Higher Boost or higher RPM?

[lapazleo]

I found the fuel economy difference is stark between high RPM/low boost and low RPM/high boost. I haven't used 6th since I put 35s on.

Additionally, the non turbo versions of this engine often spun 3500+ on the freeway in top gear in the economy cars they came in. They can take it.

The 2.3 eco boost has nothing in common with the old 2.3 Lima engine except displacement.

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[lapazleo]

As Professional driver of 37+ yrs dropping a gear and running a little more rpm and less boost under your conditions is the right way to do it. Less boost = less stress on the engine and less boost = less fuel use. On long drags like you're talking it's better to drop a gear and take some load of the engine. You also notice a drop in coolant temp as well because you've lightened the load instead of lugging your engine.

 

[Tricky Mike]

The 2.3 eco boost has nothing in common with the old 2.3 Lima engine except displacement.

I never said it did. The non turbo version of our engine is in a million Foci, Fusions, Escapes, etc.

 

[Mad Max]

Let it spin. Horsepower is what carries you up the hill. It is torque times rpms/5252, which is why the curves always cross at that point on a graph. If you're letting the boost do the work then you're relying on higher combustion temperature to make higher pressure to create more torque. That's ok for a bit but let the revs do the work with lower boost if you're pulling a long hill.

 

[brkdncr]

High boost for extended lengths will raise your temps pretty good. Probably no long term effects.

 

[KABQ]

It's been alluded to but not said explicitly that higher RPMs will also turn your water pump faster, aiding in cooling. You'll also have lower IAT with less boost. I concur with most above that higher RPM is better.

 

[JohnnyBronco]

Thanks for the quick replies - my intuition has been telling me to look at the boost gage for upshifts rather than listening for RPMs like I have done all my life on every non-turbo car I've ever owned.

No sense in upshifting if you are still sitting in boost. But figured I'd ask, I'm not terribly mechanically inclined and some of you have been running these Ecoboosts for a long time now.

Thanks again!

Watch the boost on offroad maybe but it should have no effect in my opinion on when to shift. If you were on a flat highway for max fuel economy you would want zero boost at all times.

Boost happens when more engine power is required than without boost. But I have never seen max boost (around 16-19) at less than 5000 rpm

Shifting at too low an rpm would be more detrimental to the clutch than to any other driveline part

 

[Brian_B]

Boost happens when more engine power is required than without boost. But I have never seen max boost (around 16-19) at less than 5000 rpm

I can get 15psi+ at under 3k if I try to leave it in 5th going up a hill. It will hang in there but the turbo whines like a bad dog

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