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

[Frank Lee]

I think a lot of that "coking" cool-down theory is for the worst-case scenario ie. racing, hard-working heavy equipment, etc. and probably not needed for garden variety street driven stuff.

[comptiger5000]

With gentle driving, it is less of an issue. Good quality oils (especially good synthetics) with good heat tolerance reduce the issue further.

[Domman56]

Originally Posted by Varn

Good job getting 50 mpg. I might suggest running low octane fuel since you are still operating in the intake vacuum side of things.

U don't run low octane in turbo motors or any forced induction motors for that point It would ruin the turbo after a while

[Drive Stick]

Originally Posted by Domman56

U don't run low octane in turbo motors or any forced induction motors for that point It would ruin the turbo after a while

I'm not sure who told you this, but I'll tell you the reason turbocharged or high compression engines use higher octane gasoline.

The turbocharger sees no gas, it's predetonation you're trying to avoid with the higher octane rating. I would take the time to explain what detonating is, or how octane ratings work but.. I must go to work.

[Varn]

I don't think he ran any boost. I believe he kept the engine at 10"hg vacuum.

Part of being eco in my opinion is to not use the more highly processed fuel. When the lower octane will run the engine without detonation. He was keeping his cylinder pressure down with his driving style.

I have had a turbo truck. The manufacturer recommended premium fuel but stated it was safe with lower octane as the fuel map and boost and or timing would adjust to prevent engine knock. I never drove it for economy. It had a turbo and I was going to use it. In my part of the country premium fuel is not always available. I had to fill with unleaded regular or gasohol many times.

Cool graphic showing the extended butt of the Saab.

Are they out of business after the GM collapse?

Originally Posted by Domman56

U don't run low octane in turbo motors or any forced induction motors for that point It would ruin the turbo after a while

[cookerq62]

I picked one of these cars up. Just got 32.6 mpg in hilly terrain by staying out of the boost averaging about 65mph. Not bad for a $400 car with 178k miles and a bad o2 sensor. They published a max economy rating around 45 mpg @ 45 mph back when they first came out. Since then Saab made some minor mods for the Talladega record to reduce drag (ie. dish like wheels and ride height) . These cars will do 150mph+. I will post more results as I get this thing tuned up.

[Arragonis]

I had a reading of -39mpg on my SG2 today.

[tumnasgt]

Originally Posted by Arragonis

I had a reading of -39mpg on my SG2 today.

Driving backwards?

[cookerq62]

Originally Posted by Arragonis

I had a reading of -39mpg on my SG2 today.

I payed a little more for this car than you did for your SG2. I will recoup my investment vs driving my Tacoma in about 6 months. What do you tow your boat with?

[henticules]

ok so i"m a little late to the party (story of my life!).
having owned a ng900 saab i can tell you from my personal experience that the SID (SAAB Information Display) on the dash takes quite a bit of time (and/or different driving style) to make a change in the mpg number.
I say great job even if you can't make it happen everyday.
***a side note about my experience with switching to synthetic fluids, I saw a 1.2 mpg increase in the MPG #'s after switching to synthetics (it took about a month to get there but it stayed there for the following 8 months i owned the car, so probably not a fluke.