The Subaru SVX World Network   SVX Network Forums
Live Chat!
SVX or Subaru Links
Old Lockers
Photo Post
How-To Documents
Message Archive
SVX Shop Search
IRC users:
SVXBot

Go Back   The Subaru SVX World Network > SVX Main Forums > Technical Q & A

Reply
 
Thread Tools Display Modes
  #1  
Old 01-29-2005, 05:10 AM
pavanbabut's Avatar
pavanbabut pavanbabut is offline
Registered User
 
Join Date: Jul 2004
Location: Fremont. CA
Posts: 1,269
Send a message via MSN to pavanbabut Send a message via Yahoo to pavanbabut
"Help! How can I get better mileage?"

Hi Guys,

This is the thread that belongs to all SVX members who are getting low mileage. This posting idea is of UberRoo.

Here please post replies on how to get better gas mileage and to improve the efficiency of gas. Any suggestions and advices are needed from those who get better and high mileage and help low mileage (including me) svx members to boost their gas efficiency atleast to acceptable levels.

thanks,
Pavan.
__________________
Pavan

1992 SVX Green/Teal (81k) #0211 (4.44 4EAT) (Sold)
1993 Alfa Romeo 164L Green/Teal (155k) (5spd) (Parted Out)
1995 Alfa Romeo 164Q Alfa Red (137k) (5spd)

Mods: K&N Air Filter, 4.44's, B&M ATF Cooler, PermaCool ATF Filter, ATF Guage, '02 WRX 6 Disc changer, Alternator Mod, 9005 Silverstars, 9006 Xenon conversion, 4-way(600W) Rear & 3-way(240W) Front speakers.
Reply With Quote
  #2  
Old 01-29-2005, 07:19 AM
n00b on demand's Avatar
n00b on demand n00b on demand is offline
OMGWTFBBQ!!1!11!LMAOROFLC OPTER
 
Join Date: Apr 2004
Location: New York City
Posts: 5,114
Get new O2 sensors.
__________________
1993 25th Anniversary Edition # 156 of 301 ~ 121, 488 miles ( SOLD TO svxfiles 8/6/06)

2006 Subaru Impreza 2.5i....5spd - My daily driver

2006 Subaru Legacy 2.5i -7k miles..Mom's daily driver

2,543 Member of the SVX World Network
Reply With Quote
  #3  
Old 01-29-2005, 07:34 AM
michael's Avatar
michael michael is offline
What Potholes ???
Subaru Bronze Contributor
 
Join Date: Sep 2002
Location: Scranton, PA
Posts: 2,425
Registered SVX
ECUtune stage 1, You can then run 87 octane.
__________________
"The things you own end up owning you. It's only after you lose everything that you're free to do anything."

92 Pearl White Ls-l (138k) Euro Headlights & Blinkers, 97 Grill, Euro Tail Lights, SS Brake Lines, Stebro Exhaust, Slotted Rotors, Classic Registration
96 Legacy Outback (206k) 5-speed 2.2 Lightweight Crank Pulley, Group N Trans & Motor Mounts SOLD
Wanted: Steering Wheel
Reply With Quote
  #4  
Old 01-29-2005, 08:05 AM
gsodonis's Avatar
gsodonis gsodonis is offline
Registered User
 
Join Date: Jul 2004
Location: Knoxville, TN
Posts: 614
New O2 sensors

Quote:
Originally posted by soobiesvx93
Get new O2 sensors.
I second that.

My 92 with 92,XXX miles was averaging a consistent 20 - 21 MPG on a 80% hwy/20% city driving cycle. I had no CEL's, but replaced the O2 sensors with new ones. It was obvious the old ones were original. At the same time, I replaced the main cat with a high flow Magnaflow and also installed an ECUtune v.4 chip. The end result was a gain in MPG to a conmsistenmt 24 with the same driving style and hwy/city mix. On extended hwy rides, I average 27 MPG.

I have a 5 speed with the 3.90 rear end so I don't think I'll ever see 28 or 29 MPG like some members have on the boards, but I'm pretty pleased with 24 MPG.

Keep in mind that as O2 sensor performance degrades over time, the default condition of any ECU is to run rich to prevent detonation which often shows up as decreased gas mileage and sooty tailpipes. You don't have to spend a fortune either. I bought Walker direct fit replacements for around $64 each from www.oxygensensors.com (factory Denso sensors are around $94 ea.). If you feel confident of your soldering skills, you can buy Walker universals for around $40 ea, but you have to solder and terminate the ends of the wires yourself.
Reply With Quote
  #5  
Old 01-29-2005, 09:19 AM
STORMINORMAN STORMINORMAN is offline
Registered User
 
Join Date: Feb 2002
Location: Upper Left Coast, USA
Posts: 335
Thumbs up Last week's 625+ mile trip through Seattle...

...I averaged almost 28 mpg. I suggest a cruise control set @ 80 helps on longer trips. Maintaining your SVX (plugs, timing belt, fuel filter, air filter, the DREADED PCV, any and all electronic engine controls) to spec certainly helps mpg. BTW, I use mid-grade gas almost exclusively, now.

But, in the final chapter, it REALLY all is centered about your right foot in non-freeway situations: fast starts and the need to apply the brakes really tears up the stop & go gas mileage. TWENTY is GOOD! if you are rip-roaring about town, IMHO!

My O2 sensors are original and I don't think I have ever had an engine light code appear in 12+ years and 121+K miles.

Knock wood! & CHEERS!

Norm
__________________
' 92 SVX @ 185K
' 91 420SEL @ 223K!
' 88 420SEL I. @ 178K (what a buy!)
' 87 F250 @ 180K
' 93 ZX-11D @ 29K
' 93 SC400 @ 93K
2001 Valkyrie Interstate @ 6.6K (Brynhild)
Y2K NightHawk 250 @ 1,500 miles
' 88 420SEL II. @ 208K
'85 F150 @ 135K
Reply With Quote
  #6  
Old 01-29-2005, 01:07 PM
UberRoo's Avatar
UberRoo UberRoo is offline
SVX Appeal
 
Join Date: Feb 2004
Location: Puget Sound, Washington
Posts: 843
The rated capacity of our tanks is 18.5 gallons. I've been keeping a gas can in the trunk and running my tank empty. After pouring in the contents of the gas can (1.8 gallons), I can usually squeeze another 17 gallons into my tank. I run out at about 300 miles. That's about 16 MPG. Grrr... The rated mileage is supposed to be 17 city, 24 highway.

MPG = Miles Per Tank @ 18.5 Gallons (@ 16 Gallons)
--------------------------------------------------
10.0 = 185 (160)
10.5 = 194 (168)
11.0 = 204 (176)
11.5 = 213 (184)
12.0 = 222 (192)
12.5 = 231 (200)
13.0 = 241 (208)
13.5 = 250 (216)
14.0 = 259 (224)
14.5 = 268 (232)
15.0 = 278 (240)
15.5 = 287 (248)
16.0 = 296 (256)
16.5 = 305 (264)
17.0 = 315 (272)
17.5 = 324 (280)
18.0 = 333 (288)
18.5 = 342 (296)
19.0 = 352 (304)
19.5 = 360 (312)
20.0 = 370 (320)
20.5 = 379 (328)
21.0 = 389 (336)
21.5 = 398 (344)
22.0 = 407 (352)
22.5 = 416 (360)
23.0 = 426 (368)
23.5 = 435 (376)
24.0 = 444 (384)
24.5 = 453 (392)
25.0 = 463 (400)
25.5 = 472 (408)
26.0 = 481 (416)
26.5 = 490 (424)
27.0 = 500 (432)

I included miles per tank at 16 gallons because I figure that's when most people fill up again. Notice that near the end of this scale, running the tank dry lets you go another 50 miles.

Still, at 10,000 miles per year, the difference between 16MPG and 20MPG only adds up to 125 gallons. At $2 per gallon, that's $250. Probably not worth the expense of having a shop investigate. That's about the cost of new oxygen sensors, a set of spark plugs, an air filter, and a fuel filter. If you have a shop do the work, you can stack labour on top of that.

I've heard some people say that replacing the O2 sensors can perform miracles. I've heard other people say rubbish to the whole notion. Both sides have a reasonably strong argument, so I figure it's not a black and white issue, and worth considering once the other [cheaper, easier] options are exhausted.

Has anyone seen any conclusive evidence that the EGR valve significantly affects fuel economy? I haven't really looked into it, but I could certainly see the potential. I'm pretty sure it's rather exclusively an emissions device, but no doubt it's presence is reflected in the design of other engine systems.

...still miffed that mileage would get so bad so suddenly without turing the CE light on...
__________________
1994 LSi, Laguna Blue SVX Appeal
1992 LS-L, Ebony Pearl SVX-Rated
UberLocker
Reply With Quote
  #7  
Old 01-29-2005, 02:42 PM
Merz's Avatar
Merz Merz is offline
halfsharkalligatorhalfman
 
Join Date: Dec 2003
Location: Coos Bay, Oregon
Posts: 192
I've been checking mileage at every fill-up for the last few months and have been getting a consistent 16 - 16.5 mpg with 80% city driving. I usually use around 16.5 gallons before i fill up. I changed my PCV valve a few days ago and the one that i took out was definately not working. It was plugged up with sticky black stuff and the little thing inside it wasnt even moving. So I put the new one in and im hoping for an increase in mileage. If it works I will let you all know.


-Evan
__________________
`92 pearlie 220k
Tranny Cooler, shift kit, stage 1v4, d/s rotors, axxis pads, Perrin Pulley
'00 GMC Sonoma ZR2.
Reply With Quote
  #8  
Old 01-29-2005, 02:43 PM
Weasel 22
Guest
 
Posts: n/a
want to save gas? take the bus.... seriously if mileage is a big issue..one should not drive an SVX...heavy car..awd...big engine...its not a Geo Metro..cant expect miracles...now the RX-7's ive owned got horrible gas mileage...and didnt perform too well for such bad mileage..my SVX gets about 23-25mpg average and I drive 'spirted'..my Probe got about the same and performed less..it balances out for me
Reply With Quote
  #9  
Old 01-29-2005, 02:49 PM
pavanbabut's Avatar
pavanbabut pavanbabut is offline
Registered User
 
Join Date: Jul 2004
Location: Fremont. CA
Posts: 1,269
Send a message via MSN to pavanbabut Send a message via Yahoo to pavanbabut
Quote:
Originally posted by Weasel 22
want to save gas? take the bus.... seriously if mileage is a big issue..one should not drive an SVX...heavy car..awd...big engine...its not a Geo Metro..cant expect miracles...now the RX-7's ive owned got horrible gas mileage...and didnt perform too well for such bad mileage..my SVX gets about 23-25mpg average and I drive 'spirted'..my Probe got about the same and performed less..it balances out for me
Hi Weasel 22,

we are not worried for bad gas mileage, but rather we are concerned about the engine. Bad mileage = Something wrong with the engine (Hoping the average driving conditions). So we want to rectify those engine defects by taking advices from other members getting high mileage.

Anyway your idea of takin a bus is wonderful and great.... .

Pavan.
__________________
Pavan

1992 SVX Green/Teal (81k) #0211 (4.44 4EAT) (Sold)
1993 Alfa Romeo 164L Green/Teal (155k) (5spd) (Parted Out)
1995 Alfa Romeo 164Q Alfa Red (137k) (5spd)

Mods: K&N Air Filter, 4.44's, B&M ATF Cooler, PermaCool ATF Filter, ATF Guage, '02 WRX 6 Disc changer, Alternator Mod, 9005 Silverstars, 9006 Xenon conversion, 4-way(600W) Rear & 3-way(240W) Front speakers.
Reply With Quote
  #10  
Old 01-29-2005, 02:55 PM
Weasel 22
Guest
 
Posts: n/a
Quote:
Originally posted by pavanbabut


Hi Weasel 22,

we are not worried for bad gas mileage, but rather we are concerned about the engine. Bad mileage = Something wrong with the engine (Hoping the average driving conditions). So we want to rectify those engine defects by taking advices from other members getting high mileage.

Anyway your idea of takin a bus is wonderful and great.... .

Pavan.
after drinking more coffee im seeing what the subject was about...yes tuning the engine to better levels is ideal..I have many friends who constantly complain about their cars mileage..which puts me at the Geo Metro thing..buy the car for your needs..if you are getting terrible mileage from your SVX and know it can do better, I fully agree on the tune up
Reply With Quote
  #11  
Old 01-29-2005, 07:07 PM
SVXRide's Avatar
SVXRide SVXRide is offline
Official AutoX Part Breaker
Subaru Gold Contributor
 
Join Date: Aug 2002
Location: Dunkirk, Maryland, zip code=20754
Posts: 8,137
Registered SVX
Once you get past the basic pieces - plugs, air filter, keeping the tires correctly inflated, 4 wheel alignment- you'll also want to make sure the TB is clean (make sure to use Fuel Injector spray, not carb cleaner), the MAF is operating correctly, the Cats (all three of them!!) aren't clogged up with age (thus restricting exhaust flow), all of the various vacuum lines are intact - and not cracked due to age, thus creating vacuum leaks, the PCV valve is operating correctly, and the O2 sensors are functioning correctly.
What I'm finding is that a lot of the various lines - emissions, vacuum, electrical have seriously gone brittle on my SVX after 13 years and 186k miles!
-Bill
__________________
NASA future mission development - MAVEN (now orbiting Mars and making amazing discoveries) and OSIRIS-REx (asteroid sample return, launched in September 2016, returning with samples in September 2023)
Center Network Member #989
'92 Black LSL aka Shooting Star -- FP class in the works with multiple interesting one-of-a-kind "improvements"
'92 Pearlie LSL aka Mach 5 -- STX class now being pushed to the rule book limits
Official sponsor of OT's RaceCar - now with sticky Hoosier 295 A6s on Cobra rims!
My Locker
Reply With Quote
  #12  
Old 01-29-2005, 07:12 PM
UberRoo's Avatar
UberRoo UberRoo is offline
SVX Appeal
 
Join Date: Feb 2004
Location: Puget Sound, Washington
Posts: 843
So that gallon of toluene seems to be doing something. It doesn't feel faster. The fuel gauge seems to be dropping at the same rate. My check engine light still comes on sometimes and leaves EGR and temperature sensor codes. But... I've found myself looking down at the speedometer only to discover I'm going a little more than ten miles per hour faster than I was expecting. It doesn't seem to make any difference around town, but I think I may be getting quite a bit more top-end. ...that or the placebo effect is amazing.

Normally I go up certain hills on my commute at about 65 with the torque converter locked up. It unlocks if I go much faster. I've found myself above 80 three times now with the torque converter locked up and I didn't even notice until I started wondering why traffic around me seemed to be moving so slowly.

Driveability so far is otherwise unaffected. It'll be at least another week before I can check for any fuel economy changes.
__________________
1994 LSi, Laguna Blue SVX Appeal
1992 LS-L, Ebony Pearl SVX-Rated
UberLocker
Reply With Quote
  #13  
Old 01-29-2005, 08:18 PM
n00b on demand's Avatar
n00b on demand n00b on demand is offline
OMGWTFBBQ!!1!11!LMAOROFLC OPTER
 
Join Date: Apr 2004
Location: New York City
Posts: 5,114
So wait a second....i usually fill up at the quarter tank mark...how much is left in the tank when it gets to that point? I usually get 165 miles up to that mark. City driving with a tiny bit of highway.
__________________
1993 25th Anniversary Edition # 156 of 301 ~ 121, 488 miles ( SOLD TO svxfiles 8/6/06)

2006 Subaru Impreza 2.5i....5spd - My daily driver

2006 Subaru Legacy 2.5i -7k miles..Mom's daily driver

2,543 Member of the SVX World Network
Reply With Quote
  #14  
Old 01-31-2005, 03:12 AM
UberRoo's Avatar
UberRoo UberRoo is offline
SVX Appeal
 
Join Date: Feb 2004
Location: Puget Sound, Washington
Posts: 843
Quote:
Originally posted by soobiesvx93
So wait a second....i usually fill up at the quarter tank mark...how much is left in the tank when it gets to that point? I usually get 165 miles up to that mark. City driving with a tiny bit of highway.
In theory, at 165 miles you should have another eight or nine gallons left, but in reality it's probably not quite that much. We all should be able to go 300 miles on a tank, but I guess we don't all make it that far.

I don't even think about filling up until I get the low fuel warning light. I don't pay any attention to the gauge because it's so far off. When I see 275 miles, I start looking around for an oil station.

The real key is how many gallons you put in at the pump. I make sure that mine always sucks down at least sixteen gallons.
__________________
1994 LSi, Laguna Blue SVX Appeal
1992 LS-L, Ebony Pearl SVX-Rated
UberLocker
Reply With Quote
  #15  
Old 01-31-2005, 07:16 AM
n00b on demand's Avatar
n00b on demand n00b on demand is offline
OMGWTFBBQ!!1!11!LMAOROFLC OPTER
 
Join Date: Apr 2004
Location: New York City
Posts: 5,114
Isn't that bad for the fuel pump if you let the gas get low to the point that the light stays on? Doesnt it let dirt get in? Thats why ive always been filling up at the quarter tank mark. If i let it get low enough for the light i could definitley get at least 250 out of it.
__________________
1993 25th Anniversary Edition # 156 of 301 ~ 121, 488 miles ( SOLD TO svxfiles 8/6/06)

2006 Subaru Impreza 2.5i....5spd - My daily driver

2006 Subaru Legacy 2.5i -7k miles..Mom's daily driver

2,543 Member of the SVX World Network
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 11:59 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
2001-2015 SVX World Network
(208)-906-1122