A Quest for 35mpg (Subaru Outback Limited Sedan 2.5L auto) - Page 21 - Fuel Economy, Hypermiling, EcoModding News and Forum

NachtRitter · 10-13-2010, 12:04 AM

Could always fiberglass over the holes, if you take off the bottom bar...

jedi_sol · 10-13-2010, 01:11 AM

If you remove the bottom bar, wouldn't the fiberglass be rigid enough to hold its shape?

Zerohour · 10-20-2010, 05:02 PM

Updates! I know its been a while..

Got new LEDS, swapped out the bulb today. So I'll see if it worked tonight.

Vise was Delivered last Saturday, so I have a free style mill. And the Drill press is working.

Been working on a friends car, door has been started to rust through the paint, so that has been the project last few days (week basically).

Wheel skirts are still on, haven't changed them anyway yet.

Just filled up today, 25.77 MPG versus 25.41 mpg last fill up. I drove more eco this time, but we hit sub 40's (37 degrees to be exact) in the morning this week. Killing my warm up times. I've made the decision to swap over to a full synthetic trans fluid. I'm do for a change anyway. So I ordered new filters, gasket, and picked up some Mobil 1 full syn ATF. The normal 75K+ valvoline/castrol was 5.xx/per qt so 8.99 for the full synthetic isn't too bad. But considering trans fluid as thick/thicker than oil, it should make a big difference for warm up times (when fluid is thickest/more resistive).

On the bright side, by this time last year I was down to upper 21/lower 22 MPG so I'm about 3.5 mpg above last year. I wish I had more gas receipts from over winter, but I only found the ones I had saved from when got the car last summer. oh well. Its doing better than before, and thats what matters!

d0sitmatr · 10-20-2010, 06:30 PM

the one thing I noticed with my old outback (98 outback ltd (wagon), 5 spd MTX, no AC) was the power of the engine could easily handle longer gears.
my 70mph rpm was horrible (3300 !!) but I managed to hover around 27-28mpg hwy driving.
city driving I netted around 23-25mpg with minor conservative driving. (still would take it up to almost 3k in 1st gear, but down to 2k for the rest)

I honestly hated the car after a few months, not only was I very disappointed with its mpg, it has got to be the worst car for cleaning and aero. so many little nooks/crannies that I considered pointless. purely aesthetics.

anyways, if I had decided to keep the car I was going to look into a much longer final drive and was going to try and bring my hwy rpm down to somewhere in the neighborhood of 2500 or even less.
I did look around but couldnt find anything except for racing final drive gears which were much shorter than the stock.
Im not sure what your FD is, I think I read its different than the MTX are @ 4.11(?)
but if you could get an FD to extend your gearing, Im betting you could easily see the 35mph mark, then add to that some aero mods you might even see close to 40mpg.

Zerohour · 10-20-2010, 07:44 PM

I never considered change the final drive with the ATX. Not sure if it can be done. There are probably variations over the years. Not sure what is interchangable. Sometimes I miss my Caprice. with a 4 spd it could do 90mph where the Subaru is doing 65. :cry: Of course the Caprice got 18-19 summer and 17-18 winter lol The LT1 block with the interceptor package has very little variation in its FE. It just went how ever fast you wanted it to go. I think my worse tank was something around sub 17, maybe 16.5ish. And that was an entire 21 gallon tank of nothing but short trip driving around the holidays. The car never fully warmed up!

brucey · 10-20-2010, 08:04 PM

The subaru 4EAT's are completely interchangeable, across models and years. The automatic outback's came with 4.444 and I think you can go as low as 3.7, but probably more like 3.9. That's as low as it goes for subies, how much of a difference would that make at interstate speed?

Zero: You might want to try a block heater. I finally figured out how to install a circulating one on our cars. Having the car already at full operating temperature before I leave is very very nice. It's not even that cold yet and I want to kick myself every time I forget to plug it in.

Zerohour · 10-20-2010, 08:46 PM

Nice Brucey! My car sit outside. I would need to run a 50 foot extension cord or longer to reach the car where it's parked lol! What amperage is your block heater?

I'm kinda excited to see how much a difference the full syn trans fluid makes. The only part that sucks is that I'm gonna do a flush, then I'm gonna go filters and a flush. $9/qt is gonna be $$$ till i'm done. But the fluid is more than due @ 83K miles. And I'm not sure if it was ever changed before...

brucey · 10-20-2010, 09:36 PM

8.5 amps, coming in at a nice 1000 watts. Yeah, you'd need a 50 foot heavy duty cord, but not having to clean the snow off the windshield might be worth it.

Also, I had Mobil 1 ATF in mine at one point. When I put it in, I noticed it was a little smoother in shifts. But It had never been changed (80k miles). Recently (140K) I did a partial flush with cheapo cheap ATF and the stuff came out looking brand new. I think simply regularly flushing it is better than using high end fluid. Although it probably can't hurt to do both, I just don't budget that much for car maint anymore.

d0sitmatr · 10-20-2010, 10:16 PM

Quote:

Originally Posted by brucey

The subaru 4EAT's are completely interchangeable, across models and years. The automatic outback's came with 4.444 and I think you can go as low as 3.7, but probably more like 3.9. That's as low as it goes for subies, how much of a difference would that make at interstate speed?

Zero: You might want to try a block heater. I finally figured out how to install a circulating one on our cars. Having the car already at full operating temperature before I leave is very very nice. It's not even that cold yet and I want to kick myself every time I forget to plug it in.

except for 6cyl vs 4cyl

Ive read even the 2.2 trans is a straight swap for the 2.5, which was another thing I had considered doing, removing the AWD by removing the rear transaxle and running at a FWD car only. but I heard that it might have given me a max of 1mpg extra, mostly likely .7 or less, which didnt add up for the cost of doing the AWD delete.

Zerohour · 10-20-2010, 10:46 PM

haha pretty sure a WRX/STI rear diff should put up with all the "power" the NA 2.5 creates.

I would go straight RWD if you wanted to make it better FE.

yeah I'm pulling for the Mobil one stuff. I'm not sure if I'm gonna do the double dump or not. It depends. When I drain the pan, if it looks really bad, I'll do a double dump. If it just seems spent/looks off color. Then I'll only flush once. I'm looking at it more along the lines I can tell the trans isn't warm at sub 50 degree temps. For PA that is Oct to April. So 10 minutes to warm up is alot for the trans everyday, plus every other startup during the next 6 months. Its a serious FE Loss. The Subi pulls 19-20 if I do all short trips. I am already lossing 2-3MPG from the cold changes. So if I can pull another 1mpg for the next 6 months it is well worth the try to switch to the synthethic transmission fluid. Even if it isn't "cost effective". I'm still going to make the vehicle as efficient as possible within a reasonable manner. If it ends up costing $50 and I don't make any money back, its still a worth wild mod to me. I could easily go and waste $50 on something that won't be of much benefit to the car. But modding is my hobby. It my spare time entertainment. Some people drop $50-$100 at the bar on a weekend night. I drop 50-100 bucks on a parts counter Saturday morning :-)