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ideal rpm on highway ?


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That is pretty normal. It is a short stroke engine with durable cylinder sleeves, and it would run nearly forever at that engine speed.

 

im used to a engine that is spinning at 1800 rpm in 5th gear in my f150 straight 6 300.. so i was like is this normal for a sub spinning at 3k rpm in 5th gear

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The subaru engine is most efficient and happy between 2500 and 3500 rpm. the gears are spaced that you rev out to about 3500, and the rpm lands at about 2000-2500 during upshifts.

 

anything below 1500 rpms is lugging the bottom end, and is not recommended.

 

the engine has a short throw and big pistons, and by horizontal arrangement is very balanced, and is designed for mid rpm operation

 

typical cruising rpm at highway speeds is anywhere between 2700 and 3200 rpm

 

you may find you will get better fuel economy at 65mph than 55 mph because of this.

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I have wondered this very thing... I have an automatic brat and around 65-70 im seeing 4k rpm but have yet to see any other automatics to compare it to. Gas mileage with a Weber is sitting around 18mpg as well and occassionally the rpms fluctuate by up to 200rpm just idling at a stop light so I have been wondering about stuck lifters or something.

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I have wondered this very thing... I have an automatic brat and around 65-70 im seeing 4k rpm but have yet to see any other automatics to compare it to. Gas mileage with a Weber is sitting around 18mpg...

 

I have an 87 automatic GL, and yeah, the ratio in 3rd is 1:1 I think. at 70 it's running 4K ish also. and about 24mpg. Can't wait to get an MT behind my engine!

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