If I go with 21/26 torsion bars, what about the rest?

Doug&Julie · 04-07-2006, 04:22 AM

Thinking about a new suspension here...all I know at this point is I'm thinking 21mm / 26mm torsion bars. Of course we'll update the bushings all around, and probably go with turbo tie rods and a strut tower brace. The question is what sway bar(s) will go best with this combo? I don't have any on the car at all right now. Do I need them front and rear? ..or just front? Four wheel alignment will of course be done at the same time.

I don't want to spend a fortune, FYI. This is my fun driver that might see some AutoX action...but not for track. Go easy on me, I'm obviously a rookie here.

Thanks!

Eric P · 04-07-2006, 04:29 AM

I'd just do the torsion bar and alignment so you can feel the difference before going to sways. If you are really itching, you could do a front sway too.

IMHO the 21/26 ratio is too close (I used 20/27, now 23/30 and and feel the 7mm difference is great). How'd you decide on 21/26?

Doug&Julie · 04-07-2006, 04:33 AM

Quote:

Originally posted by Eric Pickering
How'd you decide on 21/26?

I just remember reading that 21/26 was the best for "mostly street but with some AutoX" ride and handling balance. Should I go thicker? I'm not looking for a monster, just a fine handling car.

What is stock on a 1970 911T?

Eric P · 04-07-2006, 04:54 AM

I don't remember stock specs anymore. I'm pretty sure they have been posted here. Something like 18.5 or 19 front and maybe 24 or 25 rear. NOTE: I'm not an expert on this but I think the torsion bars the factory picked were biased to understeer to "protect" the street/average driver. I think this is why most people beef up the rear more than the front.

I found 20/27 to be very nice but not a monster. It IS stiffer though.

Not to turn you upside down on your plans but shocks make a HUGE handling difference and may be the answer for fine handling. Of course it is a system so ALL parts of the suspension should be considered.

Eric P · 04-07-2006, 04:56 AM

I just saw where you are. Any chance you are doing the IRAC MidOhio Auto-X in Columbus in May?

Type911 · 04-07-2006, 04:57 AM

Doug,

I went with 21/26 torsion bars on my 70E.
At the same time, I replaced all the bushings front/rear,
ball joints, turbo tie-rod ends, bump steer kit, SC rear spring
plates, aligned & corner balanced. I have an S front sway bar,
but have not installed a rear sway bar.
Complete transformation in the car...its now on rails.
Not a harsh ride though....just right

Doug&Julie · 04-07-2006, 04:59 AM

Quote:

Originally posted by Eric Pickering
Not to turn you upside down on your plans but shocks make a HUGE handling difference and may be the answer for fine handling. Of course it is a system so ALL parts of the suspension should be considered.

Yep, thanks. The P.O. did the shocks, so they're good. The car just feels a little "floaty" overall. (..relative, of course!) I'd like to stiffen up the ride a little bit and get rid of a lot of the roll.

I'll look up the specs (if they don't get posted here first!).

Hadn't planned on the IRAC at Mid-Ohio. I'm hoping to get to at least one AutoX here locally this year. Not sure which, though. Maybe Taj Kruezers in June or P2O in July? Are you going to P2O?

Doug&Julie · 04-07-2006, 05:01 AM

Quote:

Originally posted by Type911
Doug,

I went with 21/26 torsion bars on my 70E.
At the same time, I replaced all the bushings front/rear,
ball joints, turbo tie-rod ends, bump steer kit, SC rear spring
plates, aligned & corner balanced. I have an S front sway bar,
but have not installed a rear sway bar.
Complete transformation in the car...its now on rails.
Not a harsh ride though....just right

Excellent, thanks! How thick is an "S front sway bar"?

Eric P · 04-07-2006, 05:03 AM

Heck, I've got some 20mm fronts if you want to borrow them to try them out. You could buy or find someone to borrow some 26 or 27 rears. Changing the fronts doesn't require new alignment.

I don't know what P20 is.

Check out: www.auto-x.org
You could come to the event, even just to hang...

Doug&Julie · 04-07-2006, 05:09 AM

Quote:

Originally posted by Eric Pickering
I don't know what P20 is.

Check out: www.auto-x.org
You could come to the event, even just to hang...

Check out my thread here:

http://forums.pelicanparts.com/porsche-911-technical-forum/268006-porsches-2-oxford-2006-a-post2489572.html#post2489572

I just might come up to just hang...maybe shoot some video, too.

Wil Ferch · 05:55 AM

From a historical perspective...Bruce Anderson and others have pretty much settled on 21/27 for the early, light cars...and going to 22/28 for the later, heavier cars.

The recent trends over the last 10 years or so seem to indicate that these combo's retain some of the built-in understeering tendencies that were used to combat the terminal oversteer these 911's are prone to have, due to the rear weight bias.

So....the trend has been to increase the rear a bit more than before...and now we're seeing 21/28 ( or 21/29)....and 22/29 ( or 22/30).

The bob-weight of the rear end....regardless of the "balance" factor discussed above.....lends itself nicely to slightly more aggressive bars, without having it degrade the ride ( at the rear) as much as you'd expect.

- Wil

Eric P · 04-07-2006, 05:18 AM

Ah, VERY cool. I didn't even know about that!

Give me a shout if you see me:

Doug&Julie · 04-07-2006, 05:22 AM

OK...thinking long term...if I end up putting a 3.2 in the back, does that affect the dicision here? Should I go 27 or 28 in the rear? I'm hoping (and planning) on keeping it as light as possible.

Doug&Julie · 04-07-2006, 05:24 AM

Quote:

Originally posted by Eric Pickering
Ah, VERY cool. I didn't even know about that!

Give me a shout if you see me:

Will do! You should definitely come to P2O. There weren't a lot of early cars there last year. And now that they've added the AutoX...

Eric P · 04-07-2006, 05:25 AM

I noticed the lack of early cars. I'll look into it!
Good looking event.

Eli K · 04-07-2006, 06:44 AM

Julie, before being able to offer advice on your suspension project, first we need to know: How often does Doug let you take his car out?

domtoni · 04-07-2006, 06:54 AM

Doug,

I have a 69 911E with a 2.0. Being that we had salt on the road until a few weeks ago, I am about to embark on rebuilding my suspension doing:
- 21/26 mm TBs
- Koni front and Bilstein Sport rears
- turbo tie rod ends
- EPR poly bronz bushings
- adjustable spring plates
- new ball joints etc

The car has a 15 mm 911S front anti roll bar. I will let you know how this works in a few weeks.

Best
Dom

Doug&Julie · 04-07-2006, 06:56 AM

Thanks Dom. I won't be tackling this project right away, so whenever you get yours together I'd love to know how it goes.

Cheers.

Doug&Julie · 04-07-2006, 07:04 AM

Eli K,

Doug would let me take the car out anytime I wanted. Actually I have never driven this one......yet. Maybe I will have to drive it this weekend just to say that I have. The old 911 is more his passion than mine.
I love my little Subaru wagon. Of course once he makes all the changes to the 911, I think I will be driving it more.
So thank you to everyone for all the advice so we can get the upgrading started.
Julie

Tyson Schmidt · 04-07-2006, 08:39 AM

Doug, I think you should go 21/27. Especially if you plan to go 3.2 in the future.

If you were more serious about track work, you'd want at least 30's in the rear, but that really makes it a lott less fun on rough, bumpy streets.

What shocks did the P.O. install? If they aren't up to snuff, it won't ride or handle well. You'll need at least Bilstein HD's with those torsions.