"Finally, I believe a lot of guys are sleeping on their headers. They've bought something out of a catalog, bolted it on, and not thought much else about it. We have one header that we developed out of the Midget program. We've flanged it up for a stock Ford four-cylinder head and found as much as 13 hp in many applications. It is a stepped header that goes from 151/48 inches to 131/44, to 171/48, and it really builds the power in these engines.
"Also, you can gain power where you need it by putting some thought into the pipe you are running from the header out. I'm talking about the exhaust pipe that runs from the header collector to the exit of the car. The longer that pipe is, the more low-end power you are going to gain. If the pipe is shorter, it will move the powerband higher in the rpm range. Generally, the pipe should be between 3 and 4 feet. I know we have customers that will change the length of the pipe depending on the track they will be racing. If it is a small track with tight turns, they will run a longer pipe. If the track is bigger with sweeping turns, they will shorten it up."
DEPEND ON THE BATTERY
Just like the water pump, an alternator is a drain on the engine's power. In many cases it is necessary because it continually recharges the battery, which enables the ignition to provide an adequate spark to the combustion chambers over the course of a long race. But if you are running 10- to 20-lap features, you may be able to get by without an alternator.
You can get away with running short features without an alternator, but you'll have to charge the battery before every race to make sure it is at full power. To have an additional safeguard against battery failure, install two lightweight batteries, such as those made by Dyna-Batt. Two of these weigh as much as a regular store-bought one and you'll always have a backup. Often, racers find that it isn't worth the trouble because forgetting to charge the battery means being significantly down on power by the end of a race. But if you are looking for every advantage for the last race or two of the season, ditching the alternator might be worthwhile.
Electric Cool At the beginning of this article, we stated that you will need to pick and choose which of these tips will work for you. Some of these tips won't work well together, and this one is an example that definitely clashes with the idea of ditching your alternator.
Switching out a mechanical radiator fan bolted to the end of the water pump for a fan powered by an electric motor can potentially save you several horsepower. Using a fan attached to the motor to pull in air through your radiator is a big drain on power, and the higher the rpm, the greater the drain. You can think of an electric radiator fan as an additional engine under your hood. The only drain on horsepower is the added load on the alternator, but this is much less than the drain caused by a spinning radiator fan. Generally, an electric fan placed behind the radiator (called a "puller") is more efficient than an electric fan placed in front of the radiator designed to push the air through. This is because the electric motor in the center of the "pusher" fan blocks some air trying to get to the radiator.
This tip will not work with our previous tip (ditching the alternator) because an electric radiator fan places an additional load on your race car's electrical system. Powering the ignition system and an additional electric motor at the same time for an entire race is simply too much for a car battery. In our experience, if you are currently running both an alternator and a mechanical fan, keeping the alternator and adding an electric radiator fan in place of the mechanical unit is definitely the way to go.
Oiled-gauze air filters are...
Oiled-gauze air filters are the best and offer the most protection for your engine, but they can cut airflow to your engine if not properly maintained.
We all know that oiled cotton-gauze filters work better than the cheap paper filters sold at discount auto parts stores, but oiled filters don't last forever, either-especially if they aren't properly maintained.
"You might not believe this, but I found over 100 hp once by changing the air filter," says engine builder Dennis Wells of Wells Racing Engines in Duncanville, Texas. "That was a worst-case scenario, but it can happen. The guy who owned the car knew the engine was down on power, but he couldn't figure out why. He had already changed the carburetor, the distributor, plugs and wires, just about everything you can think of, before he brought it to me."
"I put it on the dyno and it did the same thing until I took the filter assembly completely off, and then it picked right back up. He had been washing his filter with dishwashing liquid, which is a big mistake. You have to use the cleaner made for those filters. Using dishwashing liquid or hand soap causes that material to mat up, and it won't flow air. When you take care of those filters properly, they will last a long time. But if you have had yours for a while, you might be able to pick up a little power by replacing your old filter with a new one."