what can be done to get an IRS/beam beetle to handle best?

[beetletom]

drop the rear 1 spline, with an anti roll bar? or would a csp kafer bar be better?

has anyone used the front beam strengtheners, do they stiffen up the front end much?

thanks!

[pupjoint]

I think Greg ward wrote an article on this, posted on Aircooled,net too.

I use br stiffeners in all my cars, can't really tell the differences myself.

[Zach Gomulka]

Track use or street? Or both? Everyone has their own opinion, this is mine (for street)- 5/8" sway bars front and rear. Koni shocks. Beam stiffeners. 944 vented brakes. 185 tires front, 215 rear on lightweight wheels. Try to keep the beam stock width. Slightly lowered in rear.

[hotrodsurplus]

As Pupjoint wrote, Greg Ward's notes on ACnet are insightful.

Air-cooled Volkswagens suffer oversteer so anything you can do to induce understeer is going to make the car handle a ton better. You're at least starting with the best rear suspension design.

Front anti-roll bars induce understeer. Rear anti-roll bars induce oversteer. So don't put a bar in the back until you replace the front one with a stiffer unit. Larger anti-roll bars usually aren't necessary with a quality monotube damper like a Bilstein. 

Good quality mono-tube dampers like Bilsteins will do wonders for handling. Their greater low-speed damping force minimizes body roll by a pretty significant degree. That's usually the first modification and it will yield the fastest and probably greatest improvement

Increasing rear track width induces understeer. Decreasing front track width also induces understeer. So as a rule narrowing the beam will actually improve handling (within reason of course).

Increasing front spring rate (a consequence of narrowing the beam) also induces understeer. Whatever you do, do not increase the rear spring rate if improved handling is your objective.  A stiffer rear spring rate (like a stiffer rear anti-roll bar) induces oversteer.

Increasing front tire pressure induces oversteer so don't exceed VW's recommendations. Increasing rear tire pressure induces understeer but at the expense of ride quality, braking traction, and tire wear. Best stick with VW's recommendations there, too.

A fortunate thing for Cal Look is that a front tire that's smaller than the rear induces understeer.

An unfortunate thing for Cal Look is that lowering the nose more than the rear induces oversteer.

Caster shims restore caster in vehicles that have been lowered more in the nose than the rear. It won't do much to mitigate the oversteer induced by lowering the nose more than the rear but it will certainly help high-speed tracking.

[beetletom]

will be for the street.

thanks for the advice guys!

[qubek]

Air-cooled Volkswagens suffer oversteer so anything you can do to induce understeer is going to make the car handle a ton better.

I don't know what was your intention, but the way I understand the sentence above, it is not at all true.

First of all, most Beetles understeer a lot at least initially and only then, under specific conditions, start to oversteer.

If Greg Ward agreed with your statement above, he would not recommend negative camber on front wheels as one of the first steps.

I agree that his article here at aircooled net http://www.aircooled.net/vw-handling-suspension-tuning/ is helpful.
   

[modnrod]

First of all, most Beetles understeer a lot at least initially and only then, under specific conditions, start to oversteer.

Dive them in hard, brake late, clutch in momentarily then release hard mid-corner with full throttle in third.
Adjust steering as necessary.

They corner just fine.
 

[cnfabo]

http://m.youtube.com/watch?v=J4sNeWPKiTo

this was my old hillclimb circuit beetle but recently wrote it off.....they are pretty easy to make handle very good..this particular track is slippery and worse when you have old semi slicks that have gone hard and you have been doing motor sport for only a few years...

back to subject, if you read gregs article you will get the drift..he has a article on how to do street suspension mods and race mods....you cant go wrong with upgraded shocks lil bit of camber and some off the shelf sway bars...a big difference would also to corner weight the car but that would be more leaning toward serious racers..i have made my own sway bars out of chromoly tube 20mm front and 25mm rear with 2mm wall and thay are adjustable......i still had some tuning to do,like corner weights and more sway bar adjusting.......and if you have the dollars i have been told by a good source is if you get custom valved shocks you will notice another gain.....us hillclimbers in australia run upto 4.5 deg neg camber on the front and to get this much you have to bend the top trailing arm in a press by about 6-8mm......hope this helps

fabo.
in oz.......................

[hotrodsurplus]

First of all, most Beetles understeer a lot at least initially and only then, under specific conditions, start to oversteer.

That's the problem. They're incredibly susceptible to drop-throttle oversteer. Push a car real hard into a corner and lift to feel it. It's pucker-scary, especially on a swing car with positive rear camber. That's the reason Volkswagen started installing anti-roll bars on the front as early as the late 1950s. And those cars sat nose high.

Ward's recommendation to set the front wheels to negative camber is indeed valid but you have to also understand the full dynamic and the context. Setting negative camber up front improves turn-in properties that make the car behave a lot better prior to the apex of a turn. It also tends to keep the front tire planted as the chassis rolls.

The negative is that it also induces a little bit of oversteer in the follow-through but as long as the rest of the chassis has been set properly to mitigate the oversteering tendencies in those situations. Racers also tend to favor more oversteer than understeer, at least to a certain extent. A car that's on the verge of oversteer will turn in really quickly but you have to really pay attention to keep it from biting you in the ass. The same thing goes for setting the front wheels to toe out; the car is always wanting to turn in which makes the car feel really twitchy.

Racers don't mind that; their nerves are already on edge and they're paying attention to every little thing. But daily drivers mind it terribly, especially on rutted or grooved roads. A toe-out car will wear you out on a normal stretch of highway. Those are only a few of the consequences.

I still stand by my statement that as a rule Volkswagens (remember, we're talking street here) benefit from inducing understeer. I do it for the same reason that the OEMs induce understeer in their cars: a car that understeers slightly will rattle a person's confidence well before they enter a turn. A car that enters a corner beautifully can artificially build a driver's sense of confidence and that's a dangerous thing if someone enters a corner way too hot, gets scared, and lifts. That's a recipe for a rollover or at least a broadslide into a tree in a rear-engine car, even a more modern 911.

We also have to take the other things that we do in the name of style into consideration. Lowering the nose more than the rear also induces oversteer (transfers more front weight). So in those cases greater negative front camber could be considered dangerous. You have to take the entire vehicle and its prevailing modifications in mind. It's not a good idea to just blindly pick and choose. It's pertinent to understand the dynamics of every consequence.