Saab’s engine rightsizing theory…

It’s funny how one comment from a Saab head honcho can be picked up by a news service and sweep the web.

Saab GB’s Jonathan Nash made some comments at an official Saab 9-3 launch last week in the UK and these have been doing the rounds as if they were new news. The comments pertain to ‘rightsizing’, which was Saab’s buzzword back at the Geneva Motor Show earlier this year.

Autoblog Green have written an article about this and strangely, it appears as if the writer isn’t aware of Saab’s BioPower model range:

Potential benefits of biofuels seem obvious with a reduced carbon footprint being a key reason. But, as we’ve covered in the past, alcohol fuels such as ethanol can also increase the performance of an engine if the engine is optimized properly. Saab realizes this fact and is considering implementing the idea for future powertrains.

My emphasis added.

ABG – the future is now.

Saab have offered their BioPower vehicles in Sweden for around two years and currently lead the European market in terms of E85 capable vehicles. The technology isn’t new, but I’d venture a guess and say it’s not yet perfected either.

Apart from favourable government policy in several countries, there’s some real reasons why Saab’s BioPower works. Here’s my limited understanding as to why that’s the case.

Opponents of E85 say that ethanol, as a fuel, doesn’t contain as much energy as regular gasoline. Scientists say this is true, so I believe them.

One of the things ethanol does have in its favour, however, is a higher octane content, which Saab have been able to exploit through turbocharging the car and using higher compression ratios to obtain higher output from the engine. So whilst they still take a mileage hit, they get better performance from the vehicle.

Getting higher performance per unit of displacement means that theoretically they can install a smaller engine, get better than expected performance and produce more respectable mileage figures through smaller displacement – rightsizing.

With their BioPower range, Saab has applied E85 technology to existing engines. I have a feeling that future engine designs will make a stopover in Sweden for some E85 optimisation – and this is where rightsizing fits in.

Saab BioPower 100The concept of “rightsizing” was most recently featured when Saab showed the BioPower100 concept vehicle at the Geneva Motor Show earlier in 2007. Not only did this vehicle have the coolest tail lamps EVER, it also had an E100-capable engine that developed 150hp per litre of displacement.

This isn’t a production engine, but it was used by Saab to show the future potential of biofuel engine development. Saab consider that this blueprint for higher output engines can be used in the future to provide customers with potentially high hp-per-litre vehicles. So instead of shoehorning a 200hp two-litre engine into the future Saab 9-1, they may be able to install a 1.4 litre engine that gets the same output when required.

This smaller engine will probably be tuned in way that optimises it’s fuel economy when running on E85, and of course, it’d be available as a flex fuel model for the customer’s convenience.

And that tuning issue is probably the next main element in BioPower technology.

As mentioned, the current range of BioPower vehicles are adaptations of existing engines. Future engines will likely be designed with BioPower capability in mind, and engineered to suit. Engine tuning can be tweaked to optimise for a number of different circumstances and I’ve already featured a vehicle with software from Nordic that in tests so far has been seen to get better economy whilst running on E85 than Saab’s own numbers.

Future engines will also have further developments like HCCI or direct injection, that will further enhance fuel economy and output.

Saab pioneered rightsizing back in the 1970s when they introduced the turbocharger. Other companies caught up in years thereafter and now Saab has a chance to set a new pace.

I tend to think that future BioPower applications will focus on smaller engines and as Saab have hinted at in recent weeks, with hybrid drivetrains. This will work well with smaller, lighter vehicles and there’s definitely going to be a market in Europe for this type of vehicle in years to come.

Will they also develop it in bigger vehicles? I’ve heard whispers that Saab have had some trouble getting reliable performance from it’s V6 engine using E85. I know that’s the case in motorsport, so I assume it’s the case with regular cars as well.

Hopefully they’ll get that solved sometime as it’s an option I’m sure they’d like to be able to offer. Engine smoothness is an important factor in the bigger vehicle classes and whilst they could tune a BioPower engine to 300hp, the character of the engine may figure against them when compared to the competition.


In short, I think Saab’s investment in BioPower is a good thing. It’s not the solution, but it’s a part of the solution that’s available now. With cellulosic ethanol becoming more of a realistic option as time goes on, long-term BioPower viability becomes more of a possibility, too.

Saab’s current BioPower offerings are a good introduction to the technology, but from what they’re saying the future seems to be in using the technology to develop engines that are smaller but still just as capable of delivering power when required.

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  1. I wonder about the BioPower100 concept. I know it was to demonstrate Saab’s ethanol technical expertise and it is pretty impressive to get 150 bhp/l but it’s not like they demonstrated the ability for “rightsizing” with this engine. They basically took an engine which is already available in the 9-5 (the 2.0T is available in the 9-5 outside the U.S.) and ran pure E100 in it (which is unavailable anywhere outside Sweden, I believe).

    Yes, I’m impressed with the efficiency of this engine, but hardly see this as a good example of a “rightsized” engine. It seemed more to show that Saab can get 300 bhp out of a 2-liter, 4-cylinder engine than the prospect of “rightsizing” using ethanol.

    Maybe they should have used a 1.4-liter or 1.6-liter engine and shown that they can get 210 or 240 (respectively) horsepower out of it. In a car the size of the 9⁵ Combi that would have been even more impressive to me than getting 300 horsepower out of a 2-liter! Heck, Hirsch can get 300 horsepower out of a 2.3-liter 9⁵ running E0! I know, I’m hard to satisfy… 😉

    What is the point of “rightsizing”? So that one can use less fuel (smaller displacement engine uses less fuel)? Well, with ethanol one gets one-third less fuel economy than running gasoline. So a 1.4-liter engine running E85 would be just as fuel-efficient as a 2-liter running straight gasoline, right? But the horsepower and torque would be slightly less. And you have the additional problem of horsepower/torque when you can’t find E85 and have to settle for straight gasoline. The car would then assuredly be grossly underpowered, and be completely reliant on the owner’s ability to fuel-up with E85 exclusively.

    Swade, you optimistically wrote, “Future engines will likely be designed with BioPower capability in mind, and engineered to suit.” This seems to assume GM is going to allow Saab to use some engines that are specially-engineered for BioPower? Or do you assume that GM will provide a smaller-displacement engine to Saab but they’ll have to share the BioPower technology with Opel and other small GM cars?

    Remember that just about all of Saab’s engine engineering work has been ancillary to the core engine functionality. They’re given a globally-sourced (Holden, Opel, whatever) engine and then allowed to play with it with turbocharging and flex-fuel and such. I don’t know of any Saab core engine engineering going on after the demise of SVC. At least the Saab engineers were able to use the SVC prototype to find the optimal compression ratio for the BioPower100 so the thing’s not collecting dust in an archive somewhere, so that’s good news. 🙂

    BTW, so I don’t forget: great ‘blog post, Swade. I found this one particularly interesting (though they’re ALL interesting…). 😛

  2. 1985 Gripen wrote “It seemed more to show that Saab can get 300 bhp out of a 2-liter, 4-cylinder engine than the prospect of “rightsizing” using ethanol.”

    And they already did the same in 1985.. The EV-1 had two liter engine with 285bhp, so I´d say they had the tecnology already back then.
    But that´s only showing what they could do. And it´s totally different make it a production engine and sell it to customers with 5 year powertrain warranty!

  3. Saaboy: what’s “turbo-matching” (sorry for my ignorance)?

    Another short-term fuel economy trick Saab can use on top of Swade’s aforementioned Direct Injection and HCCI is a dual-clutch transmission. They could buy one off the shelf from Getrag (as ovloV does) or Borg-Werner (as Audi does).

  4. …as I wondered before, why isn´t Saab useing the 170HP 1.6 Turbo patrol Opel/Vauxhall already is useing?
    Saab could drop the 1.8i, 1.8t and 2.0t models on some markets. They still could use their stock of these tiny stickers and thus hide the fact, that “just” a 1.6 Turbo is doing the job.
    Maybe, Saab has to use these 2.0l engine parts produced by GM.

    Remember, in the 80s and 90s, Saab had one of the most modern engine lineup in the market and VW one of the stoneaged. But VW found a way out of Neandertal. The question is, where is Saab going? Only jag?

  5. Could displacement on demand provide an answer? Say, 4 cylinders working all the time when running on petrol and only 3 working at any one time when using E85.

    Or perhaps a greater amount of exhaust gas recycling when running E85.

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