You can also take 100% acetone from your paint supply store or beauty store and put about 2 ounces to a full tank of gas. The acetone actually helps to better atomize the gas which will actually give you about a 7-10 mpg. That is the gain that I have experienced in my 99 chevy blazer.

 

so what are you getting for total mpg? 24-27? i don't see that as being possible with an auto 4.3L

 

If some other people try the acetone and their car doesn't blow up, i might try it.

 

yes and no... there is a silencer on the front of the box(or at least there WAS on mine) that restricts airflow but quiets the intake noise.

They have to design an air intake wich keeps in mind all of the 'normal' people who buy these vehicles and don't like to hear these noises from their engines.

With the stock airbox, silencer removed, and k&n drop in I see ~2 degree temp differences while driving between intake temp and outside temp. so factory air intakes now adays are designed as a 'cold air' sort of deal. The best improvement will be illuminating the flexy piano tube... IMO

little off topic but my old 5L got (dyno'd) 14hp by just removing the air silencer in the fender. goes to show what company's do to 'quiet' what they can

 

I have a 97' Blazer, does that mean I cant get PCM tuning?

 

How much of a difference would it make to run a electric radiator fan instead of the stock pulley fan?
MPG and HP wise?

And I'm trying to find out if my 1998 bravada has a intake silencer , I couldn't find any pic's of them on google.

 

According to Wynjammer, a company that makes super chargers, the E-fan swap makes a 12+hp difference. I'm not certain how accurate that is, but I would imagine that it was done with some dyno testing considering the source.

The intake silencer is the small tube on the front of the air box that has the rounded mouth, like an aeroport, and is narrower at the mouth than where it meets the box.