Does anyone here care about gas mileage or is everyone hell-bent on acceleration? I recently upgraded my air filter, y-pipe and exhaust with a K&N/JIC/Amuse R1 combo for looks, sound, and power, and my normal mileage went from 25 to 27. So with $3/gal gas prices, are there things that you've done to improve the Z gas mileage, intentionally or otherwise?

 

I have a Popcharger and Nismo cat-back. Havent really done any tests as of yet, stiff loving the new sound too much But I am driving from San Diego to Virginia Beach on Tuesday and Ill be logging everything.

 

Allright, I'll add one more. Changed over to Mobil 1 oil and filter yesterday and took the same trip to work and back this morning (minus the working), and saw 28.8 mpg avg. Not bad at all considering I was going to change the oil anyway. So between the exhaust and oil (and the engine being broken in), I picked up almost 4mpg. Anyone done any other mods with fuel economy in mind?

 

28.8 mpg? That's amazing considering im avg about 17 i believe. I should really stay off the gas pedal, but i just can't help it.

 

I heard the HKS hyper voltage thingy II improves mileage.. but noone has really given any hard numbers yet to justify the $500 + to get one :P

 

Heah, I heard about grounding systems. Unless there's something already wrong with one's wiring (old and rusted) grounding systems are a waste. We did some testing over on the SpecV forums, and there was absolutely NO benefit for new cars. I wonder if iridium plugs or the new CD ignition system I saw here recently would have any effect on mileage. I would much rather give my money to a high tech Japanese firm than a camel jockey, anytime.

Yea, 29 mpg is only a dream when I put my foot in it, but as long as I just keep up with traffic instead of trying to race everyone, it is nice.

 

Don't flame me on the looks aspect, but lower your car and give it a slight rake, with the rear slightly higher. Add a front air dam and side skirts, and it will pull the car even lower on the highway, reducing the undercar turbulence. I do not think getting 35 mpg on the highway is too dificult with the right mods, and 40 is not dreaming.

 

seems about right, i average 17-18 if i drive the way i like. but if i treat the gas pedel like it was glass and skip shift (1st,2nd,4th,6th) i can get as high as 30

 

then why even drive a Z? buy a civic hybrid

 

Because a civic doesn't look like a Z?

 

Because only getting performance and not efficiency is a thing of the past. 300hp and 30+mpg are possible on this engine, and both at the same time if you work on it.

 

I see that the HKS Twin Power DLI II has a lot of potential for improved gas mileage due to higher ignition energy and hence more efficient combustion. I just ordered it with the Denso Iridiums. I will post the effect next weekend after I install these and have a chance to put some miles on it. I doubt the combined cost ($583.) will ever be made up by the improved gas mileage, although several have claimed improvements of 3+ mpg in a recent thread. But then again, I would rather pay my money to Japan than to the middle east.

 

cruise control is ur best friend. I skip gears like 1 3 6 on highway or 1 3 4 below 35mph. I got a 5 mpg boost just by doing that. I average 22 mpg w/ heavy city style driving.

 

only if you drive heavy freeway with no traffic. once again all your efforts are going to be negated by the cost of the mods your trying to do in the first place. Kindof seems silly to me. Getting the 300hp and ~ 22 mpg is great efficiency when you factor in ac and the high gearing we have. You want to save mpg? drop your gear ratio, but then you have a slow car imo.

 

Synthetics are suppose to reduce friction and improve MPG. While VQ engines are rated for X-W30 oils, Fords are using thin 5W-20 oil to improve their fuel economy (some would say at the expense of engine logevity, but most of the time the engine will outlast the rest of the car).

 

Check your tire PSI they could enable some gas mileage. Also try to use cruise as possible.

 

I noticed a nice improvement with high flow cats.

Synthetic also helped.

I consistently average 25 mpg city/highway and redline at least once a day.

 

My mileage went up a few points with MREV2 and 5/16" plenum spacer. Because I'm running lean... but not for long. Soon my gas mileage will suck again but I will be making much better power

 

+1 . Leaned me out a little too (+.5 accross the band), I/E musta already had me a little lean cause although where it's at now is still safe for the motor, it's too lean for my taste. Adding hfc's and a tune myself in short order. For the sake of this thread though, breathing mods would be the thing to do to get fuel consumption down. Some cars seem to adjust a differently than others though so I would recommend adding the mods and then checking a/f with wb's or at a dyno to make sure you don't get so lean you hurt the motor.

 

I've seen a lot of threads regarding going lean after breathing mods. Why is it that the ECU doesn't compensate? Isn't this a closed system with the O2 sensors and MAF? If it's not maintaing A/F, what exactly is it doing, anyone?