19bonestock88's 07 "Malibu Eco" build
 

So, this all began about two months ago when I was complaining about my cars fuel mileage, but I usually would add, "I'm sure it would help if I slowed down"... I was at the time driving aggressively and pretty fast, usually 10-15miles over the speed limit on my commute, and getting 22mpg...

I decided I would plug in my UltraGauge and see if I could improve this number...

Trip averages(on the un calibrated device) went from around 25 indicated mpg, to around 35... Intrigued by this apparent 45% fuel savings just from driving a little smarter(slower), I started pushing further, and on a really slow trip into town, I managed an indicated 36.1mpg...
And so, the Eco-modding began...

I decided that since everybody is making "Eco" versions of existing models, with minor weight reduction/aero improvements, I figured I would try that out...

I started with an air dam extension and some rear tire spats, partly to offset my buying a wider than original tire...

http://i1140.photobucket.com/albums/...sleempvgn.jpeg
In this photo, I was also experimenting with a partial lower grille block, which did basically nothing...

For a couple weeks, I managed trips to work between 36 and 37mpg indicated, and including all my short trips, the car itself was slowly creeping up past 30mpg average, over a couple tanks of fuel...

On the highway(cruise set at 80mph), I noticed I could get right at 30mpg indicated, and decided I was shooting for a 33% improvement, to 40mpg indicated...

... And then I started with grille blocks...

http://i1140.photobucket.com/albums/...svofovjcj.jpeg

This was phase one, done yesterday... Full, 100% grille blockage... A good thought,but about eight miles into my drive to work, the engine got too hot(225F) and I removed my upper grille block, leaving the lower in place for the remainder of the drive... Now, the engine was partially warm when I first set off, but despite having to stop(engine idling during this) and remove the upper grille block, that trip returned a shocking 39.3mpg indicated... The best I got before with similar conditions, was about 37 indicated, with lower speeds...

When both grille blocks were on, there was a noticeable reduction in throttle(load) required to maintain 55mph... Usually, it takes between 36.1 and 36.5% on flat ground, but I found the car wanting to accelerate past 55 with as little as 35.7%... Intake temps were probably about 20* above ambient during this, which also helps with mileage...

I'm currently revising my upper grille block in hopes of not having to remove it tonight

I would leave the upper and open the lower a little bit. Kind of like the cup cars do. The uppers are blocked and they adjust the lower with tap to get the temp they want.

Had I seen this before cutting, I might have started there... However, I opened a 1.5" by 19" rectangular hole in the lower half of the upper grille block and went to work last night... The trip started with a cold engine, but I did make it fourteen miles or so before the engine got uncomfortably hot and I had to take the upper back off... Trip average was 38.0mpg indicated, still not bad all considering... This gives me some insight into the FE benefit of a block heater...

I plan on opening the existing hole in the upper slightly and trying again, as the temp climb from 195 to 210 was way slower than before, so I might only need one more revision to the upper to stabilize the running temp between 200 and 210 degrees(my goal)

So, yesterday I made the existing hole in the upper grille block 1/2" higher, roughly an inch and half wider on top(width not changed at bottom), and the half inch strip between the hole and the bottom edge removed... I did drive all the way to work and back in this configuration, but at the end of the trip to work, temperature was flirting with 220*, and at the end of the trip home, the story was the same, but I decided to try cycling the heater to remove heat, with much success... I'm not comfortable with temps staying above 210F(even with no cooling fan kick on until 228F), so I enlarged the opening again, carving a "bow tie" emblem in the center, just 3/8" above the opening, and raising the top of the opening 3/8" around the bow tie, for visual effect... Considering how well it mounts up, and the nice, almost dealer accessory-like appearance it has, I'm considering the upper grille block done, except for paint and semi-permanent mounting(not plastic tape)... If my current version of the upper doesn't bring the temps down enough(it was pretty close), I'll make small holes in the upper half of the lower grille block...

The trip to work(starting with a cold engine) averaged 39.0mpg indicated, and the trip home averaged 41.0mpg indicated, this was due to my driving to the fuel station and thus preheating the engine and while I was getting fuel the UG shut off, resetting the trip mileage figure

So, I've been working on my grille block, and did a passenger wiper delete... But, ever since my trip into the mountains, my fuel mileage has been consistently low, by between 5 and 10 percent... I'm not sure if high engine temps during the trip are to blame(breaking down my non synthetic oil), or my focus has dulled or what?

It just occurred to me that I figured out that running the A/C drops engine temp on the trip into the mountains, and I've been running it constantly on, even if I didn't need it for comfort... Maybe that's the difference?

Not sure... I know non-synthetics will change viscosity over time, regardless of temperature. And those new Malibus get pretty crazy mpg for a full-size car, right?

It could... My oil is about halfway through its usual 3k-ish mile interval, but I spent perhaps half of that mountain trip twenty degrees above normal trip... I was never actually overheating, but was between 215 and 225 degrees on most climbs...

And yes the new Malibus can pull down some pretty killer mileage... Some guys over on CMF are getting 50+mpg averages with the Hybrid... They're also much bigger and heavier than my 2007 is, so that's pretty amazing...

In my car, A/C is worth about 25mpg when cruising at 50mpg - that is, I get 75mpg with it on, and 100mpg with it off. Your engine runs cooler because with the A/C on, there's a fan running full tilt all the time.

The (percent) impact on your car may be smaller, because it's probably about the same amount of load but your vehicle is much larger, but I'd expect better economy by opening up the block a little and not using the A/C to keep the engine cool.

Not sure on the Malibu's but on my Cobalts, if air position control knob is just about to the floor position or anywhere farther towards the defrost it turns the A/C on. I'd guess A/C on is a 2-3 mpg hit for my XFE and Impala.

I actually just did some testing, and you're right... With the APC knob any further than floor, it kicks on the A/C compressor, adding approx 10% load at idle... Coasting in neutral (engine running)at 40mph, it'll cut my MPG in half...

Since discovering that, I've been running with it off if at all possible...

So, I've had a bit of a setback on my build, in the form of a broken spark plug that initiated a misfire... I noticed the miss on my way to work, last night of last work week... When I got home, I eventually removed plug 1 and noticed that the electrodes were gone, along with the center insulator... Feeling sick, I tried sucking it out with vacuum to no avail... Thinking it was already gone, I put in a different(but functional) plug and fired it up, and the misfire persisted, and eventually I heard a loud tapping that abruptly stopped... I removed the plug and found tap marks on it and the center insulator was broken(sliding up and down the center electrode)... Another functional plug was installed(only two of those left before needing to buy one), and re-fueled, and the miss finally went away... Maybe water in the fuel or something, but I've never heard of a 15k mile NGK plug failing...

Anyway, I did a compression check on 1 and 2 for a rough guess as to engine health... 2 had 190# and 1 had 140#, so I'm guessing something was damaged in the whole ordeal... Mileage is consistently down about 5% too... While in the same weekend, I switched to a 26 inch wiper blade, I doubt it was a 5%FE loss by itself...

So, I guess this engine(and car) will live on... No signs of imminent death and running as it has always... On occasion, the idle is a little rough, but it's not out of the norm for a car nearly ten years old...

I have found a sticking caliper pin that'll need attention before long, and at least the rear rotors need replaced...

I'm also getting my best mileage, averaging over 40mpg indicated on most trips from home to the local towns...

So, I've come to a point, where I have to ask, what next? I've got wheel skirts, rear wheel spats, an air dam, belly pan, and max pressured tires...

I still need to tuck the exhaust in order to build a diffuser, and really should redo my belly pan for smoothness(and ease of oil changes)...

Will making a higher flowing exhaust system help mileage?

Changing from panel filter to cone filter? I've got a K&N sitting around meant for a Cobalt SS... Higher flowing intake tube as well?

Not deleting the functional A/C, even though I don't use it...

Maybe higher voltage coils and wider plug gap?

impressive mileage for a 07 malibu.

I don't know how your stock airbox is in your malibu, but I did a box delete in my 06 aveo, and went with a cone filter attached to the stock intake hose. My stock airbox has an hole that takes in air near the passenger front wheel. We blocked that hole to prevent cold air from entering the new intake and to hopefully only allow warmer engine compartment air thru the new filter. After adjusting the ECU, I noticed about a 5% gain in my total miles on my tanks. Hope this helps

I have been considering getting HPTuners software to tune my other car, and would also use it to tweak my Malibu for both performance and economy... My thought was lower idle(600 vs 800 RPM), leaner mixture across the board(though still richer than stoich at WOT), more timing advance across the board(except maybe idle), slightly earlier shift points(allowing 3rd and TC lock at 25bs 30, and allowing 4th and TC lock at 35 vs 40), and slightly more throttle allowed before downshift... This would allow me to lug the engine down to nearly 1000 RPM in some cases, and hold higher gears longer before kicking down...

That sounds like a good plan. Wish I could help point you in a better direction as far as reprogramming your factory ECU, but I know nothing about it.

Be aware that k&n air filters let more dirt through as well as more air.

I'm already aware of that, but the engine is already damaged from a spark plug disassembling inside cyl 1, the car is rusting in a couple places, and it does have 157k... I figure it's not long for this world anyway...

Well, the round K&N filter didn't work out, as it was way too big to even fit inside the air box, and wouldn't have clamped onto the inside of the lid like I had originally thought... However, I felt the urge to modify something and noticed the side of the airbox closest to the engine was warm, so I drilled some holes there, in hopes of pulling in some warm air...

I also smoothed out the inlet of the tube inside the airbox lid, figuring that turbulence in the air right before the MAF could give inaccurate readings... I'm also in the process of making a non-accordioned intake tube, with the PCV inlet deleted to keep the oil deposits out... When it's finished, I'll probably clean my TB too, as the plate is covered in sludge from the PCV feeding oil vapors to the engine...

So, I finished the intake on my Malibu... Here's the stock one removed... I already attached the PCV breather...
http://i1140.photobucket.com/albums/...sx73r21jf.jpeg

You can see here where the PCV was depositing oil on the inside of the intake... I didn't photograph my TB, but it was pretty nasty... I didn't remove it, but wiped it off...

http://i1140.photobucket.com/albums/...sxi970edl.jpeg

... And here's the finished(ish) intake... I cut about 3/4" off the 45* elbow to make fitment easier... All together, one 90, one 45, and one 6" straight piece... I used the clamp from the stock intake on the TB end of the intake, the 3" plastic was a slip fit on the TB anyway, and used a 3" silicone coupler on the MAF end of the intake...
http://i1140.photobucket.com/albums/...scdne5o2q.jpeg

And so far, no CEL! Mileage also seems to be up, but I need more data before I make any claim... However, in the past two days, I've been setting records for UG indicated mileage on both of the trips I usually make...

Some data I've acquired after installing my home made intake...

Engine load is just slightly down at cruise(43-45%), meaning that on flat ground, I can cruise at 50mph, at an instant reading of 50.0mpg or more, or 46-50mpg at 55mph...

Hills can be managed with less throttle, or a further distance maintained while still in overdrive, TC locked status...

On my usual work commute, I've been consistently averaging ~42mpg indicated since the intake install, in sixty degree weather..

... And on my benchmark trip, from Flatwoods to home(on WV-4 and CR-23), I averaged a record shattering 53.4mpg indicated, in 93 degree weather...

I now find myself accidentally going too fast in places I used to be fine cruising at 50/55mph, and nailing the ever smaller throttle angle at cruise is getting difficult...

If the car weren't drive by wire, I would be seriously considering a hand throttle by now...

Congrats, those are some astounding numbers for a Malibu.

The Eco-tec name really means economy. Your 07 should have variable cam timing. I am running early stuff, 02 L series Saturns.

The L61 never had variable valve timing, that was the 09-up LAP... It was 2.2 liters, but had VVT and other stuff from the LE5...

However, in 07 they got coil on plug ignition, and a different reluctor wheel on the crank...

Keep in mind that my UG is still reporting around 10% optimistic... I never bothered recalibrating it, because of the time it would take to zero its odometer...

So, given the posts of some owners of similar transmissions about being flat towed safely, and info from the service advisor at the local GM dealership, I've tried coasting with the engine stopped... Other than the brakes and steering taking much more effort, the car is still manageable, but I haven't got any useful info about gains from switching to full-on EOC, yet...

However, if full-on EOC is safe, then I need to figure out a way to kill the engine without turning the switch off... Maybe running a kill switch to the injector fuse?normally closed momentary switch, and an inline fuse? Run the wire to a safe place in the cabin, and mount the switch as cleanly as possible...

The reason for the switch is that during that moment when I have the key in the ACC position, I'm pretty certain that the odometer stops recording mileage...the UG, however, never stops recording...

You're absolutely right. I used an injector kill switch on my Insight for a long time, just as you've outlined, because by turning the key off, none of the computers record anything for a brief time.

What connector did you use to tap into the fuse panel for the wires? I don't wanna just shove wire in there, and possibly short out my injector circuit... A good junkyard source for such a momentary switch?

I actually cut the injector grounds and put a relay between them and the ground. I don't think there's just a fuse for it in my car.

Since I have the fuse, I don't wanna cut any wires... I know that removing the fuse disables the injectors(I pulled it to do a compression test)... For now, I'll just key off and back on quickly and add maybe 1% to the odometer reading when I refuel...

So, I've gathered some data from trying out full-out EOC... First off, steering is very tough due to the extra resistance provided by the power assist motor on the steering column, and the brakes suck once the vacuum assist is used up(a vac reservoir may be coming), but there are lots of EOC opportunities on my work commute... Using them all, I've been averaging around 42-43mpg indicated... Wait, that looks like no improvement, except that all week(up to tonight), my commutes were made in forty degree weather(one morning started at 38 degrees)... Tonight, the ambient temp was 52 degrees on my trip home, and I averaged 45.3mpg indicated... To put it in perspective, the last time I got numbers like that on that particular trip, it was 90 degrees outside the car...

To clarify the numbers, the UltraGauge calibration still hasn't been changed, so the actual mileage should be around 10% less...

Had to replace a faulty battery, went with a cheap one to keep me going until later... Now, I can aggressively use EOC on my work commute... If I'm not concerned with my average speed (extending coast down distances) I can average way better mileage than usual... Last night, I managed a 49.0mpg indicated trip home(but at 3am and no traffic at all)... Usually, I try and keep my speed up around posted limits, and average 42-45 indicated with these brisk fall temperatures...

Anyway, winter is quickly approaching, and I'm soon to mount my winter tires(just waiting for mornings consistently under 45 degrees), and wondering what other ecomodders do for winter time, with respect to their mods... My Ver2.0 air dam is right at 2.5" off the ground, and scrapes on about everything, should I remove it for snow? Do you guys usually remove wheel skirts?