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Discussion Starter · #1 ·
i'm getting VERY low gas milage, and i think its partly due to the car running abit rich. heres why: i think the unichip isn't mapped properly (not sure which way, but maybe its mapped for the wrong octane) i also think the ecu is pulling timing a bit, especially when i go WOT (cause you can feel it most then) and that may also be the cause why i feel some loss in performance.

possible solution: do you think that re-gapping the spark plugs at a higher setting might do a better job of igniting the air/fuel mixture? i have the NGK colder range spark plugs gapped at .28 right now. is it possible that because of the grounding mod i did, that there is less resistance/interference in the wires, and therefore the spark plugs might be in need of being re-gapped? my basic conception of this is that by gapping the spark plugs higher, you produce a stronger spark which will do a better job of igniting the fuel mixture - resulting in both more power and more efficient running car.

thoughts?
-Robert

for car mods, look below at signature
 

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I dunno how the ignntion packs work. Heck, I haven't even seen em yet. If you can pigtail a connection and create a spark that you can see, that would be the route I go. Big gaps can do some oddball things, like arcing to the wrong place, retain more heat and so on. Just don't get shocked, it hurts....lol( I grabbed a broken wire once, hand was wet, and I got zapped three times before I could let go, my dad almost wet himself laughing at me).

But gettin in there and having a look at the plugs will help determine if you are indeed runing rich. Checked the air filter recently?

Oh, and K&N's(from what I've read) clog up quickly, and they clog up bad, very restrictive flow. When clean they flow like mad, but the oil soaked guaze does do its job very well, and hence gets pluged up fast.
 

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I agree, I dunno if I'd re-gap, the voltage fluctuations on our cars would probably see some arcing, if not, so glazing. What kind of gas mileage are you hitting? What's the most miles you've gone on a full tank? Could be a number of reasons why your gas mileage sucks.

It might not even be an electrical issue. If you have suspension mods, I'd get your alignment done, that could give you an additional 10-40 miles on a full tank. On my previous car, I was getting about 320 miles on a full tank, after my alignment, I was hitting about 410 miles.

And like what brembo said, check your air filter....good luck man..
 

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Discussion Starter · #4 ·
i have the stock filter, all ive done is the silencer hack (air still comes in thru stock intake)


alright, so get my alignment checked? -was this what you did w/ your subaru?


i get about 200-230 before i see the little yellow light come on for low fuel tank. my mpg is around 18 or so. usually less, but now that its starting to cool off, i use the a/c less, so it's a bit higher than usual.
 

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The Vishnu Stage 0 comes with a MBC, right? If so, I don't see 20mpg very often with my MBC-equipped WRX. It's the bomb for power, but it's hell on your mileage. I think it's worth it, personally. :D
 

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Discussion Starter · #6 ·
i tried that - i set my mbc down to a whopping 10psi for a whole tank, to see if that had any affect on it. nope. did nothing. so i said to myself, why sacrifice the extra fun w/ ur car when lowering the boost does nothing to help w/ mpg? maybe its that partial throttle boost then....?
 

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i do about 230-250 before my light comes on also. See mods below, i think im a bit low, but performance rocks!!! So like Richard, im not complaining.....ive had cars that got that kind of mileage with ZERO performance, and i dont mean STAGE zero! LOL
DML
 

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I get about 320 on a full tank. Most of my driving is freeway though, just commuting to work and back mostly. As for alignment, I haven't got my car aligned...but I know I should. That mileage increase mentioned was on a Toyota...Before my small # of mods, I was getting about 280 on a full tank. I'm trying to do the math, and I thought I get 20mpg. Isn't 230 miles on a full tank only 14.5 mpg????
(# of miles on full tank/fuel capacity)


DarkMoonLord said:
i do about 230-250 before my light comes on also. See mods below, i think im a bit low, but performance rocks!!! So like Richard, im not complaining.....ive had cars that got that kind of mileage with ZERO performance, and i dont mean STAGE zero! LOL
DML
 

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Even if you have your MBC turned down to 10psi, I think it will still build boost faster then stock and still cause poor gas mileage. Not sure though because I just took off my MBC and I also got 230 miles when the light came on. Glad to hear I'm not the only one getting bad mileage, maybe it's the weather here in Houston.
 

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230 miles and THEN the light comes on.......signifying two gallons left in the tank.......at 20 mpg that means 270 to tank of gas.......19.28 MPG
 

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I thought the correct way is taking the # of miles on a tank (including the approx. 20 miles on in the reserve tank) and dividing that by fuel tank capacity (15.9). 270 miles on a full tank to empty is only 17 mpg. If you do a search online, there are tons of mpg calulators that will tell you the same...
 

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Calculate gas milage.

Fill tank till pump auto-shuts off. Drive till reserve light goes off. Fill tank till auto shut off happens. Note the amount you *just* pumped in. Divide that into the miles. Repeat about 3 times to average out the difference in auto shut-off valves. Then you have a very, very good estimate of mileage. :) No guessing about reserve amounts and whatnot.
 

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Fill tank till pump auto-shuts off. Drive till reserve light goes off. Fill tank till auto shut off happens. Note the amount you *just* pumped in. Divide that into the miles. Repeat about 3 times to average out the difference in auto shut-off valves. Then you have a very, very good estimate of mileage. No guessing about reserve amounts and whatnot.
EXACTLY! This is how I was taught to do it, and it is THE MOST accurate. :cool:

-Jason
 
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