ean611 Posted July 8, 2008 Share Posted July 8, 2008 Fuel brand shouldn't matter. It all starts off as the same fuel, then the truck gets added in whichever detergents they prefer. SLegacy99, I'm going to try 89, as honestly, the first fillup was 10 gallons of 93 + 7 gallons of 87 left in the tank, with good results. That's around 89-90. I'll report back, but seeing as gas is 'spensive, it'll take me a week or two before I have more data. Link to comment Share on other sites More sharing options...
SLegacy99 Posted July 9, 2008 Share Posted July 9, 2008 I'll be giving 89 a try for 150 mile trip I have coming up. I've found though that even with A/C on I can get almost 33 MPG if I hold 68 MPH. Thats running 87. I tried 89 on a trip like this once before, but my mileage was only about 27 MPG. However, that was definately due to the change to winter gas, not to mention I had to drive up a mountain. Link to comment Share on other sites More sharing options...
konrad Posted July 9, 2008 Share Posted July 9, 2008 Just came back from 700 miles round trip. Avg was 32 mpg with A/C always on, avg speed ~65-70 Link to comment Share on other sites More sharing options...
Sponge Posted July 9, 2008 Share Posted July 9, 2008 Everyday commute is 20 miles of toll road and 3 miles of getting to the toll road and office 25 - 27 mpg during non construction season 23 - 25 mpg during construction season 29 - 30 mpg highway at 80 mph w/the AC on or sunroof/windows open 12 mpg at the track My vB Gallery Link to comment Share on other sites More sharing options...
mfl Posted July 12, 2008 Share Posted July 12, 2008 Just bought a 2.5 my08, with auto (my mistake) and the city (heavy stop-start traffic) consumption is 19 - 20mpg and a recent highway trip saw about 28 mpg. The engine is still tight with about 1400 miles on the clock. Link to comment Share on other sites More sharing options...
katalyst Posted July 12, 2008 Share Posted July 12, 2008 Just bought a 2.5 my08, with auto (my mistake) and the city (heavy stop-start traffic) consumption is 19 - 20mpg and a recent highway trip saw about 28 mpg. The engine is still tight with about 1400 miles on the clock. nah the auto tranny is kinda nice for all that stop and go. i'm in the same situation, hitting like 17-18mpg in the city, it's terrible haha but i'm gonna try filling premium next tank and see how it goes. Link to comment Share on other sites More sharing options...
MJ in PA Posted July 12, 2008 Share Posted July 12, 2008 Well, on my last tank I think my trip computer was significantly off. It said I averaged 30.3 mpg. I drove 298 miles, and if the gas station pump was right, I put in 10.3 gallons when I filled the tank. So, that's 28.9 mpg. That was probably with a mix of 80% highway driving, 20% city. Link to comment Share on other sites More sharing options...
Legacy_2.5i_Boxer_Denver Posted July 13, 2008 Share Posted July 13, 2008 That is about right for Gas mileage 33 is what I get on the highway and 26 or 25 in the city even with heavy driving. I put Royal Purple in and SFR Fuel additive and I get way better gas mileage. Since I only have 3k on the car this is my second oil change on the car. Link to comment Share on other sites More sharing options...
Sean05 Posted July 13, 2008 Share Posted July 13, 2008 In my 2.5i 5-speed I routinely average 28-29 mpg mixed driving. On long trips (VA to NY) I average 33 at roughly 75 mph with the AC on. If I can stay in the 60-65 range I usually average 36 mpg. Link to comment Share on other sites More sharing options...
ean611 Posted July 13, 2008 Share Posted July 13, 2008 MJ in PA, with the 10:1 compression ratio, 89 may be all we need to get the benefit. So far, I'm experimenting with 91-93 (premium), but I'll experiment with mid-grade in a bit to see the difference. Link to comment Share on other sites More sharing options...
junichi Posted July 13, 2008 Share Posted July 13, 2008 I have a 08 2.5i (5MT). mix of high way and city, and it works out to be 9.4-10L/100KMs. so around 450-480KMs per tank. Link to comment Share on other sites More sharing options...
mikesae Posted July 14, 2008 Share Posted July 14, 2008 car only has 1500km on it; still breaking in. Just drove 540 km on 45 litres, so 8.4l/100km or 28mpg. 30% city, 70% hwy Almost twice as better as my Ford Ranger. Link to comment Share on other sites More sharing options...
ShrinerMonkey Posted July 14, 2008 Share Posted July 14, 2008 MJ in PA, with the 10:1 compression ratio, 89 may be all we need to get the benefit. So far, I'm experimenting with 91-93 (premium), but I'll experiment with mid-grade in a bit to see the difference. Around these parts (Iowa) 89 or premium gets you E10. No way I am putting that boondogle crap in my car. Regular 87 octane for me... even though I have to pay more for it than 89 octane because of the ridiculous tax breaks ethanol gets around here. Link to comment Share on other sites More sharing options...
ean611 Posted July 14, 2008 Share Posted July 14, 2008 ShrinkerMonkey. Everything I'm using is E10, as that's what Massachusetts does. I would guess that 87 without ethanol probably is better than 89 or 91 with ethanol, as most people report switching to E10 causes a fuel efficiency drop. However, just a note. All new cars for the past few years (including your '06) have been designed to run on E10. When an engine is properly tuned for ethanol, you don't see big cuts in efficiency. However, that depends on engine tuning. The way you make up for ethanol is by raising compression in the engine, as ethanol can be compressed more than standard petrol. That being said, you're still lucky that you can buy fuel without ethanol in it. Link to comment Share on other sites More sharing options...
ShrinerMonkey Posted July 14, 2008 Share Posted July 14, 2008 ShrinkerMonkey. Everything I'm using is E10, as that's what Massachusetts does. I would guess that 87 without ethanol probably is better than 89 or 91 with ethanol, as most people report switching to E10 causes a fuel efficiency drop. However, just a note. All new cars for the past few years (including your '06) have been designed to run on E10. When an engine is properly tuned for ethanol, you don't see big cuts in efficiency. However, that depends on engine tuning. The way you make up for ethanol is by raising compression in the engine, as ethanol can be compressed more than standard petrol. That being said, you're still lucky that you can buy fuel without ethanol in it. I know that E10 won't hurt my car, I just don't use it because of the fuel economy hit and issues I have politically with ethanol... it's a boondogle and is WORSE for the environment. The energy loss can't really be compensated for because ethanol just has less energy per volume than gasoline does, it's just chemistry. How do you increase compression in an engine? Link to comment Share on other sites More sharing options...
ean611 Posted July 14, 2008 Share Posted July 14, 2008 Increasing compression? Turbo!! NA engines are typically fixed, and all you can do is play with the timing (slightly) and the fuel-air mix. The Koinegsegg CCX tuned to E85 gets better HP than the standard petrol version. I'm not sure how they do it, but in all likelyhood, they're adding boost, as E85 can take more compression without pre-detonation as compared to standard petrol. I'm well aware of the Ethanol boondoggle, and I didn't want to address it here, as that would be quite off topic. That, and I cannot control what fuel is available to me in my state. Bottom line, corn is food, not fuel. Link to comment Share on other sites More sharing options...
ShrinerMonkey Posted July 14, 2008 Share Posted July 14, 2008 A turbo doesn't exactly increase compression. Compression is the sense of a ICE is fixed based on piston movement. A turbo just allows you to add more air and fuel into the cylinder before it is compressed by the piston. Our 2.5i will be 10:1 compression wether it has turbo or not. The only way to increase compression is to change out the head or put in longer piston rods to increase piston travel (impossible without new heads). Link to comment Share on other sites More sharing options...
ean611 Posted July 14, 2008 Share Posted July 14, 2008 ShrinerMonkey. Of course, you're right. I'm being simplistic, turbo doesn't increase compression ratio, but at the end of the day, we're all dealing with how much pressure is in the cylinder pre-detonation. Higher pressure requires higher octane fuel. Everything else is details. /Still hates ethanol in my gas Link to comment Share on other sites More sharing options...
katalyst Posted July 18, 2008 Share Posted July 18, 2008 filled up, tried 89 yesterday, hit about 32mpg with highway driving at about 70mph, w/ AC finally seeing some good numbers, but yea i think the engine does rev a little smoother with the 89, or it's just a placebo effect haha Link to comment Share on other sites More sharing options...
gianspi Posted July 18, 2008 Share Posted July 18, 2008 28.5 mpg mostly highway, but that is from my 2.2L 95 Legacy. enough zip ties and duct tape will fix anything. Link to comment Share on other sites More sharing options...
ean611 Posted July 18, 2008 Share Posted July 18, 2008 katalyst, I saw the same thing. I was NOT expecting a difference when I tried, I wanted to debunk the idea. Link to comment Share on other sites More sharing options...
phenryiv1 Posted March 5, 2009 Author Share Posted March 5, 2009 I got bored and thought that I would give the 1-year update. With mixed driving, about 90% highway and uncontrolled-access primary roads, I travel between 55-80 MPH for about 100 miles per day. Over the last year, I have driven 24,xxx miles and have seen an average MPG of 27.3 over that time periods. Some individual tanks have been as high as 29.1, but overall, I am seeing about 27-28 MPG, as the carryover average fluctuates up to 27.6 from time to time. I do regular oil changes, whch average about 4500 between changes, always conventional 5W30. I am aware that this was an old thread, but I wanted to give a historical update for any new members. Car is a 2008 2.5i SE 5MT. Patrick Looking for spacers or adapters to install aftermarket speakers in the doors of your Legacy? CLICK HERE or PM me! http://www.carstereoadapters.com./ Link to comment Share on other sites More sharing options...
aldouse Posted March 5, 2009 Share Posted March 5, 2009 just for the hell of it. i tried stay between 2500-2800 rpm and no higher. mixed city/hwy 60/40%. i pulled 380 miles and according to the trip computer avg'd 30.7 mpg. @_@ WOW! -- yay for the sig! -- my garage! Link to comment Share on other sites More sharing options...
4S-TURBO Posted March 6, 2009 Share Posted March 6, 2009 just for the hell of it. i tried stay between 2500-2800 rpm and no higher. mixed city/hwy 60/40%. i pulled 380 miles and according to the trip computer avg'd 30.7 mpg. @_@ WOW! ...and that's WITH a hoodscoop! Link to comment Share on other sites More sharing options...
phenryiv1 Posted June 3, 2009 Author Share Posted June 3, 2009 Just a little update. I just turned 30K this week, and I had reset my tripometer at exactly 20K. As I approached 30K, I was watching my cumulative MPG over the 10K period, and I was relatively impressed to get 28.2 MPG with the 5MT on mixed driving on my 2008 2.5i SE. My commute is 97 miles per day, with 80 of that as highway (interstate) and divided 4-lane roads. On the interstate, I average 75-80 MPH, and on the divided 4-lane, I hover between 60-70 MPH. I also ascend/descend a mountain each day. The last 17 miles of my commute are a twisty mountain road with constant switchbacks and elevation changes. This is normally driven between 25-75 MPH, depending on traffic, weather, etc. The vehicle is also drive on weekends for around-town trips, errands, etc., and has been through about a dozen auto-X runs. I also don't hesitate to drive the long way home from some places, just to hit a curvy road and drive it in a spirited manner. I run 87 octane fuel and 5W-30 conventional oil, with changes around 3500 miles (about one per 4-5 weeks). All in all, MPG on the 2.5i has been pretty good, considering my driving habits and style. Patrick Looking for spacers or adapters to install aftermarket speakers in the doors of your Legacy? CLICK HERE or PM me! http://www.carstereoadapters.com./ Link to comment Share on other sites More sharing options...
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