Catasstrophic converters and MPG???

[Aerovette]

[Gene] Back in the moldy daze, we had a plastic bottle and a hose run to the base of the old CAR-bib-orater to mix H-too-Oh into the cylinders and stretch the gazz mileage out.[/Gene]

[slewfoot]

Originally Posted by bill_daniels

Question for everyone quoting mpg.....do you pen and paper calculate these numbers, or do you accept your car's calculation. I ask, because I've found over the years that the car's calculations are.....optimistic. With every truck I've had, and even the Cruze, I have found my actual mileage is always 1-3 mpg less than the trip computer advertises. Obviously the accuracy of one tank calculation is going to be off a bit due to how much gas you put in at a fill up, but over time, those differences average out and you get an idea of real world mpg v. trip computer calculated mpg.

Well, as for me, been there done that with the oversized vehicles used as DD's. This is why my wife and I have Sonata Hybrids. Both are 2015's bought at the same time.

We get 36mpg in town, yes I use the the car calculation but as a back up, filling up a 16 gal tank every 3 weeks tells me it's fairly accurate.

Besides, the MPG on the stickers is set at sea level calculations. Drops dramatically as you increase in altitude

[Wathen1955]

Gene lives in Florida right? Do they add ethanol to gas? When I had my 2000 Ford F150, I got 17-18 all the time. When they started to add ethanol to the gas (10%), my mpg dropped down to 14.

[Yadkin]

No mileage reported by the OP. The cats could be clogged. That would really affect mpg. I agree with some here, the Acadia (my sister had one) is a POS. Dump it.

[Vette40th]

If they are clogged, you can generally see them glow pretty good at night while running.
Or if they are starting to clog/ internally broken, may be the issue. When breaking it can cause the engine to sense knock, as one of my cars did, and it killed fuel economy..
Ethanol is in all fuel, with the exception of the ethanol free of course. You need to look these stations up. FLorida has allot of them due to boating. My 4runner go 1 mpg better from Georgia state line to Charleston. I did four calculated runs within a couple months.
My Corollla got 2 mpg better with ethanol free fuel.
Use this link to find the stations near you.
https://www.pure-gas.org/

[mrvette]

Over 20 years ago, when playing with the vette and DPFI and MPG, it was said to buy gas with no ethanol, so I went to the BP station up the street, who SAID/ADVERTIZE they had REAL gas......so I tried several tanks of it.....

no cat, but closed loop on the FI......NO help on MPG......alky fuel same as gasoline......go figger......

[Vette40th]

With no ethanol, you can retune the engine to take advantage of it.. Air Fuel Ratio is not 14.7 its more like 14.3 with ethanol. I know there are smarter people out there that know this, especially tuners.
Ethanol free you can make more power, adjust timing etc... Is it worth it, maybe, as the fuel costs more sometimes..

[Onebadcad]

Originally Posted by Wathen1955

Gene lives in Florida right? Do they add ethanol to gas? When I had my 2000 Ford F150, I got 17-18 all the time. When they started to add ethanol to the gas (10%), my mpg dropped down to 14.

I believe our pumps in FL advise up to 15% ethanol in all unleaded grades.

I used e85 in all my cars once I do the flex fuel kit and tune, none are driven too much, as a while ago it was explained to me that ethanol is very corrosive for fuel pump, lines and injectors.

One day I may win the lottery and get a reliable daily driver,,,

[GTOguy]

Originally Posted by Vette40th

With no ethanol, you can retune the engine to take advantage of it.. Air Fuel Ratio is not 14.7 its more like 14.3 with ethanol. I know there are smarter people out there that know this, especially tuners.
Ethanol free you can make more power, adjust timing etc... Is it worth it, maybe, as the fuel costs more sometimes..

Wrong-O. Lots of mis-information on this thread. Ethanol has 50% of the energy of gasoline and when mixed with fuel even at the current 10%, it LEANS OUT the fuel mixture, it doesn't make it richer as you posted. A vehicle without onboard fuel management set to run 14.7 will run more like 15.7 with ethanol added. OBD2 vehciles (all vehicles built since 1996) adjust for this. As I said earlier, no polishing this turd. I'll say it again, as I said to VJ (who is doing yet another head gasket on the Sonic) Get RID of that crap.

[Vette40th]

When running straight alcohol, what is your air fuel ratio. 7 to 1.
So, explain how adding alcohol leans the air fuel ratio out.
I have no problem beomg corrected, and will take contructive crticism, but I know af ratio with 10% ethanol reduces af ratio
https://www.carparts.com/blog/what-i...hart-included/

[GTOguy]

You're talking apples and oranges. 100% pure Ethanol or E85 has to run at 7:1 because it has 50% of the energy of gasoline, which runs at 14:1-ish. Add E-10 to a fuel system designed and jetted to run pure gas, and the system runs lean due to the diminished energy in the ethanol. Ask anybody who runs pure ethanol or E85 how they jet their carburetors. They will tell you that they either removed the jets entirely, or went up 100% in jet size. If you tried to run pure alcohol in a fuel system jetted for pure gas, you would be over 25:1 and so lean you would burn up your pistons. Hell, I saw that happen maybe 6 times this month at the vintage drags....lean condition on the top end, and Poof go the pistons.

[PLRX]

Originally Posted by mrvette

Wife has a 2012 GMC Acadia.....6 cyl/auto/loaded with crap......car looks new inside and out.....but the MPG sux only about 14 mpg......

Car is 11 years old, do you expect 30 MPG?

[Vette40th]

Originally Posted by GTOguy

You're talking apples and oranges. 100% pure Ethanol or E85 has to run at 7:1 because it has 50% of the energy of gasoline, which runs at 14:1-ish. Add E-10 to a fuel system designed and jetted to run pure gas, and the system runs lean due to the diminished energy in the ethanol. Ask anybody who runs pure ethanol or E85 how they jet their carburetors. They will tell you that they either removed the jets entirely, or went up 100% in jet size. If you tried to run pure alcohol in a fuel system jetted for pure gas, you would be over 25:1 and so lean you would burn up your pistons. Hell, I saw that happen maybe 6 times this month at the vintage drags....lean condition on the top end, and Poof go the pistons.

I am not talking apples n oranges. You didnt read the article.

[GTOguy]

Correct. That's the IDEAL ratio. So you need to jet RICHER to run it. If you put E-10 into your non-computer-controlled car, your car will run leaner (15.7 or so) UNLESS you re-calibrate your carb or fuel injection. Newer cars like my Tundra do this automatically. I simply get about 2 MPG more when I run pure gas out of state on trips. Back in CA, it drops due to the E-10 being less efficient because of its lack of energy compared to gasoline.

[Onebadcad]

GTO DOOD is the man, as always!!

[GTOguy]

Originally Posted by Vette40th

With no ethanol, you can retune the engine to take advantage of it.. Air Fuel Ratio is not 14.7 its more like 14.3 with ethanol. I know there are smarter people out there that know this, especially tuners.
Ethanol free you can make more power, adjust timing etc... Is it worth it, maybe, as the fuel costs more sometimes..

I missed this, and you are correct. I skipped right the hell over that part!!

Apologies for the 'wrong-o'. I interpreted that you said that ethanol simply made the mixture richer all by itself, and went on my tirade. We both agree on this.

[mrvette]

Originally Posted by PLRX

Car is 11 years old, do you expect 30 MPG?

It's a damn 6 cyl, I would hope for 20 at the worst....

[simpleman68]

Originally Posted by Onebadcad

I have removed all cats at time of purchase.
I have never gotten over 10 mpg with any car.
I have never gotten over 8K with any tires.
I have never owned a car the neighbors did not hate.
I have never owned a car for which the purchase price exceeded the modifications added.

I am a terrible person to get car advice from,,,
I am a terrible person,,,

I see we are closely related.
Scott

[Rodnok1]

Originally Posted by mrvette

It's a damn 6 cyl, I would hope for 20 at the worst....

Friend's Jimmy is 6 banger and gets horrible mileage... 13 to 15 around the town and not much better on highway.

[GTOguy]

Originally Posted by Rodnok1

Friend's Jimmy is 6 banger and gets horrible mileage... 13 to 15 around the town and not much better on highway.

Number of cylinders don't really gauge mileage. The old 305 CID GMC V6 was a torque monster but pretty much a pig on fuel. My friend's 490 CID 4 cylinder National is no fuel sipper, either. Our old V8 powered Grand Marquis got over twice the MPG's ....more like 3 times.

Again, the OP needs to dump the current turd while it still runs and drives, because it won't shortly.