P&G not helpful in Saturn SL2 - Gas Savers

Project84 · 06-23-2008, 03:22 PM

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.

RoadWarrior · 06-23-2008, 03:36 PM

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 · 06-23-2008, 03:48 PM

Quote:

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 · 06-23-2008, 04:08 PM

Quote:

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?

**theholycow** · 06-23-2008, 04:31 PM

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 · 06-23-2008, 05:28 PM

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!!

tvsteve · 06-23-2008, 07:01 PM

Quote:

Originally Posted by 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.

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.

Greetings,

When I first got my scangauge last December the first thing I noticed was the temp at 160-170F. I replaced the thermostat with a oem. Temp now climbs to 195F and stays there. That low temp of yours is hurting mileage.
I have a 99 and 97 SW2. The 99 is a automatic and gets 32-34MPG 75% highway at 65-70MPH. The 97 is a 5 speed, just recently purchased and averaging 3 tankfulls it gets 38MPG. My IAT is at outside air temp, no hot air intake. Did you check your ECT sensor? BTW I dirve at a constant speed, use cruise control and take it easy off highway. Tire pressure at 35 F & 33R. Also I don't use the scanguage to calculate mileage. I use the same pump to fill and calculate amount used by mileage driven.

Steve

RoadWarrior · 06-24-2008, 04:38 AM

Driving Marvin, "trying too hard" is keeping the revs under 2K rpm and grannying it away from intersections... gets 18-20mpg like that. All the gases "ooomph" goes bye-bye in the the tranny fluid. I'd imagine that staring at an instantaneous MPG gauge would tell you, you're doing quite well.... would probably say 22 mpg.... so you strain it up to speed over 5 or 6 blocks at 22mpg then get 25mpg for one block before the next stop. OTOH, if you are somewhat spirited with the gas pedal without flooring it, staying between 2K RPM and 3K RPM when accelerating, you get maybe 15mpg for 80ft and and 25mpg for 6 3/4 blocks, and if you're not staring at the MPG gauge, you can probably spot that you can glide the last block or two.

With a DOHC and an automatic, you've got a less than ideal combo, I mentioned 4K RPM because I think that's about where your torque peak is, and your lowest BSFC will be somewhere around there. I'm attempting to accelerate between 2K and 3K all the time because my tq pk is at 2800, I'm thinking you should be aiming for 3-4K

Project84 · 06-24-2008, 06:28 AM

So would you suggest I go to the dealer for the thermostat? Sucks, the Napa one I put in was $17 w/ my discount!

dosco · 06-24-2008, 10:03 AM

Quote:

Originally Posted by Project84

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.

There's the problem. I've noted only marginal improvements in city driving, with substantial improvements for highway driving.

Project84 · 06-24-2008, 10:34 AM

I'm working w/ someone selling his '02 SL 5sp.... that would put me into the 40's condsidering I don't drive much highway.

Aside from that, I called Napa and they warranty the thermostat I put in, so it's coming out and another is swapping in, probably this evening.

Might as well spend some time working the heat shield for the HAI as well.

SolidLiquidSnake · 06-24-2008, 01:52 PM

Quote:

Originally Posted by Project84

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.

Call me a newbie, but what exactly is P&G. Is it a form of driving where you are non-agressive and shifting the car in neutral whenever possible? Also I'm confused on HAI? I read these terms constantly on these forums but unsure what they are...

dosco · 06-24-2008, 01:57 PM

Quote:

Originally Posted by Project84

Aside from that, I called Napa and they warranty the thermostat I put in, so it's coming out and another is swapping in, probably this evening.

I wonder what it is about Saturns and thermostats. I had a '93 and replaced the thermostat when I was living in Phoenix. Turns out it was bad, ended up blowing the radiator about 1 week after driving cross country from AZ to MD.

Funny.

tvsteve · 06-24-2008, 04:20 PM

Quote:

Originally Posted by Project84

So would you suggest I go to the dealer for the thermostat? Sucks, the Napa one I put in was $17 w/ my discount!

After having problems with aftermarket thermostats I only use oem. Tried a non oem in a 94 SL1 last winter. Car would not heat up. The third try was with an oem. Worked with great fast heat. Another thing to keep in mind is the housing check valve. Saturn sells the t-stat for 17.00 and the t-stat with housing for around 35. Those are on line prices. I get my parts from Saturn of Glen Burnie. Order on line or call an 800 #. I also have 4 post 96 Saturns and using the scangauge all read 190-195F warmed up.

Steve

RoadWarrior · 06-24-2008, 05:40 PM

Hmmm if they were that much trouble I'd figure a way of putting in a housing for one of the standard type $4 thermostats.

**theholycow** · 06-24-2008, 06:14 PM

Quote:

Originally Posted by SolidLiquidSnake

Call me a newbie, but what exactly is P&G. Is it a form of driving where you are non-agressive and shifting the car in neutral whenever possible? Also I'm confused on HAI? I read these terms constantly on these forums but unsure what they are...

Glossary

P&G: Pulse & Glide. Briefly explained, it involves accelerating and then coasting in neutral repeatedly, instead of just cruising at a steady speed.

HAI: Hot Air Intake. The intake air is heated before it gets into the engine.

Project84 · 06-24-2008, 08:18 PM

I'm gonna give NAPA another try since I deal w/ them through my work and know the guys pretty well, I'm not sure if it's warranty or not, I mean, how do you prove a thermostat isn't working properly? They said bring it and and they'd exchange it, if that doesn't work, I'll get my money's value back in parts the next time when I'll change it out w/ OEM.

The problem is the water neck goes into the block just under the A/C compressor, I'm seriously doubting any way/shape/form of alternative housing or modification to utilize a different style thermostat.... besides, I really like the design of these specific thermostats, they just sorta snap into place in the water neck and then you swap o-rings and you're done... no adhesives, no "line it up perfect" like a SBC, no gaskets.

I'm over 300 miles right now and I'm still tetering on the "E" mark, i'm thinking of running it up to 330 so I have roll the odometer over to 140k, I'm about 17 miles away right now! I'm a nerd, but that excites me! What better way to cross another milestone mark then by doing so w/ my best ever MPG? sweeeeeeeet! I'm thining it'll only be 31.xx though, still, this tank is nearly all city.

Project84 · 06-25-2008, 10:33 PM

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 · 06-26-2008, 07:43 AM

Quote:

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 · 06-26-2008, 07:58 AM

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 · 06-26-2008, 08:05 AM

Quote:

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.

Project84 · 06-26-2008, 08:14 AM

It makes sense to me that your larger car, with larger engine, would have better gearing for highway.... a larger engine makes more power, takes less of a gear to get it moving.

My Car shifts into 4th at 35 mph when warmed up, and the RPM's climb quick after 45mph. 60mph is like 2,800 RPM.

My parent's Bonneville for example weighs nearly 1,200 lbs more, has an engine which is larger by 1.9L (double my engine), but at 60mph it's cruising at 1,700 RPM, probably very similar to your Camry.

SolidLiquidSnake · 06-26-2008, 01:15 PM

Quote:

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.

I have an automatic and I use P&G quite frequently here in the city. I used to average 32 mpg highway when I didn't used to P&G and drive like I depended on the gas. Believe it or not, our cars are nearly identical the way you are describing yours. When the car is warm P&G is easy and almost refreshing to know that I can save assloads.

I want to do something with my car though, I want to learn how to HAI or do something small and not ugly to my car to better enhance aerodynamics. After my next fill up I'm finally going to inflate my tires from the door's recommended psi to the max sidewall. So this is only the beginning.

dosco · 06-26-2008, 03:21 PM

Quote:

Originally Posted by Project84

It makes sense to me that your larger car, with larger engine, would have better gearing for highway.... a larger engine makes more power, takes less of a gear to get it moving.

From an energy perspective, it should take more energy to move the Camry (~3300 lbs) than a Saturn (~2400 lbs) and therefore should have poorer mpg than a Saturn.

Looking at the Gaslog entries, there are many Saturns that get better mpg numbers than my Camry. A quick look shows 40+ mpg.

The confound, of course, is how the car is driven. I can get 40+ mpg with solely highway miles. Local traffic kicks my butt, bringing mileage down to the low 30's.

Project84 · 06-26-2008, 03:51 PM

The saturns in the 40+ are all SOHC... I know of ZERO DOHC Saturns in the 40's. Just my 2 cents on that topic.

Solid - I just did a ghetto HAI, took about an 30 minutes and $15 at the hardware store, also got heat shield material which will also be utilized when I do the grille block. HAI takes nothing away from aesthetics, so go for it!

My SL2 is a '96 w/ 140k, pw, pl, sunroof, rear drum brakes, 15in. alloys, spoiler, and cruise control. I have 205 tires on it for a bigger foot print, but went to a 60 profile rather than stock 65, so I should be getting the same speedometer readout + 1%. A short in the wiring disabled the DRL, oh well... lol, wipers operate by themselves intermittently, can't track that down. exhuast system has been worked on numerous times. All in all though, I've come to really love it.

**theholycow** · 06-26-2008, 04:45 PM

Quote:

Originally Posted by dosco

Quote:

Originally Posted by Project84

It makes sense to me that your larger car, with larger engine, would have better gearing for highway....

From an energy perspective, it should take more energy to move the Camry (~3300 lbs) than a Saturn (~2400 lbs) and therefore should have poorer mpg than a Saturn.

For highway mileage, weight is not a very large factor. At steady high speeds, aero is the largest issue, along with engine/drivetrain efficiency. With tall gearing a larger engine may actually be more efficient than a small engine, as engine friction goes up exponentially, not linearly, with RPM.

SolidLiquidSnake · 06-27-2008, 09:24 AM

Quote:

Originally Posted by Project84

Solid - I just did a ghetto HAI, took about an 30 minutes and $15 at the hardware store, also got heat shield material which will also be utilized when I do the grille block. HAI takes nothing away from aesthetics, so go for it!

My SL2 is a '96 w/ 140k, pw, pl, sunroof, rear drum brakes, 15in. alloys, spoiler, and cruise control. I have 205 tires on it for a bigger foot print, but went to a 60 profile rather than stock 65, so I should be getting the same speedometer readout + 1%. A short in the wiring disabled the DRL, oh well... lol, wipers operate by themselves intermittently, can't track that down. exhuast system has been worked on numerous times. All in all though, I've come to really love it.

I'd like to know how you made your ghetto HAI, it's really appealing to me and I want to do it to my car, probably this weekend if I could. I've heard of seran wrap, but I'm unsure if that's what should be used or really, how I do it in general.

Your car sounds like you've been through some craziness.. You can't fix the wipers or the DRL?? I'd be more annoyed by the wipers then anything..

I'm glad you love your car as I love mine too and bought it for the soul purpose of Saturn SL2's being good on gas.. The only problem I've had with my car is the car rpm when shifting to park or drive jumping way too high and staying there too long before correcting itself. We discovered it was the PCV and we fixed it with making a little catch can because it did also seem to burn some oil and we were trying to find out if this synthetic oil was just the cause or if my car actually was burning oil. Turns out my car is running fine and synthetic oil is out and 10w 30 is in!

**theholycow** · 06-27-2008, 09:30 AM

Please, don't fix the DRLs on your '96 Saturn. They make WAY too much glare, doing far more harm than good.

Project84 · 06-27-2008, 10:52 AM

I used a 1 1/2" to 2 1/2" silicone plumbing coupler, a 1 1/2" 90* plumbing PVC elbow, and 3" flex tubing for dryer exhaust.

Remove the resonator from the air box, drill the hole where it was out to roughly 1 1/2" diameter, stuff in the 90* elbow from the inside, keeping the flared end in the airbox to prevent it from pulling out, put the silicone cuppler on the elbox on the outside of the airbox, oh, I forgot, I used a 1" section of 2" PVC pipe, put that in the 2 1/2" end of the coupler, band clamped the flex tubing over the coupler and routed it through the A/C lines, next to the coil packs, and under the exhaust manifold.

I then drileld and tapped a hole in the lid of the airbox and relocated the Intake Air Temp sensor there, so it would read the hot air, and I blocked off the old inlet fo the IAT sensor. On hot days, so far I've seen 160*F w/ no heat shield or grill block.

As for the DRL, if I could fix them, I would, I cleaned all the grouned, checked the wiring, fuses and relays.... all is well. I can't find the source, so they'll stay messed up. I didn't care for DRL's, but knowing they won't function properly makes me wonder if there's an electrical short somewhere draining voltage, because the DRL's went out the same day the passanger side high beam stopped working... goofy electrical issues w/ this car.

I've also replaced the radiator, rotors TWICE in 15k miles, pads once, and front control arms/ball joints.

Just did oil change last night, car still sounds like a diesel. ho-hum.

dosco · 06-28-2008, 07:30 AM

Quote:

Originally Posted by theholycow

For highway mileage, weight is not a very large factor. At steady high speeds, aero is the largest issue, along with engine/drivetrain efficiency.

Sure.

Quote:

With tall gearing a larger engine may actually be more efficient than a small engine, as engine friction goes up exponentially, not linearly, with RPM.

I'm still having a hard time buying that a SL2 could not achieve 35+ mpg, OTOH he's stated that most of his driving is city, so I wouldn't expect anything stellar.

For ****s and grins I pulled out some of my uber-old fillup records from when I owned a '93 SL2. Mileage numbers varied from 20 to 30 mpg, which I'm sure has do do with driving types (city versus highway) and regular "gagging the engine" (I used to hammer the hell out of that car). Back then (the records are from when I lived in NorCal, so it would be 1996 or so vintage info) I tried a product called "petromoly" (oil with moly disulfide in suspension) and was curious to see if the stuff improved mileage. It didn't.

Lastly, I don't know what the gear ratios are compared between an SL2 and a 99 Camry LE. From experience driving a '93 SL2, I recall that on the highway in 5th gear and 65 mph the engine wasn't running at an unusually high rpm. City driving is a different story, though. The engine was easy to work over the entire rev range...