Backed out the air mod saturday afternoon, the power dropped slightly but noticeably especially at lesser levels of gas pedal. My mpg has increased for my work commute (about 2 mpg), which is essentially a big long hill climb (7 mi) into work.

I can't say for sure why but offer the following uneducated guesses:
o - the computer compensates for the greater air intake by changing the mixture, which provides more power which translates into lower mpg if you use that power which I certainly did as my hill climbs tend to use whatever the engine can produce.
o - more ICE power means a relatively smaller IMA contribution, bad for me as I rely upon the IMA on my hill climbs.
o - less willing throttle simply means I accellerate slower without the mod and unwittingly drive more efficiently without it.
o - increased power would tend to adversely affect city driving (which is what I saw). but for underpowered cars it could increase highway mileage as underpowered engines are not operating at optimum efficiency at high speeds, thus accounting for ducs observations. The same is probably true of the muffler mod.

My conclusions based on our small sample size: if you do a lot of highway driving at high speeds, or just plain want more power, these mods are for you, but if it is a mix, or you have a lot of (big) hill climbs, then they may be a net mpg loss (small loss however).

YMMV, I will be interested to hear what happens to others when they try it.

Hey malditos, what kind of driving do you do? Would like more info to try to understand why you are seeing the increase after the mod.

 

well kmh3, the city where i live in is only 2 miles long.... that is, if you start at one edge of the city, you only have to travel 2 miles to get to the opposite edge, regardles of which direction you're traveling in. I use my car mostly to commute to work... which sometimes it may be 1/8 of a mile away to 2 miles away (my job requires me to be at different sites in different days). I guess you could call this Extreme City Driving as the car does not really get used in long trips as much as it does for short ones. Another thing is that I live in a desert and the temperature changes quickley in October from Freaking Hot to Freaking Cold, which is cool with me as I prefer the cooler weather. We also live, I beleive, two feet under sea level so the air pressure is kinda heavy. The other thing that really kills my mpg's besides the use of AC in the summer are the trips over the border, as I live in a border town to Mexico. When I travel over there and come back, I'm usually stuck between 30 to 80 minutes in a slow moving line to cross through inspection. When the wait is not too long, I usually drop about 10 mpg's, otherwise it can go up to 15.

 

Hey Duc, I've been trying to find a coupler to fit the air filter into the intake of the engine so that it just wont' be hanging from the plastic intake. If my calculations are correct, I need a 2.25 pipe to 3 incher right? Do you know where I could get one, preferably one that is bended because my filter hits the hood whenever I close it.

Also, regarding the muffler, did you simply cut the pipe after the cat converter and adapted the new muffler to the smaller diameter of the pipe?

 

So if I am reading this correctly you have your filter hooked directly to your intake manifold or you want to do this? I have seen small to large adapters at Auto Zone. Why don't you just attach it to the hose (like mine) and secure it so it does not/cannot move around?
The stock pipe bolts up to the CAT so I cut off the adapter (from the stock pipe) and welded it to the new exhaust so I can/could unbolt it if needed.
Clif

 

I have it hooked up exactly like you do Duc, it's attached to the plastic tube that used to hold the old air filter. The thing that I'm worried about is that the the cone filter touches the hood of the car and it seems to me that the hood seems to make a little pressure when on the filter and could damage the plastic tube in the future, besides, the whole part of the filter that is facing towards the hood does not get as much air as the rest of the filter. I've been to autozone but they don't seem to have the appropriate diameters for the couplers.

Good to know about the muffler, I'll be ordering mine today.

 

Mine doesn't hit the hood, odd.
Is yours on evenly all the way around?
Also if you look closely at my pic you sill see where I used 2 blue (around the end of the filter) and 1 black (going through the blue and to the metal frame below filter) to secure it. Did you do this or secure it in any other way?
Clif

 

I have not secured it at all.... perhaps that's the problem... so is it ok If i just leave it how it is and don't worry about coupling the fulter to the hose with some kind of bended tube?

 

Mine has been this way since Apr with no problems at all so I would say, yep.
Clif

 

Did you install the exhaust yet?

Clif

 

due to some technical difficulties (I'm Broke) I hadn't had the money to buy it... but I just got some $$$ today and just ordered it online from the same place you did. I beleive I'm going on a crosscountry trip next week, California to Massachusettes and back in 8 days... we'll see how that goes if the muffler gets here in time to be put on....