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Old 06-04-2012, 07:23 PM   #1 (permalink)
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95.Saturn sw1 highway entry, what to do with automatic? performance mode?

Anyone know the best way to get up to 65 to safely merge with this car and not waste gas? I don't know the open loop point so just stay under 50% throttle and have tried the performance mode switch which changes shift points. The best we have gotten is 2moro mpg highway at the recommended tire pressure and the car runs great only 87k miles from the original owner with a good filter. The only issue is the muffler is rotted out so I don't know how the lack of back pressure affects gas mileage. A new one is on the way.

It's a sohc 4 speed with 100HP 1.9l and odb 0. I don't know if it has torque converter lockup or how that even works. My 98 Acura Integra gs-r sedan with 145k gets 33mpg overall or more without getting into the vtec high rpm load lobes. Of course I do coast to a stop somewhat and stay out of open loop with an ultra gauge. It's odb2 with a 1.8l and 180HP with a 5 speed stick. It gets on the highway much easier as it's unfortunately geared for acceleration. It runs 3.5k rpm at 70mph where the Saturn is at 2.4k. It does have iridium plugs, napa synthetic oil and Amsoil synthetic transmission fluid where the Saturn has fresh standard plugs, oil, and unknown atf which I plan to change. The previous owner seemed to take care of it as it had receipts for oil and coolant change plus plugs last year as well as new tires and idler pulley plus belt.

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Old 06-04-2012, 11:03 PM   #2 (permalink)
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I've driven the 1996 model - it still had the performance button. I would leave it on the Economy setting if you're after fuel efficiency, a Saturn tech at the time told me that Performance moves the shift points higher and advances the spark timing. It was my dad's car, I don't think the Perf/Econ switch was ever switched to perf the whole time he owned it except when I drove it, and it had no problems merging on to the interstate in Econ mode either.

Yes, the TC locks down on it - every GM I've ever had the TC has locked, at about 45 MPH. If your Saturn has a tach you should see it lock down, it's a 4 speed automatic and it will look like it shifts 5 times - the 5th shift is the TC locking.
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Old 06-05-2012, 12:38 AM   #3 (permalink)
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If it's true that it advances ignition timing, it should help FE a little bit by going into performance mode once you're up to speed. The later shift points would more than negate that on acceleration, though. Accelerate in econ mode, but I'd say it's worth playing with performance mode at cruising speed to see if it makes a noticeable difference.
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Old 06-10-2012, 08:00 AM   #4 (permalink)
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I suspect that saturn tech is full of it regarding ignition timing. There is no benefit in retarding ignition other than maybe allowing it to run on lower octane fuel, but, as far as I know, this engine has a knock sensor which allows it to run max. advance without pinging at all times anyway.
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Old 06-10-2012, 07:20 PM   #5 (permalink)
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Hello -

I went here :

knock sensor questions - SaturnFans Forums

And found this :

Knock Control Using Fuzzy Logic
Internal combustion engine ignition timing is adjusted in response to a sensed knock condition and in response to a determination of engine knock propensity through application of fuzzy logic, wherein an inference engine comprised of a predetermined knowledge rulebase generates a set of truths in response to application of a set of input signals from a set of membership functions. The set of truths are combined according to both relative and absolute strength in indicating engine knock propensity.

What's your EPA MPG? Go Here and find out!
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Old 06-11-2012, 08:17 PM   #6 (permalink)
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Sc1 auto here
Safely merging on to the interstate for me is basicly about how far I can see and where traffic is at. I'm wide open until I have a good view of traffic and then back off as I can.
I've found that light acceleration doesn't pay off in this car until you hit 4th gear, and even hard accel isn't a killer if you can avoid braking later, kinda halfass pulse and glide, don't be afraid of the pulse if you can cruise/ glide.

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