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Torsion Bar Info

 
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Sat Dec 04, 2021 1:20 am    Post subject: Torsion Bar Info Reply with quote

If someone has stock torsion bar laying around could you measure the length of the splines on the outboard side for me.

The reason I want this is that I want to change torsion bars in the race car and had set it up for thru the rocker panel change out. Way back when, someone tried it with CP1 bars and found that the spline was longer, (apparently some VW thing) than stock and couldn't adjust them as the longer outer spline engaged before the inner and you are working in the limited space between the end of the carrier and the rocker panel. I want the spline length so I can call Sway Away and find out their spline length. Sway Away's about 50% higher than CP1.s. Rasta was involved in this old time Pelican discussion.

Many thanks in advance, I hate pulling TB carriers.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)
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Cedric  



Joined: 27 Aug 2004
Posts: 2600
Location: Sweden

PostPosted: Sat Dec 04, 2021 2:29 am    Post subject: Reply with quote

No measurements, but Found some pics from 15 years ago, but i don't think its much help, Thick red are cip1 28mm, black are 25.5 (968) and red are standard 23mm. Do you have the early rear suspension? Didn't it have height adjustments? I found it fairly easy to set the bars correct at one shot and then fine tune with the excenter.



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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Sat Dec 04, 2021 4:37 am    Post subject: Reply with quote

Ride height isn't the issue. I'm changing from a 23.5 to 27 and then have my 154 wheel rate coil over that I would like to shorten 1/2" as it is loose at full drop to deal with. A set zero rate springs is about $140+ over here and the 1/2" is almost too short to deal with.

Apparently in the thru rocker setup you have to set the spring plate at the right angle and then slide in the bar and hope it stays close as it engages both inner and outer splines. Regardless of finding a shorter spline bar I'll try it anyway as 20 times trying it is much quicker than dropping the TB carrier.

I'm just trying to get as much information as possible before ordering T-Bars and dealing with the inevitable headaches I will encounter. With the coilover to set ride height it might prove much easier than I envision.
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Cedric  



Joined: 27 Aug 2004
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Location: Sweden

PostPosted: Sat Dec 04, 2021 5:01 am    Post subject: Reply with quote

If you already have coilovers, couldn't you just ditch the bars completely? Like many 924/944 race cars have raced since the dinosaurs walked the earth
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MikeJinCO  



Joined: 08 Jun 2010
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Location: Maysville, Colorado

PostPosted: Sat Dec 04, 2021 7:14 am    Post subject: Reply with quote

I have the GAZ coilover which have the 1.9 ID springs, that is the only size that will fit with the steel trailing arm. My springs are 7" lg with a 275 lb rating, Hyperco's strongest 8" is 250 and their10" which will not fit goes to 600. The spring multiplier to wheel rate is .56 so some 450 springs would be needed to go with my fronts at 368(.92 multiplier). But bigger issue to me is that I think the chassis would have trouble on the upper mount with that much load. I have tried to reinforce it and it is difficult.

I would have to go up to 2-1/4 " springs, the locking collars would interfere on the trailing arm if over 6" and at 6" I would only have less than .5" of threaded adjustment on the shock body.
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Mike


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Cedric  



Joined: 27 Aug 2004
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Location: Sweden

PostPosted: Sat Dec 04, 2021 7:55 am    Post subject: Reply with quote

Did a quick check on faulkner springs website, their 1.9 springs seems to go to 400lb/in for 7 long springs and 450 for 8in ones. Haven't seen people over here had any issues with the top mount, some have reinforced the bottom to be sure.

Apart from the extra weight the t bars are of course simple to put in there, and they surely work. I used an excel sheet from the 944 spec racer website to calculate spring plate angle for when i went from 23.5 to 28mm bars, worked very well.
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MikeJinCO  



Joined: 08 Jun 2010
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Location: Maysville, Colorado

PostPosted: Sat Dec 04, 2021 11:41 pm    Post subject: Reply with quote

Yes, I'm just stuck with changing Tbars, only question is how. If you look at the History section you will see that the "kit" 933's had the trailing arm modified so that a much larger spring could be put in there, Ground Control suspensions says their 924 kit is for use with the 944(assuming aluminum) trailing arm, so they have no solution either.
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Mike


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holcopa123  



Joined: 05 Nov 2021
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PostPosted: Tue Dec 07, 2021 5:58 am    Post subject: Reply with quote

Couldn't you go with the 944/924S aluminum arms and carrier? I think you could interrupt the GCR that the 924S is just a later year and parts are inter-changeable between years.

Phil Holcomb
1987 924S
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Tue Dec 07, 2021 11:04 am    Post subject: Reply with quote

The rules our organization(Rocky Mountain Vintage Racing) uses are the 1981 SCCA GCR or 1972 or 1965 depending on the car. Except for maybe the Le Mans GTR/GTP the aluminum trailing arm didn't exist. Now the rules are followed voluntarily and there is no real inspection for rules compliance, one insanely fast Lotus Super 7 is rumored to have a Lotus Elan rear end. We all have some things that didn't exist back then, how many 1965 MGB's and Sprites had a dry sump, and nobody had Accusumps which are critical these days for motor longevity. So I along with most others try to follow the spirit of the rules, but we all bend them a bit.

If you look in the history section of our site you will see the modified trailing arm that was supplied with the 16 race kit cars, the shock bucket was over 3" instead of the existing 2-1/4 " and the coil over spring much larger. I doubt I would ever find a pair of those and that mod would be well beyond my fabrication skills.
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Mike


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holcopa123  



Joined: 05 Nov 2021
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PostPosted: Wed Dec 08, 2021 7:54 am    Post subject: Reply with quote

Yep, you probably have better odds of winning the Lottery then finding a set of the race kit trailing arms.

What about Hanksville Hot Rods? They are in Littleton. They might be able to do the fabrication on some old existing trailing arms for you, put a new shock bucket on and box in the arms.

BTW - I think your car is awesome. My dad drove an EP Speedster for decades and I grew up watching Bob Hagestad's 933. Awesome cars.

Phil Holcomb
1987 924S
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