgraded to in my '69 and one stock '85 without the issue, and seen a few threads where others have had the same issue.

As far as the torsion bar sizes go, there definitely is no single right answer, and unless you are racing and can measure the changes in lap times on a specific course, it's all just "feel" in my opinion. I stayed with the stock sizes on my '85 and went with larger 21 front 27 rear on my '69 hot rod build. Both cars have full Elephant Racing polybronze bushings and adjustable front and rear sway bars, Bilstein sport inserts. I don't drive at the limit of traction so I don't have any objective measure of the over/understeer characteristics, but both are joys to drive and don't feel that much different from each other and are both far better than before the upgrades.

Good luck with your refresh.

Thanks for the tips, can you take a look at the pic below and let me know if this looks okay. This is without any washer at the bottom of the strut.

[Antomero]

I’m also replacing my torsion bars on my 84 3.2.
Consulted with Chuck over at elephant racing, and with my current suspension set-up Boge HD struts/shocks and car weight, he recommended I go with 19mm front 26mm rear for spirited street driving

One other thing… whoever thinks torsion bars don’t tgo bad over time is wrong. Mine did !

[wjdunham]

Hard to say exactly, but definitely looks better than mine and should be high enough for the nut to properly clamp the insert. Try tightening up the gland nut and see if you get any up/down play with the insert.

Originally Posted by 4kidsno911

Thanks for the tips, can you take a look at the pic below and let me know if this looks okay. This is without any washer at the bottom of the strut.

[PeteKz]

Another check: remove shock insert. Screw gland nut all the way down snug. Mark its position on the strut. Remove gland nut, reinstall insert, and screw down gland nut. If it doesn’t go as far down as it did without the insert, then it is tightening on the insert and you are good.

[4kidsno911]

Originally Posted by Antomero

I’m also replacing my torsion bars on my 84 3.2.
Consulted with Chuck over at elephant racing, and with my current suspension set-up Boge HD struts/shocks and car weight, he recommended I go with 19mm front 26mm rear for spirited street driving

One other thing… whoever thinks torsion bars don’t tgo bad over time is wrong. Mine did !

I agree steel flexing like that over 30 plus years and 1,000's of miles has to wear out eventually. Do you think the reason he said stick with the stock 19mm size for the front is due to the heavier duty Bilstein stut inserts? They certainly are much bigger than the stock one I pulled out the other day.

[Antomero]

Originally Posted by 4kidsno911

I agree steel flexing like that over 30 plus years and 1,000's of miles has to wear out eventually. Do you think the reason he said stick with the stock 19mm size for the front is due to the heavier duty Bilstein stut inserts? They certainly are much bigger than the stock one I pulled out the other day.

19mm work best with 26mm rears on HD struts/shocks. Going 20mm fronts would require to increase rear to 27mm or 28mm.
I love the way the front feels now with 19mm and don’t necessarily need or would want it any stiffer. Besides the front is very light.