Mirage Turbo/Colt GT

I have noticed some guys we are racing against have wired the alternator to a shut off switch and only turn it on during caution laps . We dont have any accessories running except the fan and we dont use it very much since we put in the bigger rad . Is there much of a HP gain to be had by doing this with our cars , if so how much ?

It is suppose to help, just beause there is less of a load on the engine. I am not sure how much hp you will gain, but I have heard people compare it to driving with the a/c on and off.

When I was young our family went to a dam one year. They had a modified exersise bike there with a generator on it to show poeple how much power certian items in there house were drawing. You could run a small radio, one light, or try for a tv. Pedaling and powering the radio was no problem, but most people couldnt even do the radio and light bulb for a couple minutes. When people fliped the switch to turn the tv on the generator was acting like a major brake and nobody made it work.

You still have the belt pulling the internals of the alternator, but obviously without much resistance when the alternator is not charging and manipulating a heavy field of energy in the windings. You might gain a little horsepower, but your electronics run better and your ignitions is stronger when you have better voltage to keep things stabilized. That's what I would have thought anyways.

With a fuel injection car it will probably hurt you.

Fwiw, the mitsu ecus use battery voltage to base the injector pulsewidths off of, along with other parameters.

you are better off keeping the alternator on, if it costs even 10 hp, it is still worth the 10 or 15 it will give to keep the ignition, fuel pump, ecu and injectors happy at 14 or so volts (as opposed to 12.7 or less)

This is one of those areas where I'd feel better knowing what the professional racers are doing. Or at least hear from someone that has tried back to back tests to compare.

In theory, you want to supply the ignition system with as much voltage as possible. But in reality, you just need enough to keep the spark from failing. Starting the car and letting it recharge for a bit after the starter sucked down the battery a bit should be good enough. Then recharge between runs.

Anyone killing their cooling fans during 1/4 runs?

Most of our races are fairly short 10 to 20 laps on a 3/8 mile oval that we are getting around @ about 18 seconds . What would be the down side (damage) by trying this besides wasting my time and possibly slower lap times ?

Possibly damaging any of the sensors, or anything else electrical (including your battery) I wouldn't do it for any miniscule gains you might get why not get some under drive pulleys machined or adapt some from a 4g6x and keep all of your electrical system in check.

This is an absolutely terrible idea.

Thanks for all your imput and and you have convinced me to look else where for cheap horse power .

nascarcolt.

it seems like it would stress the battery over time also

Look I'm no Race-r, but when I had a bad altenator it felt like I had lost power...even on a full charge of the battery. My on-boost powerband completely sucked. Not quite 4g15 sucking but close...Mitsus rely heavly on a nice charged battery and a good altenator. Take one of those out of the mix and life just sucks.

Your car probably ran like crap because because the voltage was so low the sensors and fuel pump weren't functioning properly.

On our K series N/A race cars, we are going to eliminate the Alt. We are just going to use a 16 Volt battery so the car will have the juice it needs to run properly.

http://www.apexbattery.com/car-batterie ... eries.html