MetroMPG's 1998 Chevrolet Metro (Pontiac Firefly) mods & repairs kitchen sink thread
 

http://ecomodder.com/forum/attachmen...1&d=1494527057
(The unmolested 1998 Pontiac Firefly 1.0L 5-speed, shortly after bringing it home.)

I figure it's about time I made a "kitchen sink"/catch-all thread to document everything - eco and otherwise - that I've done/am doing to the Flea.

(I've had the car for 12 years now -- I think it's safe to say it's a keeper!)

If you don't know the backstory, the car was a lucky barn find: it had been driven less than a year, and then parked in a garage and not driven for 7 more years before I got it with ~2500 km / ~1500 miles on the clock.

Mods & Tests index...
 

(This list is a work in progress - will be adding links to related threads.)

Transmission & engine

• Installed transmission with taller final drive - 5.2% improvement
• synthetic transaxle oil - untested
• efficiency camshaft from XFi model installed March 2007 - untested
• lower viscosity synthetic engine oil (at first: 5w30 2L + 0w20 1L), changed to full 0w20, summer 2006 - untested
• timing advanced - untested
• engine block / coolant heaters (on the Blackfly) - Update: April/07 installed additional 850w inline heater
• alternator disable - ~10% improvement
• warm air intake (WAI) - tested
• K&N air filter (Busted! Removed & sold. See Testing a 'performance' air filter for MPG)

Aerodynamics

• prototype removable boat tail - ~15.1% fuel economy improvement
• partial grille block & rear wheel skirts - ~5.7% improvement
• streamlined wheel covers - untested
• deleted passenger outside mirror - ~2.3% improvement
• Kammback hatchback extension - ~4.9% improvement
• radio antenna repositioned - untested
• gap filling around headlights - untested
• hood/bumper gap sealed - untested
• partial cowl block - untested
• smooth undertray - ~2% improvement
• gap filling around headlights - untested
• massive cardboard air dam - tested

Other

• tire pressure 38 psi (front) 36 (rear); boosted to 48/46 Feb/06; again to 52/48 fall/06 - tested
• LRR tires (Bridgestone Potenza RE92 from 1st gen Insight)
• lightweight 14 inch alloy wheels (with wheel discs)
• aftermarket cruise control (only used for testing, or on flat roads)
• new brake calipers (on Firefly #1 - the original ones were dragging slightly & replacement noticeably improved rolling resistance)
• daytime running lights switch - so I can turn them off on a divided freeway, where DRL's safety contribution is lowest. (It's highest on undivided highways where there's an oncoming overtaking hazard, and where other cars are approaching your path at right angles - e.g. urban driving).
• engine kill switch (to keep the ScanGauge alive if the engine is stopped while at rest or coasting)

Tools

• a good tire pressure gauge
• a ScanGauge
• Accessing the brain trust at EcoModder.com
• Books: Road Vehicle Aerodynamic Design by RH Barnard; Aerodynamics of Road Vehicles edited by Wolf-Heinrich Hucho

exhaust work - getting harder to find parts!
 

The just car's coming up to 40k km / 25k mi., and it's time for its first ever "major" repair: exhaust work. Original exhaust, and I've been patching various leaks with muffler cement (bondo, actually :D) for a couple of years now.

Well, the intermediate pipe busted last week, and no reasonable amount of bondo can hold it together any more. It's time to actually spend some money on this heap! The original pipes only lasted 19 years - shameful.

Interestingly, the car is now getting old enough that the first 2 parts stores I called couldn't get the parts. The dealer doesn't stock it anymore either -- their parts guy said GM sold off all its OEM stainless Metro exhaust parts to a U.S. company. They could special order it, but the price was crazy.

Luckily, the 4th place I called could get it. So I'm getting an "aluminized steel" replacement for the intermediate pipe w/ resonator.

http://ecomodder.com/forum/attachmen...1&d=1494531540

Not as good as stainless, but I wonder how the cost:durability ratio compares between the two metals. This was 1/3 the price the dealer quoted for the stainless part. Think this'll last 1/3 of ~17 years?

I'm about to find out, and then I'll know for the next time it needs replacing.

Since you haven't been driving the Firefly in the winter, I think you'll get some pretty good life out of it.

unmuffled
 

True. Also, I rarely do short trips where you fill the system with condensation, then turn the engine off & cause it to rust out from the inside. Longer trips heat everything up & dry it out, which helps keep things shiny.

UNFORTUNATELY...

I discovered last evening it definitely needs a new muffler too. I couldn't see how bad the top of it was - it's coming apart!

http://ecomodder.com/forum/attachmen...1&d=1494603573

I'm surprised it was still muffling. Also cool: note the Suzuki name stamped on it!

Here's the whole mess:

http://ecomodder.com/forum/attachmen...1&d=1494603573

Yes, that's duct tape! (You know you're a shoddy mechanic when there's duct tape on your exhaust system.)

And it looks like I repaired this before and completely forgot about it -- the section of pipe between the flange and the resonator was replaced. It has the telltale signs of my awesome welding skills on it. Pretty easy to tell from factory welds.

I really should make a repair log for the car. Hey, I think I just started one with this thread.

Hah, yeah that muffler looks pretty far gone. Aluminized replacement I take it?

Re-muffled, for life!
 

I splurged and went for the stainless muffler with a lifetime warranty.

http://ecomodder.com/forum/attachmen...1&d=1494723025

Very happy with the results: The exhaust is tucked up snug & tight to the underbody, it doesn't rattle against anything, and the car purrs like a Rolls again.

I joked (half joked?) with the parts guy that there is probably a 0% chance that the company will still stock this particular muffler by the time I need to claim a warranty replacement. In another 10 or 15 years maybe?

We'll see. I'll post back when that happens. :)

Getting hitched...
 

http://ecomodder.com/forum/attachmen...1&d=1494887468

Next up... it's not as bad as it looks!

I just took the bumper off to measure for a trailer hitch.

For occasional towing of my light utility trailer... and as a mounting point for something that rhymes with "bloat trail".

Moat rail? Float sail? Goat jail?

Definitely goat jail! :)

Go directly to jail. Do not pass goat. Do not collect $200.

I've no experience, but I've been warned against welding aluminized steel. Either grind off the coating or wear a gas mask :eek:

My vote is for a goat jail. With 59 Cadillac taillights in 39 Chevy bullet housings. Three to a side.

I laughed twice when I read "goat jail".

Once, for general creativity.

Twice, because when I made the Firefly's first boat tail (the cardboard proof of concept), for a brief time it was a "raccoon jail". Seriously, one chewed its way inside and set up camp. OK, OK, more of a nest than a jail. Similar visuals though!

Now that I think of it, I know Phil had problems with an actual goat destroying one of the aero toppers on his truck.

Life something something art.

I for one am looking forward to the concept sketches.

Turnpike cruiser bubble skirts?

Please use something other than cardboard and trash bags for ths goat jail! :)

hitched!
 

Lookin good. Time to hook up the boat!

For some reason, I still have the goat jail from the Prius. It's wood, cardboard & shrink wrap. Does that count as an upgrade?

I will look at whether it can be easily altered to fit the Firefly before I get around to making a more durable one. But based on the stuff on my to-do list, I probably won't be making a proper one before winter.

http://forkenswift.com/album/21-fs-trailer3.jpg

ForkenSwift was a better boat tower! Torque, baby! (Unibody flex, baby!)

I am not going crazy
 

I was right! That WAS my crappy welding!

I found my previous exhaust repair thread from 2013, wherein I rebuilt both the front pipe and part of the intermediate pipe:

http://ecomodder.com/forum/attachmen...1&d=1376271784

http://ecomodder.com/forum/showthrea...art-26633.html

... which means I'd better start pricing a replacement for that front pipe. :D

Let me know if you can't find what you need.

gratuitous trailer hitch pics
 

I towed my wee trailer wth my wee car this week! Picked up some 4x8's at the hardware store.

http://ecomodder.com/forum/attachmen...1&d=1496948417

http://ecomodder.com/forum/attachmen...1&d=1496948417

http://ecomodder.com/forum/attachmen...1&d=1496948417

http://ecomodder.com/forum/attachmen...1&d=1496948417

http://ecomodder.com/forum/attachmen...1&d=1496948417

I should probably make a dedicated Metro hitch thread for the benefit of search engines.

Does the crossbar do anything?

That's a remnant from the way this attached to the Prius.

But I left it on as a possible means to help stabilize a small hitch-platform thing I'm thinking about.

Reminds me of one I have, that I think will fit many different vehicles...

Something like this:

http://assets.curtmfg.com/masterlibr...1024x768_a.jpg

I like the hitch.

Yeah, it's a variation of a commercial one I saw on eBay or somewhere...

http://ecomodder.com/forum/attachmen...1&d=1497364415

Lowdown on the next mod
 

http://ecomodder.com/forum/attachmen...1&d=1497365530

The stock ride height of the 96+ Suzukiclones is really high. (It looks so high that GM actually lowered the cars for some of the promotional photography at the time).

I've never really thought the car had excessive body roll, and I don't think its ride is wallowy. That's not my motivation.

Motivation: excessive ride height = poor aerodynamics. Lowering should have the effect of slightly reducing both frontal area and Cd.

Time to address it, with what should be a simple swap. Pictured above is a 20 year-old set of very ratty looking aftermarket lowering springs from...

http://ecomodder.com/forum/attachmen...1&d=1315783546

...the very ratty Swift GT parts car that I junked last summer.

From everything I've read, swapping the parts is supposed to be a super quick job: only about 10 minutes out & 10 minutes in per corner.

My main concern is ride quality -- I drove that Swift GT briefly once, and I vaguely remember it being quite harsh and bouncy. I'm not sure I'll be able to tolerate that for slightly better MPG.

We shall see.

You will probably be alright with the newer Firefly weighing more than the older body style. Then again its probably going to sit lower than the GT. We will see. Love that Firefly.

Thanks, iveyjh!

Is yours lowered too, or do the side skirts just make it look lower? I love the look of your car every time I see it. Black & white futuristic aero Metro cop car vibe, or something.

---

Another thought on lowering...

I was thinking I may be able to kill 2 birds with 1 stone: the stiffer springs may let me delete the sway bars, for a weight reduction bonus!

Not one to cut springs?

Cutting springs is the route a lot of Metro owners have taken with good results, and it's Plan B if I'm not happy with the Swift springs.

Swift springs will save a bit of time, though.

If it's bouncy, it's probably under-damped, and if so, putting the springs on a heavier car (with the same dampers or dampers with the same rates) will only exacerbate that...

10 minutes to remove* ... NOPE
 

http://ecomodder.com/forum/attachmen...1&d=1497449168

Well! This is not going to be the quick job I thought it might be.

Rear spring removal is supposed to be a quick job of removing 2 nuts, 1 bolt+nut, thus freeing one end of the control link (toe adjustment) from the axle carrier/hub assembly, and then the axle/carrier hub assembly from the control arm, which you then simply push down and the spring falls out! Easy as pie!

HA!

The sleeve in the bushing of the control link is siezed to the stud on the hub assembly. I'll destroy the bushing if I smash it or pry on it any more than I have. (Or heat it.)

Also well and truly siezed is the bolt holding the axle carrier/hub assembly to the control arm. No amount of penetrating oil or hitting it with a mini-sledge is going to free it. And I don't have a torch. And I just broke the adaptor for my little impact driver!

This Firefly has only been winter driven a handful of years, but apparently it was exposed to enough salty mess to convincingly lock these bits together.

* I actually went back to GMF to see if I misread the "10 minutes per" comment. Guess where the poster lives? California! Haha, of course. Rust free California.

The GT had a lot of extra stuff and a heavier twin-cam 4-cyl engine. Weight is probably very similar.

That might even improve ride quality! I took the front bar off my Wagon. I couldn't tell from behind the wheel whether it was there or not.


Spring compressor?

I gave up on the rears, for now. But Plan B formulated! (Spring compressor is Plan C... I don't have one.)

The fronts are in. They were much easier - I only stripped 1 siezed nut per side. :D But they ultimatedly succumbed to big vice grips. GRR.

Hmm. Can you just jack up the rear control arm, unbolt the strut, lower the jack and pull out the now uncompressed spring?

LOW! Very firm. Not bouncy.
 

Yup! That was Plan B. And I disconnected the control rod at the inboard end (fortunately not siezed). I just had to mark the eccentric adjustment bolt to preserve the same toe setting when I put it back together.

In the end, what should have been a 1 evening job stretched out over a couple, but it's done.

And MAN, is it low:

http://ecomodder.com/forum/attachmen...1&d=1497540874

How low is it? A teenager walking by gave it a sign of the horns wave at a traffic light. (I think that means something.) That has never happened before. Devil stance?

And MAN, it is not smooth riding. :D

It's not what I would call harsh. But it's quite a bit firmer than the stock Miata, which I drove briefly yesterday for comparison. And it makes my 216k kilometers 2000 Metro feel like a 1970's Buick by comparison.

For me, it's right on the verge too firm. But it is not bouncy, which would have been an immediate deal-killer. I will definitely be removing the sway bars, but I'm going to leave these springs in, for now.

And I'll have to check my alignment - the steering wheel is off center by an inch or so.

Oh, also the air dam is scraping all over the place now. Will need trimming, if it doesn't self-trim before I get to it.