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Sept. 24, 2009 9:25 p.m. CarKid1989 Reader

My Planetary Adenture has begun and the Saturn is in the repair bay.

While its in there I am planing on doing some home made MPG mods.

I am planning on a/an:

-undertray

-sealing gaps

-warm air intake

What else can i do for stupid cheap , besides driving style?

For the undertray, how much do i need to cover?

Ideas for a permanant gap sealer? (no welding) I was thinking silicone sealer of sorts and razor blading a seperation.

Any other ideas? Stuff that works, not hypothetical-one-in-a-million-snake-oil stuff.

Thanks
Sept. 24, 2009 9:37 p.m. Carson Dork

I was going to add this:

But since you added that last line, I won't.

Over-inflate your tires.

Can you smooth the air over your wipers?
Sept. 24, 2009 9:54 p.m. patgizz Dork

landscape edging air dam to keep air out from under the car?
Sept. 24, 2009 10:59 p.m. slantvaliant HalfDork

Some cars do better with a little rake - can you easily change the ride height?
Sept. 24, 2009 11:05 p.m. Trans_Maro HalfDork

Add spats to the fronts of the wheel openings (eg: 2nd gen Z28 and T/Z) to create a low pressure area in the wheel well and help draw air from under the hood. Air comes in through the radiator and has a hard time escaping.

Add a tailcone to reduce drag.

Shawn
Sept. 25, 2009 4:41 a.m. petegossett Dork

Ok, I'll be the one to ask the dumb questions... Have you already adjusted your driving techniques to get the most mileage you can? I'm not talking 'hypermiling' crap, just basic common sense stuff we all already know, that just might not be much fun? You'll make 10x the improvement from that then you will from mods.

Beyond that I'll just add that aerodynamics is another one of those fields where what you would 'think' is beneficial isn't always the case. So unless you're planning on really researching into the engineering involved & searching for the right answers, I think you'll end up wasting your time & money - and possibly more gas - then you would by adjusting your driving.
Sept. 25, 2009 7:33 a.m. 02Pilot New Reader

patgizz wrote:

landscape edging air dam to keep air out from under the car?

I put one of these on my E39 just to see what would happen. Really easy to install with 8 machine screws, and seems to be improving mileage by about 2% (~.5-.6mpg) in limited testing over known highway routes. Conveniently, it matches up almost perfectly to the factory aero tabs in front of the wheels.
Sept. 25, 2009 8:21 a.m. Autolex Reader

again +1 on the edging air dam...

how much does it weigh? did you gut it yet? (AAA card (0.2 ounces) offsets a spare tire, jack, lug wrench (40+lbs) by a lot!)
Sept. 25, 2009 8:49 a.m. flountown New Reader

Covering up the rear wheel wells like the Honda Insight also helps.
Sept. 25, 2009 9:35 a.m. z31maniac Dork

This would make a great GRM article............
Sept. 25, 2009 10:11 a.m. Gearheadotaku New Reader

Saturns already get great mileage, how much more do you want? What powertrain do you have? Yes, adjusting the driver is most effective. I get 33mpg combined, 39 HWY with my '97 SC2 5-speed. Car is bone stock.
Sept. 25, 2009 10:28 a.m. iceracer HalfDork

As everyone said, the driver is first on the list. In theory, the under tray should go all the way back. Taping or sealing the seams on the front of the car is good,otherwise will have no affect. If you have a Scan Gauge or similar. Tape the grill area until you can drive with the coolant temp around 200 dgrees F. This also helps to increase the intake temperature. I recently did this to my ZX2/SR and 10psi+ in the tires and I got 59.09 mpg. Of course this was an economy run,I wouldn't drive like that regularly.
Sept. 25, 2009 1:59 p.m. GameboyRMH SuperDork

To seal gaps on the doors, maybe you could use thin strips of plastic sheeting stuck to the door edge. It would form a good seal when the door's closed but still allow you to open the doors normally.
Sept. 25, 2009 3:16 p.m. poopshovel SuperDork

Things that don't look goofy:

Remove mudflaps if equipped.

Remove excess weight - glove box, change tray, etc are good, easy places to start.

Remove rear spoiler if equipped.

Remove rear wiper if equipped.

Find the lightest, skinniest, tallest, wheels you can, and inflate the tires well above recommended levels.

Things that do look goofy:

Aero mods.

Covering rear wells.

Using 15" walmart pizza pans as wheel covers.

The belly pan seems like a tremendous pain in the ass. Good luck with that.
Sept. 25, 2009 4:49 p.m. SupraWes Dork

Hack the exhaust off as close to the head as you can. Prefferably after the o2 sensor and before any cats or mufflers.
Sept. 25, 2009 8:03 p.m. karlt_10 New Reader

You need to find a copy of an ad from when the Prius first came out. It had a pic of the car and pointed out the aero tricks. Things like low-profile wiper blades (or tucked under rear of hood). Nearly flush-faced wheels with small fins to help expel air from under the car. Small 'dams' mounted under the body- in front of the tires to keep air from hitting tires and being disturbed. Etc.

If you find the ad - get me a copy. I've searched....
Sept. 25, 2009 8:27 p.m. JFX001 Dork

Some have already been covered, but you might be able to get some ideas:

http://ecomodder.com/forum/fuel-economy-mpg-modifications.php
Sept. 25, 2009 10:17 p.m. jj New Reader

Add a vacuum gauge to help you keep an eye on your driving style.
Sept. 25, 2009 10:44 p.m. mad_machine SuperDork

so you get better miliage from a warm air intake than a cold air one?

I do agree with adjusting the nut behind the wheel first. If I take it easy and try to limit how much stop and go driving I do.. I can see high 30s in my ti.

Driving normally, I lose 10mpg to 27/28mpg

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