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Old 05-06-2020, 09:38 PM   #37 (permalink)
Ecky
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Join Date: Dec 2011
Location: New Zealand
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ND Miata - '15 Mazda MX-5 Special Package
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Quote:
Originally Posted by EcoCivic View Post
I have not done a specific test but my 05 Civic's engine doesn't seem to run efficiently at lower RPMs. Whenever I try to get more MPG by keeping RPM down such as by locking the torque converter and cruising at 1500 RPM in 4th gear going 35 (the soonest I can without the engine lugging) I have always gotten lower MPG than when I leave it in D3 around town up to a sustained speed of 40+ MPH.

I also seem to get my best MPG at higher speeds. When I was on my way to North Carolina to visit a friend it was raining most of the way there so I was going 60-65 most of the way and I averaged about 33 MPG. On my way back the weather was good so I was going 70-80 MPH at 3000-3400 RPM and I averaged 38 MPG! Sure there are other variables, but these results seem to reflect my experiences around town. I don't have any significant aero mods either, about my only aero mod is I lowered my car by 1.5 inches.

I have a Crower stage 1 cam and other engine mods though, so my results may be different with the stock cam, I started manually controlling torque converter lockup after I installed this Crower cam. I'm thinking that my Crower cam might just not be efficient at lower RPMs, but I'm not sure.
What engine management are you using with your cam and mods?

If you haven't remapped your fuel tables (and to a lesser extent your ignition timing values, as they're fuel dependent), they're probably a mess.
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