Want to mod my 95 Saturn SL2

[spacemanspif]

Hey all,

I thought I'd start a kind of build thread for my car. For a little background I am starting out with a 1995 Saturn SL2 with 237,000 miles and an MP2 swap. MP2 swap is a taller geared trans from the Sx1 cars. I measure economy on a tank to tank basis and have been getting 37-38 mpg thus far which is an improvement over the 33-35mpg it got with the original trans. Car is a 5spd manual with manual locks and windows, power steering and A/C (rarely use). I know it goes against convention on most cars, but my car does worse on the highway with the A/C on than with the front windows rolled down. Right now I also have a 3rd gen. Firebird Formula spoiler on the deck lid that adds considerable weight (15lbs?) that I plan to take off soon. I also need to get the under engine pan and associated air dam that I just found out the car has been missing since before I bought it. I commute ~25 miles to work everyday, ~23 are highway. Delaware is pretty flat other than multiple overpasses, and I rarely hit traffic, just set my cruise to 65 and go.

I have some mods I am considering and want a little feedback on them if you all don't mind.

Bumper swap: the SL2 bumper is a bit different from the SL1 one. I'm wondering what you all think of the differences and if its worth it to get the SL1 lower bumper? I can post pics for help on my next post, just at 4 right now and need 5 (this one)

Rear wheel skirts: Thinking about building some of these. Are wheel covers usually used in conjunction with these or are they unnecessary within the skirt? I am running stock, 15" steelies and am wishing I still had my horrible, 6 spoke with fake rotor wheel covers that came stock on the car because they were good aero wheel covers with no mods.

Pro-stock/Bonneville spoiler: Thinking about making 1 of these. I found a dead thread from member "captain chaos" titled "Satun SL airflow study" (again, can't post links) with a small simulation, I'm wondering why its dead? Bad science? No one cares? He recommends a 6" spoiler which is easy enough to make, just wondering if its a total waste of time...

Belly pan: Considering a rear belly pan, I don't like the idea of having to remove a bunch of junk to service the car so a full pan is probably out of the question. Not much out back other than a parachute so I think that area could probably use it the most.

'Template': can someone overlay the 'template' on 1st gen SL? I haven't found a thread with a 1st gen Saturn 4 door with the 'template' overlay yet and I suck with photoshop/paint tools.

Roof mods: I think I might tuft test it, but judging by rain and snow on the rear window, I am pretty sure the entire center of the rear window is a dead space. Not sure I'm willing to build a kammback, but might I benefit from vortex generators or a mini kamm maybe? The problem with 1st gen Saturns is the wrap around glass so no metal to mount anything in front of the rear window...



I'm sorry for the huge post. I want to move in a good direction and not just spin my wheels with failed/misinformed plans. Ideally I'd like to keep all functionality of the car and get super good mileage. I'm sure the trans swap will have the biggest effect on the MPG than any 1 aero mod, but if I can get another 5mpg out of a few, cheap, easy mods I'll be a happy camper.



Before you ask, Yes, I have already read all 18 pages of "SC1 aero mods"...Not really a fan of boat-tails.

[betasniper]

Not Sure about the difference in bumpers but skirts should be pretty easy to do and give a large (for the labor) benefit.
Before you do the rear belly pan, make sure to read this thread
Talks about how heat trapped under the belly pan covering the tank can "boil" the gas and overload the Evap system.

Here is an Template Overlay (of a 93 SL1)

Those Hub caps would have been nice.

Looks like you could comfortably go out to 15% template without restricting any rear visibility if you make a kamm/roof spoiler.

[arcosine]

I moded my 2nd generation saturn: I still get 50 mpg, with the boat tail off. I would say anything in the back deck would be almost useless since, the rear glass is at a bad angle. How about a camel back?

The MP2 trans 1998 and after have the best fifth gear ratios. Ive read that the cruse doesn't work with the trans swap, maybe thats only the obd2s.

Putting a diode on MAP sensor on the dual cam engines will give it more low end torque.


http://ecomodder.com/forum/showthrea...ods-15529.html

[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.

arcosine: I read your build thread a few times before signing up here so I think I am pretty familiar with your setup. I wish you used the car more though so that we could see the benefits of each individual piece of the puzzle. So you are getting 50mpg with your front bumper mod, front and rear skirts and full belly pan? Am I missing anything else? I can't remember what year the MP2 trans came out of but it was a later model, either way, Mp2 still beats MP3, and lucky for me the OBD1 cars are able to keep cruise with the swap. What is the function of the diode? Fool the map and make the car run more rich? I am thinking about a Kamm back but am unsure how to mount everything due to the wrap around glass... I don't think suction cups will last very long... any thoughts on mounting it.

Back to my original post, the link below is the one I referenced about the dead air flow study. I guess its more flawed that I thought because it assumes attached air across the back window when in reality is seems to be a vortex just like at the back of car. http://ecomodder.com/forum/showthrea...udy-24010.html

Picture below is of an SL2 bumper (I don't have the fog lights though) and I need to get the front air dam assembly which I don't currently have.


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...

[arcosine]

No, it advances the ignition timing at low manifold vacuum.

[justme1969]

Isnt that the same model saturn that the overdrive gearswap covers? I hadnt seen it in about 5 mos. but if ya search in the history, it will be there someplace.

[spacemanspif]

arcosine: gotcha. I'll have to look into that, although I don't think the car is hurting for power right now so I think that will be lower on my list than things like skirts and coming up with a kamm back of some sort.

Originally Posted by justme1969

Isnt that the same model saturn that the overdrive gearswap covers? I hadnt seen it in about 5 mos. but if ya search in the history, it will be there someplace.

Yes...tried it...blew up the trans. Got a little too happy with the impact gun I guess and the trans ate itself in about 200 miles. So I just swapped in an entire MP2 tans and don't plan to attempt the 5th gear swap ever again lol.

[justme1969]

From what Id read it was infacto too high and caused lugging issue.
so a gentle foot was the obvious answer.

[aerohead]

Originally Posted by spacemanspif

arcosine: gotcha. I'll have to look into that, although I don't think the car is hurting for power right now so I think that will be lower on my list than things like skirts and coming up with a kamm back of some sort.




Yes...tried it...blew up the trans. Got a little too happy with the impact gun I guess and the trans ate itself in about 200 miles. So I just swapped in an entire MP2 tans and don't plan to attempt the 5th gear swap ever again lol.

One of Wunibald Kamm's last official projects was a K-form roof extension on a 1960s DKW (AUDI) notchback car,for the Frankfurt division of Battelle Institute.
Kamm created,what looks like a fiberglass extension which fully enveloped the aft portion from roof header to tip of trunklid.
He included his signature dual split-fins for stability.
He'd also done this for Briggs Cunningham in 1953 with the C4K LeMans entry,minus the fins.

[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.