Did a search and I didn't really find anything relevant, apologies if I missed something. About 7 months ago, I bought a 2002 with about 25k miles on it (it now has close to 30k, love this car . . . ) It came with:

Stage 1 GIAC tune
EVO headers
EVO exhaust
EVO Performance Exhaust System
EVO Venturi Intake
EVO Billet Diverter Valve

So, the car is essentially "done". Since then, I have only replaced the intake with the stock airbox. I do realize that we don't buy these cars for gas mileage, but I noticed I was only getting a little over 150 miles on a tank of gas (not putting my foot it in and tootling around town). I have been conducting an experiment, where I flashed back to the stock SW and (while trying to drive as similarly as possible), it isn't difficult to get over 200 miles to the tank. Finally, my question:

Is this negative MPG effect "normal"?

Of course I expect crappy mileage if I'm driving like an idiot, but in a normal week, I can find myself in 2nd gear going from LG to San Jose on the 880 . . . Not a lot of boost going on there Thanks for the thoughts, I'm wondering if I should be considering a different tune. Thanks! KH

 

I can only give my personal experience with two tunes I've had vs stock
a. Stock tune no mods, combined 17mpg
b. EPL tune, exhaust , combined 16-17mpg so no big difference other than the 30-100mph pull
c. GIAC tune, K24, 60lbs injectors..... 15 mpg combined and 18 mpg highway (and my miles to empty fuel gauge all screwed up)

Sounds like the slower moving speeds and 2nd gear usage of the area you live may be a contributing factor

 

Yeah, I guess I don't mind so much the total miles/tank and while I can't claim that I drove identically, I do believe I was at least consistent. It just seems like the only real change was the tune, I imagined (pure speculation) that it wouldn't have made much difference going to back stock as I wasn't into boost in either scenario. But this experiment proved otherwise . . . Thanks! KH

 

I've got a tune on my car although I'm not boosting past .9 right now. I get a good 180 miles on a tank with gas left in the tank when I fill. Dash indicates 18-19mpg but I've got injectors and don't rely on it. I'm getting about 17mpg I'd estimate and that's both heavy traffic and WOT every chance I get. You're MPG sounds a little low to me.

 

I have an 02 x-50 with GIAC tune peaking @1.1 bar and I get ~16.5 mpg with 70% city and 30% highway mix. If I am all highway I get 17-17.5 mpg and rarely see 200 miles in a tank

 

I get with my 18g set-up with 72 injectors ,,23mpg on the highway at around 75mph AND in the city 13mpg..
When I had back in the day the stock K24 with my GIAC tune and exhaust ,, 26 on highway and 14 in city..

 

my avg is 17 but only with a lot of fwy driving which i dont do. most I've ever seen is maybe 20? my normal is 12/14mpg and that is it! i literally fill up, for a circuitous mountainous drive and end up back at the filling station to topoff will have used btw 1/4 and 1/3 tank.

still I'm gonna have fun while i still can. in oregon they are testing a drive by mile TAX ...and talking about it here. it's comin' fellas

 

OP - if your GIAC tune is one of the really old ones they run very rich.. I mean really rich with lambda sub 0.77 and fuel mileage will be poor to very poor

On E85 and a 16 gallon tank TTS I get around 11 mpg.... on 93 octane I get closer to 19 mpg on a highly tuned car

 

Sad thing is we ALREADY pay a drive by mile tax. It's called the fed and state fuel tax. Every gallon we buy we pay taxes on. The more miles you drive the more tax they get. Government justs bends us over at will. Don't even get me started.

 

lol, i know i started it. sorry. this ( as i'm sure you know..) is in addition! to the fed/state taxes we already pay!

beneath the guise of protecting us from ourselves "they"? will legislate the last of our freedoms in the form of another tax. in this case, the sunday drive will become even more of an economic decision beyond the usual "gee honey, can we afford the gas?"

it will also of course impact our insurance rates clever huh?

add: apolgy to the OP for the OT rant, and i dont even have a giac tune. truly sorry

 

Just by the smell alone, I would say I am running rich . . . What is considered really old? The receipt says the tune was done 4/2006, which seems like an awful long time ago. Thanks for the input, this is exactly the kind of info I was looking for! KH

 

No worries, I feel your pain, Brother!

 

That's old. Garrett has updated the file many times since then

 

Sorry for the dumb question, does GIAC upgrade to a different owner? Maybe I stay with GIAC since I already have the dongle? I'm being lazy, I know . . . KH

 

Call them , they are very friendly guys. I doubt it would be free but maybe a discount for repeat offenders.