Project: modding sixth gen Corolla sedan on a budget
 

Name this project!

Goals:

• Save up, get rid of it and get a Prius. :p
• Practice ecomodding. Hopefully make it look good or at least have some nice looking bits on it so the wife won't feel so nervous when I go after her Civic, or the Prius.
• Have fun.
• Improve mileage for a given speed.
• Try to keep mod ROI under 7,000 miles.
• Keep it running healthy and keep emissions down.

I'm going to be editing this first post for index, status, and current pics.

Latest results: 46 MPG @ 65 MPH for 1300 miles! Stock Cd of 0.36 reduced to 0.28 (maybe).

Outdated pic:
http://ecomodder.com/forum/attachmen...1&d=1351489789

Finished mods:

1. $33 - Smooth wheel covers.
2. $15 - Rear wheel skirts. (Coroplast on steel strip.)
3. $35 - The air dam is dead. Grill block, and gap filler. Air dam early on. Braces and opening. Refinements and upper grill block. Broke the corner, painted it, repaired it, ducted it, cut it higher and added a soft chin. Death of the air dam.
4. $15 - Passenger mirror delete. Added wide angle rear-view mirror.
5. $62 - Block heater (here is a tutorial I wrote)

Other mods I hope to finish:

• Air dam.
• Side skirts (look at how the stock body curves in on the sides, that's gotta penalize drag on the wheels)
• Aero hood cowl to streamline windshield wipers
• Soften edge radii on front wheel wells
• Kammback
• Spoiler or Box-Cavity combo
• Killswitch

Mechanical condition:

• Fixed! Rolling resistance high when cold. Primary problem: high viscosity of 75W90 tranny oil, switched to Honda MTF. another cause in the transmission. Secondary problem: drum brakes need to be turned. Got the 'self-adjuster' in a better spot (doesn't self-adjust anymore), but still need to turn or replace the drums.
• Abnormally severe groove wander. Could be the shocks?
• Shimmy at 70 MPH (but when do I drive that fast?) Could be the shocks?
• Leaky trunk
• Broken parking brake equalizer
• Fixed! (AAP diaphragm leak) Rough idle See Carb rough idle

Enjoy!

I forgot to mention: this car does not have an overdrive, despite having a 5-speed manual transmission. It also lacks a cruise control. Solution: P&G - reduces throttle loss and keeps my heel moving around so it doesn't get sore. Too bad the carburetor makes it a poor candidate for EOC / killswitch. Or does it?

Aero front-end mod plan, grill blocking and smoothing
 

I feel that the stock bumper design is particularly crummy aerodynamically. I wouldn't be surprised if I have 5-10% to gain here without too much effort.

I failed on the first attempt, but learned how to gather good coast-down data and discovered that I have a mechanical problem (BTW, now I think the problem is the rear drum brakes). http://ecomodder.com/forum/showthrea...ast-23162.html

Edit: I took off my v1 "bullnose" this morning. I'm certain I can hear a lot more turbulence against the windshield and hood without it, with a sudden onset around 55 mph. Although my bullnose didn't work properly, probably due to the open sides, I'm even more convinced that my aero eye is correct; the stock grill-to-hood angle / radius on this car is a disaster. A grill block by itself would not fix the problem.

Anyways here is a crude photochop of my v2 mod design - more conventional ecomodding:

http://ecomodder.com/forum/attachmen...1&d=1349292032

I've got 1/8" clear PETG to go above the bumper, although I think it would look nice to paint it black over the grill location. Below the bumper I'm thinking coroplast, reinforced with coroplast, unreinforced at the bottom 4 inches so it can fold if it scrapes. The blinkers you see low on the the bumper will either get moved forward or clear covers. The cooling inlet will be bottom middle of the coroplast. I might hand-mold a smooth inlet trim. Cooling ducting would probably not be very aerodynamically effective without more distance between the mod and the radiator, so I might not bother.

As a tangent, the 4x8' 1/8" PETG rolled up without too much trouble and fit in my back seat, which is good because the seats don't fold. It was about $90 = $2.80 per sqft.

http://ecomodder.com/forum/attachmen...1&d=1349292239

PETG top-to-bottom would be a little cost-prohibitive here. My motive is primarily environmental, which also means evangelical, but I aim for cost-effective energy reduction. That's what I really mean by shoestring budget. This car isn't going to see that many miles, in my possession. So I'm trying to keep mod ROI down to ~7,000 miles. That sets the bar pretty low, like $33-$66, depending on whether this is a 5% or 10% FE mod. Most of the PETG is going to be for the Civic.

I'm subscribed! Should be interesting.

Going across country next week? Then make sure you pump up the tires and that you slow your speed. Those two by themselves, free and quick, will save you bigger percentages than most other things, if the experience of this group means much. Good luck driving cross country! I love long road trips. Love 'em.

My logs don't reflect it very well, but I'm pretty good at hypermiling. The Civic's SGII reports 55-62 MPG for my round-trip commute when I drive it. (The Corolla logs are probably mostly limited by mechanical problems, and the Civic logs limited by its owner, who doesn't hypermile quite as well as I.)

I'll probably be around 5-10 under PSL, for MPG and the fact that I'll be alone. Also I don't know yet whether the mechanic will be able to fix the shimmy that set in at 67 MPH when he looks at it tomorrow.

That being said, I'm afraid I have exactly the opposite feeling toward long road trips. Time spent driving is time I wish I could spend on something else. I have several neglected hobbies, in addition to several active ones. Plus a house and kids. One of my hobbies does not happen to be books-on-tape.

Aero is the magic genie of vehicle optimization. Or automation and road trains, even better. Or all together, even better.

Actually I would prefer a greyhound for this trip, all other things being equal. Unfortunately the greyhound's schedule happens to be awful for this route (12am - 2pm or 12pm to 8am - I really like to sleep in a bed).

Another 10 minute pre-road trip must: quick 'n' dirty partial grille block. It's one of the best ROI mods in terms of fuel saved for effort expended.

True generally. But I added a comment yesterday you might have missed (sorry about my editing habits):

To my eye there is a similar problem on bottom - below the bumper - although I wouldn't expect to be able to hear the turbulence as clearly.

The timing belt gets first dibs on my time, but I'm optimistic about finishing that and having time left over to fabricate my target mod.

I'd bet the opposite - it's just fine. A 5-minute tuft test will probably show everything is as it should be - attached flow streaming smoothly away from the leading edge of the hood.

EDIT: maybe you mean something else by "disaster"?

That's a good idea. I'll have to see if I can find the yarn when I get home. (That is indeed what I meant.)

EDIT: I started working on the timing belt, tufts will have to wait for the weekend.

I did the tuft testing, with and without a cardboard / tape mod to smooth the grill and headlight area, and I agree with you. The flow looked the same either way. There was a bit of a turbulent spot in the lower middle of the windshield. Perhaps because of the windshield wipers.

So, my question is, should I just focus on grill blocking and air dam? The idea I drew earlier included a clear plastic transition smoothing from the bumper to the hood. That seems unimportant now.

My thinking is that the point of stagnation is the most important result of the air dam. Ideally I want it to start at the existing point of the bumper and slope forwards to get as much air up and over the car rather than under it.

Adjustment to front-end plan (grill blocks / air dam)
 

I'm just polling for (dis)agreement here before I finish this up tonight.

http://ecomodder.com/forum/attachmen...1&d=1349725250

BTW, the under-body clearance is about 6", so I'm shooting for about 5.5-6" air dam clearance (probably 6" toward the middle and 5.5" toward the wheels). I'd rather err on the high side if I must err.

Possiblr front lip for your car
 

See attached photo: home depot styrofoam 4 x 8 x 1.5" gorilla glue
cheese cloth w/latex paint total cost $20, good to 90mph add $8 for
led turn signals.
Last photo of my 88 civic dx conversion to a woody flatbed. It gets 40 mpg

Your Civic Styrofoam nose looks sweet! If you had posted that before Sat I would probably do it that way, at least on the Corolla if not both my cars. Your design is almost an exact match to my ideal mental aero form.

I've already got a piece of PETG cut and half bolted on the Corolla's bumper, and it doesn't seem like a good idea to jump ships now. I am going to try some hand thermal forming with it and see how close I can get to that shape, but it's probably not going to be as steep of a forward angle.

I found your thread on the pickup conversion, that is also a lot of fun. Before I checked your sig I felt certain you must live in CA. An open form like that would not be fun in a UT winter.

EDIT: I meant to ask, what is the clearance of your Styrofoam nose-piece? does it extend below the stock bumper level?

Glad you tufted the leading edge of the hood. Despite the car's "blocky" front end appearance, those relatively small leading edge radii really work to prevent flow separation.

It seems that an angled airdam that lowers the stagnation point makes sense. Haven't seen any hard data or testing against a simple vertical dam though.

Why err high? Do a mockup with cardboard: go aggressively deep (say 3 inch clearance) and compare to 5.5-6 inch clearance.

I went very deep (3 inch clearance) with the air dam mockup I tested on my Firefly which has similar ground clearance to your Corolla. A-B-A coastdown testing seemed to show an improvement. I did not try a shorter version though.

http://ecomodder.com/forum/showthrea...down-9732.html

I know, I've been thinking my jacknut installation is well suited to doing a Cd vs angle test suite. Unfortunately I'm not ready for coast-down testing right now, and I don't see any way to answer the question with tufts.

1) Clearance is desirable. I angled into my driveway and measured 4.5" corner clearance before I put on the dam - the problem being that I was not in the car when I measured (also it's hard to put the tape measure in the right imaginary spot). I put the dam on last night with 5" corner clearance and scraped in 3 different locations, a) my driveway, b) an intersection dip, not even the worst dip I expect to encounter, c) at work, in all cases doing my best to hit the low spot at an angle. Either I'm going to get better at this, or the PETG is going to get cut even higher than 5". SLC in general has some really gnarly dips and driveways. It's a headache.

2) My own personal untested theory: you can either A) push the leading edge of the dam forward until it more cleanly shears top and bottom flows, or B) push the leading edge of the dam down to throttle the flow coming from the high pressure zone in front of the dam going under the car. I expect option A should be the best choice for FE as well as clearance, all other things being equal, since the final result is less frontal area. (Option C would be an underbody airfoil, i.e. paneling and boattail, with a smooth nose but no air dam, like the Aerocivic.)

Again, it's a big hindrance that I'm not ready for coast-down testing... yet. It may even be a mistake to do this type of mod without mockup and coast-down. But maybe I'll get lucky. :D Or maybe I'll be able to edit the design as I go without making it look too chopped up.

Initial air dam, needs more work
 

Here's what I got done last night:

http://ecomodder.com/forum/attachmen...1&d=1349810566

I used jack-nuts (a.k.a. screwdriver installed rivet-nuts) for attachment. This is my first time using them, and I really like jack-nuts, particularly for fastening stuff onto a plastic bumper. Reversibility is not as good as some other fasteners because of a larger drill hole. If I took the mod off I could paint the jacknuts or maybe drill them out and putty and paint (but I'm set against totally reversing a good mod anyway, even for a prospective buyer. Find me someone who likes the mod instead). Jack-nuts are fairly easy to install, easy and quick to remove the mod, they're not too expensive (less than $0.50 per location), and the fastening is really quite strong and durable. I ordered them from McMaster.

Todo:

• Try heat gun to soften corners and then push leading edge even farther forward.
• Add air inlet and ducting.
• Add braces in the middle for rigidity at high speed.
• Maybe add features on bottom to smooth underflow (radius bottom edge, panel to cover underside gap)
• Paint it black (except over the blinkers). Some folks may really dig the stealth look. I'm okay with it, but I'd much rather have a more blatant ecomodder look, as long as it looks smooth and relatively attractive. Because I'm an evangelical ecomodder. Anyways the crystal clear probably won't look that great when it gets mud on it.

I was surprised by the result just because car noses have gotten softer and softer and softer, even since this 89 model. There must be something to be gained, but clearly I'd have to do A-B-A testing to find out how much, again a hindrance that I'm not ready for it.

(The reason, I mentioned earlier, is my rolling resistance problem, most likely drum brakes. Just a question of free time and priority.)

I think noses have gotten softer because the fashion/design world has moved away from boxy stuff.

Why do you think drum brakes are a problem for RR?

The clear air dam is kinda cool but you're probably right in painting it. Do be sure to cover the hole it's creating underneath, or the air may just swirl under there. Do you know if it stays stable and keeps it shape up to about 90mph? Figuring a 60mph cruise with 30mph head winds...

I can feel more drag when the car is cold. I had a test on my "bullnose" that demonstrated higher drag when cold (rather than finding the aero effect of the bullnose that I was looking for). Sometimes I think I can hear the rear brakes when cold. Can't say I know for sure.

I'm still debating what to do with the hole on the underside. I believe several ecomodders have left the edge harsh and still had positive results, although I doubt that's optimal... I might split some pipe insulation or large rubber hose into half-cylinders and add it to give the bottom edge a radius, then do a little coroplast to close up the bottom. Surely that would help.

I forgot to mention in my todo; you're right that I need a pair of braces in the middle; I'm pretty sure it bends in the wind. I have a little video camera I can strap to the lower grill temporarily to verify rigidity at speed. That should make for some fun shots too, assuming I manage not to lose my camera.

That's also possible. :)

Pizza pan slick covers
 

Here are my wheel slicks, similar to many other pizza pan designs posted here.

Costs ($33 TL):

• $27 - 14" aluminum pizza pans, set of 4 (can't remember why I spent that much, there are much cheaper sources available)
• $5 - Liquid nails
• <$1 - Rivets

http://ecomodder.com/forum/attachmen...1&d=1349817509

http://ecomodder.com/forum/attachmen...1&d=1349817509

I cutout the center of my existing snap-on plastic wheel covers. I remember someone saying their pizza pans are loud, so I put a heavy bead of liquid nails around the lip between the plastic and pizza pan, then cleaned it up to form an edge (there would have been less void to fill if I had managed to find deeper pizza pans). I was careful with the saw to leave enough plastic to support 4x 1/8" pop rivets applied from the outside. So far they've been quiet, easy enough to install and remove for air, and tough enough. On the rear wheels I used indoor/outdoor caulk instead of liquid nails. It's too early to be sure, but I think the liquid nails is better because of higher stiffness and yield strength. A couple of the 1/8" pop rivets slipped out of the plastic during installation, when that happened I drilled out the failed rivet and upgraded them to 3/16" rivets. Longer rivets and rivet washers would have been better than riveting into plastic. If any fail in service hopefully I'll notice while airing and upgrade them before I lose any pizza pans on the road.

Air dam braces
 

Minor update; added cooling opening and braces, checked for flexing at freeway speed. This shot is about 67mph, taken from the bottom of the lower grill. The braces have pushed the dam lip forward an extra inch or so.
http://ecomodder.com/forum/attachmen...1&d=1349897789
(I almost didn't post this because my heat gun work looks so bad, sorry.)

Still plenty left to do.

EDIT: I almost forgot; this is the best way to take a picture of an air dam at freeway speed:
http://ecomodder.com/forum/attachmen...1&d=1349900279
This is an old picture from back when I thought it was necessary to have a friend drive. But I've found that's not really necessary. Now I just do a long EOC / P&G.

I'd consider to use smaller and more streamlined sport motorcycle rearview mirrors instead of delete the passenger-side one.

By the way, I'd also think about some weight-saving tricks, replacing a few body panels, such as front fenders and hood, with plastic ones, and also taking out some of the interior trim such as door liners and carpet. A single-arm windscreen wiper can also be quite effective to reduce the drag, and also shaving that antenna out of the A-pillar. An internal windscreen-mounted antenna is better if you won't ever consider to get rid of the radio.

Air dam and grill blocks, done for now
 

Now the upper grill is blocked, and I have a barrier to keep the cooling inlet from spilling under the bumper and contributing to the underbody flow instead of cooling the engine (I decided ducting is too much trouble). Also I plugged a large gap above the bumper. (Too bad I couldn't find the backer rod in black though.)

http://ecomodder.com/forum/attachmen...1&d=1349983121

I'm fairly pleased with the forward slope. I'm sure it could be even steeper before being optimal, but it looks effective to me. I'll probably do my road trip just like this.

My defunct bullnose contributed pre-painted coroplast that I wrapped around the upper grill and screwed in place on the top and bottom. (The plastic stock grill pops off for easy modding.)

Also, here is an upward shot so you can get an idea what the airflow might look like underneath. (Despite how it appears, the air dam is actually the lowest point.)

http://ecomodder.com/forum/attachmen...1&d=1349983121

There are still a few items on my todo for the air dam, but I think these are less important:

• Add half-tubing at the bottom lip for smoother flow underneath.
• Add sides to the barrier to better separate cooling flow from underbody flow.
• Paint most of it black.

Would half tubing even be worth the effort? Even if you could maintain attached flow (with no belly pan) would a radius make a difference? The front of the car is a very high pressure zone and you shouldn't have even a hint of trouble there.

It seems to me that what you're trying to do with a radius would be better accomplished by building a whole new bull nose with compound curvature and everything.

For sure duct the cooling. If you can patch that hole, it'll probably be better for aero to make it a "bottom breather" and move the cooling intake underneath the nose. This maintains clean airflow over the nose instead of breaking it up when it passes the vent.

I'm afraid I don't see your point. I think the goal for an air dam lip radius is to prevent (or reduce) vortex generation at that location. I thought flow attachment is an issue for sloping surfaces in the wake.

The reason I didn't move the intake down further is because the nose doesn't seem long enough; the intake duct would have to be at a steep angle if I put it all the way at the bottom. I could see why it still might be an advantage but I felt uncertain.

Another todo I forgot: intake block, esp. for commuting.

Okay, hopefully without talking too much...

If you have a belly pan under there and cover up the hole you won't have vortexes anyway. So, just throw some coroplast on there and don't worry about a radius. Flow attachment usually is a problem on the rear, but with a slope like that on the front everything that goes under the air dam will be completely detached. There's nothing for the flow to "ride" on.

With ducting you should be fine. The Probe is fine even without ducting. If you're not aware, P&G and EOC keep engine temps down pretty well also. Mutual benefit.
http://farm9.staticflickr.com/8318/8...2c80f1e56f.jpg

My uncertainty on that design wasn't cooling effectiveness, but rather on the drag experienced by the air traveling through the scoop. After all, the advantage is that taking air from that location will reduce the drag elsewhere. But it may not be a net benefit if the scoop itself is lossy.

I know it would be better with a belly pan... and a boattail...

(BTW, the inlet is supposed to be designed for climbing 5% 2000ft mountain passes, one of the things it will be doing tomorrow. I can always block or partially block the inlet for less demanding applications.)

Trip results and analysis
 

1300 mile trip results: 46 MPG!

For analysis, I note that this car looks very similar to the 1986-1992 VW Jetta in the CdA list. It also has similar outside dimension specs. I don't have specific CdA data for the Corolla.

Analysis:
Assumptions:

• 65 MPH (trip time minus approximate stops / total distance)
• 59°F average outside temperature
• A=21.8ft^2 (like the Jetta)
• Gross weight 2300 lbs (including me and my tools)
• Crr >= 0.008 (generic tires at 44 PSI)
• engine efficiency <= 25%

Result:
Cd <= 0.28 or >22% reduction from stock 0.36 (Jetta). Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com (Why I used trip data with the calculator: long haul results are dominated by CdA, with very little city driving, etc. The primary uncertainty is wind speed, followed by engine efficiency and Crr. My impression is the wind was neutral overall on this ride. It tends to be so on a round trip.)

Not bad for a >23 year old car with just a handful of mods. (EDIT: maybe. I'm pretty sure I'm at least 10% ahead of stock. Really it's tough to know since I don't have a baseline for this type of trip.)

Mod list for this trip:

• Blocked upper grill
• Air dam with cooling inlet
• Slick wheels
• Rear wheel skirts
• P&G (but not much EOC)*
• (Earlier I had a gap filler right above the bumper. I had to take it off within the first 100 miles for the little bit of extra cooling it offered. It's a big gap, basically a third grill. When I finish the ducting I should be able to close it off.)

* I have never done a long trip with high speed P&G before, but now I love it. It solves 2 problems: a) throttle loss, especially in this car with its not-so-tall gearing, b) prevents fatigue of my heel, especially in this car having no cruise control. I believe that EOC is not so beneficial with the carburetor, since it takes a couple seconds for the engine to die and I expect it consumes fuel while it tumbles. Bump start is also a bit slow and consumes more energy than in my other car. If the glide is shorter than about 10 seconds I leave it on.

Other thoughts:

• It has really bad groove wander. The shimmy is not as pronounced but still present, although it depends on how smooth the pavement is.
• After the first 630 mile leg, I ran a 6 mile errand and the passenger drive axle fell out enough to leak transmission oil and made a big mess. I put in a refurbished axle (by chance this happened just outside my dad's garage) - and found the old axle was missing the retaining ring. Weird. Bizarre even.
• I tried to make this a reliable car and feel like I got burned. Maybe it was a fluke... like the two tire rod ends... and the muffler... and the clutch... and the groove wander... and the shimmy... :rolleyes:

Woah a flat bed eco car nice!

I have a 97 corolla and am getting around 40mpg currently with just grill blocks and smooth hubcaps (plastic). I do drive slower and have a scangauge 2. Your corolla is one body style older than mine, but the same/similar engine I think (mine is a 1.8L). Food for thought, my BEST mpg is between 42-45mph at around 55-65mpg depending on temp/wind durning the summer (80F+).

Very interested in how good you can get, since I haven't done anything to mine for months now.

Hey ps2fixer,

Thanks for your interest! I really like Corollas, they have noticeably bigger back seats than Civics, the engines are not interference types, and they're fun to work on. (My Corolla is not in good all-around mechanical condition though, very sad.)

Your Corolla has a more similar body style to my 97 Civic, which I haven't modded so much yet. My 89 Corolla also has a carburetor.

I would suggest you look into P&G and EOC, if you haven't already. I can pull 55-60 MPG out of the 97Civic/SGII on my commute (~70% @ ~55-60 MPH) in the summer, with a mod set similar to your Corolla, but its a manual so I can go wild with EOC (bump start). Traffic is usually moderate for me. I think most of the potential is still there with an automatic but it requires some extra thought (mine are both manuals).

Modding is fun. :D

Cheers

I have tried P&G and never had much luck on it based on the scangauge. Besides that, I have more than enough problems with traffic, since 66% of my trip is on a major road (only 1 lane for each direction of traffic...).

I really do need to get into modding mine more, but one thing nice about this car, it is weird lol. My MPG isn't linear like most other cars for mpg vs speed. At ~42-45mph it spikes up quite well to around 55-65 while driving steady vs it dropping to around 47 @ ~48-50mph. I can still get around 40-42mpg @ 60mph (running late for work).

Looking at your fuel log, your 1.6L + manual isn't doing much different than myself with the current weather. I think my car weighs more, but has overdrive, while the 1.6 was lighter (body style and engine size), and the trans didn't have OD? I always thought about putting a 1.6L with a 1.8L manual w\ overdrive in since my car is over 241k miles now and isn't in that great of shape either. The thing was a city beater, so tons of small wrecks in the front end, and the rear is messed up on one side.

I'm kind of interested what kind of results you can get with yours compared to mine since we have similar cars :). You have the advantage of the 1.6L, lighter car, and manual trans, while mine cuts off the injectors well when coasting and has overdrive as well as a different torque curve, max torque is at like 2800rpm vs the 1.6L model at 5600rpm.

I had a 92 corolla (wrecked and scrapped) that I was going to fix before getting this one, the body under the rear seat was rusted though, looks to be the only problem area for rust. Michigan winters eat cars (heavy salt on the roads).

I think you're right, they're similar enough and it should be interesting. (And they're definitely both beaters. :thumbup:) I may disappoint you though, for one if it sits in the driveway and I don't have enough tank data to report... (The thought of 'competition' makes me want to list mechanical excuses, too.)

I've decided to post something on my wheel skirts sometime, but the theme may be what not to do. Also, yesterday a quarter of my air dam shattered on a big dip, once I get it fixed I'll write an update on it.

You drive in a city environment right? Another thing to compare, I'm in the country, seems my car likes steady speed and long coasts to corners (in gear) :).

Good luck on reworking the air dam, make v2.0 a better design and I might copy you :).

Air dam damage, repair, paint, ducting
 

I broke my air dam going over a dip, near my office, but not a route I usually take. I remembered the dip halfway down the road, but decided to proceed. Got to work and decided to take a look, surprise, it's broken! (Surprising because it survived a lot of scraping before breaking.)

http://ecomodder.com/forum/attachmen...1&d=1351487804

You can see the fractures focused on the brace location. At the time I put the braces on I was mindful of how rigid they were, but having more flexibility might not save this dam from fracture on a hard strike anyways, since this dam is angled forwards and as it bends it's just going to go under and get itself in a tight spot.

I walked up the road later and picked up the missing piece, covered in mud and leaves in the gutter.

To start my repairs, I marked, then masked off the blinkers and painted the dam black. I painted the rear surface, since this is clear plastic I can do that and achieve chip proof paint. It seemed like a good time to try brush-on enamel. I've been thinking brush-on should have less VOC smog-contribution than spray, might even be a big difference, but not sure.

Then of course I pop-riveted some aluminum sheets over the fractures. Also I put some foam weather strip along the top. The real purpose is to prevent paint transfer to the bumper.

http://ecomodder.com/forum/attachmen...1&d=1351487672

EDIT: then I enclosed the ducting. It could be better, but I think I'm done, give or take some black paint. The sides are attached to the bottom via L brackets and #12 sheet metal screws. I'm glad I chose to attach the ducting to the braces rather than to the dam. Assembly is easier this way. BTW, the aluminum strip braces bolt onto the car at the engine pan locations (sharing the bolts with the engine pan).

http://ecomodder.com/forum/attachmen...6&d=1351487672

Then I used a white paint pen on a staff and marked a uniform height, and cut by jigsaw. Previously the hard plastic ended at 4.75-5" clearance at the front-corners, and about 5.5" in the middle of the bumper. Now the hard plastic has about 6.75" clearance all around.

Then I added lawn edging using sheet metal screws, final clearance at about 4.75". Coroplast would have been a strong choice too (better wind-stiffness, spring-back, cheaper per area, but requires painting and might be stiff enough to push the whole dam around during a ground strike).

http://ecomodder.com/forum/attachmen...1&d=1351487672

I'm going to do a highway camera test to see how well the lawn edging holds up against the wind. I don't remember anyone else reporting on that subject.

At this point I should note that thin aluminum sheet probably would have been a better choice over the PETG for this project, even considering a little added effort to add clear lenses for the blinkers. Using aircraftspruce.com, Al is a little cheaper than PETG, it is actually more paintable (although doesn't have the magic chip resistance of backside paint), I believe Al is probably easier to bend (heat gun was a pain). I did stretch the PETG a little in this project for more forward angle, not actually sure how much, but I doubt it mattered much aerodynamically and it was a pain to do. Anyways the same thing could be achieved by starting with a wider cut and doing a steeper angle on the sides, or since I cut the bottom back anyways the same thing could be achieved without any tradeoff if the correct height were used initially. Al also has a better failure mode, unless you can't stand the look of beat-up un-bent sheet metal. Either material choice requires adequate clearance and a softer bend-away chin, like Coroplast or lawn
edging.

EDIT: I thought about hiding the rivet and screw heads, and fracture lines, but I think I might just leave them. Maybe I should add some more decorative rivets on the other side. Bullet-hole-decals also crossed my mind for the side of the car. That could be taken wrong though, I suppose.

Name this project.
 

I forgot to mention, I've been reminded I need to stencil something on the car somewhere. Here are my ideas so far:

• ECOrolla, EcOrolla or ECOmod-olla (I'm favoring ECOrolla89 right now)
• ecomodder.com (obviously)
• 45 MPG (it seems like I ought to finish it and run it a few seasons first though, otherwise it's just a guess)
• Prius ;)
• Priusolla or Priusorolla or Prius-C-orolla
• MPGorolla or OMMPGorolla

I have a coworker who likes to tease me about my MPG enthusiasm. I can't remember how many times he's asked me what my wife thinks about this or that. He reminded me that if I don't write something on it people will assume it's a failed ricer, which I was already thinking hard about because it's my worst fear.

My commute is about 10 miles by the way, ~70% freeway, ~6 stops. That should be a pretty good prognosis for MPG, but warmup eats this car, and winter is coming. (EDIT: I park it outside.)

100% agree, cold temps is killing my mileage. A block heater might be a good idea since your trip is so short. I plan to block my lower grill more this year, last year I blocked around 75-80% and never ran any warmer than summer (204F with 192F thermostat).

mmm more corolla's

Engine block heater!
 

I have had an OEM engine block heater sitting on my shelf for years. Last night I installed it!

http://ecomodder.com/forum/attachmen...1&d=1351895196

More info here...