Alcohol Fuel Delivery Systems for Micro & Mini Sprints

Fuel Delivery Diagrams: It is highly recommended that you install a flow through type fuel delivery system with our fuel injection systems. To view the fuel delivery system click on the links below, a pdf file will open in a new window. There are two pages to each of these documents, please click on both pages to see all relevant information.

Fuel delivery systems are a very important part to your engine's performance and you ability to finish races. The system can be divided up into five main areas:

  • Line
  • Pump
  • Tanks
  • Filters
  • Regulator

The Fuel Line: The Fuel line generally used on micro sprints is the blue Super Stock hose manufactured by Earls or the blue Aeroquip line. Both are essentially the same thing, and they both are not compatible with methanol. No material is compatible with methanol except Teflon. The Pro Gold fuel line we sell is made from Teflon, and will never break down. It is without argument the best investment when it comes to buying fuel line, I highly recommend saving your money and getting the Pro Gold line and fittings.

The blue line needs to be replaced every year, you may get away with more, but it is at high risk. The line will break down and cause major problems ranging from clogging fuel filters to causing stuck nozzles. I know there are many stories out there that state "a friend of my friend told me they ran the same line for 3 years and didn't have any problems" ...yea, and you might not die from lung cancer if you smoke 3 packs a day, but the odds are pretty high that you will.

 

The Fuel Pump: A common failure on the fuel delivery system is the pump. We have tried many different brands and styles of pumps. None of the inexpensive pumps are rated to pump methanol. On all the inline pumps, the fuel flows directly through the electric motor and bearings.

Cavitation is the formation of gas bubbles in the fuel where the pressure of the liquid falls below its vapor pressure point. When the pump can't pull the fuel in, it creates a vacuum forming gas bubbles, when these gas bubbles collapse it creates a shock wave that destroys the bearings and veins. Key items that cause cavitation:

  • Clogged fuel filter
  • Clogged inlet of pump (the Walbro pumps have a screen on the inlet that can cause severe restriction)
  • The pick up inside the tank is sucked to the side of the bladder, or it is clogged
  • Pinched fuel line
  • Shut off valve not turned on or one that vibrated off

Many times, the pump will work fine at idle and low fuel demand RPMs/loads, but not be able to keep up at higher RPMs/loads when the engine demands the most fuel. A problem such as this is easily diagnosed by watching the fuel pressure gauge while on the track. If you are having issues with the engine blubbering or breaking up at some point on the track, glance at your fuel pressure gauge and notice how far it is from your set point. If it is more than 5 lbs, you may have a faulty fuel pump or restricted fuel filter or pickup.

The Walbro pump is the most popular, but it's life span is very limited.  A common failure on the Walbro pump is the bearings go out. It becomes obvious when you hear the pump making a squealing sound. This is usually caused by cavitation or just wearing out. Top lube can help the bearings last longer, we recommend Pro Blend top lube.

The Aeromotive pump has been reworked this year (2010) to now have mechanically fastened magnets, a previous weak spot for these pumps. With its new redesign, it is now our recommended pump. You must run a -8 (1/2") inlet system to help prevent cavitation. This pump has very high quality bearings and components that simply do not wear out. Send it to Aeromotive during the off season, and this pump can last for years. This same pump works both for fuel injection and carburetors, although it will generate over 70 psi, it's flow is no more (well maybe a little) than the pumps many carb guys use.

The Fuel Filters: Elements: With our methanol fuel, paper or plastic elements will not work, after a race or two, they will choke off the delivery system to catastrophic results. Stainless steel is the only material that works. You need two filters, a 120 micron before the pump to remove the large particles but still allow good free flow, and a 25 micron between the pump and the fuel rail. If you put the 25 micron before the pump it will cause the pump to cavitate and destroy it rather quickly. The two elements can be identified by closely examining the element mesh, the 25 micron has a finer closer knit mesh.
Capacity: Our filter elements are pleaded to provide maximum surface area enabling tons of particle entrapment without restriction. 6" long x 2-1/4" filter bodies provide plenty of storage and house a big element.
Cleaning: The 25 micron filter must be cleaned every 2-4 weeks and the 120 micron every 4-6 weeks. If you clean the element with an air hose, blow it from the inside out, the particle swill be on the outside of the mesh. The best way (and really the only way to clean the 25 micron) to clean your filters is with an ultrasonic cleaner, this is the same thing jewelers use. We sell a low cost ultrasonic cleaner and the cleaner fluid to go with it. You can also use this cleaner to clean your injector nozzles and your wife's jewelry.

The Fuel Regulator: The regulator is responsible for controlling a constant fuel pressure between the pump and the regulator. Generally in a two port design, it is placed after the fuel rail, see our fuel delivery diagrams at the top of this section. They can be adjusted from low to high pressures by the turn of a set screw, and bypass all the unneeded fuel back to the tank through the return line. A general setting for Hyper Racing fuel injection is 60 psi, although when we dyno tune each engine we may change the pressure setting. After a dyno session, we ask that you do not change this setting.

The 1/8" NPT port on the front side of the regulator is where a fuel pressure gauge is installed. The small nipple coming off the side of the regulator is merely a vent and needs only to be tightened. We have seen no advantage to tying this into the vacuum lines on the throttle bodies. Viewing the regulator as pictured in the image below, the left port is the inlet and the right port (hidden) is the outlet leading back to the tank tail.

The FueLab regulator can be purchased in three configurations, two port for injection, three port for injection, and a three port for carburetors. The two port is the normal regulator we sell on our fuel injection fuel delivery systems. The three port design is used where a dead head style fuel rail is used, like those used on the factory motorcycle engines. The only difference between the carburetor and the injection regulators is the spring inside, the spring is what regulates the pressure "pop off", a light spring will allow low fuel pressures. The carburetors regulators are a three port design since there is no flow through rail. It utilizes a return line to the tank for the unused fuel.

The Aeromotive regulator comes in a three port design but we just plug the one side port to make it a two port design if we need to. It is a fine unit, just more expensive than the FueLab and does not have the two year warranty.

The Fuel Tank:In recent years almost all tracks now mandate a bladder of some sort as a safety zone. When this change occurred, Hyper Racing developed the Fuel Forward Tank Tail, a revolutionary tank that keeps the fuel low and forward, two critical areas of focus for optimum chassis handling.

There are two styles of bladders available for the tank tails, an orange one made by Alliance Performance Group (APG) and a black one made by the manufacturer of the tank, Fuel Safe and Saldana are the two big manufacturers. The orange bladder, although it is known to seep fuel, is lighter (by at least two pounds) but more importantly holds up better to methanol. The black tanks break down and turn the fuel black, particularly when new. These tanks will eventually break down and can cause fuel problems. The APG (orange) bladder will not do this. The APG bladder is also more expensive.

The tank tails with bladder kits come with a -6AN bulkhead outlet, however a -8AN bulkhead is available. If you are using a Walbro or similar pump, the -6AN outlet is used. If you are using an Aeromotive or FueLab pump, a -8AN bulkhead is needed. Keep this in mind when ordering a tank.

Pickup::An improperly installed pickup hose can cause intermittent, hard to diagnose problems. If you are purchasing a Fuel Forward tank tail with a bladder, it will have the pickup installed, it is installed correctly, all you will have to do is tighten up the pickup and the bulkhead fitting. They are not tightened when you receive the tank. If you are installing your own pick up, ensure it is long enough to lay on the bottom of the tank and also to make sure the end of the pickup hose cannot suck  to the inside of the tank.  There are two common ways to prevent the pickup hose from sucking to the inside of the tank.  One is to cut the end of the pickup hose in a V shape. The second way is to use a ½” NPT x 3/8” Barbed fitting (Hyper Part # 816-105).  Drill four to six ¼” holes in the ½” NPT portion of the fitting.  Then insert the barbed section of the fitting into the end of the pickup hose.  Our customers have had almost no problems with their pickups when one of these two methods is used.

Fuel Delivery system Maintenance: Methanol is a very dry fuel with no lubrication such as that which is present with gasoline. For this reason we highly we recommend Pro Blend top lube. It will help lubricate your pump, regulator as well as help keep that white chalky stuff from forming. That white chalky stuff occurs when the methanol evaporates. The trick is to not let the methanol evaporate, keep your fuel system filled with methanol, if you clean a fuel filter, replace it then turn the pump on and remove all the air from the lines immediately. For more information on fuel delivery maintenance go our fuel injection maintenance page.