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I've been reading Grassroots Motorsports Magazine for quite some time. For us SUV lovers it has some valuable information that we in the forum have asked for quite some time. So I more or less took out the abstract and posted here. Of course I renewed my subscription for one more year. It is an excellent magazine. Enjoy.

Few things are more satisfying than taking a car with minimal modifications to a club race or track event and doing far better than the competition thinks possible. I have been fortunate enough to be able to do just that on occasion, so I'd like to pass along the tips that get one to this happy situation. Although these tricks apply to all vehicles, it will be the enthusiast who is budget constrained who will benefit the most.
We'll simplify our plan of attack by tackling the components on the entire car in alphabetical order. But first, a little on the mental approach to doing well at the track.
Through the years, I have observed that the most successful racers spend a great deal of time thinking about how to get around the track faster. It is, in essence, a near total preoccupation. Also, whatever is done to the car often falls into the fine-tuning category and cannot, for the most part, be done the evening before the race.
This means one must steadily and regularly work on the car so as to avoid those last-minute, mistake-inducing, pre-race rushes. With that in mind, let's see what we can do.

Cold Air Box and intakes

The hotter the air entering the engine, the less dense it is. The result is a reduction in torque and, consequently, horsepower. Your first move here is to see how you can isolate the induction air from the under-hood heated air. If there is an easy way of doing it, then do so. For the record, every single properly designed cold air kit�that is, one which does actually induce colder air- that I have tested over the years has produced positive results. Cold air boosts power by virtue of increased torque, and that translates into a proportional increase in acceleration

Air for your Tires

Still on the subject of air, let's consider the tires. Having a car that handles well allows the driver to run it with greater confidence and consistency while at the limit.
Tire pressure can be a very effective chassis-tuning tool, but only if you know what to do. The tires' pressure increases with heat, so you need to record the cold tire pressure and then run the car until the tires reach operating temperatures; then stop and recheck the pressures. Note that if you are measuring the tires cold, you will always have to factor in this difference. Also, writing down your tire pressures will make them a more useful tuning tool.

Brakes, Rotating Assembly and Wheels

Although most enthusiasts concentrate on a car's forward motion, stopping is usually more important. Remember, he who brakes last has the corner never mind the fact that brakes keep us alive.
Two prime factors to consider here are brake fade and brake balance. First, let's address fade.
Brakes often lose their potency for reasons other than friction material fade due to excessive heat. If your car has been stored during the winter, do yourself a favor and replace the brake fluid. Most fluids attract water, and that drops the boiling point. When the fluid boils into a gas, it is no longer incompressible. Result: The brakes get really spongy and, in extreme cases, the pedal goes to the floor without producing any useful stopping power.
The brake fluids of choice, which have boiling points around 600 F, are expensive. If they are out of your budget, then the Valvoline SynPower fluid has over 500-degree capability and is next to dirt cheap at any auto parts store.
Now let's address brake fade from the pads themselves. If the car has brakes that are too small, you're only going to manage a partial cure as there's just not enough of a heat sink. Still, the difference between totally inadequate and undersized brakes that have marginal pads, and totally inadequate and undersized brakes that have the best pads possible is like night and day.

Body Roll, pay attention

Anti-roll bars are a great means of flattening out a car's cornering attitude. On a car that is a little short of the optimum amount of negative camber, these pieces can have a very positive effect on cornering speed.
But before assuming that a stiffer anti-roll bar will be a nearly instant fix for cornering woes, be aware that they can have a significant effect on the car's overall handling.
Ignoring other factors for the moment, we find that putting a stiffer anti-roll bar on the front will tend to induce understeer, in that the car wants to go straighter than the steer¬ing input would normally dictate. Stiffening up the roll
resistance at the back will normally induce oversteer, meaning the back end wants to come out earlier.
Having said that, if the front end has insufficient negative camber, then reducing roll at the front end so the tire stays more nearly perpendicular to the road can actually cut understeer.
Anti-roll bars will also adversely affect power transfer on the driven wheels. If you've got problems putting down power, you might want to disconnect the anti-roll bar from the rear of a rear-wheel drive car, or the front of a front-wheel drive car. You might need to add some spring rate on that end if you remove bar rate to keep the balance the same.
Here you need to do some experimenting. To get the roll stiffness at either end right, I would normally go to the track with anti-roll bars that I expected to be too stiff. I would also take along a big right-angle body grinder: Grinding a flat edge along the working
length of the bar adjusts the stiffness until it feels right.
Some of our low-buck friends have also had good luck welding sections of plate steel onto the middle of an anti-roll bar or clamping anti-roll bars together to add wheel rate. If your bars are not adjustable, this is a simple and cheap way to add some stiffness.

Lowering your Ride

There are few simple suspension mods that do as much for a car's road holding ability as lowering. In a pinch, you can cut the stock coil springs, which has the effect of reduc¬ing ride height and stiffening up the rate by about the same percentage that it was shortened.
Do not overdo lowering unless you are sure about the effect it will have on various aspects of the suspension and steering geometry. If you know that dropping the car 2 inches or more will not incur such maladies as shocks bottoming out, excessive lowering of the roll center or bumpsteer in the steering geom¬etry, then go ahead and do it. Otherwise, limit the lowering to an inch or maybe an inch and a half below stock.


Caster and Chamber

One of the most important angles of the front suspension is the wheels' camber angle. Having this set so that it maximizes front-end grip not only increases the overall cornering capability, but also sharpens the initial turn-in and the car's overall agility.
On most production cars, the camber angle is adjustable to some degree. Although you may not be able to get the 2 to 3 degrees often needed, it is better to have whatever is avail¬able rather than having positive camber. Setting the front camber angle is usually not too long of a job, and it usually costs nothing other than time. If you can adjust the caster angle (that's the lean, back of the line of action, of the steering in relation to the center of the tire contact patch), then do so. The greater the caster angle, the greater the steering's self-centering action. Also, increasing the caster usually increases the negative camber on the outside wheel as the steering is turned. This is exactly what is needed to increase cornering speed on very tight turns. If you have a front-wheel-drive car that has a tendency to understeer, do not put negative camber on the rear wheels. All this will do is increase the car's tendency to understeer.

Exhaust

Experience through the last decade has shown that many manufacturers are taking care of business in the exhaust department much better than has been historically the case. Unfortunately, this does not apply across the board.
The question is, how do you know whether or not the muffler on the car you take to the track is holding you up? The answer is, you don't unless you measure that back pressure.
All you need do here is to drill a hole in the exhaust pipe just in front of the first point of possible restriction. That could be a catalytic converter or muffler.
Here you need to braze in a length of copper tube�about 3/i6-inch in diameter�long enough to dissipate exhaust heat. Usually about 2 feet will do. Using rubber hose, con¬nect this to some form of pressure gauge. A device that measures in inches of water is best, but a plain old boost gauge will do, although it is somewhat less sensitive than we would really like.
Next, find a stretch of track were you can safely go to full throttle in, say, second gear�or a chassis dyno would be perfect. If any back pressure over about 1 psi is recorded, then the exhaust is costing measurable power. Figure each psi is dropping about 1 to 2 percent of the engine's output if a rela¬tively short camshaft is used. If a long-duration camshaft has been installed, then this number escalates really quickly.
Let's assume luck is against you and you find your engine is being choked to some extent due to inadequate flow of the converter and/or muffling system. This now brings us to the subject of how much flow a system needs to meet the engine's requirements.
A simple rule here
is that approximately 2.2 cfm of exhaust system flow�measured at 1.5 inches of mercury, which is equal to 3A psi�is needed for every horsepower the engine is capable of making on open exhaust. For instance, an estimated 125 flywheel horsepower needs a minimum of 2.2 x 125 = 275 cfm. Erring on the high side of this number won't hurt, but it won't help, either.

Oil

There is definitely power to be had by being a little more selective than pouring in any cheap 30-weight oil. And since the matter of pouring in has been mentioned, it pays not to fill the pan with any more oil than is necessary to stop the oil light from coming on when braking or cornering at race speeds. A crank that is dipping into oil can easily sap 5 or 6 horsepower.
If you want to get a good off-the-shelf deal, Mobil 1 from AutoZone or Wal-Mart is a good start. When it comes to making oil comparisons, Mobil 1 appears to have become the unofficial standard by which other oils are judged. It truly is a good oil and its manufacturer's ads extolling its engine life-extending capabilities are, if anything, understated. That's not to say it's the best there is, but you will have to look long and hard and pay more to do better.
If you want an oil that is about as good as it gets in terms of fighting wear and producing power, then some experience with a small custom blender that goes under the name of BND Automotive will be of interest. When I say this company custom blends, I mean they blend the oil specifically for you and your vehicle. The containers even come with your name on them, so the exact blend can be identified when you reorder.
BND has been making some inroads into Pro Stock drag racing lately, and I asked them to blend some brews for me to do long-term testing for both wear and power. I am now two years down the road and can say with reasonable confidence that, from oil analysis, the wear on rings, bores, lifters and camshafts is about 35 percent less than with Mobil 1. There's about 1 5 percent less wear on bearings and piston skirts. The oils blended for my application also address the noisy lifter problem which affected many LSI- and LS6-spec GM engines. After about a thousand miles, the lifter noise had gorfe. When building a race engine, many enthusiasts tend to think of oil pumps in terms of extra volume, pressure or both. It takes power to drive an oil pump, and the greater the pressure the more power it absorbs. For most stock applications where there is no question of the lube system having design shortcomings, 45 psi will do. For a modified engine, 50 to 55 psi more often than not will get the job done. In reality, the life of the engine is more dependent on the oil used rather than the absolute pressure.

The Spark

To most effectively light off a charge�especially in four-valves-per-cylinder engines, which typically lack sufficient mixture motion at speeds below as much as 4000 rpm�a good, strong spark through a big plug spark plug gap is needed. This means having a coil that will not only supply the voltage but, equally if not more important, the current for a high energy spark. Once you've made sure the coil side of the ignition is up to the job, it is important not to squander the benefits between there and the spark plugs. Old or substandard plug cables can kill the spark very effectively. Cheap carbon string cable will, when new, get the job done, but be prepared to replace them every year.
A better bet is to use the wire wound type of plug cable, which has lower resis¬tance so more energy gets to the plug. Do not assume, however, that a cable with a lower resistance is better. If plug cables of too low a resistance are used, the spark extinguishes itself sooner, thus resulting in less spark energy and duration. The maximum energy dissipation at the plug appears to occur when the plug cables have between TOO and maybe up to 1000 ohms total.
Now, once the means of generating a good spark have been handled, it's up to the plug to produce a strong spark. Just for the record, in 99 cases out of 100, the easier it is to fire the plug, the less energy is dissipated in the working part of the spark in the gap. If you want to produce a big, healthy spark, then big, healthy gaps are the way to go.
But big gaps have a much higher initial resistance, so to avoid sparks occurring elsewhere instead of across the plug gap, cables with above-average insulation are needed. In some of my engines, I have used gaps as large as 0.070 inch to good effect, but that takes getting everything just right. For most purposes, 0.050 to 0.055 is likely to be less problematic and will almost certainly realize 95 percent of the improvement possible.
Another piece to the puzzle of maximizing the effectiveness of the plugs' ignition ability is the form of the electrode tip. I think I can say with reasonable confidence that multi-electrode plugs do nothing for ignition quality that cannot be achieved as well or even better with a single electrode. (Probably the principle asset to multi-electrodes is their longer life and reduced emissions toward what would be the end of a single electrode plug's life.)
First, try to use non-resistor type plugs�the right resistance should be in the cable. Next, make sure that the plug is as cold as the engine will tolerate without plug fouling. Here, chassis dyno tests show that dropping to one heat range cooler than the manufacture recommends is often a good move.
The next aspect to deal with is the plug-side electrode. You do not want the side electrode to span the center electrode. When viewed looking end on, the side electrode should, at most, only span over about 20 percent of the center electrode. For what it's worth, most of Autolite's race plugs�$1.88 apiece at AutoZone�come out of the box this way and only need the corners rounded off as shown in the diagram below.

This article was from Grassroots Magazine that I read it and I’ve followed. So much that I’ve subscribe to the magazine. This article was written by David Vizard. June 2005.
 

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I'd love to read it but can't see the yellow print. :frown
 
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