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Fuel and Line Maintenance

Now is a good time to get that carburetor rebuilt. If you do it yourself, make sure to clean the jets and all passages. Check to be sure the throttle shaft is moving freely and is free from any restrictions that might make it stick. A sticky throttle shaft is hard to detect when the carburetor is on the car with the throttle springs attached.

Remove, clean, and inspect the fuel tank and bladder once a year. This item, too, has a life and a manufacturer’s date stamped on the fuel cell. Most sanctioning bodies require using a fuel cell that is less than five years old from the date of manufacture. Check your rules.

The fuel filter should be replaced often. This is not a budget breaker and is good insurance in making sure adequate fuel is supplied to the engine.

 

Fuel lines, fuel tank, and fuel filters – Fuel lines can get hard and brittle over time. Rubber has a limited life span, and we should never push our luck on keeping our fuel lines around too long. If the budget allows, replace them every year. If you ever have problems with foreign matter entering the fuel tank, be sure to replace the fuel lines once the fuel tank has been cleaned out.

 

 

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Maintain Rearend Effectivness

Rear end maintenance – The rear end must be maintained properly and, in many cases, often. Rear lube temperatures can be very high. This reduces the effectiveness of the lubricant and can help shorten the life of some of the internal components.

In a Detroit Locker-type rear end, the springs are the life of the system. High heat can weaken these springs, and if the rate decreases over time, the rear end will not lock up properly and only one wheel will end up driving the car off the turns. The handling goes away once this happens, and the crew often searches for a setup fix to no avail. If running this type of rear end, rate and/or replace these springs often. To neglect this critical area is to tempt fate. Many racers have lost out to differential springs that have gone bad.

For traction sensing types of rear ends, the many gears that work to sense torque in order for the system to function properly must be in good shape or the car will not handle properly and will be inconsistent off the corners. Often, replacement must be done for these small gears every three or four races, depending on the extent of heat and abuse. Contact the manufacturer for detailed information on proper maintenance.

Rear end lubricant coolers and circulatory systems can greatly increase the life of any rear end by keeping the temperatures down to levels that will not weaken the locker springs, reduce the effectiveness of the lubricant, or, in some cases, literally melt the aluminum gears.

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Brake Rotor Wear

Rotor failure – The brake rotors are a source of failure that can cause damaging effects such as a locked-up wheel. This can, in turn, lead to loss of control and a high-speed impact with the wall or other cars. When cracks appear in the face of the rotor, it is time to replace them. It is common for rotors to exhibit hairline surface cracks across the entire surface of the rotor. But if the cracks are too deep in appearance, they can lead to pieces of the rotor breaking off with obvious negative results.

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4-link suspension information

4 LINK DIRT SUSPENSION
TIGHTEN CAR ON CORNER ENTRY
• Raise left side frame mounted panhard bar on chassis
• Lower panhard bar on pinion mount
• Stiffen left front spring
• Raise left side ride heights (rock up)
• Soften 6th coil spring
LOOSEN CAR ON CORNER ENTRY
• Raise panhard bar on pinion mount
• Soften left front spring
• Stiffen left rear spring
• Increase left side percentage
• Lower left side ride heights
• Stiffen 6th coil spring
• Increase left rear bite
TIGHTEN CAR ON CORNER EXIT
• Increase left rear bite
• Move 5th coil or torque link left
• Stiffen left rear spring
• Soften right rear spring
• Stiffen right front spring (may affect
ability to steer in middle and entry).
LOOSEN CAR ON CORNER EXIT
• Decrease left rear bite
• Soften left rear spring
• Lower left side ride heights
• Move 5th coil or torque link right
TO MAKE CAR STEER MORE
POSITIVE ON CORNER ENTRY
AND THROTTLE
• Soften right front spring
TO TIGHTEN CAR OVERALL
• Raise center of gravity height (raise ballast, left side ride
heights)
• Stiffen left side springs
• Decrease right rear trail (shorten right side 4 link rods
2 turns at a time)
• Reduce stagger
TO LOOSEN CAR OVERALL
• Increase stagger
• Increase right rear trail (lengthen right side 4 link rods
2 turns at a time)
• Lower center of gravity height (lower ballast, left side ride
heights)

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Wheel Offset Changes

Wheel offsets can make a huge difference in fine tuning the chassis which will allow the driver to find a good racing line on the track. “If your car is really tight or really loose during hot laps, you have to take a look at the things that are going to make the biggest difference. Wheel offsets are very important. You can change a wheel on the car without disturbing the scaling that you’ve done at the garage.

“ illustrated the point by telling us what he has seen at various tracks over the years, “Too many times we see guys go out on the track for hot laps when the track is muddy, come off the track and dial in 10 rounds on the weight jack.  Then they go out and run a heat race when the track is tacky.  When they come off they take the 10 rounds back out and dial in 10 rounds somewhere else. By feature race time, these guys have no clue where the weight and balance of the car is.”

The changes that you can make using wheel offsets, “If you find yourself with an extremely tight car during hot laps, you can run less offset in the right front or you can move the left front or right rear out.” Merritt explained that it helps to have a set of eyes watch the car on the track to verify what the driver is feeling. “Your spotter can watch the driver’s hands on the corner entry and it will pretty much tell him everything.”

 Continued by saying, “If the problem is tight on entry, you can move the right front in to help the car pivot better. If the track is a flatter track with minimal banking, I like to move the left front out which will also help the car turn better.” If your car is wicked loose, Merritt says you do the reverse. “If you are making changes with tire stagger and wheel offsets, you’re never messing with the true balance of the racecar. “Key to success is making any changes for the track conditions you expect to see at the later stages of the feature race.

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SFI Rated Fire Suit Safety

Each sanctioning body will have a minimum suit rating required for competition. The standard for driving suits is 3.2A/X which is typically represented by a patch on the drivers’ left shoulder. The higher the SFI rating the higher the TPP value.

The SFI’s 3.2A spec (3.2A refers to suits specifically), in particular, is a test of a garment’s fire retardant capabilities, with a rating system put in place based on that item’s TPP (Thermal Protective Performance) when subjected to direct flame and radiant heat. This rating is designed to measure and correlate to the length of time one could be exposed to a heat source while wearing the garment before incurring second degree, skin-blistering burns. TPP is a product of exposure heat and exposure time, and is converted into a length of time before the second degree burns occur. The higher the number, the greater protection that a garment provides.

A common misconception is that the TPP ratings are the number of layers a garment has, but that is in fact not the case. Higher-rated garments do, however, generally contain more layers than a lower-rated one, as additional layers insulate and keep the heat source away from the skin by way of air gaps between the layers of fabric. An SFI 3.2A/15 and SFI 3.2A/20 suit are typically at least four or five layers, whereas an SFI 3.2A/5 is typically a two-layer suit.

 
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Tire Grooving

Grooving is exactly what it sounds like. You trim out a narrow strip of rubber from your tire to channel all the mud and dirt and debris to the outer edge, increasing your contact patch, and thus, your traction. There is most definitely an art to this, however. You can talk to five different people and get ten different patterns that they say are the best to groove into your tires. Horizontal, vertical, diagonal…heck you can even carve diamonds into the tread if it works for the particular track you are running at that point in time. Most tire groovers use V-shaped blades that are heated using electricity to provide a quick, clean and precise cut. Blades typically range from 1/32” to 1/2” wide and can have either a flat bottom or round bottom, depending on the type of groove you want to make.

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Tire Siping and Its Importance to Dirt track Racing!!!

Tire Siping and Its Importance to Dirt track Racing!!!

 

 

Siping is also cutting the surface of the tire, but instead of creating a tread pattern, when you sipe a tire you are only cutting slits in the rubber. The slits may not look like much, but they serve multiple purposes. When the car first hits the track, the sipes help the tire heat up faster. But once the tire is up to temperature, the sipes will “open up” and then keep it from overheating and loosing traction. Sipes generally help improve traction but also will increase tire   wear, so how much you choose to sipe any tire will often become a balancing act between traction and durability.