Turbocharged Saab hit 99.9 Mpg highway, 51 Avg after fill.

[VegasDude]

51 MPG unassisted is pretty high for that car on the freeway even at the speeds listed. I suspect the drafting may have played a big part. Warm air into the engine certainly helps too.

BTW, I'm 450 miles into a 48+ MPG (indicated) tank myself. 100% slow speed city driving with traffic lights! As long as I stay away from China it should be my best tank ever.

[autoteach]

Originally Posted by Frank Lee

What exactly do you teach?

I find one-run fe claims hilarious.

What do they mean?

See "Sport Coupe" as exhibit A. Coupe's numbers are not fake... but you can be damn sure the whole gaslog average fe is nowhere near that of the particular "snapshot" I have here, for the reasons you derisively listed above and even more.

Frank,
I teach high school technology education in the areas of metals and automotives. I also tend to teach realism, acceptance, patience, politeness, and other lost arts of humanity. Some of these are lacking in many of the threads. If you would like to question the validity of my teaching degree or the magnitude of my brain power (and its possible battle for supremacy over room temperature), go ahead. I would suspect that this would be par for the course. I maybe should start it in another thread as "I am a teacher" to which many can tell me how that isn't possible, how I have mental handicaps, or how I must be a preschool teacher (as first graders appear to be more intelligent). I have no idea on whether I should leave this forum all together or stay so that there is a balance in this microcosm that is ecomodder.

[RobertSmalls]

Originally Posted by autoteach

I also tend to teach realism, acceptance, patience, politeness, and other lost arts of humanity.

It looks like you still have a bit left to learn.

[Drive Stick]

Originally Posted by autoteach

Frank,
I teach high school technology education in the areas of metals and automotives. I also tend to teach realism, acceptance, patience, politeness, and other lost arts of humanity. Some of these are lacking in many of the threads. If you would like to question the validity of my teaching degree or the magnitude of my brain power (and its possible battle for supremacy over room temperature), go ahead. I would suspect that this would be par for the course. I maybe should start it in another thread as "I am a teacher" to which many can tell me how that isn't possible, how I have mental handicaps, or how I must be a preschool teacher (as first graders appear to be more intelligent). I have no idea on whether I should leave this forum all together or stay so that there is a balance in this microcosm that is ecomodder.

This is the best / funniest thing I've ever read, and I've read some pretty great books! haha Thanks for lightening the mood, I appreciate it.

When all is said and done, I say just take what people say for what it's worth. When I receive positive feedback, it encourages me to continually strive for better results. When people doubt the factual material I present them, I smile and say to myself "everyone is entitled to their own opinion."

In this case, I completely understand how it might be hard to believe in my results. They were difficult to achieve and conditions may not present themselves to be so ideal again. The human variable in the equation is really the limiting factor in most vehicles. People may consider themselves great drivers, savvy hypermilers, but in reality somebody else can always do it better. If people can't duplicate what somebody else did.. their reaction is to say "it's impossible" or "highly unlikely." I accept this as human nature. I can't jump 4 feet off the ground, but I still believe Mugsy Boughes @ 5'-3" did.

Perhaps my lack of contribution to this forum has lead some to believe I am not a significant part of the community. Well, that's because I work 3 jobs.. am in the process of designing / building a net-zero energy house in NY and have been working on design and theory for my boattail saab project. Guess I'm just usually too pre-occupied to post on forums. I prefer to post when something significant happens.




I'll be back when this is done, of course.

[user removed]

Originally Posted by autoteach

Frank,
I teach high school technology education in the areas of metals and automotives. I also tend to teach realism, acceptance, patience, politeness, and other lost arts of humanity. Some of these are lacking in many of the threads. If you would like to question the validity of my teaching degree or the magnitude of my brain power (and its possible battle for supremacy over room temperature), go ahead. I would suspect that this would be par for the course. I maybe should start it in another thread as "I am a teacher" to which many can tell me how that isn't possible, how I have mental handicaps, or how I must be a preschool teacher (as first graders appear to be more intelligent). I have no idea on whether I should leave this forum all together or stay so that there is a balance in this microcosm that is ecomodder.

Then I would assume you know the rules of a civilized debate.

In case you forgot.

State your position clearly and succinctly.

Do not attack or denigrate your opposition.

Your grade so far is not worth mentioning.

regards
Mech

[euromodder]

Originally Posted by Drive Stick

In this case, I completely understand how it might be hard to believe in my results. They were difficult to achieve and conditions may not present themselves to be so ideal again.

I believe you posted them in good faith - though I suspect the numbers were off because of the infinite-mpg error while coasting engine-off for an extended period.

am in the process of designing / building a net-zero energy house

We call them passive houses over here, I'm looking into building one as well

have been working on design and theory for my boattail saab project.

It reminded me of the older Saabs (99 ?) and the SAAB 92 prototype (1947)

[user removed]

Originally Posted by Drive Stick

Well, for those who thought you needed a naturally aspirated or electric assist engine to achieve unheard of mileage, think again!

Vehicle: 1998 Saab 900 S 2.0L Turbo 5 Speed Coupe.
MPG Modifications: Gutted interior, only 2 front seats (reduced overall weight by about 200lbs. Hi-flo filter + intake located right next to the engine (gets crazy hot.)

Trip: Belleville, NJ --> Pittsfield, NY = 180 miles each way over mountainous terrain.
Conditions: High humidity, partly cloudy in the low 80's.
Fuel: BP Ultimate (93+ octane rating on pump.)
Techniques employed:
- Acceleration on boost gauge remaining in -10 in/hg of vacuum. (gently depressing 50% throttle max.)
- Speeds not exceeding 65 mph using throttle. (GPS said 61, Speedometer said 63 typically.)
- Drafting behind large vehicles where roadway was full of cars... (never do this on the open road)
- Engine off neutral coasting down every incline. (Speeds vary, please be aware of local laws and speed limits.. lets just say "I got really far" after many of the hills with the engine still off. Vehicle brakes do not work with the engine off, keep this in mind if you are doing this at highway speeds. Simply let out the clutch to restart the car in 5'th gear once speed reduced to below 55 mph.)
- Neutral coasting during in town driving (it's much easier to maintain slow rolling speeds due to less wind resistance.)
- Always parked facing next direction of travel. (avoid unnecessary back-ups and turn around)
Luck factor: There was virtually no stops or traffic in front of me for at least 350 miles of my total trip. I chose good times to travel, and misses traffic on purpose.

It took 2.5 hours of constant downhill coasts I watched the MPG gauge go from the high 50's to the mid 70's for a while. Finally at the bottom of a hill it had maxed out at 99.9 mpg where it remained for the next 30 minutes before it's descent back down to earth at around 35 mpg (construction zones and traffic forced me to slow down out of my "sweet spot."

Stopped at the BP gas pump I had used to fill before leaving, mileage was reset to 0. Upon arrival it was 410 miles, the tank took 8 gallons of gas to fill back up. = 51.25 avg / mpg tank.

The plan for this vehicle was to be fun to drive and perform double duty as my race car, and gas mileage experiment. While some may argue burning up gas for fun at the racetrack negates all fuel savings, I tend to disagree. I find saving fuel to be a great challenge and equally as satisfying as running 13 seconds in the 1/4 mile or running a road course. The benefits of this vehicle aren't in the dollars saved, if money were my main concern.. I wouldn't drive an automobile. My Saab just goes to show "it can be done." You can have a fast / fun car that also sips fuel when off boost to the point that hybrid owners may be envious of.

I have recently purchased a laptop and run a program which basically controls all parameters of the ECU and how it operates the vehicle's engine. I'm working on several new maps, some for increased hp and performance, and some for ultimate fuel conservation. There's a fine line between sipping fuel and pre-detonation when it comes to turbocharged engines though. When reducing the amount of fuel going into the engine, one must also reduce the throttle input to match, or risk catastrophic engine failure.

This, my friends.. is my eco-modding story.



(The top row of pixels are out on my information display, but you can see for yourself.)

If you look carefully at the road ahead in the photo, you will see a hyper milers dream, almost the perfect grade conditions to allow pulse and glide while maintaining a fairly constant speed. Apparently some of the grades were steep enough that he could gain speed downhill and use that to climb some of the uphill slope beyond.

Combine that with drafting opportunities and you have the ingredients for success.

That prototype Model 92 Saab is one I don't think I have ever seen before, and one of the best designs aesthetically I think I have ever seen.

regards
Mech

[Drive Stick]

I love that prototype, I was inspired in part by the fact that almost all saab vehicles have quite a nice slope to the rear window! Very cool photo you posted there.

The Passive Haus concept is something I was reading about, so yes essentially net-zero / passive haus techniques are very similar. The two books I read most recently were:

- Green From The Ground Up
- Toward A Zero Energy Home

By: David Johnston & Scott Gibson

Great reads, kinda the same book.. but one covers houses which employ the techniques for producing their own energy and being self sufficient, and the other talks about the different systems in a bit more detail.

[bestclimb]

For your engine off coasts down hill what are you doing to take care of your turbo? What I mean is those things get hot while compressing air, and spinning at high RPM and flowing lots of hot exhaust gasses. Then with the engine off for coasting the oil lubricating and cooling the bearings stops flowing and starts to cook off in the high temp of the turbo.

Even if he short filled a whole gallon he is still in the 45mpg range. After a few more tankfulls we may know better how well a saab turbo does.

[Drive Stick]

You are correct, turbocharged vehicles should be allowed to run for a couple minutes before being shut down in order to avoid coking. (For those who aren't yet familiar with coking.. basically the oil that sits in a turbochargers oil passage around the bearings essentially "cooks" in place as the turbo cools down.)

On this particular vehicle, the turbo oil return line comes directly off the bottom center of the cartridge. This allows just about all of the oil to drain-back to the oil pan. Since the drain line is only about 3 inches in length, and sits a mere inch above the standing oil in the oil pan it does a great job at draining itself before much coking can occur.

The turbo is the original T25 with 130K miles on it so far. A look inside didn't reveal any crude build-up when I changed the drain line. I don't really cool it down when the turn the car off either. Partially because it's got 130K miles and partially because it's done so well thus far I guess the engineers did a good job setting up the lubrication system.

Engine off coasting / shut downs with out cool down are relatively the same minus the engine turning back on after coasting (usually no more than 2-3 minutes at a time) the oil doesn't seem to get a chance to bake in there as the hot oil resuming flow would push any buildup right out. (this is my theory anyway.)