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Old 06-04-2002, 10:58 PM   #1
scaryfastskier
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Default Uppipe MPG improvement? (long)

I recently installed a cat-free uppipe, and have noticed a signficant change in gas mileage. previously, I would get 200 miles per tank before the warning light came on....this was conisitant like clockwork. The most it vaired was 10 miles. The last two tanks I have used since the install have given me 220 miles for 3/4 my tank...I filled up then out of habit at this miles. I always use the same station, 93 octane.
Is it normal for such a minimal mod to get 25% better gas mileage? It is the only mod I have done since I noticed this. If needed, I will post a full mod list. (Nothing major)
Possibilities
1) The gas station switched from winter gas to summer gas (Do they even do that?)
2) Uppipes really help alot
3) Warmer weather ( I rule this out because I got the same mileage last summer as I did all winter)
4) I am a beta tester for the new Gas-Monkey and it really kicks arse (They must have forgot to inform me)
5) You tell me!
thanks,
Grant
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Old 06-04-2002, 11:56 PM   #2
QA Guy
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Lots of people have reported better gas mileage with a catless uppipe.

A different gas formulation might be a contributing factor, too.
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Old 06-05-2002, 12:24 AM   #3
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I would lean more toward the up-pipe improving efficiency. The only extra milage formulation I've seen recently has been the Shell Formulation which was pulled about a week and a half ago. I have been consistenly getting 22 mpg stock on Shell 93 for the past year. Any one else with MPG figures?
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Old 06-05-2002, 12:26 AM   #4
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200 mi???? I usually get 340 if I wait till the light comes on. Although I think my mileage decreased with the uppipe install due to the more aggressive use of my throttle
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Old 06-05-2002, 12:40 AM   #5
scaryfastskier
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Quote:
Originally posted by mr2guru
200 mi???? I usually get 340 if I wait till the light comes on. Although I think my mileage decreased with the uppipe install due to the more aggressive use of my throttle
yea...my mpg sucks arse, but it IS consistant. The wierdest part of all is that I have driven more aggressivly since I have installed the pipe. The last tank I even went to the 1/4 track! To me, that is the most confusing part. (excessive excelleration and 25% better mileage on the same tank!?!)

I too think it has something to do with efficiency. The only reason I question it at all is because it is a very large change.
Grant
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Old 06-05-2002, 01:00 AM   #6
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I put mine on while I was visiting my brother (900 miles away)

The trip up I got 23-24 miles per gallon (very flat, and consistent)

The way back, after stage 0 install I got 27-27.5 MPG. And that wasn't the Unichip if it's closed loop, and I didn't install the pulley.

The catless uppipe significantly improves volumentric efficiency, primarily by creating less exhaust backpressure. Less exhaust stays in the cylinders and more goes out the tailpipe, combusition is more efficient, cylinder temps are lower. All good stuff.
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Old 06-05-2002, 07:59 AM   #7
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I installed a Stromung downpipe that has a cat and I know I am getting better mileage. I also installed a Blitz SBC-ID the same day too but I doubt that is doing it.
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Old 06-05-2002, 08:16 AM   #8
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Driving more aggressively may actually help your mileage, as long as it's not *too* aggressive.

Accelerating fast usually means you are in higher gears for a larger percentage of the distance you've been driving. If you drive like a grandma, and it takes you 1/2 mile to get up to third gear, you're going to have awful gas mileage.

I remember an article out of England posted on this board a year or two ago where someone actually did a scientific study and concluded that you should accelerate faster than most people do, but try and shift early, to get the best gas mileage.
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Old 06-05-2002, 09:27 AM   #9
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yeah...200!! thats pathetic!

Maybe you should stop beating on your car-I get 340-350avg and thats still doing over 80mph on the highway.

I bet if I totally babied the car for one tank I could get almost 400

Greg
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Old 06-05-2002, 10:08 AM   #10
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Quote:
Originally posted by GCSUPRAMAN
yeah...200!! thats pathetic!

Maybe you should stop beating on your car-I get 340-350avg and thats still doing over 80mph on the highway.

I bet if I totally babied the car for one tank I could get almost 400

Greg
I only get about 230-240 as well. but I have seen 300's but thats when driving on the highway. I drive 45-55 min to work each way in traffic thats why I get 230-240, and I usually fill up at 1/4 left, so I put in about 12 gallons. I think thats about right when Subaru says in the city the WRX gets about 20 mpg
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Old 06-05-2002, 10:24 AM   #11
scaryfastskier
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Quote:
Originally posted by GCSUPRAMAN
yeah...200!! thats pathetic!

Maybe you should stop beating on your car-I get 340-350avg and thats still doing over 80mph on the highway.

I bet if I totally babied the car for one tank I could get almost 400

Greg
I honestly don't beat on my car too bad... I live and work in the Suburbs, so most of my driving is shorter trips, off-highway driving, or short (<10 miles) highway drives.
I may have to lose the rest of the cats in my car and get 500 miles per tank. (Or something like that )
grant
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Old 06-05-2002, 11:01 AM   #12
ellisz
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Default ECU correlation

I know I was getting 300-320 miles to a tank before the uppipe and my last tank after the install I got 340. The light has never came on for me either.

The question I have is this: I get better gas mileage than a friend of mine in his wagon but he pulls me on the hwy in my sedan. We have always attributed it to his driving style/conditions vs mine and that his ECU migh have a more agressive map. We have the same mods but most of my driving is done in decent traffic between 60-80 mph but no WOT pulls. He can run 90 mph daily and has plenty of opportunity to try WOT pulls.

Can you have good mpg and a good map? Maybe his car is just stronger though.

Just wondering how much the ecu meddles.
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Old 06-06-2002, 07:27 PM   #13
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Yeah the red wrx's are usually the slowest.

J.K. I read you guys have the same mods. Could he be pulling more boost than your or something? A couple of pounds of boost is a lot.
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Old 06-07-2002, 08:05 AM   #14
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Default boost

LOL. Guess I should of researched the color better huh

Same boost. We were as scientific as possible ..
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Old 06-07-2002, 08:25 AM   #15
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I'm sure that you've taken this into account, but the type of driving that you do has alot to do with the mileage. On a tankful with mostly highway driving, I've gotten over 25mpg several times. Other times when I've been stuck in traffic for a few hours for a few consecutive days (nothing like driving in NY), my mileage has slipped below 20mpg.

Rich
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Old 06-07-2002, 08:49 AM   #16
ellisz
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Yes, I know that mileage will vary depending on your driving style. I have owned turbo cars since I started driving.

I just wonder of the effect, if any that driving sytle and the resulting gas mileage will effect the ECU settings. I have heard the the ECU is a bit flaky but I just don't know if the difference in our cars was ECU map differences or just that his car is stronger. We thought it might just be the ECU but I don't know if the ECU can make that much difference.

Kind of stupid subject but what I wonder is when I take the car to the track if I should reset the ECU a week before and drive the snot out of the car before hand
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Old 06-07-2002, 09:19 AM   #17
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At least we know now who drives like an old granny

I commute about 100 miles a day, 80% freeway, I still only get about 220-240 miles to a tank. Then again on the 5 north in the morning if you are not doing between 80-100 you're holding up traffic. If someone's getting 300 miles to a tank you need to loosen up and put the pedal to the metal!
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Old 06-07-2002, 09:34 AM   #18
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Hell, I wish I could. When I was in Nashville, I was doing 90 just to stay with traffic. In Louisville, If your doing 70 your blowing by people and the road is never open. Lots of Left lane Ms. Daisy drivers. I can't do 100+ when I have my 2 yr old son in the car either.

Some of us are just not as lucky as others. On a side note, I got 6 less tickets last year than my buddy did
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Old 06-07-2002, 11:27 AM   #19
scaryfastskier
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In minnesota the average highway speed for the left lane is 50. The right lane? 55. Stooopid stoopid people think they are doing society a favor by blocking traffic. They even write letters to newspapers proclaiming themselves "vigilantes" that keep the highways "at a safe speed" by not allowing faster cars to pass. (long, long, long strand of words that are not allowed on this forum, followed by violent seizure)

The good news is that I am moving to Saint Louis where you are shot for driving less than 80. I'll never forget the first time I went drove in STL...I was doing 80 on the highway and got passed by a cop going about 90. He wasn't even in pursuit of anyone. Thats my idea of speed limits
grant
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Old 06-07-2002, 11:53 AM   #20
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Quote:
Originally posted by MadWagon
At least we know now who drives like an old granny

I commute about 100 miles a day, 80% freeway, I still only get about 220-240 miles to a tank. Then again on the 5 north in the morning if you are not doing between 80-100 you're holding up traffic. If someone's getting 300 miles to a tank you need to loosen up and put the pedal to the metal!
I have about 9,000 miles of gas receipts in a Lotus spreadsheet, and I've been averaging about 23. I do get over 300 miles on many tanks, but my morning 80+mph commute is south on the 5 (sorrento->downtown). I think what limits us to lower MPG than other people here is that we have big hills on our freeways.
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Old 06-07-2002, 12:26 PM   #21
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I usually get 320 per tank, no mods.

Kinda funny that my WRX gets the same gas mileage that my 1.8T GTI did, and it's almost 2 seconds faster in the 1/4. Japan out did themselves on the efficeincy of this motor compared to the German 1.8T.
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Old 06-07-2002, 12:30 PM   #22
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Quote:
They even write letters to newspapers proclaiming themselves "vigilantes" that keep the highways "at a safe speed" by not allowing faster cars to pass. (long, long, long strand of words that are not allowed on this forum, followed by violent seizure)
Grant, I feel your pain.
Quote:
The last tank I even went to the 1/4 track!
How did you do? Was it Rock Falls?

Paul
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Old 06-07-2002, 02:29 PM   #23
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i get 200-220 miles per tank myself, 15.0-15.5 mpg on city, and 17.5 on highway.. i got like 240 miles as a best on a trip from SD to OC..

my driving is fairly aggressive, but i don't think these cars should get mileage like that.. i've had Subaru look at it, and they couldn't find a cause. I have no mods as well, except for a removed silencer box.

I mean, there are people who drive extremely aggressive in their cars and get 280+ regardless of weather conditions, gas formulation, mods...

-ryan
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Old 06-07-2002, 03:29 PM   #24
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My highest was @330. My worst was when it was really hot last Summer. I got a whopping 160 out of a tank drving around town.
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Old 06-07-2002, 03:44 PM   #25
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scaryfastskier's method of computing fuel economy probably has more to do with his mileage improvement than his uppipe. He ought to divide miles travelled by gallons consumed to calculate fuel economy. But that would involve using {GASP!} arithmetic.
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