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stefanv 08-06-2017 09:21 PM

2001 Saturn SL1 Mod Thread
I've been on staycation this week and have devoted a fair bit of time to starting the ecomods on my 2001 Saturn SL1. I'll use this thread to describe each modification. There isn't going to be an A-B-A testing of individual mods, but there will be A-A-A-A-B-B-B-B-... tests of each group of mods.

The mods I completed this week are:
  • Fixed fender-to-bumper gap caused by drooping bumpger
  • Sealed gaps around hood
  • Extended air dam most of the way to the wheels
  • Completely enclosed the front grill

I'll write a separate post for each mod.

stefanv 08-06-2017 09:40 PM

2001 Saturn SL1 Mod - Fix Gap Caused by Drooping Bumper
6 Attachment(s)
Apparently this is common problem with Saturns. The bumper cover, which is one large plastic piece that wraps all the way around to the wheel wells, is held on by three bolts on each side. Quite a bit of it (probably the vast majority of it by weight), hangs out past the front-most bolts, and over time, it begins to sag, causing an unsightly gap at the front:

To fix this, I undid the front bolt on one side (after removing the headlight assembly), inserted a piece of cardboard, and traced around the fender. I then cut out the resulting shape and checked that it would fit under the top lip of the bumper. A local metal shop then cut me two pieces of 1/8" steel in the same shape (for a total cost of $12):

I simply bolted these pieces in place, leaving out the flat washer that was there before, but retaining the lock washer:


That took care of the problem at the sides. The center of the bumper cover is held to the frame by three plastic snap in fasteners, and there's a lot of free play. I replaced these with bolts and washers, tightening them down while lifting the front of the bumper cover:

The last picture also shows some of the weather stripping I installed for gap sealing (to be covered in a separate post in this thread).

stefanv 08-07-2017 09:50 AM

2001 Saturn SL1 Mod - Sealing the Gaps Around the Hood
3 Attachment(s)
This one was easy. I simply purchased a few rolls of good quality closed-cell foam weather stripping. I used 1/2"x1/2" over top of the head lights and center of the front bumper cover, as seen in the last photo from my previous post, and here:

For the sides of the hood, I used 3/8"x3/8" tape, applied to the small horizontal lip (visible in the previous photo) on the inside of the fender:

I also applied a small piece of foam to the outside edge of the headlight, since there was quite a large gap between it and the fender:

stefanv 08-07-2017 10:14 AM

2001 Saturn SL1 Mod - Air Dam Extension
5 Attachment(s)
The SL1 already has a front air dam which deflects air upward into the radiator. The resulting vacuum created behind it probably helps draw the air through the radiator. However, this air dam is only about 2/3 of the width of the car, and a lot of air can spill around it, where it has to flow through the suspension.

I started by making a cardboard template to figure out exactly the size and shape that I would need:

After reading a lot of other modders' threads on air dams, I took a trip to Home Depot to find some suitable material. I didn't like any of the lawn edging I found, but then spotted something really interesting. It's called a KwicKan, and is basically a 48"x30"x1/16" sheet of tough recycled black plastic (polypropylene?) with some holes cut into it for handles. The idea is that you roll it up, insert it into a garbage bag, and let it go. It expands to turn the bag into a fairly rigid can. When it's full (e.g. of leaves), you pull the sheet out. It seemed to the be the perfect material for my planned mods, so I bought one ($12).

Using a yellow paint marker, I traced around my template, and cut out two copies of it, one the mirror image of the other (the KwicKan material is textured and printed on one side, and smooth on the other):

To fasten the air dam extensions to the fender, I made brackets out of 1/16" aluminum, cut into to 1"x2" pieces, and bent so that the air dam mounting surfaces would be vertical:

I used stainless steel 10-24 bolts, finishing washers, flat washers, and lock nuts, both to fasten the brackets to the fender, and to fasten the air dam extensions to the brackets and existing air dam:

Here's how it turned out:

I was careful to make both pieces exactly the same (except mirrored) so that they can be swapped left to right if I ever want the textured side outward (I'd have to paint them of course).

stefanv 08-07-2017 11:01 AM

2001 Saturn SL1 Mod - Complete Grill Block
14 Attachment(s)
I've been driving my car for a few weeks now with the grill completely blocked using two pieces of foam pipe insulation. This was a temporary measure, so I could monitor the engine temperature to see if this would be detrimental. After finding that it was fine (the temperature never got above 91C, same as before blocking it), I decided to do a more aerodynamic grill block, including the fog light pockets too.

I knew I wanted use the KwicKan material, but I pondered for quite a while on how to cut it to exactly the right shape. I finally arrived at the idea of constructing a template piece by piece, by taping narrow strips of thin cardboard across the grill, and marking the edges of each piece with where the edges of the template should be. A few pictures are worth a thousand words:

I used progressively narrower strips as the curvature got sharper, and at the end, I fitted in small pieces to match the curve:

Before removing the template from the car, I applied clear packing tape over the whole thing to make sure none of the pieces could shift. I then connected the dots, using a spline for the very long nearly-straight curves, and a set of french curves near the ends:

Next I cut out the template, traced around it onto the KwicKan material (one each way), and cut them out:

To mount the grill blocks, I again used brackets made from 1/16" aluminum, this time in 3/4"x2" pieces. The pieces had to be bent to various angles ranging from 55 to 93. To facilitate bending them, I made a poor man's bending brake out of a hinge, a piece of wood, and my bench vice:

The lower bracket for the fog light area needed to have its mounting surface curved slightly:

I attached all the brackets to the bumper cover using 3M body side moulding mounting tape, after thoroughly cleaning everything with hot water and then rubbing alcohol. My car has teeth:

My plan was to drill and thread holes in the brackets to take 10-32 bolts, but since I didn't have any handy, I drilled 3/32" holes and used stainless steel #4x1/2" self-tapping screws for now. I think I will order a bag of 10-32 black nylon bolts to replace these with eventually:

At the ends, I used a single #8x2" screw, through a 1-1/4" long aluminum spacer, screwed into the black fake grill at the back of the fog light recess:

Here is the completed grill cover. I left approximately 6" open in the middle, because this would be covered by the license plate:

And finally, here it's all done. The license plate has been installed over the opening, and the holes from the original license plate holder were plugged using the plugs from the bumper cover fasteners, painted to match the car, and press-fitted into the holes after drilling them out to 6.5mm:

I'm back to work next week, so we'll see how it all works out as far as fuel economy goes.

I have a few more mods in mind, most notably wheel covers. I was going to make these using the fabric and fiberglass resin over snap in wheel cover technique, but now I want to see if I can heat form the KwicKan material to make black plastic pizza-pan covers instead.

Daox 08-07-2017 02:40 PM

Nice job fixing up and modding the SL1. :thumbup:

stefanv 08-14-2017 09:38 AM

2 Attachment(s)
First partial tank result is in. I had burned 1/4 of a tank before doing these mods, and this morning, with 744km (462mi) since my last fill up, I put 38.3L (10.1USgal) into the tank, for a record fuel economy of 5.15L/100km (45.6mi/USgal, 54.8mi/ImpGal).

I'm hoping for even better next fill-up, where the whole tank will be with the mods in place. After that, I'm going to put on smooth wheel covers.

elhigh 08-14-2017 11:53 AM

Brilliant work. And this is all done with no modifications to the vehicle's mechanical systems, just driving style and a little aero. That's really excellent.

cRiPpLe_rOoStEr 08-14-2017 12:20 PM

Where does it pick the intake air from?

jimhs 08-14-2017 02:24 PM

Excellent numbers from a 1.9 l engine!
Is it a lean burn engine?
I struggled a lot with my BMW 1.8 to see less than 6.3l\100Km..
Good job!!

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