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Open-Track; Level 1
Continued from link; OPEN-TRACK CAR DESIGN BLUEPRINT
When it comes to preparing your entry-level street car for a road course, the first thing you might think about is additional horsepower, then the suspension and brakes, in my opinion, the order of priority is in the reverse order.
(1) Brakes: If you are still running the inadequate factory front drum brakes, they will most likely be hot and fading by the end of the first lap. Thereafter, when you cannot stop as quickly as others on the track, you become an accident waiting for a place to happen. This would probably be a good time to upgrade to front disc brakes, together with good-quality street/race front pads and rear shoes (see Level 2). At the minimum, put some street/race quality shoes on the front drums until you can upgrade to front disc brakes. Porterfield Racing Brakes has several compounds of high-performance pads & shoes and a helpful staff to help you choose the best for your application. www.porterfield-brakes.com
2) Oil: Assuming you still have the stock oil pan, I recommend that you run at least 2 quarts over the full mark, in an attempt to prevent sucking air in the middle of the corner. Even if it creates a little blow-by, it is better than starving the crankshaft of oil and ruining your engine. Of course you should use a high-quality racing oil and with zinc additive if you have a flat-tappet camshaft. It is also a good idea to install a mechanical oil pressure gauge with a larger ¼” tube. Then start the engine and bleed all the air out of the tube at the fitting where it connects to the gauge. This will make your mechanical gauge react instantly to any fluctuation if air is being sucked during hard cornering. If so, immediately add more oil to the pan.
Note: In my opinion, #1 & 2 above are a must before attempting an open-track day.
(3) Tires: The only thing getting all that horsepower, handling and brakes to the ground is your tires. The better the tires are, the better your car is going to perform. Generally, you will need to run street tires at their highest pressures in an attempt to prevent excessive sidewall flex. Of course, wide rims and low-profile tires are helpful.
(4) Sway Bar: A 1-1/8 inch diameter front sway bar works very well on both the street and track. This bar will greatly improve your handling with little adverse affect on the street.
(5) Suspension: Replace any/all worn out or sloppy front suspension parts. You cannot expect your car to handle well with sloppy suspension parts. Factory replacement rubber parts will work fine at this level. If you plan to upgrade to a higher level in the future, this might be a good time to use polyurethane replacement parts where applicable and while the upper A-arms are removed, re-drill/relocateis the mounting holes 1 inch lower as done on 65 Shelbys (see Level 2).
Monte Carlo Bar: Is needed to stiffen the unibody between the shock towers. Good export bracing to the firewall is also needed.
(6) Strut-Rods: The stock front strut-rod bushings are especially troublesome. They are so soft and flexible, that it allows excessive fore and aft movement of the lower control arm, therefore your front end geometry is constantly changing especially under braking. A cheap fix is to disassemble the strut-rod bushings and cut the inner tube spacer a little shorter (shorten as needed – (as I recall about ½”) so that when reinstalled, the rubber bushings will be squeezed tighter and be much firmer.
(7) After you replace front suspension parts, (and assuming you have already got your car lowered to desired ride height), you should realign the front end for high performance street/track settings: Caster; 2 degrees positive, Camber; 0 to 1/4 degrees negative, Toe-in 1/8 inch (1/4” if somewhat worn/sloppy suspension parts).
(8) After you get your car braking and handling well, then you can start adding more power.
PLEASE FEEL FREE TO JOIN IN AND ASK QUESTIONS.
9/18/2011, 9:48 pm
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