Front Sway Bar and Rear Suspension Upgrade

What do you suggest for a Front Sway Bar and a Rear Suspension Upgrade.

My car has a 1969 Platform/IRS Rear Suspension and KYB Gas Shocks.

Thanks for your assistance.

JackB

I just bought a set from Kymco - they sell the Sway-a-way brand.
$49 for the front and $86 for the rear.
JC Whitney also sells them, but they're out of stock on the rear bars.

Dave

If you are going with the thicker front sway bar make sure you put a sway bar on the back too. I went 3/4 " (or 5/8", can't remember). and it made a BIG difference. I'm running KYBs front and back and they seem okay, but gas shocks on the front are an overkill (makes the front bouncy). I got my sway bars from California Imports (mainly because they are so close to where I live). My 84 IM also has an 69 beetle pan.
Ron

Aask first what you want the car for and the roads you will be driving, too much of a stiff suspension will render your car uncomfortable after about twenty minutes of driving. Because the front is lighter than a stock VW, stock sway bar and soft shocks are enough. With IRS only stiff shocks in the rear and you will have more control than you can handle. With a heavy sway bar in the rear the rear will deceive you in hard cornering and let go with no warning, with no rear sway bar the rear will pick up when you push too hard and squat when you corner correct, giving you an indicator when you are driving harder than the car can handle. The replica Speedster has about 40/60 weight and can dance when you controlled properly but will steep all over your feet if pushed incorrectly.

Jack, John's comments are right on the money. It all depends what you want from your car. Me, I want the best handling I can get and I'm willing to give up some comfort for it. As for the rear end letting go, without warning, at the limits (with a rear bar), I haven't come even close yet and don't want to. Years ago I had my 70 beetle (with a rear bar) let go while going through a tight corner. Scared the crap out of me! Luckily, I had the foresight to stay on the throttle and make it cleanly through the corner.
Ron

John & Ron,

Thanks for the reply. I primarly drive the car in the Sierra Nevada Mountains in California - Windy Asphalt Roads that ar "Course". They asphalt is grippy and eats tires. Slow to Medium Corner Speeds and dictate for a low of 2nd & 3rd Gear Speeds.

My car is lowered and and has gas shocks. As for "Breaking Loose", I'm not concerned much. I've held SCCA and Nascar Competion Licence's and have lived in this area for over 20 Years.

I appreciate your expertice.

Best Regards,

Jack Blake

Jack: I have an 84 IM on a shortened 74 pan with IRS. I have the Sway Away 3/4

Bruce's settings are pretty close to what I will be running - 1.5 deg. negative camber front, 2.0 deg. neg. cmbr rear, with 1/8" toe in for the fronts with 0 toe in/out for the rear. The 1/8" front toe out may tend to cause "plowing" (understeer).

The most important thing is to get camber for both front wheels set the same and both rear wheels set the same (or as close as possible).

In terms of suspension "stiffness', everyone likes a different "feel" and it's fairly easy to learn to "competitively" drive what you've got unless the setup is truly abominable.

Actually toe out reduces under steer and helps turn in. If you start turning with toed in front wheels, by the time the inside wheel has turned enough to be pointing straight the out side wheel has already turned quite a bit and is dragging itself across the pavement. This drag on the outside of the car causes the car to rotate out of the turn or plough. If you start with toed out front wheels the initial turn in causes the inside wheel to drag, which causes the car to rotate into the turn. Too much toe out is hard to control since if one wheel catches the car darts off in that direction. With toe in the car is more stable and corrects to the center.

Here's an idea. Take the car out one weekend after adding the components in the proper combinations. Run it on a familiar circuit that you enjoy and know. Then ask yourself, did you improve it in the most limiting part? Keep tweeking the car for that road and course that you enjoy and drive a lot. Maybe have a pal run a trace vehicle and observe how the car handles in tilt, lift and you can tell if it is more tight/loose. Change the air in the tires and see if the big, thick bars add anything except rough ride. Check it out for yourself. Go to the groove and document the speed at the edge of the envelop after about three runs. (nobody want's a surprise)

Bruce, with toe out the only time a wheel will be "pointing straight" relative to the chassis is partway through a turn when it is the OUTSIDE wheel.

George, Bruce is correct. A little toe out helps turn in, and reduces understeer, especially in low to mid speed corners.

This is a matter of degree - a small amount of toe out will help the inside wheel "fall into" the turn but too much can cause plowing - I've expereinced it when roadracing, and when we cranked the toe in a tad it went away (but that wasn't on a Porsche replica).

(Message Edited 4/23/2003 2:52:59 PM)

Road racing, formula, sports racing, they almost all use a slight amount of toe out if they want to increase mechanical grip on the front on turn in during low and mid speed corners. Although I use a slight toe in on my road car.

George: You are correct in you observation that when you initially turn the wheels on a toed out car, when the wheel on the outside of the turn is pointed straight the inside one is pointed more in towards the center of the turn. The inside wheel is now being dragged across the pavement and the outside wheel is rolling free. This increased drag on the inside of the turn side of the car causes the car to rotate into the turn. This is analogous to dragging an oar when rowing a boat. You drag the oar on the side you want to turn to.

Jack

How are you guys driving a 40/60 car (rear engine) car that you are getting understeer? (Call it plowing, push, tight or whatever.) I think you can adjust your driving style, set the car up a little faster and earlier for your corners and eliminate that altogether. Drive the dang thing in there hard and go for it! I really do know that these cars are light in the front end and that does contribute to it, but chidding you aside, I think if you set the car up in the turn earlier, hang that rear end out there a little and get back on the throttle you will see what I mean.

Ideally you want a neutral handling car. The front and rear break away at the same time. With a car set up this way, the driver can induce understeer or oversteer with his or her driving style.

Jack, IM's are a little better on the weight distribution. For instance, my new IM will have a 10.4 lb. flywheel, biral cylinders (another 20 lb. savings), no heater boxes (another 15 lb. savings), and a full sized spare in the trunk. The IM also has the engine/transaxle mounted about 2 3/4" farther forward.

With the approx. 45 lb. weight savings taken off the back and about 23 lb. spare tire and large fuel tank added to the front the weight distribution will probably be about 53% rear and 47% front which isn't bad at all for a rear engine car.

Certainly that weight distribution approaches optimum, and I've learned IM moves the engine forward. However, you don't see too many people complaining about the 911Ts and latest Porsches. Now they are very different to drive from a Vette.

Did you see what Mario did at 63? God love him, he's still a maniac.

I loved it when Mike ("The Bike") Hailwood came out of retirement, climbed on a Ducati 900S/S desmo, and blew everyone in the weeds at the annual Isle of Man roadrace.

George,

I still have my Chassis Scales and I'll weight the car and it will be interesting to note how the Front/Rear Weight Distribution turns out.

Jack Blake