How did this happen?

[JB]

I have had "Li'l Blue", my 2010 Subaru Forester, for 2 years this month.

Lately I have been doing advance research into replacing her when my lease runs out next year. Why? Well, I almost feel guilty criticizing such a great little car, but. . . I was spoiled by driving Mercedes MLs for 10 years before I got Li'l Blue.:redface:

The engine is a bit short on thrust, the tranny searches for the right gear on hills and the engine sounds like a mad hornet when she downshifts and an annoyed hornet when she doesn't.:facepalm: There are other imperfections, but they don't matter in this post.

Last week I got a recall notice from Subaru. Needed to replace the engine management software to improve emissions. She was also due for routine service, so I took her to the Subie Dealer yesterday. Asked them to replace the air cleaner in addition to the routine stuff. Had a lot of dust here lately.

Didn't notice anything different on the trip home (70 miles).

This morning the drought and heat wave broke. Rain and 72*. Daily highs had averaged over 105* for June and July, first rain since May.

So much for background.

Had to go to Miserable Wells for groceries this morning. Li'l Blue shot out of the driveway like a WRX STI. Engine sounded more like a sewing machine than a hornet. Throttle response greatly increased, engine sounds actually pleasant. Mileage was 24.5 (up from 22.4).

So, what caused this?

The new software in the engine 'puter?
The new air cleaner?
Cooler, damp air?

Am I missing anything? What do you think?

 

[lncoop]

Re: How did this happen?

All of the above. Plus, she found out you were thinking about replacing her and decided to straighten up and fly right for a while.

 

[KDAVID1]

Re: How did this happen?

I am new to this forum stuff so forgive me if I'm not up to speed--but I am into cars as well. Although I am not an expert on the Subaru I would be pretty confident in the fact that the software would be what fixed it. The filter and change in weather would help as well but
not as much since all of these cars now days are managed by the computer which compensates for alot of things we take for granted like air filters, timing, worn plugs, etc.
Glad it has worked out for you so far.

 

[KDAVID1]

Re: How did this happen?

oh--glad to see some one from AR--I grew up there.

 

[rbh]

Re: How did this happen?

+1 !!!!

But I would go with the fresh air cleaner more than anything.

 

[marcoalza]

Re: How did this happen?

Throttle response greatly increased, engine sounds actually pleasant. Mileage was 24.5 (up from 22.4).

So, what caused this?

The new software in the engine 'puter?
The new air cleaner?
Cooler, damp air?

Am I missing anything? What do you think?

I used to go out late night/early morning on my own (when I was a boy) when it was damp & misty just to race around the countryside in the winding lanes to enjoy the extra 10-15 bhp that the natural water injection gave you.
Was really noticeable and enjoyable.

Your clean air filter probably helped a lot too!

Having said that, when I finished waxing it on a Saturday morning it used to drive better in the afternoon

 

[DJ]

Re: How did this happen?

"Electronic Updates" are GREAT!

We are in a different world now-JB.

It is amazing what can be done, to an engine, with a few keystokes.

We always thought that one HP/Cubic inch was amazing. Now, we have twice that+-more to come.

 

[Tim Frank]

Re: How did this happen?

My wife's Subaru is going in on Friday for the same update.
I'll ask her to tell the dealer not to do ANYTHING extra until she has had a chance to try it after the software mod.

Less than scientific, but we'll see what she thinks of the before and after shots.

 

[bruceb58]

Re: How did this happen?

+1 !!!!

But I would go with the fresh air cleaner more than anything.

That wouldn't help at all actually. The engine management system calculates fuel delivery based on airflow so the fuel/air mixture always remains constant. If it was a carbed engine that is a totally different story.

As far as mileage increases are concerned, I would base my findings on more than one tank of gas. My car varies a couple MPG just by slightly different driving conditions.

 

[rbh]

Re: How did this happen?

Kind of a stick in the the mud comment Bruce, air cleaner changes are next to gospel, regardless!!!

They rate right up there with fresh underware!!!!!!

REGARDLESS!

 

[puddle jumper]

Re: How did this happen?

A clean air filter and clean fuel filter can make a world of difference.

The software up date probably changed the shift patterns in the trans and the timing curve for the engine. Very similar what a lot of people do with tuners in just about all the vehicles out there.

 

[bruceb58]

Re: How did this happen?

Kind of a stick in the the mud comment Bruce, air cleaner changes are next to gospel, regardless!!!

They rate right up there with fresh underware!!!!!!

I agree you should change them. It will help your car have more power but it just is NOT going to help your fuel economy.

Read this:
http://www.fueleconomy.gov/feg/maintain.shtml
"A new study shows that replacing a clogged air filter on cars with fuel-injected, computer-controlled gasoline engines does not improve fuel economy"

Go to page 14:
http://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf
Shows it is more likely that clean underware will give you better mileage than a clean air filter

And to disturb you guys even further, a clean fuel filter won't help you with fuel economy either.

As far as why JB is getting better mileage, I have read that this recall has made the fuel injection run a little leaner. Would kind of make sense since the recall was emmisions related. One drawback I heard was that some people have seen a little less power at times.

 

[JB]

Re: How did this happen?

Hmmmmm. Well, I have improved the performance and economy of a couple of vehicles with K&N air filters. It is not rocket science to figure out that a restricted air intake is going to result in less air (and less fuel in EFI engines) getting into the engine and making less power. (The K&N filters also increase intake noise.)

I didn't have him put a K&N filter in it, just a replacement for the one that has been driving around central Texas for 2 years collecting portions of Mexico and AZ that blew in.

I haven't tried a performance improvement chip in the ECM. They do claim a lot, including better MPG. I do agree with DJ that there is potential to greatly increase power in the software, but too often it would increase hazards to long engine life along with the performance bubble.

Economy is largely in my right toe. If my engine is performing better, my toe gets lighter and I use less gas. It is not an engine change, it is a driver behavior change.

Cooler air is denser. There is more air in a given volume. That is why modern EFI systems measure air mass instead of air volume, and why cooler air makes more power.

Well those are the theories I have about the changes in Li'l Blue's behavior, I just don't know which are actually contributing.

Thanks for all the input, gents. Lots of food for thought there.

 

[mnypitboat]

Re: How did this happen?

We had a similar thing happen with my wifes Saab 9-5 V6 turbo when we owned it. Differance was it was fine before, I just thought it was boring. When we got it back it had a completely differant feel. Shifted more crisp, not as much turbo lag, better gas mileage, and the a/c didnt shut off when I stomped on the gas. LOL. It was a recall or program or something on the computer and all they did was update the computer. No air filter or anything.

So it might have been exactly what people have mentioned. New shift points, new timing curve etc. I also had my Z28 dynotuned back when I owned it and gained 42 horseys at the rear wheels. That is significant. So yep, a computer tune can definately change a cars personality.

 

[MH Hawker]

Re: How did this happen?

computer softwear up dates and chip changes will make big diffrances, i changed the chip and injectors in my 120 hp 4 banger S 10 and brought it to 180 hp

 

[mnypitboat]

Re: How did this happen?

computer softwear up dates and chip changes will make big diffrances, i changed the chip and injectors in my 120 hp 4 banger S 10 and brought it to 180 hp

A 50% increase in a 4 cylinder. Now that I would like to see a dyno sheet on. I was tweaked and running race fuel on an LS1 V8 and only got 42. Kinda hard to beleive 60hp increase on a 4 cylinder. I think I will call BS on this one.

 

[bruceb58]

Re: How did this happen?

I would call BS on a lot of the tuner mods. When I worked for GM/Delco and was working with the ECM guys, they said a lot of the people that did the profiles didn't know what they were doing and basically just richened up the mixture to get more power. In doing so, they would eventually wipe out the o2 sensor in short order. They basically said that there was so much insider knowledge needed to program the ECM correctly that no aftermarket tuner could possibly know what they knew. There were basically to many interdependencies. In the old days before you were able to flash the memory, the chips on a lot of the aftermarkets would basically force the ECM into default mode and richen up the mixture that way. They tried all the tuners and the chips before that so they were well aware what was out there.

 

[sasto]

Re: How did this happen?

Sometimes life is just simple. You put some love in her, and she's just giving some back.

Good Luck!

 

[WaveJumpingMaxum]

Re: How did this happen?

A 50% increase in a 4 cylinder. Now that I would like to see a dyno sheet on. I was tweaked and running race fuel on an LS1 V8 and only got 42. Kinda hard to beleive 60hp increase on a 4 cylinder. I think I will call BS on this one.

180 hp is possible but hes alittle off the 2.2L 4cyl s10 starts at 162 stock!! not 120. hahahah 18hp gain sounds a bit better huh?