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Old 07-21-2000, 02:04 AM   #1
Keirik
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Location: Long Island, NY/ china
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black

Post terrible gas mileage with MY00

here's my setup
stromung dual with midpipe
short shifter
amsoil filter
UR pulley

now..my gas mileage is terrible...probably averaging approx 200 miles per tank with 93 octane, under a mix of city/highway like conditions...i'm a pretty agressive driver, but not like WOT 24/7 or anything like that..
next week the AFC should be installed, that should help a bit to lean out the mixture a little, already tried an eCU reset which did not seem to help (maybe try a second one? or just wait until AFC goes in?)
any other ideas ? I'm guessing I'm running extremely rich...with gas prices so high lately, this is rather expensive
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Old 07-21-2000, 02:07 AM   #2
Fusion
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What does that come to? I mean how many gallons do you fill up?

Haig
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Old 07-21-2000, 05:52 AM   #3
99 RS 2.5
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what kind of gas milage do you want? Dam the best i've ever seen was like 24mpg and that was on a good week! Just teasing ya the AFC should help that some your 2000 if it has an intake will run way to rich so bad gas milage comes with that. When you get that AFC watch the O2 sensor readings it give .8v is ideal
 
Old 07-21-2000, 06:14 AM   #4
SilverSuby
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Try running 87 octane and see what you get. I get MUCH better gas mileage with the 87 than all of the other octanes.
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Old 07-21-2000, 06:42 AM   #5
Opie
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Post

I agree 87 octane gives me nuch better mileage than 89 or 93, better performance too!
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Old 07-21-2000, 07:50 AM   #6
edekker
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Supercharged - and STOLEN

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Keirik,

I don't know ... I think something's definitely wrong more than what could be accounted for in just the change in octane level IMHO. I run octane 94, with an Eaton blower to boot I still get 25mpg when I whip along at 90mph.

When I was running N/A I was getting 27mpg (at the same 90mph average speed). Changing the octane level didn't seem to affect the fuel economy all that much it seemed to me anyway. I had tried them all, from 87 to 94 (and even higher with octane boosters).

Personally I would get your car checked out.

Good luck,
Ed.

[This message has been edited by edekker (edited July 21, 2000).]
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Old 07-21-2000, 08:34 AM   #7
8Complex

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Ease up on the speeding man! I went form lead foot to an easy driver (too many tickets... must lay low...) and I found my mileage went up from 17-18mpg up to 20-21mpg or so. This is with an intake on the car and running either 87 or 89 octane gas, also.

If you're getting 200 mlies to the tank, you NEED to reset your ECU, for sure.
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Old 07-21-2000, 09:01 AM   #8
Matt Monson
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Drop the octane and do another ECU reset and see what happens for a tank or two.
You can't really compare your set-up to an Eaton SC because that will up the CR and change the needs of your engine. I was sceptical about the lower octane fuel at first, but found my mileage went up 3-6mpg depending on conditions with lower octane fuel.
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Old 07-21-2000, 09:36 AM   #9
edekker
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8,
Actually I normally do go slower [but it's dammed hard to ]. My test at 90mph was made, to and from my trip to Rimmer in Colorado, to see what differences the s/c would've made on my fuel economy.

Matt,
My comment had included my experience going N/A.

Ed.
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Old 07-21-2000, 10:07 AM   #10
Matt Monson
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Edekker,

My comment was not meant as a slight to your knowledge. I have just seen a lot of people confused by the compression ratio and octane needs of our cars. I was just trying to keep the info specific to Keirik's set-up. A lot of people on this board( myself previously included) run the wrong octane and then wonder why the car doesn't perform up to it's capabilities.
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Old 07-21-2000, 10:50 AM   #11
wistful
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well, I have a full stock MY00 with only 2200 miles on it. So far, I've onced made 300 miles on one tank of gas, but then again, i've also only done 240 miles (I just broke it in. I was happy. Sue me. =) I'm not sure of the gas tank capacity.

Don
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Old 07-21-2000, 11:18 AM   #12
Scooby South
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K...A couple of things here...
My MY00 gets crappy milage also but I know why....Most of my driving is City stop and go..and I take the blasted thing to redline every shift ..I know..I Know..But I can't help it...Filled up yesterday with 92 OCTANE and had 224 miles on the tank...Took almost 12 gallons to fill up...But Thats because I drive my car HARD...Now for the 2nd thing...
When I drive on the open road.(Now theres something you say alot in Hawaii)I get Way better milage because my throttle position is more constant...Everybody drives different..so some people might get 30 MPG out of a Corvette and others will get 4..So it is all the Driver and little to do with the car itself....

My 2Yen..
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Old 07-21-2000, 11:37 AM   #13
edekker
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Supercharged - and STOLEN

Thumbs up

Matt, I hear what you're saying. Thanks.
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Old 07-21-2000, 01:15 PM   #14
Keirik
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i fill up about 12 gallons to each tank. The problem is everytime i went to monitor the exact numbers I actually end up forgetting by the time i fill up again.
Anyway, I'm not driving 120 everyday or anytihng like that. For the most part, I drive like everyone else does. I wanna do a ECU reset, but thinking I'l just wait until I get the AFC installed first. I'll try switching over to 87 octane on the next fill up, se how that goes also.
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Old 07-21-2000, 02:16 PM   #15
kid22
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i don't understand, how can 87 octane perform better than 93 octane? and will i need 93 when the turbo gets installed?
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Old 07-21-2000, 02:45 PM   #16
kar250c
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Blue Ridge Pearl

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My MY00 seems to perform best on 89 octane. I have STI muffler w/custom midpipe and Amsoil air filter. Daily commuting gets between 24 and 28 mpg. I hit a fair amount of traffic, downshifts/upshifts etc. I also "let it out" whenever possible.
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Old 07-21-2000, 03:05 PM   #17
Matt Monson
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Post

Kid22:
I give you the short version cuz there is a lot to explain about it. If it is still unclear, try doing a search, there have been many discussions.

1. 92or higher Octane gas is not higher quality. Higher Octane makes it less combustible than 87 or 89.

2.The compression ratio of the engine dictates the octane needs of the engine. A higher CR engine needs higher octane to prevent detonation. Subaru fooled a bunch of us by telling us our CR was 10.1:1 But this is a static number. It is actually 9.7:1 under dynamic conditions.

3. When you turbo your ride, you make it more likely to detonate due to a number of different factors like ignition timing, air fuel mixture,etc. Therefor you need to protect against detonation with higher Octane.

So much for the stoner's version(Am I allowed to call myself that here?). Like I said, if you wanna get really techy, search Compression Ratio or Octane and you will find way more complete explanations than I can pull right off the top of my head.
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Old 07-21-2000, 03:18 PM   #18
copec
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GEEZE!!!

I just put around town in my98 impreza, all I have is a K&N air filter and I get 30mpg!!!

even when I drive agreesively when I am pissed at traffic I get like 25mpg!!!
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Old 07-21-2000, 03:21 PM   #19
copec
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oh, impreza 2.5rs,

and the lowest octain I have run is 88

I put 91 in it most of the time though
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Old 07-21-2000, 11:26 PM   #20
Keith
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wow k3 that suX! I think that the afc should help, but I guess we will find out when u get it.
Hey does neone know what the o2 sensor should read on a 00? is it the same as a my99 .87? thanks
keith
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Old 07-22-2000, 03:41 AM   #21
Shin RS
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Hey scooby south! Do you really get 240 on the tank of gas? Well, I guess you really do drive hard... I drive like a granny and get up to 360 for a tankful (12-23 gal) mostly around 320 though... (gotta keep the speed down, keep my record cleen.

Oh yeah, good luck on the t3/t4, hope you get it and make your 500 hp monster...

Shin
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Old 07-22-2000, 04:38 PM   #22
ImprezaRS dot com
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On my MY00, after I do mods and reset ECU, the gas mileage sucks for the first 4-6 weeks, but eventually the ECU gets things right and I'll see gas mileage improve almost back to normal...
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Old 07-22-2000, 09:25 PM   #23
Basil
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TXS Stg 2 - 242 whp

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Well, let's see:

Stock - about 21-23 mpg

Installed 2.5 inch catback around 9k miles - 28-31 mpg

I have no clue right now, since the ECU was just reset friday - I'll know monday or tuesday, as my full tank will probably be gone by then. I'd say there's something else going on..

Basil
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Old 07-23-2000, 10:51 AM   #24
scoobysport
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I find ever since I put in my scoobysport exhaust, my gas mileage has gone down. My conclusion, it sounds so sweet, that now I drive a little harder.
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