Fuel Efficiency: Missing the simple things?

[psyshack]

I would go thru that metro with a fine tooth comb. If you have wrench skills. Going thru that metro should be a breeze. I see no good reason to skimp on parts for any car that dosent use oil and basicly runs out good and solid. Plugs, filters, timing belt, O2, CV joints, brakes and other things would be replaced before I ever tagged it.

[JanGeo]

Originally Posted by theclencher

I thought I was cheap!

My driving conditions must be awfully clean too, as I don't change my air filters at the factory recommended mileages either- I take 'em out, clean out the air boxes, and tap and/or blow 'em out with compressed air (from the back side of course). I don't remember how many miles it was- 60 or 80,000- on my then-new truck when I finally changed it just out of guilt.

Once or twice I tried changing the oil filters with every other oil change. But I only change oil every 6000-7500 miles so for the $3 cost of the filter I just change that out of guilt too even though it's probably just fine.

I am not so sure the effects of a partially plugged air filter will be all compensated for by the FI. It would cause greater throttle opening to be required and thus the throttle position sensor could prevent all from "balancing out"? For sure peak power would be reduced. Out of principle I wouldn't tolerate a dirty filter.

Top cylinder lubes- everything my rationale tells me is to think they aren't necessary or good because the top end components consist of the valves and the upper portion of the pistons/cylinders. Well much effort is put into engineering the proper amount of protection against too much oil getting past the valve stems and piston rings; also any oils in the combustion chambers contribute to detonation (according to Smokey Yunick) so they are something I don't want in there.

I'm not familiar with any manual gearboxes with the oil fill on the top- I see 'em on the side (as a built-in protection against overfilling).

Yeah I checked the air filter and shook it out a few times but that's all - pretty much just wacked it on a hard surface to knock the dirt out.

The oil filter does have a zinc electrode that neutralizes acids in the oil that gets consumed but the last time I changed oil in the Geo was when oil was $1 a quart and the filter was like $3.95 so yeah I am cheep. Heck the car rusted out before the engine wore out so that IS my point - unless you drive a LOT then there is no point in wasting oil.

Upper cylinder lube - the top ring really may not get too much lube past the other rings and the valve stems intake at least gets a little from the gas as it blows by it. The amount of marvel is really small and it helps to break up carbon in the combustion chamber. The STP gas treatment I just put a small amount in from a 16oz bottle at each fill up and that keeps the injector(s) clean and running better especially when adding the Marvel oil to the gas - wish I knew about Acetone back then to try it on the Geo.

The manual tranny has a filler plug somewhere - I just couldn't find it so I took a little oil out the top switch plug because it was a bit too full and added some Slick50 Gear lube. It takes a while to get working but it all helps. That was in my Geo.

Slick50 Gear made a big improvement in my xB when I added some then a month later I switched to Synlube and that was a major difference in shifting feel but not much more improvment in mileage a that point.

[Peakster]

So yeah, I just finished a 4.5 hour trip in the Geo going 50mph with cruise control. I coasted with the engine off whenever an opportunity arose and was pleasantly surprised by how clear the roads were outside of the city. The temperature is balmy 16*F for December and my trip was a loop, so wind should not have been a concern.

Even after all of this, I only got 49.75mpg. Needless to say, I'm totally stumped as to why my current driving is merely doing the same as my driving previous to finding this site. 55mph in August translated to 54mpg, while even with EOC, grille block and driving at 50mph in December, I don't even break the 50mpg mark.

Can't wait for my Scanguage II to come in the mail now!

[MetroMPG]

If you're getting similar FE today in 16F on winter blend fuel compared to what you were getting in August at 85F, I'd say you're doing OK.

[JanGeo]

Yeah 16F is freeking cold man the air density alone will kill your mileage with the extra drag it presents and unless you have an WAI the poor engine is having a hard time burning that cold air/fuel mixture. I used to get 53 average in the SUMMER!

[zpiloto]

Originally Posted by JanGeo

Yeah 16F is freeking cold man the air density alone will kill your mileage with the extra drag it presents and unless you have an WAI the poor engine is having a hard time burning that cold air/fuel mixture. I used to get 53 average in the SUMMER!

Here's a density altitude calulator http://wahiduddin.net/calc/calc_da_rh.htm

Plug in the numbers for 16 and 85 degrees and you'll see a pretty big swing in altitude.

[MetroMPG]

Checked my FE history: last winter on three cruise-controlled highway trips (around 80-90 km/h) I got an average of 51 mpg (US).

To make the Suzukiclones get any better than that, you have to hypermile the **** out of them.

Driven normally - or even normally verging on conservatively - these cars will not exceed expectations.

[rh77]

Originally Posted by MetroMPG

Checked my FE history: last winter on three cruise-controlled highway trips (around 80-90 km/h) I got an average of 51 mpg (US).

To make the Suzukiclones get any better than that, you have to hypermile the **** out of them.

Driven normally - or even normally verging on conservatively - these cars will not exceed expectations.

I think this is true for most cars' fuel maps. I notice a hit in FE if the IAT goes below 60F, which is tough to maintain in 10-20F weather.

I'm thinking about experimenting with some sort of switched, dual-air intake system. At 30-40F cruising around town, I can get 100F intake temps if drawn directly from the engine compartment (and the best FE), but any hotter than that and the maps compensate again, in the wrong direction.

If I knew what I was doing (rarely), I'd set up an air intake Y-Pipe with actuated vacuum or electrical airflow valves via a circuit that reads the IAT and manipulates the valves to keep it around 90F, or as close to that as possible, based on conditions through the CAI and HAI. YMMV as 90-95F is my engine's sweet spot.

RH77

[MetroMPG]

Originally Posted by rh77

I think this is true for most cars' fuel maps.

No way man! Maybe I was spoiled by the old Accord, but I could drive it on autopilot all day, any day, and beat the EPA by 20 percent. It under promised, over delivered. These clones seem to be the opposite.

[MetroMPG]

PS - Someone with an Insight has done the switched intake thing. All automated. I think I read about it on insightcentral.net.

Thing about winter mods - do you have a heated workspace? I don't have one, so everything's on hold for 4 or 5 more months. Blah.