Suspension mods

[GARRICK.CLARK]

Hi guys.
What would you do to my bugs suspension to make a good improvement.
It is as follows
67 balljoint
swing axle rear
Front is 2 inch narrowed.
It has no sway bar at present.
runs new standard shocks
Uses drop spindles
Front beam adjusters set at standard height
No camber added at moment.
Unsure what the toes is set at.
The rear uses 26mm torsion bars
rear down an inch, has some neg camber
Gas adjust rear shocks (The white ones).
How could I improve on this.
Thanks G
Runs A Heavier than stock Type 4 Motor.

[Jadewombat]

I think you should have gone here first:

viewtopic.php?f=51&t=107390

[Marc]

If you're going to leave it swingaxle, you've already made one significant improvement by fitting the 26mm rear bars (the first thing I recommend on a `67 or `68 is to lose the wimpy 21mm bars they come with, even the 22mm which were stock in early`60s cars are worth the change) ...next either shim up the Z-bar links or take the whole setup off and add an aftermarket camber compensator...DO NOT add a rear swaybar.

If you're serious about making a major improvement in the handling there's only one answer: http://www.blindchickenracing.com/How_t ... ersion.htm

I've never been a fan of narrowed beams and would not expect a car equipped with one to ever handle as well as with a stock-width beam, but 2" isn't radical...however it still makes it impossible to fit a stock front swaybar. Best solution IMO would be to fabricate a setup like the Whiteline's, but there's a cheap & sleazy way - whack 2" out of the center of a stock bar, slip the halves into a ~4" long piece of tube (a stock tierod fits perfectly) and weld it together. I know, I know, one should not weld to spring steel but in this one case it works just fine.

If you just can't bring yourself to weld the bar, you can instead grind flats on it and press it into a short section of square tube. Either way, if the weld or fit should fail the sleeve will hold the ends together so they don't fall onto the pavement - the bar will just go along for the ride until you fix it.

[GARRICK.CLARK]

Thanks for the advice .Something I forgot to mention is the rear of this bug doesn't have the Z bar fitted. It has the 26 mm bars, also it has stiffer spring plates and a pair of spring plate caps that don't use the rubber knuckle joints.(Forgot the make).There's no rear bump stops, and the axle tubes are level not angled up or down. I'm tempted to go and modify a standard front bar. I can get a 2"narrowed 3/4 bar but I don't no if it will be too stiff and affect the ride quality of the car going over pot holes etc.

[Steve Arndt]

CB sells a 2" narrowed "HD" sway bar pretty cheap (black painted). It feels by hand like it is softer material than the Bugpack/Sway A Way gold colored bar. That may be an option. 65$

http://www.cbperformance.com/ProductDet ... tCode=4021

It comes with the good clamps too (that style clamp kit alone from Sway A Way is 30$)

[andy198712]

Where did you get the 26mm bars? Do they make it harsh ?

[Steve Arndt]

Sway A Way and Empi sell all assortment of bar sizes.

[helowrench]

Where did you get the 26mm bars? Do they make it harsh ?

If you are willing to be slightly outside that.......
Porsche944 all models with M030 option, 87 and later, or 944TurboS are all 25.5mm
(nobody seem to know what the Porsche968 TBar is sized)

[buildabiggerboxer]

968 rear torsions are 24mm.

[helowrench]

968 rear torsions are 24mm.

wow, did they make it that soft, or are they by chance hollow?

[Steve Arndt]

Early 944 are 23.5mm. Then the turbo and later heavier cars got bigger bars. A half mm in diameter makes a big difference in spring rate per degree twist. Cubic power function.

[buildabiggerboxer]

. A half mm in diameter makes a big difference in spring rate per degree twist. Cubic power function.

This,^^^^^^^, Porsche use a lot of hollow t/b for weight reasons, minus any you may find by a 2mm downsize for handling characteristics, ie, 26mm hollow bar would perform as a 24mm solid bar, try an IRS car on 29mm solid bars only if you can drive like a senna, and you will know what I mean, IRS cannot handle stiff 'bars, reason is why Porsche only use the skinny ones in 911 models, unlike swing axle cars, which love 26mm, and the chosen few can even handle 29 and 30mm bars, but not on the street please.

[andy198712]

what down sides to handling on the street are there?

[Marc]

To what? Just the heavier-rated rear torsion bars? Alone, they'll make for a harsher ride (you'll feel bumps & potholes more). The stiffer spring rate will also aggravate the inherent "tucking" behavior that causes swingaxles to roll over in extreme cornering - that's why you'll also want to have the camber compensator.
The swingaxle design has some inherent problems which cannot be resolved by any means (for one thing, its rear roll center height is at the center of the differential and there's nothing you can do to change that - smaller-diameter tires and/or lowering the suspension/raising the transmission can help, but that only goes so far; the best you can do is to find a compromise which will make it the best that it can be for your application.
Camber compensators (and the stock `67/`68 Z-bar, once the slack in the links is take up) pass the springrate of the inner wheel over and subtract it from the outer, which reduces the load on the outer wheel/tire...that reduces the jacking (upward movement of the rear roll center) and positive camber of the outer wheel (which reduces tread contact area and tries to make the tire corner on its sidewall).
When the body rolls, mass doesn't move but the load on the tires changes. Take the case of a hard left-hand corner where the body is rolling to the right. On most chassis, one would typically add a rear antisway-bar which would couple the LR springrate over to the RR additively, stiffening the RR and reducing the body roll. When you do that to a swingaxle, though, bad things happen - that's why the camber compensator or Z-bar is used instead, it actually promotes body roll in order to help the RR tire tread stay in contact with the pavement. The mass of the car pivots on the imaginary axis from the LR to the RF; when you reduce the load on the RR you also reduce it on the LF and increase it on the RF, which increases the slip angle of the RF tire. Decreasing the slip angle on the RR and increasing it on the RF will promote understeer (or at least it'll reduce oversteer) - the same thing that a front anti-swaybar does - but if it's done through the use of a camber compensator or Z-bar it does it by making the body roll worse instead of better...the car may not look as "planted" but it'll actually get around a turn at a higher speed before it barrel-rolls.
Under certain conditions it can be desirable to add a rear antisway-bar to a swingaxle, but that's really only for track use IF the suspension is lowered enough to put it into negative camber under static conditions, and limiting straps (or short shocks) are used to prevent it from going into positive camber when unladen. The resultant short suspension travel is punishing on the street...if you want good handling and a pleasant ride, IRS is the only way to go.

[GARRICK.CLARK]

Thanks for the info guy's.
After reading what has been said I'm going to use a shortened standard front sway bar.
I think this on the front of my bug will be ok. The front end is stiffer due to it being narrowed 2 inch. The front end has a good feel to it. It doesn't crash over pot holes, This I think is due to the adjusters being set at standard height and the drop coming from the drop spindles.
The rear with the 26mm bars does have a harsh ride.
I get the feeling while driving that the front is more stable than the rear.
I 'm going to put a camber compensator on it from the advice given.
By the way are the 205 70's that are on the rear too tall in the side wall for good handling.
Is there an ideal tyre pressure.
Thanks G