Not sure if this is true or not. My younger brother has been an LT1 fan for years. He's been buying nothing but LT1 police cars for the last 3 years.

According to him, he was told that before your going to race someone, turn your heater control to vent. I asked him why and the responce, as it was explained to him was " It keeps the main rad fan from turning on when it gets hot. Less things for the PCM to think about and changing the air/fuel mix, timing curve etc...to compensate for the engine temp."

Is there a secondary fan in there? I haven't had a chance to look. Or is it sending a message to speed up the fan rate?

Now I was always under the assumtion that the fans are electric. How could this be any benefit or not when the load isn't on a pulley with a clutch fan?

Could this be some sort of urban legend or an actual fact. Inquirering minds want to know..lol

Thanks Nanook

Sounds like a myth to me. I can't imagine the PCM processing capacity being so close maxed out that it couldn't handle a couple additional tasks without affecting fuel/air curves. I've always thought that there may be some small advantage to having the heat cranked on any of the "economy" settings. My logic is that it removes heat from the engine cooling system and pumps it into the interior compartment. Not much for comfort, though. To think that there would be a noticeable performance gain is probably a stretch. It is important not to have the air conditioning or defrost on because those use the compressor, which does produce a noticeable parasitic loss. (There's my two cents...)

There are two fans up there. If the car isn't hot the fan wont be on anyway. When I go to the track and make a pass,I turn the A/C on and let it run till I get back around.That way the fan comes on and helps cool things back down,me included.

.............hmmmmmm, I'm going to check into this further!