Honoured to be here

[wheel_of_steel]

Hey everybody, glad to be here.

My name is Tom, and I own a '95 Hyundai Accent. I've been reading various articles, DIYs, and discussions that are posted up on here, and I have to say it is a very impressive forum. It is nice to see that people are taking an active interest in fuel economy!

Anyway, here's a bit of a back story, I've always been interested/intrigued by hypermiling, but never practised it. I have two other cars: a beta swapped 01 Hyundai Accent, and a 92 Hyundai S-coupe GT turbo under restoration. Neither of them are hypermilers' dreams, but building and restoring both cars has taught me invaluable lessons in building and modifying cars for evil. At one point I even completely stripped out the LC accent and was getting 30.5 mpg with track use and daily thrashing!

I'm a uni student, so when the beta accent got busted by the department of transport for having a bigger engine, it was time to get a good daily that I 'wouldn't modify' and I could just 'ignore' while I studied...

So I picked up a 95 Accent (they are called Excels in Australia) for the princely sum of $850. So far I've just given it a major service and clean, and removed the roof racks. You can see in my fuel economy log that my gas mileage has only improved with each tankful. Heck, I haven't even driven for a whole tank using hypermiling techniques only yet!

I've got a few modifications that I intend to do in the short to medium term:
-I want to install a vacuum gauge to help me with my DWL and coast and burn technique
-I've got a jaycar air/fuel mixture monitoring kit waiting for me to build it. The plan is to pick up a factory tachometer-equipped instrument cluster, and integrate the 10-LED readout of the jaycar monitor into the lower portion of the new cluster. I want to see just how much load I can place on the engine before the 02 sensor is 'taken out of the loop'

The next mods aren't strictly eco-mods, but, well...
-I want to convert to J3 lantra spindles and brake rotors, and santa fe brake calipers up front. My front wheel bearings are completely buggered, so I may as well upgrade from the crappy captive rotors that would need replacing anyway.
-This will necessitate at least a 15" wheel, so I will probably go for some sort of light factory alloy with some semi slicks.

So yeah! I apologise for the essay, I tend to ramble a little bit and take too many photos, but I will share what I've done so we can compare notes and I can improve on my juice-saving skills. My first mileage goal is 45 mpg.

Cheers for reading!

[MetroMPG]

Welcome to the forum!

Another item I'd add to your list is a fuel economy computer. Since your car is likely pre-OBD-II, you'd have to go with something along the lines of the MPGuino.

You might be surprised how much of a difference it makes to your driving technique.

[larrybuck]

Welcome! I'm sure you'll find plenty of fuel for reading here, and we look forward to hearing more as you progress.

[cfg83]

wheel_of_steel -

Welcome to EM! Jaycar has great stuff. I have their "Cadillac digital AFR" and I love it.

What is your avatar picture?

CarloSW2

[mcrews]

welcome!
I love reading 'australian'!!!

your a hands on kinda guy......you'lll like it here!

[wheel_of_steel]

Thanks for the warm welcome, guys. I know it can get a little tedious welcoming hoardes of new members, especially with the amount of traffic that this forum gets.

MetroMPG, I've been reading about the MPGuino and it certainly looks the goods. I was considering making my own rudimentary monitoring circuit by clamping a duty cycle monitor on an injector wire, but this looks like a better and more complete application.

cfg83, you should get their catalogue. It makes for hours of fun browsing and scheming. My avatar is a dustbunny armed with toothpick and bottlecap shield.

mcrews - The atmosphere is great here. Don't tempt me to make my posts any longer though, I swear I could write an essay about nothing.

and thanks larrybuck, I certainly will be reading everything I can!

So, I don't have any economy updates yet, but I'll be assembling my 02 monitor kit this weekend. To prevent making a thread about potentially nothing, I just want to clarify something about coast and burn, and DWL.

If:
-The premise of coast and burn is to operate the engine at a lower BSFC over the course of a journey - by accelerating at higher-than-cruise load, then coasting down for free.

and:
-Driving with load is aimed at maintaining high levels of manifold vacuum at all times, or setting load/mpg targets


Don't we have a clash of concepts? CAB seems to welcome higher load levels (within closed loop operation), whereas DWL encourages the engine to be as lightly loaded as possible.

I'd imagine that you just get diminishing returns from increasing your manifold vacuum during the 'burn' periods - a 10 second burn might use 20 MPG whereas a 20 second burn might use 25 MPG? These are just example numbers but I hope that conveys my point. I'd like to see what the members with scangauges can say about that one.

Also, is CAB driving meant to be sensitive to hills? For example, do you just set an upper (turn engine off at this point) and lower (kick start engine again) speed limit and just drive according to that? Or do you set a maximum load for your burn periods, or a minimum MPG value, or burn until you reach a downhill, or set a burn time?

If these questions have been asked before with different phrasing, I apologise. I'm doing my best to absorb ecomodder.com's wisdom.

[MetroMPG]

Originally Posted by wheel_of_steel

Don't we have a clash of concepts? CAB seems to welcome higher load levels (within closed loop operation), whereas DWL encourages the engine to be as lightly loaded as possible.

I wouldn't say they clash, exactly - because both techniques will return better economy than "conventional" driving techniques (eg. either constant speed or even constant throttle operation).

Yes, CAB (a.k.a. Pulse & Glide / P&G ) will return the best fuel economy (assuming the vehicle in question is not so unaerodynamic as to be unable to coast for a long enough distance to make it worthwhile). But P&G can also be a tedious technique to use for extended periods, and it's arguably harder on the vehicle mechanically than driving with load.

In the last few years, I have given up P&G driving (on the open road) in favour of driving with load / target MPG driving for those reasons. My fuel economy has decreased, but it's a tradeoff I can live with.

[wheel_of_steel]

Okay, I think I'm hooked on hypermiling. I just got 47 MPG on the last tank


Anyhoo, I'm still waiting for my vacuum gauge to arrive. I'm going to mess up my fuel economy this week, as I'll be taking the Accent to the 1/4 mile track for fun. Hopefully this weekend I can track down a tachometer cluster and get to work on my AFR monitor. I've got an experiment planned, let me know what you guys think:

AIM: To find out the most efficient acceleration technique for pulse + glide driving.

EQUIPMENT:
-Vacuum gauge
-Duty cycle monitor
-Timer
-AFR monitor (optional)

METHOD:
I plan to initally run the tests for an acceleration from 50 to 60 mph. The controlled variable will be the vacuum - I'll set a particular vacuum and then time the run and record the fuel economy for the duration of the run.

This is based on what seems to be quite a common dilemma:
-low load, righ rpm driving or;
-high load, low rpm driving?

Anyway, I can't do that experiment until I get a little instrumentation first. Thanks for reading! I'll let you know how it does on the quarter mile: I'm hoping to beat 18 seconds.

[MetroMPG]

Congrats on getting hooked.

Driving for best economy is a very similar kind of fun as getting a drag time slip or lap time report: feedback for tweaking your technique & vehicle. (That's why you should really work out some kind of fuel consumption instrumentation for instant feedback.)

Originally Posted by wheel_of_steel

This is based on what seems to be quite a common dilemma:
-low load, righ rpm driving or;
-high load, low rpm driving?

I don't think you'll find anyone here advocating for high RPM driving (not clear whether you're wondering about steady state cruising and/or acceleration).

For cruising, the lower the RPM, the better.

Even under high load acceleration, the best fuel consumption will be found at low/moderate RPM managed by short-shifting.

See the BSFC maps for illustration, if you haven't already: http://ecomodder.com/forum/showthrea...-got-1466.html

[wheel_of_steel]

Cheers for your input dude. I agree that it is just as fun as driving for competitive purposes - through whatever, I think the mechanically inclined are always going to find some way to make driving interesting and a game. To clarify my question, I mean for a given rate of acceleration, is it better to:
just barely crack the throttle and let the revs reach ~3.5k? OR
open the throttle wider and short-shift?

I think you are leaning towards the latter, but I imagine there will be a crossover point where high load enrichment becomes thirstier than pumping losses and friction. Unless your EFI system is super awesome and maintains stoich AFRs at WOT.

However, my experiment won't be testing acceleration through the gears, as there are too many variables that are hard to control. I will do some 50-60 runs in 4th gear for extra data.


Having said that, this test is hardly original. There are others who have performed it with greater accuracy and better tools:

DIY Fuel rate meter/injector duty cycle meter/GPH - GasSavers.org - Helping You Save at the Pump Hypermiling and Fuel Efficiency Forum
Directly viewing the injector pulses.. - GasSavers.org - Helping You Save at the Pump Hypermiling and Fuel Efficiency Forum

So it is definitely nothing groundbreaking, but I think it is important to know the facts for your own specific car. Plus it is a fun way to spend an afternoon. So far, all I can come up with for measuring instant fuel consumption is a multimeter with a duty cycle attachment: they retail for around $60 where I live. I'll do some more digging though, an MPGuino would probably do a better job but I haven't researched them enough to make a final decision.