Carburetor Class: Methanol in Drag Racing

 

In order to be a successful bracket racer you need to be consistent. When .001 of a second matters any edge you have is valuable. One way to make your car considerably more consistent is to use methanol instead of gasoline. Methanol is the molecularly simplest, lightest form of methanol and is most commonly used in racing. Unlike gasoline or diesel fuels, it contains no lubricating characteristics, so it’s mixed with a lubricant additive. It’s legal for use in all bracket racing classes. Your speed won’t increase, but a quicker E.T. is pretty common.

 

First off, you can’t run methanol through a carburetor built and calibrated for gasoline. The increased fuel consumption calls for completely different metering blocks, boosters and needle and seats. Holley carries three carburetors that come ready to run with methanol: two hp 4150 models, a 750 cfm (P/N 80535-1) and a 950 cfm (P/N 80498-1). A 1,050-cfm Dominator (P/N 80586) is also available. These carbs come with stainless steel needle and seats, correct metering for methanol, 50cc GLFT accelerator pumps and upgraded boosters. Holley is currently expanding its new all-aluminum Ultra HP line with models calibrated for methanol and E85 fuels. These carburetors come in Hard Core Gray hard anodized finish.

 

The hard-coat anodizing makes them ideal for alcohol applications.

Here’s Holley’s all-aluminum Ultra HP; models for alcohol and E85 blends are coming soon. The hard-coat anodizing makes them ideal for alcohol applications.

 

In addition to the carburetor changes, you will need a fuel system to deliver twice the fuel of a gasoline engine. Generally you’ll see a front-mounted fuel cell in serious race cars because it’s less taxing on the fuel pump. Methanol can make plastic, rubber and even some metal components break down, so choosing parts that are compatible is very important. Holley’s HP 125 and HP 150 electric fuel pumps work great for methanol applications. A single HP 150 fuel pump with a front-mounted fuel cell can easily support 750 hp.  A new line of billet HP and Dominator regulators and fuel filters safe for methanol is available. All of the Earl’s fittings and hoses will work with methanol, though Holley’s Ano-Tuff hard anodized fittings will exhibit a longer life. For lines, the Pro-Lite 350 hose also will outlast the others.

 

Because there is so much more fuel going into a methanol-powered engine, tuning is easier to accomplish. It takes such a significant air change to affect air fuel ratio that it is possible to run the same main jets with the same tune all year. As an evening race progresses, gasoline engines need to compensate for the cooler, more dense air of the night. A methanol motor won’t need any changes, making it substantially more predictable.

 

Here you can see the size difference between a main jet for a gasoline-calibrated carburetor (left) and one for alcohol (right):122-87 (gas), 122-180 (alcohol).

Here you can see the size difference between a main jet for a gasoline-calibrated carburetor (left) and one for alcohol (right):122-87 (gas), 122-180 (alcohol).

 

Methanol-fueled engines also run much cooler than gasoline. Even with a pass every 15 minutes it’s hardly necessary to run the cooling fan. While the gasoline guys are draining their batteries running water pump and fan, the methanol guys have time for other tasks. Because engines run cooler, they  need assistance to warm up before a pass. Since it’s hard to overheat, it takes longer to warm up, so a lean out valve is used. It’s basically a controlled vacuum leak that can be a ball valve or an adjustable valve, sometimes controlled by the driver in the cockpit. Being able to control the temperature is another contributor to increased consistency. Another advantage is increased torque making for better 60-foot and 330-foot times. These improvements help when it comes time to dial in.

 

High-compression engines benefit the most from a methanol fuel. The sweet spot is between 12.5-15:1 compression, but methanol is often found in engines 10-17:1. To safely run a gasoline engine with this kind of compression you would need to run high-octane racing gasoline. The advantage is methanol fuels are around $2 per gallon, and comparable gasoline is upwards of $9 per gallon. Even though you’re using twice as much fuel, it’s still a better deal.

 

There are disadvantages to methanol. It’s extremely corrosive, making it hard on parts. Any part the fuel touches will have a reduced lifespan. There are products designed to endure this aggressive fuel, but the fact that methanol absorbs water makes it especially destructive. It’s inevitable that upon startup, fuel will leak past the rings and enter the crankcase. Methanol by itself wouldn’t be too much of a problem in small amounts, but the water it carries is. More frequent oil changes are required to keep the engine healthy and clean. Many owners will drain their fuel system after each event to help extend parts life. With the necessary changes to the fuel system and proper maintenance, methanol is an excellent fuel for drag racing. Methanol is an effective way to produce more torque, keep cool, lessen fuel costs and most importantly, become a more consistent racer.

 

By Liz Miles

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