Rear torsion bars upgrade

[Rocket Ron]

Looking at upgrading the rear torsion bars on my beetle drag car

Has anyone some recommendations for the size

The beetle is been on a diet and has no front or rear inner wings and the rear luggage and front scuttle and dash are gone. It also has a gasser style rear cage tied into the rear frame horns. I'm guessing the total weight saving from the removal minus the cage weight is around 80-100 kg

Currently have spas adjustable rear shocks on the rear

Thanks in advance

[Mike Lawless]

I know a lot of guys choose 28mm bars for lighter weight cars, but then I know several that have changed those to 30mm.

With 30mm being the max, I don't think you can go too stiff, especially if your motor is putting out some power. Since you already have adjustable shocks, the 30s will work.

I had 30s on the Blue Car and they weren't enough to keep it from smacking the sump on the ground, even with the shocks adjusted to the stiffest setting. Granted, quite a bit heavier than your car, and the bus trans also was a factor. But still, if I were building a lighter weight car, I'd put the 30s on it without giving it another thought.

[BeetleBug]

I know a lot of guys choose 28mm bars for lighter weight cars, but then I know several that have changed those to 30mm.

With 30mm being the max, I don't think you can go too stiff, especially if your motor is putting out some power. Since you already have adjustable shocks, the 30s will work.

I had 30s on the Blue Car and they weren't enough to keep it from smacking the sump on the ground, even with the shocks adjusted to the stiffest setting. Granted, quite a bit heavier than your car, and the bus trans also was a factor. But still, if I were building a lighter weight car, I'd put the 30s on it without giving it another thought.

Ditto!

I have a close to full weight 67 beetle with 30mm torsions and they are not stiff enough to avoid the sump from hitting the ground if I launch with lot of boost and clutch. As soon as I turn the clutch down or experience wheel spin then no problem.

[Rocket Ron]

Thanks for the advice, chaps

Ta Ron

[richie]

26mm short bars

[JS]

28mm long ones work for me.

[Rocket Ron]

26mm short bars

I'm guessing shorter softer bars have a more progressive action ? 

[Mike Lawless]

Ron, don't listen to Richie. What does he know anyway?

I mean, there are at least three, maybe four guys in the whole world that are as fast or maybe faster. 

[NoBars]

1700 pounds at the line, 30 mm short bars. 28s allowed too much camber change at the hit.

[Trond Dahl]

Full weight car with cage. 28mm torsions and AVO adjustable recalibrated(stiffer) shocks set to maximum.

<a href="http://www.youtube.com/v/FpQ3H-BF6kc" target="_blank">http://www.youtube.com/v/FpQ3H-BF6kc</a>

[spanners]

Different descline completely, but I ran 29 mm short bars successfully on my swing/a circuit cars,  very stiff shock settings are needed to control this size bar partly due to the stock shock mounting location having less effect than if the shock was completely re located outboard to nearer the wheel hub, stock location coil overs would likewise need a higher spring rate than a rear mac strut for example, which has far less leverage on the shock and could, in theory a use much softer spring rate and shock setting, overall track width too has some say in wheel rate and shock valuing, together with our old enemy un sprung weight.

[Rocket Ron]

Harvey

Have a look here

[Russell]

Ron

It's hard to disagree with any of the above suggestions but I run mainly 28 and 29 on the replica gassers as they are all full body weight coupled with decent shocks from Richie , I've only had success

Hope this helps

Russell

[numbnuts]

Hi guys, so reading the above I am a bit confused, I guess vehicle weight has a lot to do with the bar thickness choice, also power
I am at the point with my project where I need to buy rear torsion bars and shocks for my cal look bug, estimating 250hp and full weight
I have the intermediate size 24 11/16? Oval bug type, can you recommend the size I will need and also good adjustable shocks also
Car will see some street also but this will be of less concern as its being set up to not break parts the fiery time I go to the strip (I hope)

[richie]

Hi guys, so reading the above I am a bit confused, I guess vehicle weight has a lot to do with the bar thickness choice, also power
I am at the point with my project where I need to buy rear torsion bars and shocks for my cal look bug, estimating 250hp and full weight
I have the intermediate size 24 11/16? Oval bug type, can you recommend the size I will need and also good adjustable shocks also
Car will see some street also but this will be of less concern as its being set up to not break parts the fiery time I go to the strip (I hope)

What clutch will you run for 250hp? that has a lot to do with it as well as if its real harsh it will work suspension harder on launch so normal route is harder torsion, also 1st gear ratio has a big effect

cheers Richie

[BeetleBug]

Hi guys, so reading the above I am a bit confused, I guess vehicle weight has a lot to do with the bar thickness choice, also power
I am at the point with my project where I need to buy rear torsion bars and shocks for my cal look bug, estimating 250hp and full weight
I have the intermediate size 24 11/16? Oval bug type, can you recommend the size I will need and also good adjustable shocks also
Car will see some street also but this will be of less concern as its being set up to not break parts the fiery time I go to the strip (I hope)

What clutch will you run for 250hp? that has a lot to do with it as well as if its real harsh it will work suspension harder on launch so normal route is harder torsion, also 1st gear ratio has a big effect

cheers Richie

Richie is asking THE question! It is all about the clutch control. It is what will keep you away from breaking parts and make your car launch like it should. That said, I would go for 28 to  with a good damper to control the rebound. And IMPORTANT; do NOT use snubbers with them as it will make it bounce even more.

[numbnuts]

I have a kennedy stage 2 clutch to use. The gearbox is a bit of an unknown quantity, I was sold it as a rancho pro drag box, the ratios unknown, it came at a good price and my eagerness to get out racing made me buy it

[BeetleBug]

I have a kennedy stage 2 clutch to use. The gearbox is a bit of an unknown quantity, I was sold it as a rancho pro drag box, the ratios unknown, it came at a good price and my eagerness to get out racing made me buy it

Which disc do you plan to use with the KEP2?

-BB-

[numbnuts]

I can't tell at the moment as away

[Rocket Ron]

Guess Harvey didn't need them

[numbnuts]

It's either the stage 2 rated to 220lbft or the stage 3 rated to 260lbft
I think it was the stage 2 so will be on the limit with my engine, maybe a bit of slip but that might help the gearbox I guess

[leec]

Guess Harvey didn't need them

Harvey has really improved after his photoshop course 

[numbnuts]

So the clutch is a KEP stage 2( disc and pressure plate), what size torsion bars do you recommend?

[richie]

So the clutch is a KEP stage 2( disc and pressure plate), what size torsion bars do you recommend?

Not sure what disc that is, can you put a picture up of it? But as a starting point 28mm bars with a good single[ or double if budget allows] adjustable rear shock like the QA1, do you have rubber or urethane bushings for spring plates?

cheers Richie

[numbnuts]

So I have been looking at the 28mm bars, a random search brought up these, a lot cheaper than swayaway, any experience with these?

http://www.ebay.co.uk/itm/28mm-x-24-11-16-torsion-bars-chromoly-pr-dune-buggy-vw-baja-bug/291192627985?hash=item43cc6ee311

[numbnuts]

So after taking my pressure plate off I can see what clutch I have, it matches this:

http://www.pacificcustoms.com/ac141928.html

would the 28mm bars be the way to go? Looks like it from what you all have said. Also would it be worth taking a chance on the cheap bars (latest rage) as there are not many reviews I can find?

Cheers for your input

[spanners]

personly i would not go near unknowns, the springs are everything and go beyond short term cash saving, they ARE the car, SAW serve thousands of racers with predictable and consistent pring poundage values in the toughest off road enviroments.

[JeeWee]

Currently I run the stock and 60+ year old rear torsion bars in my 1957 oval window beetle, fitted with an okrasa motor. I am not looking for hard launches, but when I drive the car with 4 adult passengers or the vacation bagage when going to a meeting, the car is lowering quite a bit. I also think for a bit more sporty driving I would like to have the suspension a bit stiffer, but still comfortable.

Question, does the spring rate changes after 60 years of usage and does it need to be replaced if you want to improve the handeling of the car?

[63VW]

Wow this is a timely thread for me, when installing large torsion bars what angle do you install them at (ie preload) I'm guessing 17deg would be wayyy to much?

[richie]

Currently I run the stock and 60+ year old rear torsion bars in my 1957 oval window beetle, fitted with an okrasa motor. I am not looking for hard launches, but when I drive the car with 4 adult passengers or the vacation bagage when going to a meeting, the car is lowering quite a bit. I also think for a bit more sporty driving I would like to have the suspension a bit stiffer, but still comfortable.

Question, does the spring rate changes after 60 years of usage and does it need to be replaced if you want to improve the handeling of the car?

Yes it does, if you measure both sides at rear most often driver side is lower due to wearing more that side over all those years