94 Caprice Wagon 5.7L project--46 MPG so far

[hayden55]

https://youtu.be/p1AksSQB1Yc

Hey look we found you in a video! 11:00 minutes in

[aerohead]

All I can think of is the old school 'shrouding trailer.'
The test vehicle is enclosed inside this trailer, which is essentially airtight.
It is 'pulled', in neutral, or with the driveshaft disconnected, by a tow-bar linked to the trailer inside.
There's no aerodynamic drag, only rolling resistance ( RR ).
The rig is accelerated up to the test velocity, then the tow-bar is 'released', transferring all the RR load onto a strain-gauge load cell, or 'spring scale' measuring device ( like a fish scale ).
The observed load is divided by the all-up weight of the test vehicle, and the RR force coefficient ( Cfrr ) for the set of four tires falls out. Dividing by four gives the individual tire Cfrr.
Coastdown testing would spit out the value as well, but I can't recommend it. It's not for amateurs.

[ademonrower]

VERY impressive!!! 50 MPG translates to European 4.7 liters/100 km, which is absolutely astounding for a car with a 5.7 liter gasoline engine! Incidentally, if you used mainly already-existing second-hand parts (i.e. not creating much impact through manufacturing of parts), you have easily beaten the scenario of replacing your car with a new EV (of any description). I have the calculations and research literature references in my book for Oxford University Press. I'm currently working on reducing consumption of a rarely-used Volvo 245 (wagon) 1979 with 2.1 liter gasoline carburetor engine. Plan for this year: fit injection, swap 4 speed man. transmission for 5 speed man; underbody air-flow panels; tailgate air-flow prolonger... what would you say is the priority? Possibly something else I haven't mentioned. Thanks, and all the best, Andrew

[funkhoss]

I sold this car over a year ago, so the car's current owner is welcome to chime in, too.

However, just a few thoughts in response to your post...

Originally Posted by andrew.moore@freenet.de

VERY impressive!!! 50 MPG translates to European 4.7 liters/100 km, which is absolutely astounding for a car with a 5.7 liter gasoline engine!

50 MPG was a "best ever" road trip tank. On average, it was more like 42-43 MPG in warm weather in mixed driving. Still significantly more than twice the EPA rating, though, and not far from Prius mileage!

Originally Posted by andrew.moore@freenet.de

Incidentally, if you used mainly already-existing second-hand parts (i.e. not creating much impact through manufacturing of parts), you have easily beaten the scenario of replacing your car with a new EV (of any description). I have the calculations and research literature references in my book for Oxford University Press.

Yes, most of the modifications were either junkyard parts or off-the-shelf factory replacement parts from other platforms. I even bought used tires most of the time, because they have lower rolling resistance and we typically didn't drive this car that much (so they'd be more likely to rot out than wear out).

What's your book? It sounds like I'd be very interested to read it. This has been my thought for many years, also--the idea that keeping an older car running and modifying it for increased efficiency is more ecologically sound overall than buying a new EV. It's also significantly less expensive.

My daily driver, and our "family car", is a 2000 Chevy Metro. I paid (a very small amount of) cash for it in 2010 when it had 43,000 miles. Thirteen years later, it now has 305,000 miles, still has the original engine, has never needed any major repairs, and still averages over 80 MPG in warm weather. I can't imagine any other family vehicle (including EVs) that would have had a lower environmental impact over 13 years of driving than this one. And, I can't imagine any other vehicle that would have been less expensive to operate during that same time frame, either.

Originally Posted by andrew.moore@freenet.de

I'm currently working on reducing consumption of a rarely-used Volvo 245 (wagon) 1979 with 2.1 liter gasoline carburetor engine. Plan for this year: fit injection, swap 4 speed man. transmission for 5 speed man; underbody air-flow panels; tailgate air-flow prolonger... what would you say is the priority? Possibly something else I haven't mentioned. Thanks, and all the best, Andrew

Driving technique is always going to be the most important factor, period. The three most important concepts that I tell people who ask about hypermiling are:

• Slow down;
• Minimize your use of the brake pedal; and
• Utilize "pulse and glide" (P&G) with "engine-off coasting" (EOC).

Having done it 100% of the time, for over eight years and over 200,000 miles, in three different vehicles, I can confidently say that consistent and correctly implemented P&G with EOC is the single most impactful thing that one can do, with a gasoline-powered vehicle, to significantly reduce fuel consumption.

Both our Metro and this Caprice wagon had been significantly modified before we started using P&G with EOC. Both had aerodynamic treatment (Kammback, grille block, smooth wheel covers, rear wheel skirts, front air dam), improved gearing, LRR tires, engine tuning, and instrumentation (in other words, all of the "standard" modifications suggested on this site). However, when we started using P&G with EOC, the Metro instantly went from averages in the mid-60s to averages in the upper 80s, and the Caprice instantly went from averages in the upper 20s to averages in the mid-40s.

That's about a 40% increase in efficiency with the Metro, and about a 60% increase with the Caprice.

And, that's why I say what I do about driving technique.

With that said, these are the modifications I would prioritize with your particular vehicle. I'd usually encourage someone to start with aerodynamics, but that's usually assuming a fuel injected engine. In your case, switching to EFI might be just as significant as aero mods. At any rate, those are the two things I'd focus on first. EFI also allows for instrumentation (i.e., an MPG gauge)--another must. Finally, LRR tires can make a noticeable impact. Living in Europe, this will be simpler for you, since European tires have a label that shows their rolling resistance rating relative to other similar tires (I so wish we had this in the US!).

I've gotten to the point where I'm ambivalent about gearing. If you commit to P&G with EOC, it really doesn't matter. However, if you don't intend to use that technique, and drive at steady speeds on the highway with the engine on...you want the lowest top gear you can get. It still won't be anywhere near as efficient as P&G with EOC, though (have I made my point yet? )

I hope this is helpful. And, please let me know about your book!

-Funkhoss

[ademonrower]

Great pieces of advice! Thank you! I will start practising the EOC method. With an older car, it's less scary, because there is less to lose when the engine is off :-) Servo-assisted brakes would be a serious one, though...

My book is about energy and material economies of carbon compounds. It's a response to the often misguided strategy of trying to de-carbonize everything. In the chapter on cars, I do very deep analyses of whole economies of manufacture and driving at average mileages in various parts of the world. I always come to the conclusion that the best thing is to keep one's existing car, drive it sparingly, and maintain it well. Nothing else, on average, beats that in terms of energy use, CO2 emissions, environmental impact. I also look at fuels for aviation and shipping. Other chapters compare carbon economies with non-carbon economies in areas such as cement, steel-making etc.

A big focus is on energy storage once you've made it, because that's a very large under-developed aread. Hydrocarbons, in their numerous forms, are very convenient for long-term and short-term energy storage. Re-cycling CO2 from the atmosphere/industry exhaust gases is, across most large industrial sectors, a very advisable strategy to be researching.

Opponents of E-fuels say that they require horrendous amounts of energy to make. True, they are energetically costly, but environmentally they are much less harmful-residue-forming than mineral-based power-solutions, dug up from the Earth's crust, with all the attendant mining pollution problems... and then the toxic recycling wastes (if we ever get into battery recycling in a big way...). E-fuels are much more amenable to making closed-cycle economies of manufacture/recycling with relatively low environmental impact in the long term.

New infrastructures to replace the hydrocarbon-based storage/distribution infrastructures will create a horrendous CO2 bubble of their own during their manufacture, not to mention their own environmental impact (i.e. beyond just the CO2 emissions on which many people are concentrating - to the exclusion of all else). All of this rapid change away from carbon-based energy stores and carriers is going to have horrendous environmental impacts in my analaysis.

My book will be out around July this year. Unfortunately I can't reveal much more about it at the moment, for obvious reasons. By the way, I'm completely freelance, and have no industry connections or membership in industry-related or lobbying-related organizations. I just see this from a concerned-scientist-perspective :-/

[funkhoss]

Originally Posted by andrew.moore@freenet.de

Great pieces of advice! Thank you! I will start practising the EOC method. With an older car, it's less scary, because there is less to lose when the engine is off :-) Servo-assisted brakes would be a serious one, though...

There are fairly simple solutions to the problem of vacuum assisted brakes. In our Metro, adding an auxiliary vacuum canister/reservoir was enough of a solution. I can press the brake pedal multiple times without losing assist, which is more than enough for this car. It's never an issue.

With this Caprice, which has bigger brakes, more inertia, and can coast much farther than the Metro, an auxiliary vacuum reservoir wasn't enough. I ended up installing an electric vacuum pump from a VW diesel (with a vacuum-activated switch) that would "recharge" the brakes as necessary when the engine was off. The Caprice could coast indefinitely and never run out of brake assist.

Other features you'll need to do EOC successfully:

• A kill switch (you don't want to use your keyed ignition switch to shut off the engine);
• a manual transmission (for bump starting);
• manual steering (for obvious reasons!);
• a deep cycle battery (EOC will ruin a standard lead-acid starting battery pretty quickly); and
• an electric pump for the heater core coolant circuit (if you like having consistent heat in the winter!).

Originally Posted by andrew.moore@freenet.de

My book will be out around July this year. Unfortunately I can't reveal much more about it at the moment, for obvious reasons.

I looked around for it online after your first post, but didn't find anything. This would explain why! Please do let us know when it's out.

[aerohead]

Originally Posted by ademonrower

VERY impressive!!! 50 MPG translates to European 4.7 liters/100 km, which is absolutely astounding for a car with a 5.7 liter gasoline engine! Incidentally, if you used mainly already-existing second-hand parts (i.e. not creating much impact through manufacturing of parts), you have easily beaten the scenario of replacing your car with a new EV (of any description). I have the calculations and research literature references in my book for Oxford University Press. I'm currently working on reducing consumption of a rarely-used Volvo 245 (wagon) 1979 with 2.1 liter gasoline carburetor engine. Plan for this year: fit injection, swap 4 speed man. transmission for 5 speed man; underbody air-flow panels; tailgate air-flow prolonger... what would you say is the priority? Possibly something else I haven't mentioned. Thanks, and all the best, Andrew

* How will you be driving the car?
* Overall driving speed may determine where to focus your resources.
* And there may be legal constraints in Germany for some body modifications, which would not be a consideration elsewhere.

[bandit86]

Very inspiring

[ademonrower]

Many thanks for those very useful pieces of advice.
Re (from funkhoss):

Aux. vacuum canister for servo brakes: great! that sounds quite simple. Where do I get one?

A kill switch (you don't want to use your keyed ignition switch to shut off the engine); >> OK, I'll look into that
a manual transmission (for bump starting); >>yup, I have a man.trans.
manual steering (for obvious reasons!); >> yup, I have man.steer.
a deep cycle battery (EOC will ruin a standard lead-acid starting battery pretty quickly); >> many thanks for that advice: I was on my way to destroying my lead acid battery; and
an electric pump for the heater core coolant circuit (if you like having consistent heat in the winter!). >> I'll try to weather that one (no pun intended), but perhaps my passengers won't like it, so advice gladly accepted :-)

From aerohead:

* How will you be driving the car? >> mainly highway and uncomplicated country roads, typical speeds between 40 and 70 mph.
* Overall driving speed may determine where to focus your resources.
* And there may be legal constraints in Germany for some body modifications, which would not be a consideration elsewhere. >> Yes, that IS a problem: it's a pity that one is allowed to do so little to one's car here in Germany, but with a bit of cunning, and making absolutely sure that it's rock-safe, I reckon I'm on the "good" side in terms of practical measures. If I'm caught, then I can turn it to our (eco-modders) advantage and call a journalist that I know: she'd probably love the story and its environmental implications :-) I can't be caught too much though, because the fines would ruin me...

[ademonrower]

Sorry, I forgot to ask: re. the kill switch, does this have different implications for carburated engines compared with retro-fit EFI systems?

Also, sorry if this sound stupidly obvious, but with the kill switch system operated as intended (i.e. not turning the ignition off), I assume that I bump-re-start the engine after every kill. Does that do the clutch, transmission, engine any harm in the long run? I suppose I'd have to develop a refined bump-start technique, so as to mimic the relatively mild impulse that the starter motor gives...

Am I right on any of this? Thanks!