Autocross on the Cheap

For road racing, autocrossing, or just taking that curve in style. Oh yea, and stopping!
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FJCamper
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Autocross on the Cheap

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Going Autocross Racing on the Cheap for the Beginner

Air-cooled VW's run in all kinds of motorsports, drag racing, offroad racing, circle track, even road racing Formula Vee. All of these classes costs money, but there is one motorsport you can enter even with a stock car -- the autocross. It is safe, fun, and as competitive as any racing in the world.

Cars are divided into classes where performance should be roughly equal. Typically, a course is laid out marked with traffic cones, and cars are released one at a time to run the course as fast as possible, without hitting any cones. Autocross speeds are never very high, 75mph would be fast, and 40mph is more common. But speed is relative. It's like doing 40mph through the rooms of your house.

Lowest time per class wins, hitting pylons adds a time penalty, and there is one glorious overall Fastest Time of Day (all classes combined) to try for.

Autocross events are sponsored by the Sports Car Club of America and other local car clubs in almost every major city in the U.S. about once a month. Entry fees are low, usually $30 or so, and for that, you get a day on the track, making three to five timed runs, flinging your car around the course in the type of driving you only see in movie car chases through city streets.

An absolutely stock car is eligible. You don't even need special tires. Safety rules do require drivers wear helmets. Most clubs have loaner helmets if you don't have your own. At the track, make sure and take everything loose out of the car, including the spare tire and jack. It's obvious you don't want anything flying around in the trunk, but the big advantage is you're making the car lighter. The Lighter the Better.

Actually, starting out driving your car the same way it is set up for the street is very educational. You learn what it will really do when pushed to, and over, the limit. The first speed trick a stocker should use is just higher tire pressures. Street Tire Pressures Do Not Work for a car pushed even moderately. The tires will almost roll right off the rims. Good VW TP's (to start) are 20 to 24psi front and 26 to 28psi rear.

The Bug and Karmann Ghia are great autocross cars. "Quick cars" tend to win autocrosses over "fast cars." The Bug and Ghia are light and responsive. The advantages of the lower Ghia over the higher Bug will not matter until your skills are greater, and you begin to modify your car. But if you're a beginner, forget about speed parts for now. Learn to Drive before you modify the car.

You will never know how good or bad you really are until you race against other people in other cars. One of the first eye-openers in any kind of racing is learning what you thought you knew about types of cars, tires, and speed parts is hype or genuine. Remember the too-true racer’s saying. “When the green flag drops, the bull**** stops.”

You may have had the chance to walk the course before the event, and that helps, but walking it is not like driving it. The thing to keep in mind on your first run of your first event is: "Take it easy, learn the course. Precision first, speed later."

Most new drivers sit on the starting line and suddenly the track looks like a sea of cones, the path through them lost. When the starter signals go, you accellerate into the sea of cones, dodging left and right, tires screaming, and 40mph seems like 100.

At the end of the run, you may have missed some turns altogether and killed cones like a bowling ball crashing through ten pins, but your adrenaline will have your hands shaking and your breath will be short. You'll drive right back to the grid and take your place in line, more prepared, making plans on what to do different, what to do better.
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Getting adjusted

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RetroRacing’s Autocross Adjustment Prep

Getting Adjusted

Remember, quick cars (as opposed to fast cars) have the advantage in autocrossing. That's because top speed and high-speed stability and braking don't matter. A hot autocross car is prepped to act and react suddenly. You want sudden acceleration, gear change, braking and steering.

Presuming you have an absolutely stock VW Ghia or Bug, and you recall our tips on tire pressures from last time, there are several key adjustments to be made.

Adjust your clutch so that you have a half-inch of pedal freeplay. You don't want too "loose" (the common street condition) a clutch, meaning too much pedal freeplay. You want the clutch to respond instantly, like a hair trigger on a pistol. Check your clutch pedal arm to see if its cracked (they do crack) or bent, and if the clutch pedal stop is working. Under stress, a cracked arm will cause enough play to keep your clutch from disengaging, especially when you are stomping it like you will be.

Adjust your accelerator cable clamping at the carburetor so that when your gas pedal is on the floor, you really have 100% throttle. Look at the throttle plate and make sure when you are depressing for full throttle, it is open, straight up and down, and not off to either side. When you check the cable connection, make sure the gas pedal hinge itself isn't bent so the pedal leans to one side, and the gas pedal roller lever under it isn't bent. VW accelerator pedal assemblies are infamous for bending over time.

Adjust your carburetor accelerator pump to give the best acceleration. The stock VW single Solex carbs have adjustable pump strokes. Generally speaking, slightly increasing your pump stroke will give you a bit more gas on takeoff, and that should mean better acceleration. Too much or too little stroke, and you'll create hesitation. It's a cut and try operation, but it's easy. You can help out the acceleration with a little timing advance over stock, too. But just a little, usually no more than 10° BTDC. And after the race, reset back to stock. Dual carb setups and different types of distributors can all benefit from this same advice, but you'll have to find your own sweet spot.

Adjust your brakes. For autocross, you want firm brakes, and instant response. Adjust the drums just so one or two more clicks tighter would cause scraping as you rotate the wheel. Since we don't adjust discs, on Ghia's the rear drum adjustment is how you set brake pedal feel. Note: For road racing, you back off the drum brake adjustment more than you would for autocross, to prevent brake lockup once the fluid is hot and some expansion has occurred. Luckily, autocross doesn't overheat your brakes.

Adjust your steering play. By the book, you're supposed to have about one inch of freeplay at the steering wheel with the tires in the straight-ahead position. Jack up the front of the car so both front tires are off the ground, and turn the steering wheel all the way to either side. Tighten the adjusting screw on the steering box only a fraction of a turn at a time, between freeplay checks. To check, spin the steering wheel back to straight ahead. Gently rock the steering wheel back and forth as you watch the wheels. If you have one inch of freeplay and no wheel movement, you should be okay. Test drive the car, turn a sharp corner and briefly let go of the steering wheel. It should swing back to straight ahead, or almost straight ahead. If it doesn't, you have it too tight.
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The Driver

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Getting You Ready To Go Fast

It's no wonder people drive VW's hard. Racing is in the VW's DNA. The VW Type 1 Bug and Ghia front and rear suspension began life as a 1930's era Gran Prix race car, the Auto Union P-wagen. The "P" is for Dr. Ferdinand Porsche, who designed the car. VW owners felt (if just subconsciously) the built-in racing geometry and engineering, and added to that was the sportiness of the engine itself, an oversquare, short-stroke configuration required of all sports-racing powerplants.

But before we get into four wheel drifts and hand brake turns, we begin with the basics of seating, steering, and pedals.

SEATING: If you have to brace your leg against the door as you corner, if your torso muscles are flexing and straining to keep you upright as you zigzag through a slalom, you are losing time. The driver has to be seated firmly and comfortably. The seat belts must hold you in and down. The stock seats in your VW are too high and too soft, and your stock seat belts too narrow to help much in wild high-G gyrations. If they're all you have, live with them until you can get better. Your seating posture also matters. An actual set of racing harnesses will pin your shoulders to the seatback, so start getting used to driving with your back fully against the seat. Your arms should extend to the steering wheel with a comfortable bend at the elbows. Your feet should touch the pedals with a comfortable bend at the knees. Do not hunch forward and sit too close to the steering wheel, do not sit so far away so that you cannot comfortably push every pedal all the way down. And you should be able to reach down, and shift into 3rd without stretching.

STEERING: Driving gloves exist for a reason. Smooth plastic or even polished wood steering wheels get slippery if your palms sweat. Lace-on steering wheel covers help, but I've seen them loosen in hand-over-hand slapping as a driver frantically forces the wheel from one side to the other. Thick-rim steering wheels are as much for padding as grip, and you'll be surprised how much of a beating your hands will take from a steering wheel in a race. Driving gloves help. Steering wheel covers help if they're laced on tight. A nice padded wheel, in a small, but not too small a diameter for your leverage and comfort, and good gloves, is just right.

PEDALS: Notice that the VW pedal cluster is closely spaced. The bad news first. The brake and accelerator pedals are so close together that lots of people have to wear narrow shoes so as to not catch the edge of the right shoe on either pedal. The good news is the very closeness of the brake and accelerator make "heel and toe" maneuvers possible. That's when you control the gas with your (right foot) heel and the brake with your (right foot) toes … at the same time. But, we're getting ahead of ourselves. For now, just make sure the pedals have good rubber pads or bolt-on aluminum pads. It is actually possible to have your left foot slip off the clutch as your depress (read: stomp) it, and the clutch pedal spring back up and catch your ankle between the clutch and brake. Awkward. You don't need a pair of Piloti driving shoes yet, but do get a good pair of narrow sneakers with grippy rubber soles and a rounded heel.
Charles R
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Post by Charles R »

nice info.
I just want to add that per SCCA rules, swingaxle cars require a camber limiting device. (secondary to the shock)
rsb
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Post by rsb »

Good stuff!

On tire preassure... why do you recomend high (20-24 psi) on the front and low (26 - 28 psi) on the back? I bumped my fronts up to 20 and it definately seems to have more bite in the corners. I have the backs at 30 it is a little touchy, but I havent had the back end come loose yet.

On seating... alot of the SCCA classes I was looking into for racing my stock super beetle do not allow for aftermarket seating.

Your discussion gave me a good idea though. My drivers seat has most of the springs broken on the left side, and puts me about as low as I would want to be from a visibility stand point. Im thinking I might just fix the seat so it is level and padded again at the lowest height the seat frame will alow.

On pedals... my problem with pedal clusters (74VW, 78 subaru, 88 audi) is the lack of space between the clutch and brake. I hit both at the same time more often than I would care to admit. I am contimplating grinding off some material from the right side of my super beetles clutch pedal and maybe welding on a plate of a similar size to the original only offset to the left. What do you think, bad idea?

Of oil control... When I am cornering hard enough that the back end is lifting on the inside and my tires start to squeal my oil light comes on as all the oil is shoved into the valve covers. Any easy mods to help counter act this? What sort of oil control mods have you done on the ghia?

In Bill Fisher's book "How To Hotrod Volkswagen Engines" in the lubrication, cooling, and breathing chapter Theres a couple tricks that looked pretty good to me, using 3/4" pieces of push rod tube extended into the sump (unfortunately I think I would have to tear the motor down to do this), and brazing a screen to the sump cover to help keep the oil. fenced in under the oil pickup tube (this might be worth a shot, I think I have a spare so not much to loose trying this route).

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Thanks fo the advice,


Brian
Last edited by rsb on Sat Jul 12, 2008 12:13 pm, edited 1 time in total.
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FJCamper
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Post by FJCamper »

Hi Brian,

Let's take these subjects one at a time.

To begin, 20 to 24psi TP (tire pressure) is a good range for the front end, and 26 to 28psi good for the rear. The variables are your type and brand of tire, and the weather. Cold weather means lower pressures. Wider tires with lower profiles usually mean lower pressures.

Remember, when you make your run, have your crew immediately check your tire pressures when you stop the car. You're looking to see if the pressures increased. Coming in with higher pressures means the tires are working harder.

For instance, lets say you set up at 22-26 (front/rear). You check pressure on your first run and you see 24-30. The fronts are not working very hard, but the backs are heating up. They're being worked. A 2psi increase is common, but more than that means trouble.

You go back out with hot tires. when you roll in and have the pressures checked, you find 24-32. You're still working the rear harder than the front, which by now should be telling you that you need some rear suspension tuning help ... maybe a rear sway bar.

If you discover you're understeering (front tires sliding) you'd normally bump up the front TP 2psi. Oversteering (tail swing out) bump up the rears 2psi. More air, i.e., more tire pressure, is not going to compensate for poor alignment or lack of mechanical suspension help.

If you're lucky enough to see your pressures go up the normal two psi and stay there, you're working the tires and suspension evenly and have a good balance ... but your crew chief should tell you you're not going fast enough!

When your car comes in, have someone feel the outside edges of the tires to see how hot they feel as compared to the inside edges, and run a palm across the middle of the tire.

The outside edges are supposed to be hotter than the inside edges, but not dramatically so. The idea is to adjust camber so the heat difference is minimized. That means the tire is setting flatter.

Okay -- what next?

FJC
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Jadewombat
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Post by Jadewombat »

This should be a sticky.
rsb
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Post by rsb »

So if I understand this right, idealy after a run front and back tires should gain preassure (2psi) equally with roughly even heating of tires. If this is obtained suspension is set up well.

X2 on the sticky vote.
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Post by FJCamper »

Hi RSB,

Yes, a 2psi TP increase is normal front and rear. More than that tells you which end is working harder.

You asked about oil slosh control. It does not take much hard cornering to turn on the oil light in a stock engine.

The usual oil-slosh control methods are:

1. "Windage" pushrod tubes (this is what is described in How to Hot Rod Your VW Engine) which you can buy now, but must be installed at assembly time. They help but do not stop oil starvation.

2. Windage tray, another "at assembly" part which separates the crank and cam from the oil sump, and attempts to keep sump oil slosh suppressed. This also helps but does not stop oil starvation.

3. Deep sump. This works, but cuts ground clearance. It is a bolt-on, however, and is the singlemost effective anti-oil starvation add-on.

4. Formula Vee style "sump "bump" extension.
http://www2.cip1.com/ProductDetails.asp ... D3051%2D10

This is cheaper than a deep sump, and it still cuts some ground clearance, but is very effective. They were FV-legal mods that did not add enough extra oil to be considered an illegal advantage, but helped engine reliability.

I'd get a FV sump bump or a deep sump.

FJC
bigmeat
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re

Post by bigmeat »

I used to autocross a 85 chevette came it third in points. I ran kunho tires with about 38 psi.
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FJCamper
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TP's

Post by FJCamper »

Hi Bigmeat,

Yes, autocrossers in cars other than VW's run higher pressures. I've seen people in other makes up as high as 42psi.

VW's, swing-axle, IRS, and Supers, do best with what seems like lower pressures than you'd expect. Remember, stock TP's were once 18psi for the front, and 24 (or so) out back!

The pressures I'm recommending are for 4.5" to 5.5" wheels, and for standard construction street radials, none of which that are available for VW's are very sticky.

We've been running Avon 175x15 "racing radials" on 5.5" wheels.

The VW will slide and skip with too-high a TP.

FJC
rsb
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Post by rsb »

When autocrossing a AC VW what kind of handling characteristics are we looking for? It seems like every car I've owned has it's own fastest way to take a tight corner.

In the heavy rear wheel drive american vehicles ive had, it seems to be cutting the nose in early in the corner and powering the back out then lifting throttle when the car is lined up in the right dirrection.

In the front wheel drive subarus Ive owned it seems to be driving hard to the apex then cutting the nose into the corner had sending the back end around, then breaking the front tires loose to drift into line, lift throttle to restore traction, then barrel down the straight with the extra momentum and high rpm gained in the corner.

In my audi quattro, it wont torrerate such shenanigans, and seems to come down to picking the straightest line through a corner and going as fast as traction will allow.

I'm still in the process of breaking in my engine and relearning my super beetle to start looking for it's sweet spot.

Also, on a related note, how do you keep in practice with the ghia?
helowrench
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Post by helowrench »

A ghia is pretty much the same as the bug.
the major difference is found in that the bug is a little lighter in the front.

Rob

(I miss AX in the rabbit-----that was entertaining)
Theo
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Post by Theo »

Here is a fix for the oil control problem. I found this on a German web site for hill climbs. I ran two lines from each valve cover to a sump. This works great!

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theo
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