Booztd 3

iTrader: (15)

Guys

I've been doing alot of research on peoples gas mileage and how their car reacts to it, from the mods they've installed, but I'm still a bit puzzled on my gas mieage and its current state.

Around the time of the MOD even in Normal IL, I had works flash my ECU with a P2R unit. I had the Megan Turbo-Back setup on pre-order so I told them to flash the ecu for that as well. My gas mileage was doing really well after that point. i was still managing around 280-320 miles to the tank, mostly highway miles.

After the exhaust showed up a few weeks later, I installed it. Almost as soon as I put some miles on it, my CEL showed up, and I figured it would happen. I then ordered a Perrin o2 Sim for it. The whole time I had a CEL i was getting really crappy mileage, and I figured it was just because the ECU was richening the car up. I installed the o2 sim a week later or so, and cleared all codes. After this I still am managing really cruddy gas mileage. I have a 45 minute drive to work which is COMPLETELy highway miles, and cruising about 70mph with no boosting at all really, I manage to get just over 200 miles to a tank. I had the car in at Mitsu the other day for some other work being done, and I had them check the codes just for reassurance and it wasnt pulling anything up.

Anyone have any ideas? I'm debating selling all the aftermarket parts and going back to bone stock to regain my gas mileage.

MM Racing

iTrader: (6)

I get about 265 to 13 gallons with almost entirely highway miles. 100 miles a day. I have the AMS full exhaust and a MBC set at 18 that is all. But FYI gas mileage always suffers when it gets cold and they switch to cold formula gasoline.

sleet

iTrader: (9)

Did you do any runs to hear how the exhaust sounds? I know when I first got my exhaust my gas mileage went down because I was getting on it to hear it. I get about 24MPG with all my mods, it all depends on how you drive.

Booztd 3

iTrader: (15)

This wasnt just a one time thing........i stated in the post that I drive 45 mins to work every day all highway miles, little to no boosting, and at 70mph.......

use2vtec

iTrader: (4)

When I did my turbo back exhaust on my stock ECU my car was running pig rich and getting poor gas mileage. Once I sent my ECU out to get reflashed I started getting good mileage again. You just need a reflash.

silverEVO8

iTrader: (12)

You've got to get some more accurate measure than gallons per tank.... Are you running your car with a full tank until you run out of gas on the road? Anyway, take the time and small effort to actually record your miles between fill ups and the actual amount of fuel consumed. It's possible that your gauge is not showing a true picture of your gas situation.

Now, it's quite possible that your new combination of mods is causing excessive fuel consumption, but it might also be that your ECU needs to "learn" the new mods and the gas mileage will stabilize. FWIW, since I put my exhaust back to stock and had the car retuned (it was actually running too lean and had to add more fuel..), I'm getting about 27.5 mpg highway and 22.5 inb a mixture of highway and city driving. Oh yeah, it really helps if you stay off the loud pedal .. I've found that even a few starts with boost and WOT will shoot the mileage all to hell.

Booztd 3

iTrader: (15)

I run the car until the gas light comes on. I know that there is typically a few gallons left in teh tank at that point, however I dont calculate it that way. I know that I generally fill up on 11.7~12.2 gallons of fuel, and If i divide that by 200 miles, thats anywhere from 16 to 17mpg

I keep stressing this, i am NOT running the **** out of the car. I have a 500rwhp 300ZX TT I can go tear into if I wanna get nutty, and having said car, i obviously know that if you keep outta the boost, the fuel economy will improve greatly. I have specifically been keeping out of boost so that I can accurantly monitor the gas mileage the car is getting. This wasnt like a one time "i got crappy gas mileage" post.......this is a ......I fill up 2-3 times a week, sometimes 4 and its been that way for a few weeks now