The Cal-look Lounge

I am renovating my 1963 bug's chassis.

My bug has only driven about 95.000 km but has always been very loose in the back.
I had new stock shock absorbers, but it did not help much.

I have purchased new rubber bushings from Gerd Weiser, red koni shock absorbers and 26 mm torsions bars.

My questions is this: 26 mm torsion bars -  is that too much for street car and perhaps a few passes on the strip

The original torsion bars was 22 mm.

IMHO - No. But you have to decide for yourself. How long is a rope.  :)

The short answer is yes, that is too much for a street car that sees the occasional pass. In fact you have gone the exact opposite direction that Porsche and Volkswagen went to improve handling. Here is why.

By their design swing-axle Volkswagens suffer terrible oversteer (the tendency to spin when turning). Increasing the rear spring rate reduces not increases the vehicle from transferring weight to the outboard wheel in a turn. A tire relies on weight transfer to achieve sufficient traction. The tire's inability to achieve traction in a corner will cause the rear to slide laterally.

A sliding rear wheel causes a vehicle to spin. Increasing the rear spring rate also increases the rear wheels to 'jack' in corners. Jacking will increase the chance that the rear tire tucks and causes the car to roll over. These are not my opinions; they are well researched and proven facts of vehicle design and tuning and I invite you to study them for yourself. This is a very serious but misunderstood subject and you would benefit from the knowledge.

Porsche reduced these problems by reduced the spring rate in 1960 or '61. Naturally that caused the rear to sag when carrying passengers and baggage. So Porsche fitted a compensator spring (the part that people incorrectly refer to as a 'camber compensator'). The compensator spring is a decoupled leaf spring: it increases load capacity provided both axles bear the same weight but it rotates about a pivot under the transaxle when one side of the suspension loads more than the other--say in a turn. So in that way the compensator spring increases the vehicle load capacity but does not affect the load transfer when cornering. For various reasons (expense and buyers' ignorance among them) Porsche returned to the earlier heavy spring/no compensator design.

Volkswagen followed suit in 1967 by reducing the rear spring rate. Instead of using a leaf-type decoupling spring it modified the body to accept a torsion spring with brackets that form a Z. When the car is unloaded the compensator spring does nothing; however, it engages when the vehicle endures a load. Like Porsche's compensator spring it does not affect lateral spring rate. It simply pivots when one side of the suspension encounters more load than the other.

Here are ways to improve your car's handling:
Widen the rear wheel track (VW did this in 1967)
Narrow the front wheel track
Fit narrower tires in the front and/or wider tires in the rear
Use a front anti-roll bar
Fit a leaf-type compensator spring (camber compensator). The early EMPI examples apply. The later ones that cradle the rear axles in urethane do not serve the same function. They only thing they eliminate is money from your bank account.
Tune your rear dampers for less compression damping and more rebound damping.
Tune your front dampers for more compression damping and less rebound damping.
Reduce front tire pressure but don't run less than Volkswagen's recommended 18psi).
Increase rear tire pressure but don't run more than five to seven PSI more than Volkswagen's recommendation.

Also understand that lowering the nose more than the rear will increase a vehicle's tendency to oversteer. A forward rake and a stiffer rear spring rate is a bad combination. Removing the front anti-roll bar will make the car even more dangerous. If you want to REALLY make an early VW dangerous then inflate the tires to the maximum pressure indicated on the sidewalls. That increases the front lateral traction disproportionately more than the rear lateral traction and poor handling will result.

Hope this helps.

Ok thank you.... That gave me something to think about.... ;)

If your going to lower the rear of the car, No they are not too big, my 68 had stock 22 mm short torsion bars in it and was lowered a little but it used to squat way too much so I put some used 26 mm bars in it set I belive at 12 degrees preload, it set the rear height right where I liked it and it hooked up perfectly

 Dang Hotrod I did everything wrong . I have 30mm  torsion bars, JayCee spring plate retainers, adjustable spring plates , double adjustable QA1 shocks , 8.5 tread tires on the rear and 155's front , no sway bars and 2.5 dropped spindles with added caster shims . I am not planning on motocrossing my car  and this thing actually rides and handles pretty good . It will flat out hook from a dead stop and I will be racing it next year in street trim with slicks in " Super Pro ". I plan to drive this car regularly to shows and to get an occasional burger with the wife . I also forgot to mention it has a 366 rwhp turbo engine , wanna ride?   LOL
        Mike McCarthy

(http://i91.photobucket.com/albums/k300/dragvw2180/DSCI0039_zps515b541c.jpg) (http://s91.photobucket.com/user/dragvw2180/media/DSCI0039_zps515b541c.jpg.html)

FWIW, I have stock rear-end in my '68 Beetle, which IIRC is 21 mm torsion bars & Z-bar, and it seems to be fine on the drag strip.  I've raced just over 600 times down the 1/4-mile over the past eight years, now running 12.6-12.8 ET's.  This Beetle is primarily a street car, so I haven't changed the rear suspension.  Therefore, I would say a few passes on the strip should be fine in your case.

You didn't do everything wrong:


You have gargantuan tires on the rear which reduce oversteer. And everything you did is great for a drag car that sees occasional street use. I'm sure it handles okay for what you do with it. Just never ever go into a corner hard and lift. You'll learn firsthand what extreme oversteer feels like.

FWIW, I'm not at all talking about autocrossing cars. I mean this is a cal-look forum after all.

And I'm also basing my recommendations for safety primarily and cars that see almost all street driving. I think it's fine to break the rules. I just think it's important to know what the consequences of breaking the rules are.

There's a time and a place for everything. I get the impression that the OP doesn't want a drag car. And as Neil mentioned, a car with soft springs can indeed hook hard. I think a street Beetle like his that clicks a 12.6 hooks hard by definition.

quote author=dragvw2180 link=topic=21577.msg295782#msg295782 date=1380466266]
I also forgot to mention it has a 366 rwhp turbo engine , wanna ride?   LOL[/quote]

Why not? Your car sounds respectable. My meter might be a little off though.

7.60-something @ mid 180s. Stock block and as street legal as yours. I keep fast company. ;)

[attachment=1]

Why not? Your car sounds respectable. My meter might be a little off though.

7.60-something @ mid 180s. Stock block and as street legal as yours. I keep fast company. ;)

[attachment=1]

[/quote]

Is that a jet engine off a 747 or a turbo, LOL  Mike McCarthy

 ;D ;D ;D

Ironically the guy who runs that car is a tool-and-die maker at the Boeing Everett plant. He works on the Dreamliner nightmare. That engine made 1050 at the wheels two years ago when it ran high sevens. The sound is way off so you'll have to turn up the speakers.

http://www.youtube.com/watch?v=W7eJvBQUgxQ (http://www.youtube.com/watch?v=W7eJvBQUgxQ)

He went through it this last year--in fact I had to put off shooting his car because he tore it apart. I don't know the ET or speed but it got faster.

He also has a stone-stock '56 Beetle.

More turbo porn:

[attachment=1]

Sorry for hijacking the thread with Buicks.  ;D

That is okay...  ;D

What are the best spring plate bushings to use in this case? There are stock, urethane, and I don't know if brass bushings are available?

I run 28mm on my stock weight 67 and it feels great



Just replacing them for new stock versions will help level out the ride- often one side sags.