P&G not helpful in Saturn SL2

[Project84]

I'll be filling up my gas tank tomorrow afternoon and calculating my MPG as well as resetting my ScanGauge II for it's first break in full tank.

Just wanted to say, for me anyway, P&G (usually done from 55mph to 40mph) has yielded what looks to be ZERO benefit. I'm at 279 miles this tank, generally fill up at 300 miles, I'm bearing down on the "E" mark on the fuel gauge which will put me right at 300 once I hit it.

Looks to be another 30 mpg tank, but I'm thinking P&G did next to nothing for helping the mileage. I also fabbed a HAI halfway through this gas tank and it too appears to not be much help. I guess I need to finish that heat shield and fab that grill block. I'm seeing 150*F IAT at operating temp from the HAI, but I'm still wondering why my new thermostat is opening at 170*F when it was a stock replacement from Napa, supposed to be 192*F.

Just venting I guess, seems I've been trying super hard this tank and its not looking like it will have paid off at all.

[GasSavers_RoadWarrior]

Possibly been trying "too" hard on a DOHC motor that doesn't get into it's power band until 4000 RPM or so. Also bear in mind that paying too much attention to the instantaneous MPG readout will screw you.

[Project84]

Originally Posted by RoadWarrior

Possibly been trying "too" hard on a DOHC motor that doesn't get into it's power band until 4000 RPM or so. Also bear in mind that paying too much attention to the instantaneous MPG readout will screw you.

How do you try too hard? The car hasn't seen 4k rpm in over a year probably. If I steadily increase throttle it shifts on its own around 3500. What I've been doing is what everyone on here suggests, P&G w/ heavy throttle at low RPM, which according to the instantaneous MPG readout, as you mentioned, shows the best FE I've seen yet. Driving w/ the "egg under the pedal" like I used to, so far, has showed me that it was just taking too long to get into the next gear, and those light throttle low RPM, low gear, situations were only showing 15-20mpg, heavy throttle 35% or less, got me through the gears quicker and into 4th where I steadily putted along at <10% throttle and usually over 40mpg.

I'm just feeling annoyed.

If you have suggestions, I'm all ears! Thanks.

[dosco]

Originally Posted by Project84

How do you try too hard? The car hasn't seen 4k rpm in over a year probably. If I steadily increase throttle it shifts on its own around 3500. What I've been doing is what everyone on here suggests, P&G w/ heavy throttle at low RPM, which according to the instantaneous MPG readout, as you mentioned, shows the best FE I've seen yet. Driving w/ the "egg under the pedal" like I used to, so far, has showed me that it was just taking too long to get into the next gear, and those light throttle low RPM, low gear, situations were only showing 15-20mpg, heavy throttle 35% or less, got me through the gears quicker and into 4th where I steadily putted along at <10% throttle and usually over 40mpg.

I'm just feeling annoyed.

If you have suggestions, I'm all ears! Thanks.

Learn to work the auto trans more better. I have noticed in my Camry (with auto trans) that the shift points are a function of speed and throttle angle. I can induce an upshift by lifting, as well as induce a downshift by "standing" on the gas.

I don't have a SG and have seen improvements up to 34 mpg by being light on the throttle at low speed, religiously P&G at highway speed, and just generally coasting as much as possible.

Is your driving mostly city or highway?

Have you pumped up the pressure of your tires?

Is your fuel filling technique consistent?

[Project84]

31.37 mpg.... so lets say P&G added that extra 1 mpg to this tank. I drive 8k mi. per year roughly, that's only a savings of $32 at $4/gal.... I don't think that's worth it considering the workout the transmission gets. I may stop P&G except at a few key spots that I know about on certain interstates around here where I can get more than 1 mile for free, and those will actually be EOC miles, not P&G

[SolidLiquidSnake]

Originally Posted by Project84

31.37 mpg.... so lets say P&G added that extra 1 mpg to this tank. I drive 8k mi. per year roughly, that's only a savings of $32 at $4/gal.... I don't think that's worth it considering the workout the transmission gets. I may stop P&G except at a few key spots that I know about on certain interstates around here where I can get more than 1 mile for free, and those will actually be EOC miles, not P&G

I have an SL2 as well, only 3 years newer and I wonder too if you actually save gas turning the engine off or if the restart actually hurts fuel economy because it could use more gas to start than to actually just leave it on for that little hill here or there. You would think that the starter and the transmission would seriously hurt from all the shifting and starting.

Hell, the most I do is shift it in neutral whenever possible, I noticed that it doesn't matter as much when I first start the car and drive the first couple of miles in to "warm it up" because the rpm are wayy to high when I shift it in neutral(1.8 rpm), but when it "warms up" the rpm's stay at 1 to 1.3-4...

[Project84]

I'm curious to know what your SL2 is getting, and if it's auto or manual transmission.

I've been considering removing the side view mirrors, but I use them religiously and don't like turning my head to see what's in the other lane, these cars have little/no blind spot, so the mirrors are just about perfect.

I wonder what an SL2 auto could get done up like "lovemysan's car". I believe his is 5sp SL1 w/ no spoiler, grill block, HAI, underbody paneling, rear wheel skirts, and no side mirrors and he's getting over 50mpg.

I bet 40 on the highway is attainable for sure, but unfortunately for me, there's no highway around that is flat enough to get 40's. I guess that's what I get for living in KY.

[dosco]

Originally Posted by Project84

I bet 40 on the highway is attainable for sure, but unfortunately for me, there's no highway around that is flat enough to get 40's. I guess that's what I get for living in KY.

I got about 45 mpg in my Camry that has a larger engine and weighs more than your Saturn. I drove from Maryland to upstate New York, which involves driving through the Catskill Mountains.

I'm sure that proper P&G with your car, even on the biggest hills, will get you a very nice mpg number. I would wager at least 45 mpg if not better.

[theholycow]

It IS possible to try too hard. I was trying too hard at first, until I realized that it's okay to not P&G even if that's my current strategy.

Start just by taking only really good opportunities to P&G, and revert to "egg under the pedal" driving the rest of the time. As you get practice, you'll phase in more P&G at less opportune times.

It is pretty hard to P&G effectively with an automatic, though your Saturn probably can do it better than my GMC.

Also, it helps to separate your experiments so you know the effect each one has. It can be hard to tell if P&G and HAI are canceling eachother out, for example.

[Project84]

Tire pressure is 48 front/rear, I know when to let the throttle out so it will shift to 3rd and 4th by itself, and just how hard and at what speed it will downshift, I've learned this transmission well over the last few years. My driving is generally about 70 to 80% city, and although I don't use the same pump, I use the same station and the same slow setting on the gas pump each time.

I know I should've seperated my experiments, but the whole reason I wanted the ScanGauge was to monitor IAT w/ a HAI, it just so happened that I started P&G when I first filled this tank and my ScanGauge showed up a few days later so I constructed the HAI and continuied the P&G.... although I doubt they would cancel each other out.

For this Saturn anyway, the only benefit I see from P&G w/ neutral vs. just leaving it in gear and doing a P&G, is the GPH go from roughly 0.50 in gear vs. 0.40 in neutral, and obviously, in neutral you glide further than you do in gear.

I'm not sure of other Saturn owners w/ auto trans experimenting w/ P&G, but I'm thinking my results would probably be consistant w/ other's in the same car. It just doesn't seem beneficial.

We shall see though, I've got another 26 miles until I hit 300 on this tank, maybe I'll try to squeeze more out of it and go 320 for my all-time new high?

The math on my 12.1 gallon fuel tank works out to be 364 miles per tank @ 30 MPG. Maybe I'll go to 330 or 340? Risky!!