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.
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.
The Cal-look Lounge
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