help ecomodding a saturn ion

[cfg83]

2007 ion2 -

I think this is the best thread on tire pressure :

http://ecomodder.com/forum/showthrea...ires-2582.html

CarloSW2

[2007 ion2]

so, I have some results to share. I mocked up the upper grill block and nose under pan in one go, then the lower grill block (on top of the existing two mods), then a rear under pan transitioning air from the under side of the car just behind the torsion beam to the bumper cover. all of this yielded some interesting (to me, at least) results. first, I picked my road, forget about flat roads anywhere around here for a perfect coast down test, so I picked a run that gave me a decent distance out for an MPG comparison, and a decently flat run on the way back for a coast down test.

these numbers were obtained by my scangauge 2 (which everyone should know is only good for comparing two runs from the same tank), and a stopwatch on my phone (always lit for the least distraction). the first set of numbers I will give you were from early tuesday morning, the second set was with proper representations of the mods early this morning both mornings were 73 degrees (as measured by my scangauge before the first start up) and mildly breezy. all runs were made as close together as possible, and with the car configured the same every time. the scan gauge got changed twice (fill ups to calculate actual mileage), so only the first two and last two runs can be compared together

ok, as a base, I got these results: (remember, for these first couple mods, overheating was a concern, not so today).

*76F intake temp at 60
*83F intake temp at 40
*warm up time of 6 minutes in 2.9 miles of city driving (40 MPH, a few stops and gos, no lights) to 188F (warmed up for my car)
*MPG test (about 5 miles at 55MPH, using cruise to eliminate human error) *38.7MPG
*70-40 coast down 41.03 seconds
*maximum engine temp was 193 sitting at a stop light during this drive.

second run (front under pan and upper grill block)

*76F intake temp at 60
*85F intake temp at 40
*MPG test (same spot as before) 38.8MPG
*coast down test (same as before) 41.34 seconds
*max engine temp 193 (same spot as before)

I ran it with the upper and lower grill block in place, but had to abandon it after a couple blocks due to excessive heat buildup. for ions and cobalts, this is to be a 40 or below mod ONLY the radiator and fan kept the engine temp down (sort of), but what alarmed me was the huge spike in intake temperature that most people cannot monitor, but will cause detonation.

I then mocked up a hasty rear under pan and got some shocking numbers

*38.6MPG
*47.25 seconds

I doubted the coast down number's accuracy, so I went again

*39.7MPG
*46.6 seconds (starting to get traffic)

and one more coast down test a little later when traffic died down

*47 seconds

then I got a sheet of choro plast yesterday and made the under pans up. I decided to do one more test of without then with the rear under pan.

first run 73 degrees outside, slightly breezy, both front mods in place

warmed up in 5 minutes, 2.4 miles, same rout as yesterday

*40MPG
*41.35 seconds

second run, proper front and rear under pans, and upper grill block

*40.8MPG
*46.3 seconds

now, while the two front end mods do relatively little for aerodynamics (guess saturn did it's homework, here), they seem to keep the car cooler while it is moving (this will possibly reverse in the same magnitude in severe stop and go traffic), so, they stay. the real shock (because of your pessimism on here, and how the rest of the car is, aerodynamically), is how dramatically the rear under pan increased coast down time and still decently increased measured fuel efficiency.

[2007 ion2]

can anyone take a guess what my Cd could be if it started at .32 given the measured coast down increase?

[Weather Spotter]

I have a few questions about your testing, nothing too big but I want to check before I add your data to the wiki.

1 warm up times.
How many miles did you warm up the car before testing? I find that on my car the engine is warm after 5 miles but the drive train takes 20-25 miles. I found this out as I did my first set of steady state ABA testing A runs, they did not level out until after 25 miles.

2. Winds.
I found that winds are ok (not preferable but ok) if they are steady, any gusts really mess up cost down numbers.

3. Number of data points.
It looks like you only have 2 runs for A 2 for B and none for A2. for the data to solidly show something (statistically) you need a min of 3 data points per run (3 for A, 3 more for B). you also must do ABA not AB.

After all that, I like the limited data's results, they hint at a rather large gain from the back bell pan. I bet the grill block is doing more than you can see, it tends to be a small gain so it takes a lot of testing to prove what it does.

[2007 ion2]

that's why I ran my last coast down yesterday after I ran the car for hours, and ran the other tests in the order I did, to double check everything and ensure the results weren't tainted by something not being worn up, ect... if you notice, the results depend on what mods are applied, not where in the order I perform them.

[2007 ion2]

as far as why I have no second, or third "A" is because "B" was so close to "A". I was more interested in "A" to "C" , or "B" to "C". as far as that goes, "B" is so close to "A", I am considering "B" my new "A". plus, it is hard to remove and reinstall the under nose belly pan.

[euromodder]

Originally Posted by 2007 ion2

like I said, 0W30 is for better cold starts, I do not need to worry about that anymore.

It helps all cold engine starts, not just cold weather starts.
If one lives in a very cold climate, 0W30 may be required because of the low temperatures - but that doesn't mean it can't be used in warmer climates for its fuel economy benefits.

my question is why didn't volvo release a change to the recommended tire pressure for that vehicle?

Dunno.
I originally started running a higher pressure in my 17" wheels to improve handling - based on reports from other users - as steering felt quite mushy, wandering all over the place on.

nitrogen is stable enough to make a difference. I drove my saturn (with a proper nitrogen fill in all 4 tires, from the factory), from -40F weather down to tennessee (I think it was 30F), and didn't see a difference in tire pressure

I'd expect to see a small pressure difference, based on a 33°C / 70°F increase in temperature.
The laws of physics don't change because tyres are filled with another gas.

nitrogen also stays filled longer, leading to less need to check the pressures.

Making people forget about it even more ...

it does this because it has physically larger molecules.

While true, rubber tyres aren't exactly molecular sieves that differentiate between O2 and N2 ...

it will also help protect TMS equipment and alloy rims commonly found on modern cars because of the lack of contaminates.

Is corrosion on the inside if the rim a problem at all ?
It's pretty much a shielded environment.

[euromodder]

Originally Posted by 2007 ion2

what alarmed me was the huge spike in intake temperature that most people cannot monitor, but will cause detonation.

Intake temps rise high when you're sitting in traffic and the air intake is in the engine compartment
There's far less air being forced into the engine compartment, so what's inside heats up - a temporary warm air intake.

the real shock (because of your pessimism on here, and how the rest of the car is, aerodynamically), is how dramatically the rear under pan increased coast down time and still decently increased measured fuel efficiency.

I expect you're going to see some nice improvements in everyday driving.

[2007 ion2]

Originally Posted by euromodder

Intake temps rise high when you're sitting in traffic and the air intake is in the engine compartment
There's far less air being forced into the engine compartment, so what's inside heats up - a temporary warm air intake.


I expect you're going to see some nice improvements in everyday driving.

I am talking about while moving at 40MPH, it was at 116 and climbing when I shut it off and yanked the block off to keep from killing my engine. ecotecs do not take very high intake temps very well.

[2007 ion2]

and I, also see getting some nice improvements about all of this. my next day off, I will be trying various tire aero mods. this should prove rather interesting. at this point, the thing damn near refuses to slow down below 50 by wind and rolling resistance alone.