944 rear torsion bars

[oprn]

Hello all, I have put a set of 944 rear torsion bars in my glass street Buggy but have not driven it yet. It does seem to be pretty stiff now. I like a firm riding car and the feel they have on the road but this may be a bit too firm. I found the stock Beetle bars to be a bit soft. With two adults and two grandchildren it would drag the oil pan on manhole covers.

Has anyone else used them and what were your impressions?

[slayer61]

Isn't it a "math" thing? Bar diameter X length = spring rate? Are your 944 bars significantly shorter in length, or larger in diameter?


Sorry. I got nothing

[V8Nate]

On the one dune buggy I worked on I found that if the tension was set to factory then the back of the car sat too high but had proper/on the stiffer side suspension. The answer was either drop spring plates or loosen the torsions for a lower yet softer ride

Sent from my SM-S918U using Tapatalk

[oprn]

The 944 bars are identical in all respects to the late Beetle bars except that they are a larger diameter, therefore a higher spring rate. Re-indexing the bars does not change the spring rate, all it changes is the ride height.

When I put them in I indexed them a few degrees lower than the stock bars but not low enough yet. With the transaxle and type 4 engine in they are still on the bottom stops but come off the stops slightly with 2 adults in the car. At the very least I will have to index them lower yet but I want to see what the car rides like first. It may be unbearably harsh no matter where they are set.

When putting a glass Buggy body on the stock Beetle pan most of the weight loss is on the front end. The result is that while the rear is 80 pounds or so lighter the front axle sees the majority of the weight loss. This results in a very stiff ride on the front and a nearly stock ride on the rear. In fact the front becomes stiff enough that the stock front sway bar is of little effect. Many fellows remove some leaves from the front to correct this and that is the way I may eventually need to go. I just wanted to try this first as I had the bars already and had the rear suspension apart for an IRS upgrade.

[Ol'fogasaurus]

https://www.shoptalkforums.com/viewtopi ... g#p1293121

This is the torsion bar "thing" on one of my 2 glass buggies. It is using stock torsion bars, but the angle was re-set after adjusting them to 30 degrees. I reset them to 26 degrees and that is what I am still using out on the Oregon Dunes.

Stock bars as stock preload was just too light weight for the paddle tires and bouncing around on the sand. The 30 degree setting was too stiff for the buggy on the sand.

Just be careful when adjusting them as if they come loose while being reset they can do a lot of damage to hands, arms and K-noggon before you could even realize what was happening. A long while back I did post pix and dialog somewhere on doing this safely.

I'll do a look to see if I can find it.

Lee

[oprn]

Yes, there is a lot of energy in those torsion bars. I used a floor jack and a chain to control it.

[H2OSB]

I had them in my full body '73 Super Beetle. Along with my 125 lbs front springs, as well as a 7/8th inch front and 3/4 inch rear swaybars, the ride was superb. Sporty but never punishing.

H2OSB

[oprn]

Thank you for that! Actually there is a fellow with a '73 SB who is anxiously waiting the outcome of this experiment and would really like to have them if I go back to stock bars! I will carry on with confidence then. I did swap in the stock 944 rear sway bar too while I was at it. I am hoping that it will not be too stiff in combination with the bigger torsion bars and make the car tail happy in a hard corner.

[H2OSB]

I will say this, and you may have seen me say it elsewhere. I absolutely loved that suspension set up, however, I discovered, when autocrossing, upon hard launches or hard L->R or R->L transitions, the car would slam down on the bump stops. On my current car ('74 Super) I've upgraded to 26mm torsion bars, but kept everything else to same. There is a chance I could have stayed with 23.5mm bars and used higher quality shocks.

Btw, Porsche 924/944/968 all use 26 9/16 inch length torsion bars which is the same length as all T1 IRS as well as T3 cars. The Squareback uses 23.5mm bars just like the 924/944. I'm not 100% certain of the diameter of the 968 bars. The Notchback MAY use 23mm bars but I'm not certain.

The factory 22mm torsion bars are approximately equivalent to 100 lbs/in coil springs. 23.5 bars are roughly 50% stiffer than factory bars and my 26s are roughly 95% stiffer. Hopefully I like the 26s, but if I find them to be too harsh, I'll gladly go back to 23.5s and live with an occasional knock on the bump stops.

H2OSB

[Bruce.m]

OP: which size of 944 bar did you fit? There are a number of different diameters. As H2O says, the 23.5mm bar is a modest increase but some of the biggest bars will be overkill for sure.

The spring rate increases by the 4th power of the diameter increase. For example, double the diameter is 16x the spring rate!

[oprn]

I did measure them... several months ago but I am old and forgetful. Looking up the '86 N/A 944 specs it seems it should be the 23.5 mm bars. According to that chart the 968 had 24mm bars but there was 25.5 and 26.8mm bars in some of the in between models.

[H2OSB]

Good the know about the 968 torsion bars. If I don't like the 26s, I may try to find a set of 24s. I really really liked the ride with 23.5s, but I know I need a bit more to stay off the bump stops while autocrossing. Maybe the slightly larger bars will do the trick.

H2OSB

[Steve Arndt]

I have used 944 TBs and also 23.5mm type 3 square back TBs.

[H2OSB]

I found a set of 24s on Ebay, but TY.

H2OSB

[oprn]

I dug out the old torsion bars and they are actually 21mm not 22mm. Interesting...

Now the reason I got them out is because I watched a YouTube video where a fellow was changing ride height on his 944 by jacking the car up to take the preload off the bar, taking the cap off the torsion bar cover, then using a slide hammer to pull the bar out a bit. Then he let the car down to the preload angle he wanted and tapped the bar back in place. Slick! But... you would have to drill and tap the bar ends to do that.

So... I set the 21mm bar up in my lathe and attempted to center drill it... hmmm. Not with regular high speed steel drill bits you don't! Then if you did get them drilled it is going to take a pretty good tap to put threads in them! Does he have trick aftermarket bars that come tapped?