Ok, i have an s4 N/a.

Now i was reading about port overlap and how or little roto-bangers have to run rich at low RPM's so it can actaully run smoothly, because of vacuum suckin in exhaust charge and all..
so my question..

is it better, i.e. MPG better, to drive at higher rpm's at a given speed or lower?

I ask because im used to pretty much lugging the engine at ~ 1500 RPM at 40 when im crusing. But hearing aobut how our engies have to run richer at low RPM's would it actually use LESS gasoline to keep it in fourth at ~2000 RPM's at that speed?

In the same line of thinking, when i'm on the freeway, what's the best, or "most efficient" speed? I'm used to cruising around 80, just becasue the car seems to love that speed. 65 is too slow, and 90 is pushing it for long distances.

I dunno, anyone have thoughts, or facts? or am i just dumb

 

I am interested in hearing the answer to this one too.
I drive at about 80 on open roads and about 65/70 on main streets in my town. I get about 20 MPG but I hear people getting 25 or 27 how do you all do that?

 

yeah same question.......my car on the freeway loves 80....especially since u cant hear the diffy whining anymore....and it gives so well to more gas when u wanna speed up.....but good question

 

This would def be interesting to know, maybe that's why I get the same mileage when I beat the **** outta the car, and when I baby it... *shrug* lol

 

Hahaha. I thought it was just me, but apparently all RX-7s love the magical crusing speed of 80mph.

 

Not sure what the most efficient range is but think there is some truth to this. I remember reading that the reason why Mazda's early 70's cars got bad gas mileage was that the EPA test speeds was too slow.

 

When I'm hard on mine, I get HORRID gas mileage (never checked actual gas consumption, but can go through a tank in less than a day)
If i'm easy on it, it lasts for at least 2 days , maybe 3 if not driving a lot

 

Holy crap BATMAN!!!

how the hell are you waisting your entire tank in two days???? how far do you drive per day? I get about 300 miles to a tank driving a 50 50 mix of city and highway and 70 30 hard driving and normal. I drive about 50 miles a day and it lasts me about 4 days and I have an S4 with a smaller tank than your S5

Santiago

 

The wonders of Rotary
i drive probably 50-100 per day, mostly city driving, and i think that my tps is off (or something, failed emissions recently)
but haven't had a chance to sit down and fix it
maybe after that will get better? anyways...