*The official what works to improve miles per gallon thread*

[SVOboy]

I advocated the WAI heavily,

Post up an intro thread, it's good to get more saturn love on the site. If you feel like it you can get a VW wideband for like 40 bucks, but the display costs *** money usually.

[cheapybob]

Originally Posted by SVOboy

I advocated the WAI heavily,

Post up an intro thread, it's good to get more saturn love on the site. If you feel like it you can get a VW wideband for like 40 bucks, but the display costs *** money usually.

I'm trying not to put money into anything that doesn't have a payback in 10,000 or 20,000 mi of gas savings. My last mod is to heat the fuel, but its costed $30 worth of stuff and it will be very difficult to get a payback on it because it was so expensive. Its not installed yet. The hot air intake was about $30, but it was $30 well spent, IMO. Maybe this only works with GM PCM designs.

[SVOboy]

Check out the full underbelly in the DIY section, cheap and works.

[kickflipjr]

Hot air seems to help me. I can cuise at 1500rpm much better then with cold air.

[rh77]

Originally Posted by kickflipjr

Hot air seems to help me. I can cuise at 1500rpm much better then with cold air.

I as well, but for me, my power is down. I immediately noticed a gain in FE with hot air, and recently, I've seen an average of 130F and as high as 165F. I've been getting a much better FE average since when I started here, which was 26 up to 31 almost immediately. I think the hotter 'stat helps with generating more heat for the intake, and helps get the TC engaged quicker (which is where the EBH came in -- the car would stay in Open Loop for a LONG time in the Winter). Aero mods wouldn't help me much -- I'm stuck with an equal time of city driving, but of course more miles out on the highway (a good drag co-effecient helps). I've also restricted my top speed to 57 mph, even in 70-zones. A restrictor plate has helped introduce more throttle input and has forced additional hot air into the mix, and has forced a slower acceleration driving-style to keep MAP pressures low (the ScanGauge is a must to see how your car wants you to drive). I see 34-35 mpg sometimes, or 28. Really depends on the amount of city driving I have to do. If I did a road trip at 100%, I'd be getting in the mid 40's (which has been confirmed - at the lower cruise speed) Lately, the A/C hasn't seemed to effect things much, but the throttle input vs. automatic transmission action is tricky to keep MAPs under 10.0, TPS 25-30% or less, and RPMs between 2000-3000. Fuel trim numbers from a separate logger shows an increased lean situation since baseline. New tires are next on the list (out of necessity), and lots of research will be required. Of course, this is all on an Stock OBD-II Honda ECU on a car designed more for power than economy.

RH77

[cheapybob]

I built a manifold cover which covers the exhaust manifold from both above and below which feeds insulated tubing to an insulated airbox. I got some more insultation and will insulate the tube from the airbox to throttle body next. I've gotten the temp up as high as 230's with it. 200 is typical.

Trying to determine the mpg value of a mod in city driving is pretty hopeless, IMO, because there are too many other variables, so you won't notice an improvement unless its major.

Yes, you are paying for the fuel economy with a loss of power. It only stands to reason.

[Silveredwings]

One caveat to redirecting the intake: make sure it is safe from water ingestion from rain, snow and road puddles.

Ford tried to improve the FE of the Exploder a few years back. They lowered the air intake (a CAI in this case) to grab air just below the front bumper. When one of these mighty off-road beauties drove through a road puddle, this new 'nozzle' would suck water in, create a hydraulic ram in the cylinders and bust wrist pins and connecting rods. The new engine cost over $3,500. Ford claimed their warranty didn't cover it, and of course insurance didn't either.

Anyway their redesign made the Exploder into a big self-propelled wet-vac.

[yo vanilla]

Originally Posted by krousdb

I have actually done a lot of testing with overinflated tires. The following is a report from last summer. I had just switched to a new set of OEM tires which ended up dropping my mileage by 6%:

July 2005:
Well I'm back and the results seem to make sense, although I am a bit
surprised.

My first test was with the new tires (approx 5000 miles on them) at
62/62 PSI. The MPG was as high as 99.9 (100+) and as low as 96.3.
The final MPG was 98.8 at 77F. The low of 96 seems to confirm my
previous 104+ reading because at no time did it drop below 99.9 on
the 104+ MPG test.

For the second test, I dropped the pressure to 44/42. For the trip,
97.4 MPG at 82F.

For the third test, I dropped the pressure to 35/33. For the trip,
96.0 MPG at 86F.

I did expect the 6 MPG drop by switching to the new tires (my guess
was 3-5). I guess they have more breaking in to do. The larger
circumference of the new tires (due to full tread depth) had no
effect on the trip length as indicated by the trip odometer, which
was 23.4 miles. Actual measurements of the tires showed 77 3/16" for
the new and 76 3/4" for the old. The difference is about 6 tenths of
one percent, negligable in my opinion.

I was surprised however that tire pressure made such a small
difference, although the MPG's may be skewed higher due to the higher
ambient temps during each sucessive test. I guess what this tells me
is that if you spend most of your drive below 42MPH, you might see a
benefit in raising your tire pressure. Otherwise, you will not
likely notice a difference. The other thing it tells me was that
yesterday's results were not a fluke. These MPG's are repeatable.

My old set of tires spend most of thier lives at 50PSI. The wear on
them is perfectly symmetrical. Anyone who tells you that high
pressure will cause uneven wear, IMHO, is misinformed. The even wear
is also a testament to a prefect wheel alignment. If your tires are
wearing unevenly, have your alignment checked.

Based on these results, I will keep the new set on and drop the
pressure to 44/42. My ride to work is partially on a very bumpy
stretch of I-79 (Andy can attest to this) and the 44/42 PSI yields a
noticably better ride. The 35/33 yields an even better ride, but I'm
not quite ready to give up all of my advantages. The new tires will
probably drop my summer mileage from the low 70's to the mid to upper
60's. I guess thats the price I will pay for new, safe tires.

i've seen TONS of tire with uneven wear due to improper inflation. i used to write service, toyota included actually, so i've seen it on alot of toyotas . mostly camry's and tundras, since the recd pressure is way too low, IMO (iirc 29 and 26 respectively) and those vehicles always came in with lots of outer wear around 20K miles or so.

in my own vehicles i have seen inner wear from overinflation; i used to run my tires fairly higher than rec'd pressure for instance in my 16v vw to stiffen the sidewalls up. ran them around 38lbls iirc and recd was maybe 32lbls.

your prius (assuming you have a prius from your avatar) came with a "special load rated tire" due to the extra weight of the hybrid system. first off i think your not losing tread due to higher tire pressure is a special case vs the rest of us, since your tires should probably be pumped up higher than toyota tells you to anyway (due to the higher load on them). next switching to a lighter tire might help your mileage but in your car there is always the chance of that tire not holding the load.

[FireEngineer]

Originally Posted by yo vanilla

your prius (assuming you have a prius from your avatar) came with a "special load rated tire" due to the extra weight of the hybrid system.

Only the 2001-2003 Prius came with XL load rated tires. The 2004-2007 Prius comes standard with regular load rated tires with a 2 psi differential front to back for the extra weight. Still the 35/33 Toyota recommends does cause edge wear so new tires are necessary by 20,000 mikles on average. My OEM Prius tires are evenly worn at 45,000 miles. I keep them at 60/58 since most of my driving is in a totally urban/inner city environment and have seen a 6-9 MPG gain with the higher inflation.

Wayne

[GasSavers_StanleyD]

Originally Posted by Compaq888

The wai increases the air sucked in. The stock setup is very resrictive, all a WAI does is kill the restriction and let's the air in.

Im a big time newbie and never really considered warm vs cold air. From what Im hearing (Im learning throgh context clues), it seems that adding warm air increases mpg while increasing cold air increases power and decreases mpg.

I never knew any of this. I just thought that MORE air intake improved both power and mpg. Thats why I decided to get a cone filter setup in my car. The only one I could find to date (only 1day to search) was the following one on Ebay. I THINK its a warm air since the cone appears to be in engine compartment. If its cold then maybe I should hold off and just buy K&N stock-fit filters for my stock air intake for my 98 4cyl Camry LE. Can you guys please advise. I dont needs loads of power but I would like to increase my mpg. I thought the cone filter would work by inceasing air, PLUS I would save money in just over a year from not having to buy disposable air filters anymore. I just found out that you have to OIL the crap on every cleaning. Good thing someone told me to make sure I dont overoil cause I didnt know that I had to use ANY oil at all.
Thanks for your comment... I love this site. I havent done ANYTHING AT ALL to Camry yet and Im getting a crack under 30 but would like to jump it to 35-40 mpg without spending a ton of money


http://cgi.ebay.com/ebaymotors/ws/eB...6859595&rd=1,1