Want to mod my 95 Saturn SL2

[aerohead]

Originally Posted by spacemanspif

Aerohead: I have been looking for pictures of the vehicles you referenced and have come up with nothing. Do you have any that you could post?

I am thinking that I want to do a front air dam, side skirts, rear wheel skirts and a kamm on the rear window. The Civic hatch crew seem to have gotten decent results with a cam on the back and if it can eliminate the dead space in the middle of my window it should help some.

My biggest hurdle right now is finding free coroplast but a friend might have some laying around so I might have supplies shortly. I'm hoping that double stick emblem tape will be sufficient to mount a kamm to the back window...

If anyone has ideas on how to mount things or better ways of doing things, I'm all ears. Currently saving my pennies to possibly buy an MPGuino...

Currently all I have done is taken off the rear spoiler and slowed down to ~62. Once I fill up at the end of the week I'll know how much better I'm doing after the mod/new technique. Car was getting consistent 38, I'm hoping for 40 with the reduced RPM.

There from an Automotive Quarterly article on Kamm.I'll see about scanning them this Saturday.I'm back to work now,after 121 days without wheels,and may not be able to get in beforehand.

[spacemanspif]

Aerohead: take your time on the pics. I'm not doing anything so quickly that I need instant gratification.

Well I filled my take for the first time since joining EM. My only physical modification is removing my old spoiler that came off a 3rd gen Firebird Formula. I also slowed down to ~62mph. This got me a tank average of 40.6mpg. Up from 38 that has been my running average since my trans swap a month or 2 ago.

I'm happy with the results and can't wait to make it better! As soon as I get some coroplast I'm going to start putting together rear wheel skirts and maybe flat wheel covers too.

[JasonG]

We had a 95 SL2 that would easily get 40mpg.
The wheel covers helped.
Slowing down to 55-60 made a large difference.

Bore out the throttle body and have a larger (matching) throttle plate installed.
Put in an adjustable fuel pressure regulator and increase it a few pounds.
The spray pattern will improve.

At that mileage you will be nearing a ring job due to sticking piston rings. How's your oil consumption?
It's an easy in car rebuild.
While the heads is off, do the valves and clean the ports a bit.

Get rid of the cast 4-1 header. Find one from a 96 (93? Been too long) that is a welded 4-2-1 factory header.
It willl flow better and still retain the factory O2 sensor.

I miss that car, some lady t-boned my wife. The car sacrificed itself, all she got was a head gash and minor whiplash.

[spacemanspif]

Thanks Chaz!

Jason: Want another one? lol. I've thought about doing performance mods that might help eco but when it comes down to it, I don't want to spend money on the car due to its age. I keep an eye out for steals on ported TBs and factory headers but never seem to find them in my area, the adjustable FPR sounds interesting tho. If it keeps running for another 200K, I'll drive it that long but I'm not willing to rebuild it. Car has paid for itself multiple times over and been noting but good to me. When the time comes it will be sorely missed, definitely has a very special place in my heart. I burn about 4 quarts between oil changes, but I think it has gone down after the trans swap (lower RPM saves some oil) but I just let it eat and keep topping off. The only reason I did the MP2 swap was because I found it for $125 if it were any more expensive I'd be making payments on a slightly newer vehicle right now...

I wonder how you used to get 40mpg? Best I could ever do was about 35mpg and that was 80,000 miles ago lol.

[ChazInMT]

So here is the new template (a bit more aggressive) on your car, if you go out to the end of the trunk it gets you out past the 30% hash, with 0% being the hash on top of the template/roof, 10% is above the c pillar, since you are at the 10% hash to begin with , going out to 35% would net you 37% better Cd, in theory. Your Cd would go from .35 to .22.

Your car is ideally suited for a kamm because flow off the back of the roof goes straight to heck. Its appears as though the designers were thinking when they radiused the area behind the c pillars to draw the air in to compensate for the seriously dropping air behind the rear glass. So this probably does not create a devastating vortex situation, but it certainly is a disorganized build in pressure from the c pillar back.

Any way, I guess my point is, if there was a car that could really benefit from a Kamm, it's yours.




Bigger Version of Pic to Oogle

[betasniper]

Originally Posted by spacemanspif

Betasniper: Thank you for the photoshoppin of the car. Can you elaborate on the "Looks like you could comfortably go out to 15% template without restricting any rear visibility if you make a kamm/roof spoiler. " I'm still a little too new for some of the technical jargon. Are those bottom numbers percentages? Is that what you are referring to?

I saw that thread you linked, good info. and something I have always wondered about bely pans and heat.

And this is an SL1 bumper:



If nothing else I think I need to at least cover the "brake cooling ducts" that don't do anything on the far edges of the SL2 bumper...

Yes, The bottom is in percentages. You can convert the percentage into drag reduction Here

And that does look like the bumper would help a lot actually. My understanding at least.

[spacemanspif]

Ok I have been doing some reading and brainstorming and have more questions. I'll try to start with the easy ones and work up to the more difficult.

1: Should wheel spats be angled toward the in/out side of the car or just flat like a mud flap in front of the tire?

2: What is better, pizza pans that stick out a little or coroplast that is as flat as possible and jammed into the lip of the steel wheel?

3: How bad is it to have an air dam that angles under the car? I want to do a front air dam in lieu of a front belly pan. If I can't find a SL1 bumper cheap enough and extent the current bumper, I'd probably have a dam that is farther back at the bottom than top if I use the bottom part for support.

4: Are smooth wheel covers still needed when they are behind rear wheel skirts?

5: Who can estimate how long a kamm back should be on my car? I'm thinking about starting with 1 that still enables me to open my trunk most of the way. So I'm thinking of a kamm that ends at the vertical of the bottom of the rear window.

6: If I tuft test the back window and see attached flow coming in from the sides, should I make the Kamm more narrow so as to only address the vortex at the back window or just make it smooth with the side of the car?

7: Can side skirts be slightly recessed under the car or is it best to keep them as an extension of the door skin? I was looking at the car and think I found a way to attach 1/2 gutter (or something "L" shaped) but it will sit at about the inside edge of the tires.


Judging by Chaz's use of the "more extreme" template, I took some measurements on my screen (yes ruler on my comp screen) and then measured my car, it looks like my a full kamm would be 5.5" above the rear deck. I'm going to try and get a SL1 bumper for cheap at a JY, I think it would make grill blocking and air damming much easier.

Thanks so far. I promise, one day I'm actually going to do something. So far all I've done is pump up tires to 35psi (2 days ago), slow down to 62, and now 60 this week and removed my rear spoiler.

[ChazInMT]

I measure a bit under 5" above the back of the trunk, and 6.8" above the trunk at the front of the trunk/bottom of rear glass.

[arcosine]

You want to keep the airflow as smooth as possible around the car. Disks are not needed behind skirts. 10% of the car's drag is caused by the front wheels, so the better the air is deflected around them, the lower the drag will be. If your air dam is that far back, and wraps around, you might not need spats.

[spacemanspif]

Thanks Chaz, I will reference that when I eventually start putting together a kamm. Clearly you have a better measuring method than my ruler on the computer screen lol.

Right now I think I am going to focus my time on the front as I came into some small pieces of coroplast that aren't big enough to make a kamm out of but will work well for a grill block and possible spats.

Thanks for the tips Arcosine. I kind of have a plan for a big air dam like the white civic (pic below) coupled with front wheel pizza plans. Thinking about extending the air dam all the way around for more mounting spots and fill the forward gap of the front wheel wells using 1 big sheet for aesthetics. Of course I bought a teal car so any body mods I do will have to be painted flat black because I doubt I'll ever be able to find a blue that closely matches Saturn teal in an "off the shelf" can. My problem is going to be getting that 1 big sheet though as I prefer free things.