90 day average over 90 MPG
 

In the 70 MPG challenge thread, back in July, I wrote this:

Well...we did it! The current 90-day average for the "little car" is 91.08 MPG.

I gave my wife (and myself) a pep talk shortly after I posted that, we've both focused on doing our best since then...and it paid off.

I was just really excited after filling up this afternoon, and wanted to share. :D

Next goal: get through this winter without any tanks below 70 MPG.

-Funkhoss

Wow, that's very impressive.

Way to go!! Do you have a current list of mods or a current picture of your car with mods? Ar you using a Scangauge or other fuel economy instrumentation?

My goal is to maintain at least 80 MPG this winter; the real kicker will be in December when I'm in Michigan. Virginia is really nice for hypermiling, if you can stay out of the mountains. Plenty of EOC opportunities. With your lowest tank still bring in the 60s, with your MPG trend I feel confident you should be able to keep above 70 mpg this winter.

I've attached a pic of the car that I took this morning.

From the factory, it had basically no options--no A/C, manual steering, etc. We bought it in 2010 with 43,000 miles; it now has 241,000 miles. The engine (head and bottom end) has not been rebuilt.

The mods are pretty straightforward--nothing too radical. They include:
-Scangauge
-XFi cam
-Swift 3.52:1 transmission
-Ignition timing advanced 5 degrees
-Kill switch
-Auxiliary brake vacuum reservoir (for more/longer brake assist during EOC)
-Deep cycle battery
-LED headlights and exterior lights
-Bridgestone RE92 tires, inflated to 52 PSI, on 90's Accord wheels
-Roof painted with reflective white paint (for interior heat reduction)
-Llumar Air 80 "clear" window tint (for interior heat reduction)
-Engine coolant and oil heaters (for winter use)
-Trailer hitch
-Grill block with removable inserts
-Air dam
-Smooth wheel covers
-Rear wheel skirts
-Kammback

...and a whole lotta torque on the nut behind the wheel. :thumbup:

-Funkhoss

Funkhoss, that's really squeezing the pump!

Congratulations!

And your getting 44.9 mpg out of a big ole '94 Chevrolet Caprice Wagon is just as incredible.

You've obviously mastered the art of the ecomodder!

Impressive work!

Wow so cool looking mods! I need to make a skirt like that!

A 90+ MPG 90 day average has got to be unique on this site for a gasoline car. PaleMelanesian pulled off 90+ on a single tank with his 1996 Civic non-vtec sedan, but I am not sure if he had a 90 day average too.

A blast from the past! Oh, how the times have changed...

I typically travel quite a bit for work, but because of the pandemic I've been working entirely from home. I've only filled this car up once since early March.

Interestingly enough, our next door neighbor (an older lady) is actually borrowing this car this week. Her car has a leaking head gasket; we helped her drop it off at a local shop last night and she's driving our car until hers gets fixed.

It will be interesting to see what her driving does to our current tank average, which is in the mid/upper 80's according to the Scangauge. She let the car idle in her driveway this morning for 3-4 minutes before she left. I think that's more idling than the car has done cumulatively over the last two years... :eek:

-Funkhoss

She might be showing care for the car by warming it up... little does she know your shock! lol ...but I'm glad you're looking out for a neighbor like that.

How I managed to miss this thread last year, I don't know.


Nicely done! Very similar list of mods as my Firefly/Metros.

Thanks! Your website (along with this one) was certainly a source of inspiration for us when we decided to purchase our Metro in 2010. And the similarity of the mods we've done to the ones on your car definitely aren't coincidental. ;) :cool:

In our case, when you consider that this car is (a) shared between my wife and myself and (b) used as a family vehicle for our family of four, the numbers in our fuel log (80 MPG average year round since 2016, over a cumulative 100,000+ miles [I need to update it]) are even more impressive. If it was just me driving by myself all of the time, it would almost certainly be even higher.

With that said, I am incredibly grateful to be married to someone who is an extremely skilled hypermiler in her own right. :thumbup:

-Funkhoss

You're lucky! 2 ecodriving spouses sure seems to be uncommon. You're livin' the dream, man! :D

Can you describe your & her primary hypermiling techniques?

I did a 100+ mpg tank in my Firefly once, just for the heck of it, but it required a LOT of pulse & glide on back roads in warm weather, and at a relatively low average trip speed (mid-20's MPH, if I remember right).

These days I mostly drive with load at or near the speed limit, max. of 80 km/h = 50 mph on the scenic routes. But I also kill the engine approaching most stops & turns and going down some hills. And I typically see so little traffic, I can usually use whatever technique suits me at that moment without affecting other drivers.

Sure!

There's one additional factor that wasn't on my list of "mods" that I'll mention before I do: we run ethanol-free gas 100% of the time. We live in a very rural area, but it turns out that there's a small convenience store that sells ethanol-free gas only one mile from our house. They have ethanol-free because we're also just a few miles from a lake. The ethanol free gas they sell is 93 octane "premium," though. Their "regular" gas has 10% ethanol. So, because of this I have the ignition timing advanced a bit more than I could if we used regular gas, since premium is less likely to exhibit spark knock. It's not a huge factor, but it does help some.

The techniques we use are straight out of the "100+ hypermiling tips" on this site. There are a bunch of little things we do that all add up, but the three big ones are (1) reduced speed, (2) constant P&G with EOC, and (3) minimizing braking as much as possible.

We live in a rural area, so there's typically not a lot of traffic and/or stops. Most of our driving is on rural roads and highways with a speed limit of 55 MPH. Even when I travel for work (which, before the epidemic hit, I did regularly), I tend to avoid the interstate so that I can keep my speed down (and avoid the stress and traffic). I usually pulse from 35-45 or 40-50 MPH, unless the traffic or speed limit dictates otherwise. If I need to go faster because of traffic or someone following me who can't pass, I'll pulse from 45-55. On longer trips, then, my average speed is usually ~45 MPH. I pretty much never do steady state driving, though--it's always P&G (and my wife's the same way, too).

We live in southwest Virginia, which is pretty hilly/mountainous. This has advantages and disadvantages. The advantage is that the hills make for "natural" P&G--we pulse uphill, and glide down. The disadvantage is that there are some hills with stops at the bottom we can't avoid, and some hills that are so long and steep that you have to brake going down them (no matter how slowly you crest) to avoid speeding. So, route planning to avoid these stops and hills is pretty crucial.

Almost all of my best tanks have been on trips with flatter terrain--usually either to eastern VA or to OH/IN. My best ever tank happened last April on a trip to Norfolk, VA and back. Practically the entire trip was on a state highway (Route 58) that's flat, has few stops, and a speed limit of 55 MPH. The weather was warm and clear for most of the trip. I pulsed my usual 35-45 or 40-50 MPH the entire way there and back, and averaged 98.8 MPG (so close to 100!!).

So, the hills in our area are definitely a challenge, but one that can (mostly) be managed with careful planning and attentiveness to the terrain. I'm sure that our winters are much milder than they are in Canada, though!

There is one thing that I've discovered, unique to the Metro, that may or may not be helpful to you (I'm guessing you've probably figured this out already, but I'll share it in case there are others who haven't). The Metro seems to go into open loop fairly easily (i.e., with not too much throttle opening relative to the RPM) and when it does, open loop is MUCH richer than closed loop. So, I've found that making sure the engine stays in closed loop (while keeping as much load as possible) makes a pretty significant difference in fuel economy with this car.

On my ScanGauge, two of my four "gauges" are open/closed loop, and MAP. When the engine is on (again, practically always "pulsing"), I aim to keep the MAP reading at 90 kPa or more (max load) while staying in closed loop. There's usually only a very narrow range of throttle opening where this is possible, but if you keep it there, it pays large dividends over giving it too much throttle and going into (excessively rich) open loop. Eventually, you start to "feel" where that "sweet spot" is, and don't have to rely on the ScanGauge as much to keep it there.

On the Caprice wagon, I was able to tune the ECU to stay out of open loop until at least 80% TPS opening, so on that car it's super easy to stay in high load and closed loop (while still having power enrichment if you really need it). I wish I could do the same with the Metro, but unfortunately, the Metro ECU can't be reflashed. :(

Anyway...that's the long and short of our driving style. My wife drives pretty much just like I do, except she (self-admittedly) isn't always as hyper-focused as I am. :D

-Funkhoss

Thanks for the detailed reply.


I have to admit it's been a long time since I've used P&G on the open road (outside of hilly sections), but I don't recall being aware of the open loop penalty being so bad. Something to watch for. Thanks.

Yep. I've actually theorized for a while now that the tendency for Metros to go into open loop easily, and run excessively rich when they do, is a major factor in why they tend to burn exhaust valves.

I discovered the open/closed loop discrepancy early on in my experimentation with P&G. Our Metro has 254,000 original miles...and it still has good compression.

-Funkhoss

Impressive result!
Have change the clutch yet?

Well...yes, and no. When I put in the 3.52:1 Swift transmission at approximately 120,000 miles, I bought a clutch kit and thought I'd go ahead and replace everything while I had it apart. The clutch disc showed very little wear once I had the transmission out, but I went ahead and replaced everything anyway (I was more concerned about the pilot and throwout bearings than anything else, given the age of the car).

It was shortly thereafter, at about 130,000 miles, that I installed a kill switch and started using P&G with EOC. So, that clutch I put in at 120,000 miles now has over 130,000 miles on it, and those miles have been driven almost exclusively with P&G.

The clutch exhibits practically no wear. It still works great. :thumbup:

-Funkhoss

That one tank took nearly 90 days - a whole summer. But no, that was my only time up there. Ideal conditions came together all at the same time. Summer heat, light traffic, a good commute route, no extra trips required, old broken-in eco tires, etc.

What about modifying the TPS and/or MAP signals to hide the true load from the ECU?

Interesting idea! I'm pretty sure that on the Metro the closed/open loop threshold, once operating conditions for closed loop are met, is based 100% on TPS position vs. RPM (as it is on the Caprice and other ECUs that I'm familiar with). So, it's very likely that the only signal that would need modification is the TPS signal.

The question is: how would so doing affect the engine's operation in other ways?

Ultimately, it would be more about convenience than necessity. It is possible to keep it in closed loop at high load--you just have to be very careful about throttling.

-Funkhoss

mind blowing mileage!
I see you run non-ethanol gas also. That pushed my car over the hump for gas mileage. My ecu has no aftermarket support so software hacks are out. I want to explore some sensor mods but don't want to push advance to the point of cracking the head or burning the valves.

Some engines run without any enrichment, for example the Toyota Prius, or an old Mercedes M119/120 - engine from a certain year on. Issues? Obviously none. I think, this enrichment occurs often too early or too strong. A few years ago, I saw a german examination about exhaust pollutant of modern cars. It shows, that cheaper cars tends to enrich the fuel / air mixture way earlier than expensive cars. I guess, it´s just cheaper, to just enrich it, unstead to estimate, on which rpm or load this enrichment is really necessary.

Funk,

Can you buy this tint for self install? I have 3m Crystalline but its a racket. They will only sell to dealers who want an arm and a leg to install it and they are few and far between.

That I do not know, unfortunately. I had someone local to me, whose labor charges were quite reasonable, install it on both of our cars.

I can say that it does seem to work, though!

-Funkhoss

I'm a huge fan of that style of tint as well. It makes a crazy difference.