So, guys I’ve realized that I don’t have a build thread for my sedan... I wanna fix that to catalog what I’ve done, to show progress as I can, and for the regulars and newcomers alike to enjoy...

I’ll begin this to state the goal of the build, which is to have a fuel efficient, fun to drive, semi good looking, daily driver... I don’t want to sorely miss the Redline every time I get into my daily, as I stopped hoping to resurrect it, but nor don’t wanna get 20mpg either...

It all began about a year ago when I bought my car, it being completely stock and having just over 106k on it... it wasn’t too bad for a cheap car, and it had almost no options, which made the car lighter (2670# curb weight) and left less stuff to break as the car ages...

stay tuned for more more catching up!

I drove the car in stock form for a while, with my first tank being almost 37mpg, and having few tanks in the low 40s mpg, but the modding bug hit me, pretty hard...

I made some smooth wheel covers, by screwing annular discs of coroplast
onto my stock wheel covers...when I had this mod on the Malibu I had, I measured a 3% gain in instant MPG at 55mph, so I didn’t bother testing them on my Saturn

i also started with blocking the grille for faster warm up and to slightly lower the drag coefficient of the car, and landed at around 75% block...

later on, I got some more modding done, with funding courtesy of Horace-Mann insurance company. I hit a deer, and used some of the funding to order some suspension upgrades, and switched to black housing headlights since they needed replaced anyway. I chose to order the FE5 shock/strut combo for my car because they’re the stiffest ones available, and because I had them on the Redline and I liked how it handled. I also ordered lowering springs to drop the center of gravity and lessen frontal area...

Shortly after, my car developed a bad misfire which I spent lots of time diagnosing and I ended up cleaning a set of injectors and doing a ported intake manifold, ported throttle body, and high flow(non corrugated) intake tube...(more on that in the next post)

So, on to discussing the powertrain mods I have done...

Beginning at the airbox, I reshaped the outlet of the lid to accommodate a 3” round pipe instead of the oval outlet it had... while I was at it, I smoother the radii of the transition from airbox to air tube, for ever so slightly better flow... in the future I wanna cut out the oval tube all together and join the airbox with a 3.5” round outlet, for more airflow capacity...
I also deleted the air silencer that goes under the airbox, mostly because it weighed like 5# but also for more intake noise...

working toward the engine, I bought two silicone couplers, one 3” 45 degree elbow and one 3” to 2.75” 90 degree elbow, and got a free piece of 3” stainless steel exhaust tubing drilled for the IAT sensor... this allowed better airflow than the corrugated rubber hose that the OEM supplied, deletes the PCV nipple which means no more oily residue, and it looks a little better. The transition to 2.75” at the throttle body builds intake velocity for better torque while the larger diameter tube allows a larger airflow capacity than stock. Once I eventually do a 3.5” outlet on the airbox, I’ll need to change my 45 degree elbow to match the new size, and it should help high end power a little...

next, I ported my throttle body, starting with 80 grit sanding rolls and working to 160 grit and then a scotch brite wheel on a rotary tool... I made a bell mouth on the inlet of the TB and smoother out the angular size transitions inside it, but didn’t change the size of the throttle plate or do any porting downstream of it... I mostly did this due to the original TB being dirty and the IAC valve being sticky, causing a weird idle on occasion, but it helps a little over 3500RPM, and throttle response is a little better...

lastly, I ported the stock intake manifold for better airflow. I measured the intake ports in the L61 parts car I have and measured the ports on the intake and there was a huge, .080” difference in size, so I ground out the ports on the manifold with a rotary tool to within .010 of the head, to combat reversion while maximizing port size. For anybody wanting to copy my work, the measurements I went with are 1.240x1.890”... I also ground down the walls of the #2 and 3 I take runner which were encroaching on the air entering from the TB, so that they aren’t seen while looking down into the manifold...

the net net result of all this, is a negligible impact on steady cruise fuel mileage, but a marked improvement in high RPM power, especially above 5000RPM, and just a little more torque from about 2000RPM... if I had to guess, I’d say I gained about 15bhp, with most of the gains coming from the manifold, and not from the intake tube or the TB...

stay tuned for more!

Once springtime was upon me, I began working on aero mods to cut wind resistance... I also adopted a new driving style that minimizes the negative impact of the two parts of the car that I can’t readily change, engine displacement(2.2 liter) and final drive ratio(3.84:1), more on that in the near post...

i began by attempting a partial Kamm-back in the form of the rear window visor, the theory is that it allows air to stay attached to the roof instead of turbulently separating above the back glass (due to angle between roof and back glass) and allows a clean separation at the end of the visor... upon testing, my version actually caused more drag so I took it off...(hey we can’t win them all)

i then prototyped a “Bonneville style” trunklid extension, for the purpose of giving the air tumbling off the back glass something to attach to before leaving the car entirely, and testing showed a slight gain in coasting distances(related to new driving style). However the prototype version was lacking in that it didn’t seem long enough and it wasn’t supported well enough, so a version2 of this mod was made, which is what I’m currently using... it extends about 6” past the end of the trunklid (vs about 4.5” on ver1) and has more supports and more robust mounting(more places to tape it down)... it being longer helps the drag factor a little more than version1, so it seems much improved...

i also made a lower air dam by screwing lawn edging to the lower edge of the front bumper, which mostly helps by allowing less air under the car...

Now to explain the madness that is my driving style...

i quickly realized that I could get better mileage by altering how I drive (most gains on any car are made here), and worked on adopting a better technique...

The issue is that gasoline engines aren’t so terribly fuel efficient at part throttle, what with the engine struggling to pull air past a mostly closed throttle body, and other factors. So what can we do about this? Solutions used by different people and automakers include taller gearing (forces you to use more throttle to hold speed), higher EGR rates (cylinders partially filled with exhaust gas have less room for intake charge and EGR helps a lot at part throttle), or sometimes lean burn(on some older Hondas the AFR can go as lean as 25:1 to save fuel and force greater throttle angle at cruise), but the L61 Ecotec doesn’t really use any of that... as an alternative, I chose to adopt a technique known as pulse and glide. The theory is that most engines have a sweet spot in their BSFC map(shows how much fuel used per how much power made) between 1500 and 2500 RPM, at nearly full throttle... so I only use the engine in that target zone and I’m coasting, engine off, the rest of the time... on a two lane road with 55mph speed limit, I’ll accelerate to 55(2k RPM) and coast down to about 40(~1500RPM) with engine off, then restart and accelerate... it results in accelerating for .2 to .25mile and coasting for .5 to .7mile(depending on road grade) and much reduced fuel consumption at an average of 47.5mph... ideally I also adapt to the terrain and road to avoid braking as much as possible and to avoid coasting uphill except when trying to cut speed...

I wanna talk a little about suspension modding here, and say at the beginning that the mods did arise out of necessity, not just for sake of modding...

i bought the car with weak dampers and shot rear axle bushings, and drove it that way for a while... when it came time to repair the issues, i used RockAuto to secure the best possible price on OE quality parts, except for the drop springs which were aftermarket and the rear axle bushings which I thought were dealer only(found a polyurethane upgrade part the day after I ordered the GM original part)

i ordered:

ACDelco struts and shocks for 2009 Cobalt SS/TC (FE5)
MOOG lower control arms for 2007 Cobalt SS/SC (FE5)... the 09 Cobalt control arm has bigger diameter ball joint
MOOG upper strut mounts and bearings, 2004 Saturn IRL(FE3)
GM rear axle bushings for 2004 Saturn Ion(FE1)
DNA motoring drop springs for Saturn Ion 03-07 (from Walmart of all places)

part total cost was about $700 in all(labor was about another $300), but I only lacked sway bar parts of it being a full and complete suspension rebuild. I do plan to swap to a Redline front sway bar and build my own rear sway bar in the future...

i had the axle bushings and strut/shock/spring combos installed at once, and did the control arms later (fairly recently in fact)... the car now rides much better than before(much firmer though), with predictable suspension movements and predictable cornering behavior, despite having just as much body roll as before...

i also noticed two distinct MPG improvements, once after lowering due to reduced frontal area(~5%), and once after doing the LCAs and fixing the alignment, due to the front wheels pointing where they should and not having variable toe and camber depending on suspension load (~3%)...

Since we’re about up to date on any mods that matter, I’ll just dive into current goings on...

I revised my grille block this evening, widening the inlet on the upper half of the lower grille block by about 2.5”, as the car gets a little warm on the freeway and I’m hoping to alleviate some of that. I also cleaned up all the tape, covering over everything that looked loose or frayed, and instead of blending the tape onto the lower grille insert (which is hard to do smoothly), I decided to blend the opening directly onto the bumper cover... now it looks smoother and likely cuts drag by some infinitesimally small amount, but mostly was a little easier to apply and better looking...

Wanted to post a better pic of the grille blocking to show what I did...

It seems to run just a little cooler out on the road with the grille block opened up(about 2-4degrees)... I’m hoping that translates to less than 220F on the freeway... when the snow flies, IF my car is still in service, I’ll probably use a piece of pipe insulation to block the grille for faster warmup...

the stain you seen on the driveway was oil from my last change... I missed the drain pan for about half a quart