Need feedback on torsion bar choice.

[Geronimo '74]

I'd like to upgrade my stock torsion bars (18.8 and 25 for a '86 Carrera) to 22 &nd 29mm.
The shocks will be replaced from stock Boge to Bilstein HD in the front and Bilstein Sport for the rear.
My car is 90% a street car that I plan to take to a track only occasionally in the future.
So my goal is a sporty, firm street setup. I'll be running 16" Fuchs 7 and 9 or 17" Ruf Classics with Toyo R888 or similar.

I'm wondering whether 22/29 may be too harsh and maybe 21/27 would be better.

Both combinations are probably ok, right? The thicker bars being a bit firmer.

I did some searching and I ended up with these two combos.

Anybody running any of these bars and would care to comment on my choice?
Or are there other Tbar combinations I have overlooked?

Thanks guys

[Jim Richards]

Hey G-man, my old 73E w/ 2.7RS-spec engine had 22/29 with Bilstein Sport/HD's. It was a bit too harsh in city driving, but fine everywhere else. Perhaps if I had the shocks/strut inserts revalved to match the t-bars, it would have been better for city driving. Hope this helps ya!

[CMDR Perry]

Unless all your roads are smooth in Belgium go with the 21/27. I have 22/28 and they are fine in warm weather and on smooth roads. Unfortunately our roads are pretty bad due to budget issues and rough winters. DP

[Geronimo '74]

We have some pretty decent roads but also these...



and these

[IROC]

I have 22/29s on a 2400 lb '76 with a 3.2. I also have Koni red "street" shocks adjusted nearly full stiff. Anyway, while living in Alabama (bad roads) I would have said that the 22/29s were just a bit too stiff to live with on a daily basis. Now in Tennessee with much better roads, I think the 22/29s are fine. One thing I have found over the years is that often it is the shock valving that makes more of an impact on ride quality than torsion bar size.

Having said this, everything is a compromise on a street/track car. What gives you acceptable ride quality on the street will have you begging for more stiffness on the track and vice versa.

BTW, the cobblestones you show aboe would be very annoying in my car.

[trak ratt]

I ran 21/29 for years and luved them on our then mostly stock SC w/stock sways. Some track time too

[Geronimo '74]

Thanks for the input.

I think I should be looking at the 21/27 bars, seeing as it will be a streetcar.

[b rock]

Our roads look like that after they are repaired.

[Shaun @ Tru6]

Coupe or Targa?

My old 84 Targa I had 22/29s, Sports all around, ER polybronze front and rear, front strut brace, BK Targa body brace with Cup II's. Worn, older Momo fixed back buckets too.

I found the ride to be very comfortable, mostly because the Targa body flex soaked up the harshness I'm sure.

If a Targa, I'd consider the 22/29.

[wildcat077]

The roads in Quebec probably rate as the worse in Canada and i'm comfortable with 22-29 in my car ...
If you're going to make a change,at least make one that's noticeable !
I take my car to the track and i can say i'm glad i went with the 22-29 setup,next project will be adjustable sway bars !

Cheers !
Phil

[jmh61]

I started out with a 22 year old stock suspension. Rode like crap.

First replaced the shocks with Bilstein HDs. Ride was MUCH better.

Six months later replaced bushings, tie rods and torsion bars. New T bars were 21/27. Handled much better. Ride about the same.

About a year later my wrench convinced me to change the rear shocks to Bilstein sports. Handled much better at turn entry and exit. Ride is noticeably harsher.

So my impression is that shocks have a lot more impact on ride quality than T bars. My car is a street car that is autocrossed regularly. The 21/27 bars are fine for what I do.

[arbita1]

I have the 22/29 set up with Bilsteins that were custom valved by Smart Racing for the torsion bar rates.

As others have said it's a bit harsh. However, I don't think it's terrible, but my car is not a daily driver and I do (did) a lot of autocross.

I think if I was strictly a street car, I would go with the 21/27 (or maybe 28) with the Bilstein Sports.

[rolls 912]

Can someone advise what a 930 usually uses - stock setup.

[arbita1]

Originally Posted by rolls 912

Can someone advise what a 930 usually uses - stock setup.

I believe it was 18/26 up through 88

And 18/27 for 89

[rolls 912]

Matt
Why is the ratio different on turbos - front to rear versus other models? Has the front been dumbed down to assist with handling?

[arbita1]

Originally Posted by rolls 912

Matt
Why is the ratio different on turbos - front to rear versus other models? Has the front been dumbed down to assist with handling?

I believe I've asked this question before and I was told that it was due to the weight of the turbo engine being heavier.

[rolls 912]

That makes sense. Also with the extra power might make it safer / easier to handle?

I popped some turbos on the rear of my 68 running a 3.2. Yet to push things to see how it handles.

[175K911]

On my old SC I ran 21/27 for a while then went to 22/28 and frankly didn't notice much of a difference in ride quality. Then on my previous '86 I ran 21/28 with Bilstein hd front, sport rear since I swore this car would never see the track. Loved the ride, a bit firmer than OE but still nice enough that my then-wife and I could take it for trips and she was OK with it. But, then I took it to the track and everything changed.

21/28 was a nice balance for the '86. A lot of the rough ride comes from the front so sticking with the 21 helps ride. And when you keep in mind that the '85-86 911's came with 25mm rear torsion bars (all earlier were 24mm), the 21/28 keeps roughly the same increase front/rear. So:
18.8 to 21 front = 56% stiffer
25 to 28 rear = 57% stiffer

[Geronimo '74]

Anybody running 22/28?? Is that a good combination?

[rfloz]

My '84 is mostly auto-cross with a fair amount of street use and has 22/29 with custom valved Bils and later Carrera anti-roll bars (22/21 IIRC); also fairly stiff 17" tires.

The street ride is acceptable, to me, but according to my wife i have "ruined" yet another car. The two-out M&K may have contributed to that opinion. Or the lack of A/C. Or . . .

What I would note is that with 22/29 T-bars, I get some understeer in slow (bottom of second gear) corners. So, IMO, 22/28 is asking for even more understeer. I'd say 21/28 would give more neutral handling.

Also, I was told by several people that the 22/29 combo is a little past the Bil sport shocks, much less the HDs, ability to properly control the torsion bars.

If I were to do this again for a mostly street car, I'd probably go with 21/28 and Bil HD front/sport rear. And, probably 16" tires although they are getting hard to find in the wider sizes.

Finally, I'd suggest you try to get a ride in a car with 22/29 T-bars and see for yourself. If you do, ask the owner about the rest of the setup, especially shocks/struts and tires.