Subaru Forester owner wants better economy

[JV-Tuga]

Originally Posted by samandw

Lot's of engine out coasting (EOC). Almost never let the car idle (I usually shut it off well before I get to a red light/stop sign).

I have an automatic, so I don't think that is an option for me.

Follow semis on the freeway and generally drive slower.

As a bike rider I understand the principle of drafting, however I'm not really comfortable with following semis because they usually form a train and I don't want to get caught in the middle if a hairy situation arises. Yes I can brake faster, but the semi behind me won't. There is also another issue that I can foresee: even though a car can brake faster, with no wind resistance to help and maybe even the draw that was helping you save gas still in effect one might not break as well as expected under "normal" conditions. Or am I looking at this from the wrong angle?

Also, I usually upshift at around 1750 RPM, it took about 10 tanks of gradually lowering the upshift point to get the ECM to learn it. Doesn't balk or shudder much at all now.

Once again, I don't see how I can do that with an auto.

typically get 26-28 city and the car is rated at 18. I've done zero mods to the car as of yet, not even aired up the tires. . .all four at 32 psi.

Same here, no mods yet, and I got 19.34 on my first tank of mixed driving without the benefit of the options your manual transmission offers you.

Fuel injector cut button
Open/Closed Loop LED
SuperMID

I'm not familiar with those.

Bridgestone B381 LRR tires

are the basic 381's LRR or is that a special version of the plain vanilla?

Full moon hubcaps

and your source for those? ...or do you plan on getting something fabricated?

Wheel skirts (built to appear factory)

I thought of that as well but with my vehicle being a tad overexposed due to its taller stance I'm not sure if I wouldn't benefit more from covering the underside. What do you think?

grill block

Check. Are you going to do that yourself or have someone do it for you? Any resources you can share in that regard?

Full belly pan
Hood/under engine belly pan insulation.

Check.

Mirror delete

Check.

Pulstar sparkplugs

I just invested in Bosch IR Fusion plugs, which I will install after a few more tanks to establish a baseline but these pulstars definitely look interesting and I will consider them in the future.
[/quote]2nd battery w/timer hooked to block heater (warm the car before I leave work at the end of day)[/quote]Is it really worth it to have the extra weight on board?

Possible flow-turner aerodynamic mods at back and windshield pillars.

I'm not exactly sure what you mean. Can you please expand on it a little bit?

"If I win the sweepstakes" mods:
Custom built 13.x:1 compression EJ22 with custom ground atkinson cam
(87 octane)
STS remote mount turbo
Staggered intake valve opening (to promote swirl)
Standalone wideband (Insight O2 sensor) ECM
Taller gears (don't really need 4.11's with that 3.78 1st gear)

On the remote chance that I win the sweepstakes I'll call you. You share the details of those mods with me and I'll pay for your mods as well.

If I did ALL the mods and hypermiled, I'm pretty sure I could make 40'ish/50'ish city/highway. . .but it might not pass emissions.

That is not an option for me. I have to keep the car on the road.

I look forward to having more info on the points I asked about. If those have already been discussed/described at length somewhere else just let me know and I'll search or follow any links you may provide. Thanks for sharing.

[GasSavers_Dust]

Honestly, on the first point, your engine and tranny should learn you as a driver, and adjust shifting and such to you. If you always go easy on it, it should adjust by lowering shift points, meaning more MPG.

[JV-Tuga]

Originally Posted by Dust

You asked to be pointed to places you might not have thought of. Do you want to get into engine tuning, or just the easy stuff? WOuld you be willing to buy a wideband and tuning software to up your MPG?

Sorry. I have been a member there for a little while but that site has humongous amounts of info. I am slowly taking it all in.

Right now I just paid for the car and am doing a few mods to it to improve handling and fuel economy, so any further modding will have to wait. Eventually I'd like to buy a scangauge to get more info.

Most of the people on that site seem to have the turbo forester and also seem to be more in tune with HP and torque than any real economy or fuel efficiency. That is why I was very happy to find gassavers.org. I think you guys are more in tune with what I am after an have more to offer. The other downside to having the baseline model is that most of the ECU remapping that I've come across is meant for the turbo. Like I said, I am about to install a few mods and I mean to ask the shop at that time what are my options in that respect, if any.

I am not really after performance but I also don't want to detune or castrate this engine. I'm looking for efficiency wherever it is feasible but I also know that there are limitations imposed by the size and nature of the engine. Having said that what I mean is that I don't mind getting the mixture a little leaner in the city to put-put from point A to point B, but I also don't want to stomp on the gas when on the highway and instead of responding and getting me and my family away from the semi who can't stay in his lane (or whatever the situation may be) the car just goes limp and sits there.

I do appreciate any and all feedback and I apologize for my earlier response. I saw your reply out of the context you meant.

[JV-Tuga]

Originally Posted by samandw

Hello JV,

Thought I'd answer your questions in a PM since posting to the forum was giving me trouble.

You're correct, having an automatic really hurts your hypermiling ability. I'd at least consider trading your car for a manual Forester if you could. Beyond that, what year is your forester? I'd suggest your first mod be a Scangauge if your car is newer than 1995. It gives you instant feedback on mpg/TPS voltage/etc etc. I'd also look into getting a block heater installed if you often take short trips. . .driving with a cold engine is murder on mpg's. Answers to your questions below:

As far as following semis, I drove a 2008 Pontiac G6 GT rental car last weekend with an instant mpg readout. Even following a semi at a legal following distance made a difference. With a scangauge you could be able to tell what the risk/benefit looked like and decide if it was worth it to you.

Depending on your year, you may be able to adjust the shift points by tweaking with the computer. Ideally, I think you'd just want manual control of shifting and converter lockout, which might not be all that hard.

"Fuel injector cut button" would be useful for engine out coasting (EOC) which probably isn't an option for you with an automatic.

"Open/Closed Loop LED"
This would somehow indicate if the engine was in closed loop (basing fuel off the O2 sensor) or open loop (basing fuel off lookup table). If you get control of the shifting, you want to keep the throttle below the closed/open crossover and keep the engine in closed loop as much as possible.

"SuperMID"
A device very similar to the scangauge, but works with OBD I cars like mine (pre 1996)

I believe all the bridgestone 381's are B381's. They only come in 185-70-14 though, so they might not work for you. Here's a link to take a look at:
http://greenseal.org/resources/repor...resistance.pdf

"Full moon hubcaps"
Ebay is a good source:
http://cgi.ebay.com/ebaymotors/ws/eB...050193225&rd=1
Or you can just google it.

"Wheel skirts"
My gut tells me the underbelly pan would do more, but I plan on doing both.

"Grill Block"
I haven't decided on this yet, I just may make a foam/fiberglass "grill" that has no opening.

"Flow turner mods"
I have a suspicion that I can lower drag by putting flow changing devices that keep the flow from separating from the car. Think something like a vertical wing on the windshield pillar that forces the air to transition from the windshield to going smoothly back by the side windows. I'm also hoping to play with a similar concept in hopes of reducing the wake behind the car.

As far as passing emissions. . .well, you didn't hear this from me, but if you did all my mods you could easily get it to pass emissions by reprogramming the ECM with an "emissions tune" for the test. <smirks>

I'm not sure how far I'm going to take this car actually though, because I'm pretty sure if I built an all-out Honda Civic I could get way over 100 mpg, while the best I could hope for with the Legacy is maybe 50. Time will tell I guess.

Hope that helps you somewhat!

Sam

Originally Posted by samandw

Yeah, feel free to post it.

Thanks again samandw. I hope other Subaru owners will also find this thread interesting and useful to them.

[GasSavers_topher]

Originally Posted by JV-Tuga

Sorry. I have been a member there for a little while but that site has humongous amounts of info. I am slowly taking it all in.

Right now I just paid for the car and am doing a few mods to it to improve handling and fuel economy, so any further modding will have to wait. Eventually I'd like to buy a scangauge to get more info.

Most of the people on that site seem to have the turbo forester and also seem to be more in tune with HP and torque than any real economy or fuel efficiency. That is why I was very happy to find gassavers.org. I think you guys are more in tune with what I am after an have more to offer. The other downside to having the baseline model is that most of the ECU remapping that I've come across is meant for the turbo. Like I said, I am about to install a few mods and I mean to ask the shop at that time what are my options in that respect, if any.
.

You can improve both to certain point. You could always pull the heads and have them ported and polished. Ceramic coating on the pistons and maybe some dry film lubircant on the sides. Actually porting the heads would probably be the biggest gain you might see.

If you can contact the company that re-maps the computers you could have them re-map it for fuel efficiency. It shouldn't be a problem if they are a good tuner.

[samandw]

Originally Posted by topher

You can improve both to certain point. You could always pull the heads and have them ported and polished. Ceramic coating on the pistons and maybe some dry film lubircant on the sides. Actually porting the heads would probably be the biggest gain you might see.

If you can contact the company that re-maps the computers you could have them re-map it for fuel efficiency. It shouldn't be a problem if they are a good tuner.

I'm no Subaru expert, but I'd caution against porting and polishing the heads. Porting will actually slow down the intake flow velocity, likely reducing efficiency at low engine speed/throttle setting. And polishing reduces turbulence, which is useful to keep the fuel:air mix evenly distributed and preventing puddling of fuel on the intake ports.

[GasSavers_topher]

Originally Posted by samandw

I'm no Subaru expert, but I'd caution against porting and polishing the heads. Porting will actually slow down the intake flow velocity, likely reducing efficiency at low engine speed/throttle setting. And polishing reduces turbulence, which is useful to keep the fuel:air mix evenly distributed and preventing puddling of fuel on the intake ports.

Ok sorry Polish exhuast side while add swirl and tumble to the intake side promoting better air fuel mix.

[JV-Tuga]

Thanks for all the feedback so far guys.

What are your feelings towards a narrower tire?

Also...

Since I drive mostly in the city and considering that this car has a pretty good low range but mid and high response can be a bit slow, would my FE benefit from a larger tire size (lower RPM), as I've seen referenced elsewhere, or is that more for people who travel mostly on the highway?

Thank you.

[808subaru]

good to see other subaru AWD members here.

[theholycow]

Originally Posted by JV-Tuga

Thanks for all the feedback so far guys.

What are your feelings towards a narrower tire?

Take a look, I just discussed it pretty completely here:
http://www.gassavers.org/showthread.php?p=100468

Summary: All things being equal, a narrower tire will have higher rolling resistance drag. It will of course have lower aero drag.

Since I drive mostly in the city and considering that this car has a pretty good low range but mid and high response can be a bit slow, would my FE benefit from a larger tire size (lower RPM), as I've seen referenced elsewhere, or is that more for people who travel mostly on the highway?

A taller tire will, as you say, lower your RPM. Since you already have unresponsive power at high speeds, this means your automatic transmission is more likely to downshift at those speeds, which could negate any savings you get a lower speeds.