2007 Monte Carlo FlexFuel/E-85

[rh77]

This is my first real test of an Ethanol-able rental vehicle. I'm in Iowa, so I figured that's a good place to find some E-85, right?

Test route: Kansas City -- Sioux City, IA (some city driving) -- back to KC (with more city driving).

So far, it used only a bit over a 1/2 tank at around 28 mpg. I'll get a final tally at the end of the gasoline tank. I'll probably fill tomorrow on the way back (while getting the gauge down as close to E as possible).

I expect it to act the same, and perhaps FE will be similar. As we know a gallon of Ethanol has less energy than gasoline, so it'll be interesting to see how the engine adjusts.

Interesting observations:
The engine is the efficient 3.5L V-6. In top gear+TC, the engine just turns at 2000 RPM at 78 mph. I need to test 55-60 mph, but I recall about 1500 RPM at that speed.

It's essentially a 2-door Impala, with unique tweaks. It's a good, solid Domestic.

More laters...

RH77

[thisisntjared]

WOW 55-60 @1500 rpm!!!! thats crazy long! i dont think even vettes have a top gear that is that long!

wow, and it still cant beat out 30mpg? thats has to be because of the ethanol.

[2TonJellyBean]

Yup - the math says 1538 RPM @ 60... wow!

((225/25.4 x 60/50)+16) x 2.9749928 / 2.86 / 0.71 = 39.015 mph/1000rpm
tire diameter x constant / final drive / overdrive ratio

60/39.015 = 1538 rpm

That's a real highway gear!

[rh77]

...and now for the Mid-Rental Report:

Yup, it's confirmed:

1400 RPM at 60 MPH! 2000 RPM produced 78 MPH. Along with these low numbers come decent FE with the tank of Gas...

About 500 miles into the rental with the following stats

87-Octane Regular Unleaded:
28.9 MPG
Avg Speed = 62.6 MPH
Miles: 448.6
Gallons: 15.52

Then it was time to fill-up with E-85. I waited until the last station on the route that would allow a safe distance but empty the tank as much as possible, which left perhaps a gallon or two in the tank and an unknown amount available in the neck. I filled it to the brim.

Preliminary Mileage:

FE dropped...LIKE A ROCK. No Chevy pun intended.
Over about 120 miles, the same speeds produced around...
21 MPG
After about 10 miles the FE numbers began to drop when the engine management system adjusted to the moonshine.

The biggest change in feel was the amount of available power. Caution: "Butt Dyno"...

On hills where the TC would traditionally unlock, the Monte climbed steep grades with the TC locked, at 76 MPH and 1700 RPM, with the A/C on and actually gained speed as the cruise adjusted! That's V-8 kinda torque. Mid-range was unnoticeably changed, but near redline -- Woah! It's like someone added another 2 cylinders without my knowledge!

This is what happens with the Ethanol. If I was into horsepower all the time, this is probably what would go in the tank on a regular basis...

I turn it back in tomorrow, so we'll see what the final tally ends up to be. There will be more city driving, so the FE average has to stay the same or drop.

For more info on the engine, Wiki the GM "LZE 3500" 60-degree V-6 engine. It's actually pretty impressive for a pushrod design.

At one point, I was cruising around town at 1100 RPM - continuous.

RH77

[thisisntjared]

weird. chevy builds petrol motors like they are diesel.

[rh77]

Turned in the Monte this Morning...

2007 Monte Carlo LT, 3.5L Flex-Fuel

+ Handling
+ Decent FE for Size
+ Steering Wheel Controls

- Numb Steering Feedback
- Impala/Monte "Clunk" in the steering column
- Terrible seating position

You can tell they started with the Impala, and just kinda went from there with the Monte Carlo. But, good reason I suppose. The "Personal, Full-Size Coupe" segment is dwindling. The sucess of Cutlass Supreme of the late 70's peaked this segment style, and it's gone downhill since.

The Interior was much like the Impala with similar components, except for the dash -- which had oddly placed vents. The seat didn't seem to fit the car -- despite it's 6-way action with lumbar support, it just sat too high. Extras included heated leather seats and handy steering wheel buttons for the radio.

The drive: the chassis and suspension seemed to be stiffened for the coupe. It handled well, but the steering couldn't tell you much of what was going on. The Chevy essentially idled down the highway at very low RPMs, which provided good FE. 1st gear actually redline at 55 mph!

E85 Experience (check out this thread regarding Ethanol):

The final result of E85:

21.6 MPG (27.5% drop -- additional city driving included, but overall the same was noticed at highway cruise)
258 miles
52.0 mph
11.94 gallons

Power seemed to increase, and it took the vehicle some time to fully adjust (rough cold starts with idle-skip).

Look for this to be a TSB for these cars. Every Impala or Monte that I've driven from 2007 has an annoying "Clunk" in the steering column. It happens on light road bumps or giving the engine some throttle. It's like two metal pieces are striking together in the steering column -- could be in the suspension or elsewhere The model that did it the most was the Active Fuel Management model -- when it changed from 6 to 3 Cylinders (or back), the clunk was very noticable.

It was fun to drive, and reminded me a bit of High School when I had my V-6 Beretta -- but the 4-door version can be bought with the same engine and options, which is recommended (see Impala write-up).

In conclusion, the car was rented primarily to test the E85, which worked as expected, but with a larger hit in FE that predicted -- a drop of 27.5%. I attribute this to the ECU probably having never been introduced to E85, and safely compensating.

(pics to follow)

RH77