An introduction from an unlikely hypermiler
 

Hello all!

I just sorta wrote down everything I'd want to say in my vehicle description, so I'm just going to repeat it here:


Carmen is an aspiring Jekyl-and-Hyde. She's a sports car, and she knows how to drink like one. I'm often quite economically-minded. My goal, therefore, is to get her to achieve significantly improved fuel economy upon request, without having to permanently sacrifice an ounce of performance.

Carmen is a 2000 Saab 9-3 Viggen that I picked up this past October. She's a demon and I love driving her, whether it be a four-hour jaunt to Vegas or a quick trip to the store. Ultimately, I have simultaneous urges in divergent directions. That is to say, I intend to wring every last scrap of available power out of her, but I also intend to wring every last calorie of energy from the fuel she burns and convert it into motion.

My endgame is to have a car that produces in the neighborhood of 300 horsepower, but can reliably return over 45mpg highway when prompted to do so.

I know this is anathema to much of the spirit of this forum's membership, but I want to prove to myself and to others that a car doesn't have to give up one strength for another. I hope to make a few friends here, and am really looking forward to learning as much as possible about all this.

haha, just so long as you don't tell them about the inspiration to go from 0-60 quickly they won't know.

I'm likewise playing with the idea. I have a motorcycle engine that I am going to drop into my Del Sol to make twin engined AWD, when summer gets here and my load lightens.

There are still alot of things that might be able to be done.

Although. . . I am going to have to confess I do not know much about the Viggen. Saab is. . .outside my range of contact. They are pretty rare here in TN. Guess they don't sit well with us. . .?

WIKIPEDIA here I come

<edit> So. . .I couldn't find a very good data review of the car and Wiki came up dry. I am familiar with the car now that I have seen a picture. . .I wish my car were named after a fighter-bomber. There are still alot of options without sacrificing HP. Weight reduction is one that gains in all directions. Heavier wheels to lighter ones and taking stuff out of the trunk are pretty entry level.

If you really wanna get down to it. . .strip everything body-wise off and replace it with Carbon fiber or Fiberglass. Although, thats a serious PITA you save some weight. While you are at it you might be able to find more aero friendly pieces specifically maybe fenders, bumpers and hoods.

Oh, and I am the forum troll!

</edit>

The Viggen was, for lack of a better description, Saab's "M3". It was produced between 1999 and 2002. Total worldwide production over the entire model run was around 3,000 vehicles. So, within the enthusiast community, they're sort of the holy grail of modern Saabs.

EDIT: here's a wikipedia link for you - http://en.wikipedia.org/wiki/Saab_9-3#Viggen

One of the biggest draws to Saabs is the fact that they're already a great platform for 'no compromises'. In fact, I'm already not too far away from my ultimate goals... In present configuration Carmen makes roughly 240hp, and I can get 40mpg out of her on the highway.

On that note, I screwed up when filling out my profile info in the garage, and I accidentally typed the Highway EPA number in the Combined EPA field, so the graph and sig image are both underrepresenting my actual mileage achievement...and the graphs aren't updating after correcting the mistake and adding more entries in my fuel log. Anyone have a tip for me about forcing a graph update or deleting a vehicle so I can start correctly from scratch?

Ritmusic2k -

Welcome to EM!

Hit the reload button a few times and it should be recalculated correctly. You can always edit your garage entry to change any of the EPA information.

Whenever I do a fuel log entry, I need to do a reload for the graph to reflect the new entry. You can also edit any of your fuel log entries if you make a mistake.

CarloSW2

cfg83, thanks for the tip! When I went home everything was fine; I think my computer at work must've cached the image.

Now that I am equipped with the vastness of information available on the internets regarding the 9-3 Jet fighter, does yours have the turbocharger. I am going to assume yes?

I love the Viggen! I almost got a 2002 Viggen convertible last fall, but the dealer was screwing with the price. Had I gotten the Viggen I probably would have been boosting too much and getting bad mileage.

Good Luck on the horsepower and MPGs.

well either way what you can do is play with the ECU. If you have a turbo great, but that kills the idea of adding one for HP gains, but it saves you some coin. If you get a programmable ECU you can set it to run your current HP(Maybe higher) and then you could set it to run lean-burn(injecting less fuel than it can burn). The really nice(expensive) ones allow you to switch on the fly.

With the Saab I don't know much about. . .I don't know anything about anything. . .how close your engine gets to knocking on a regular basis, but I would gamble it gets pretty close since its a low volume high output engine. It could cause problems, but I suspect your car is smart enough to relieve pressure if it detects pre-ignition or intense knock.

If you're close to your goal of 45mpg, then raise it 50mpg. Or even better, make your goal getting 45mpg not on the highway, but average.

Judging by your picture, Carmen has wide, low-profile tires on alloy wheels. Switching to slightly taller and narrower tires and pumping them to higher pressure (at least max psi minus 10%) would be a good start.

And when going to the store, take the bike :)

Yep, all American-market 9-3s were turbocharged; the Viggen got an upgrade to a high-pressure Mitsubishi TD04.

Yep, this is how I intend to do the majority of my modifications; there's an amazing open-source community dedicated to cracking and modifying the Trionic engine management system. This is Saab's corporate name for their family of ECUs, which directly control boost, ignition, and fuel. In short, I can pull my ECU and use a special interface cable to reprogram it with the help of software developed by the community. This will allow me to build my own 'power tune' and 'economy tune'. Once Trionic 7 is completely reverse-engineered, it will allow for live-writing to the ECU without removing it from the car. Once this happens, I'll be able to install a carputer in my dashboard and run the appropriate software to load the maps I've created, so I can get the effective on-the-fly switching that's not available in the commercial Saab tuning market.

Until then, however, I'm forced to choose which program to run ahead of time, pulling my ECU each time I want to change it. I'll be installing a scangauge to assist in economical driving... but those functions will be able to be performed by the carputer once I have it up and running, so the scangauge is more of an intermediate step.

There's actually a ridiculous amount of headroom built into these engine blocks; as long as I use high enough octane (which is a real pain in the ass in California) and have a nice big intercooler, I should be safe. Saabs use a direct ignition system that actually uses the spark plugs themselves to detect engine knock (don't ask how; it's magic, I swear). It does so very well. This is a big reason to avoid piggyback ECU products that fool the system; modifying the ECU program directly leaves all knock sensing features intact.

I guarantee you once I hit 45mpg, I'll set my next goal ;) A major criterion for me is to make all my improvements in such a way that they do not limit my performance capabilities. So, Carmen's gonna need to keep the wide sticky tires. Down the road, it'd be feasible to own two full sets of tires, one for eco-cruising, once for, um... 'enthusiastic' driving. But before that, the majority of my mods are going to focus on software and aero.


Whenever I can, I ride to work on an old Nishiki mountain bike that I converted into a commuter hybrid :)

I kinda figured you were running high grade fuel. I would be cautious moving the horsepower forward. Obviously stock boosted cars can undergo HP performance enhancement without worrying about the engine but the greater the power-to-weight ratio of the engine the more dangerous knock becomes.

I was pretty sure Saab would have anti-knock systems in place since they are more of a up-scale manufacturer, nothing against those that don't, mine doesn't. Combining the economical driving with the performance you will want to carefully watch engine temps and exhaust temps. Squeezing the block one way a little is fine, but then squeezing it the other way a little too you get into places that pre-ignition is more common. IF that happens because WAI eco and some grill shielding while performance driving Carmen will need a heart transplant in a hurry.

There are no worries on bumping up the power. My first priority is to keep the engine healthy. Following a well-established path, I'm going to make the engine more powerful and more robust, and I'm stopping well short of where I could go. There are 450hp Viggens out there.


The key is, I won't be trying to get one configuration that is both powerful and miserly, so I'm not going to have to worry about a 300hp setup that runs dangerously lean and hot. In my mind, my eco-tune will effectively turn the turbo off, and soften the hell out of the throttle mapping. I can also set torque limits for each gear. I probably won't lean things out too much; I don't want to save a little gas at a cost of dumping ridiculous amounts of NOx into the atmosphere. But the point is, in eco mode, she'll prolly only be able to make 170hp as a result of the modifications.

Ideally, it'd be as easy as turning a knob to switch modes, but I'm a little way off from that.

If you leave the turbo on you can get outside the 14.7-30:1 NOx range. Anything leaner than 16:1 and you produce NOx while anything higher than 30:1 and it goes away again. around 20:1 is where its worst so a little lean is alot worse for the environment than a lot lean.

That said you won't have anywhere near 150 HP if you lean out to clear the NOx range. But highway driving won't require probably anymore than 50-60 HP and then you could jump into lean and burn very little fuel. If you are going lean though and forcing the ECU to do it I would stay away from WAI and go CAI as it will serve you better for the HP gains anyway and keep you well inside the quasi-equilibrium-esque dome away from turbulent knock and pre-ignition areas while boosting and running ultra-lean.

Wow, that's great info; I'll take it to my ECU gurus and see what they have to say about achieving this! Many thanks!

I would test it very carefully and very slowly. Like after the car has cycled through fast idle and moved on to "I'm not ready to be out of bed" mode. If you can get it below 400 RPM you're only getting around 2 combustions per second which is slow enough to shut it down if the engine doesn't like it.

And I would start with small ratios(A little NOx in the testing stages is way more Eco friendly than a new engine). I would also ask a mechanic more familiar with the Viggen or the B235( I think thats what you have). The particular engine really might not like the idea of that much "cool" air without as much "warm" fuel.

Ultra-lean burn is an evolving field so field testers are taking it slowly because very few autos go to that range.

I think you might be able to get outside the 30:1 because you've got 240 hp to work with. I've got 100 and 25% of that is not really enough to be useful.

Breakthrough!
 

Hey all!

So, I haven't really been posting since, well, since I wrote up my introduction... but I have been playing around very much. A quick update and some shocking developments I discovered just this afternoon.

First, I installed my Scangauge II and it made an immediate impact on my mileage. It won't look like it when viewing my fuel log, but that's because I've spent good amounts of time driving the crap out of her lately... rest assured, the SGII is, it turns out, all I needed to achieve my original goals.

And the breakthrough is this: I didn't actually achieve 45mpg highway, I achieved 45mpg city.

I never gave Carmen enough credit for it because she's tuned to be a high-RPM screamer, but she makes practically diesel-ish torque at low RPMs... I just never had the cojones to find ]out .

Well, today, on my way back from work, I short shifted a little too soon and was surprised to find out that my engine could drag me around at idle RPM at almost no throttle in 5th gear... sitting at a pretty 30-35mph. And in doing this, I was achieving sustained instantaneous mpg readings between 45-55mpg!

With a little pacing and route memorization, I think I'm going to see incredible gains over time. It's a surprisingly comfortable way to travel, and I've caught the economy bug all over again. Cheers!

Ritmusic2k -

Congrats to you and Carmen! 5th gear is your friend.

CarloSW2

Wow! You'll have us all out looking for torque monsters now ;).

Can you imagine a population of Viggens being driven for economy? We all buy 'em, and go on a road trip as a convoy.

Somebody rolls past in an M3 or a Corvette or a 370z or what have you, and sees a troop of Viggens chugging along at 50 MPH. The look on their face would be priceless!

On a more serious note, congrats on the accidental discovery! Most people say that to shift for economy, pull the lever between 1700 and 1900 RPM. You'll have to experiment, but there's a start.

Hah, the more the merrier.

Regarding the upshifting: when driving conservatively, my last 9-3 (same generation as the Viggen) would illuminate the shift-up light for 5th gear at 35mph. That would've put it at about 1200rpm. I ignored it because that 2.0 and smaller turbo didn't have the guts to chug along that slowly. But the Viggen's 2.3 and larger turbo make all the difference. I end up upshifting from about 1500rpm and setting at 1000rpm in the destination gear. It's such a weird feeling, but she seems to like it.