I bought my 94 Z28 about 3 weeks ago. My goal is to get over 20 MPG on the highway. Next weekend I am driving from San Diego to San Francisco to Sacramento and back...

First full fill-up I got 14.9 MPG. Second full fill-up I got 14.7 MPG. Both times I was doing about 60% Freeway/40% City.

I used the Seafoam product that most are aware of on this Forum. I ran it in my gas, oil and brake booster vacuum line. I also used the Seafoam product in my throttle-body.

First fill-up since using Seafoam and I was able to squeeze out 17.4 MPG (60% Freeway/40% City).

Second fill-up 18.9 MPG (80% Freeway/20% City). Still alot better regardless.

Third fill-up and I got 16.2 MPG (back to 60% Freeway/40% City). I also have been a lot more comfortable stepping into the throttle :-)

I am looking into a CAI. I will also inspect the spark plugs, cap and rotor. Any other suggestions? (Nobody better tell me the Tornado!)

 

Id say that sounds like bad mpg's but my 97 had full intake and exhuast, on the highway I could see upwards of 25mpg, the highest i think i saw was 28.xx or 29.xx is that a manual or auto? Mine was the 6 speed.... sold it b/c of gas

 

I have heard of a lot of people getting under 19 MPG.

Mine is an Auto which probably does not help.

 

Thats really wierd im not gonna lie, i sold it because i thought 15-16 in the city was bad..... Although to be specific my car had a bigger t/b and after the y-pipe there was no cat and it was 3" the whole way back.... I guess id tell ya to get an exhaust!!

 

Yep, that's another pole I have running. I am looking around for a good used cat-back (preferebly Flowmaster for sound/resonance).

 

CAI, MAF,intake eblow,TB, fullexhaust and even if you tune your fuel management you should be able to get the mpg you want and add some hp.

 

TB won't make any difference in power unless you're making 350+ RWHP, a whole new MAF is pointless, you can get the same gains from a new MAF housing that has a larger diameter (see mid-america motorworks, they make one for the LT1 vette that will fit, dyno proven by Corvette Magazine for the advertised 7RWHP 9RWTQ)

That being said, I don't think that mods will get you any better fuel economy. The concept is great, but the amount they actually get you is going to be negligable, plus, when you get more goodies on the car you're almost always on it harder because we love power

My MPG (Z28 A4) is usually around 15-16 all city, if I go highway I can get around 23-25

 

Id have to disagree. A better flowing induction system/exhaust will help fuel economy. As for the TB its not much for hp as it is for flow.

 

Theoretically it will help, I can tell you for a fact when I bought my Camaro and it was stock I got 15-16 city and 23-25 highway and to this day with my mods i get the exact same MPG, I check how well I did every time I fill up the car.

 

maybe as you modded your foot got heavier.