[vilord]

Can't argue with your totals, but +0.3mpg is significant? Seems a small number, small enough that differences in ambient air temperature/ambient air pressure might account for?

[CobraMarty]

Absolutely.
I won't be making the trip until the end of the month to verify results.
Made it home with almost 1/4 tank left. Took 13.08 gallons.

As this is my 'commuter' and not an all out build for power, The only 'game' is mileage. Because I drive the exact same road/highway 180 miles each way, it is at least a consistent test.

Still want to add a front spoiler and exhaust mods.
Modify stock muffler for near straight thru flow, mid pipe delete, and maybe catted headers.

[CobraMarty]

Today's trip was best yet, 531 total maximum mileage at 70mph.
80*, cruise control, no a/c, sunroof and passenger windows cracked 2".

It looks like closing up the 2 front vents on the aFe and letting the intake scoops work helped the mileage.
Will see in 3 days when I drive home what the actual mileage really is.

[vilord]

Originally Posted by CobraMarty

at 70mph

I think I've discovered my problem. My speed is variable from 4mph near boston to 90mph near natick, then a whole bunch of stop lights.
I'm just happy that with the new tune i'm pulling over 20mpg instead of 17

[CobraMarty]

My trip is always the same. Get fuel, get on the highway, cruise control 70mph for about 170 miles, drive 3x's hotel to work 3 miles then get on highway, cruise control 70mph for 170 miles and off and to gas station for fill up, then home.

I was trying to think what is next. Summer and all, there are other things to do.
-rear muffler mod, IDK if it will help mileage but at least it will sound better
-mid pipe delete, this should help as it gets rid of the 2 down stream cats
-3 stage intake, I have one sitting on the shelf
-install MILVs just because, they won't help mileage
-tune for 3 stage and MILVs,

Maybe have it leaned out for rpm at 70mph, like a +/-50rpm range/window. I will check with scan tool but IIRC 70mph is about 2725rpm. So lean out from 2675-2775rpm, like +1AFR. Stoich is for lowest emissions not power, tq, hp or economy.
During regular driving it will just rev right thru this rpm spot, hopefully without a hiccup.

[tlow98]

I’m getting 24.1mpg on my ~100 round trip daily. 25-30% by mileage is traffic/city.

Actually pretty happy given the traffic.

Just inserting as a reference point.

[CobraMarty]

Just got home.

Total miles 475, took 12.11 gallons and got 29.30mpg @70mph no a/c, cruise control. Best yet.

[CobraMarty]

So taping up the 2 front holes on the aFe air box really quieted down the intake noise and it seemed to increase the mileage due to not venting out the ram air effect of the front air scoops BUT it seems slower around town.

I gotta keep testing and look into this a bit closer.
Quieter, more mileage mpg, less power.

[CobraMarty]

This trip a bit different. 92*F A/C on 70mph cruise control, max total miles 472.

Last trip total miles was 531. So A/C cost 59 total miles. About 4mpg?
Will see Monday night when I complete the trip and fill up.

[CobraMarty]

So this latest trip. 90*+F, A/C on the whole way up and back, 70mph cruise control, aFe air box inlets blocked off- max 435 total miles, 13.26 gallons, 26.34mpg.

Lost about -3mpg with the A/C on.

So I was thinking about the aFe air filter box and the front top air vents.
These air vents are in addition to the stock BMW front air inlets.
They make the air induction loud.
They help power and seem to lose mpg.

I am thinking that at lower speed when accelerating and 50% to WOT that the engine wants and needs as much as able air to the filter. These air vents add air and more power.

At higher speed, 70+mph, these vents are 'bleeding off' the slight air pressure in the air box like when at cruise speed and using front air vent scoops. This bleeding off of the 'air pressure' in the air box and loses 0.3-0.5mpg. Not much but every little bit helps.

So my next mod is I bought a 4" exhaust cut out valve. I will cut a hole and mount it to the front of the air box below the blocked off aFe air vent holes.
Cruise/low throttle pedal position it is closed,
Acceleration/WOT/pedal >50% the valve will open and more airflow.

It will be controlled by a relay switch which monitors the throttle pedal position and turn on at appropriate position, IDK about 2.5v signal.

[tlow98]

Is it possible that aerodynamic aids might be more fruitful than thermodynamic efforts at this point?

Have you thought about wheel covers, inlet block offs and sealing efforts around body panels? They seem to do insanely well with the hyper miling crowds.

[CobraMarty]

Not really trying to 'hypermile'.

My mileage seemed low when I got the car and I am just 'playing' with it mostly so that I can commute to work and back on 1 tank of gas. Because I do the exact same route every trip, the trip is a constant, and I can try to get a few more MPGs.

The most I will be adding is a front spoiler for the aerodynamics.

I can now drive up and back at 70MPH even with the A/C on and still make it on 1 tank of fuel without having to run it to nearly empty and 0 miles left to go.

I really want to make the trip at 75mph on 1 tank of fuel. That's my goal. That will cut 30 minutes off my commute time.

I think that now I am enjoying 'Summer gas' and the extra mileage it gives.

[tlow98]

Originally Posted by CobraMarty

Not really trying to 'hypermile'.

My mileage seemed low when I got the car and I am just 'playing' with it mostly so that I can commute to work and back on 1 tank of gas. Because I do the exact same route every trip, the trip is a constant, and I can try to get a few more MPGs.

The most I will be adding is a front spoiler for the aerodynamics.

I can now drive up and back at 70MPH even with the A/C on and still make it on 1 tank of fuel without having to run it to nearly empty and 0 miles left to go.

I really want to make the trip at 75mph on 1 tank of fuel. That's my goal. That will cut 30 minutes off my commute time.

I think that now I am enjoying 'Summer gas' and the extra mileage it gives.

Agreed on the summer gas. I only mention the aero as I figure it’ll be bigger bang for the buck than that intake valve.

[CobraMarty]

Todays trip up- 80*, no A/C, sunroof up, 70mph cruise control.
Still with aFe 'air inlet vents' closed/taped over and with stock inlet air scoops.
Max mileage best yet 529miles (driven+to go).

[CobraMarty]

Todays trip up- 80*, no A/C, sunroof up, 70mph cruise control.
Still with aFe 'air inlet vents' closed/taped over and with stock inlet air scoops.
Max mileage best yet 529miles (driven+to go).

[CobraMarty]

Got home today and filled it up.

29.31mpg. Max total miles 487, took 12.19 gallons, 90* 70mph cruise control no A/C.

[Biginboca]

Originally Posted by CobraMarty

Got home today and filled it up.

29.31mpg. Max total miles 487, took 12.19 gallons, 90* 70mph cruise control no A/C.

How are you doing it at 90 degrees and no A/C? You have the windows down and find that comfy?

I’ve heard the drag at highway speed with windows down causes more mpg loss due to drag than running the A/C at highway speeds.

Have you tested that?

Edit: *NVM I just saw you said 3mpg loss for A/C lol

[CobraMarty]

Yeah sweat my a off.

Had the sunroof tilted up, passenger front and rear windows cracked about 1". This provided a reasonable cross flow of air. Still a bit hot.

After I filled it up, I turned the A/C on FULL for the rest of the way home.

[CobraMarty]

This trip I was a bit lazy and down so I just used the A/C the whole way.
70mp, cruise, A/C, still with vents covered in aFe box.
First half of the trip, Max miles gone+to go was 480 miles.

Last trip with no A/C was 529 miles. Maybe didn't quite fill it up as much as before or the A/C knocked off 49 miles. Interesting.
In 4 days I'll return and see what the rest of the numbers are.

[CobraMarty]

Got home, max miles was 428 and 26.29mpg. Took 13.55 gallons.
Raining, a/c on, slowed down in rain and when clear 75mpg. Not my usual drive home.

[CobraMarty]

So this trip was a bit different. Because driving on Sunday and returning late 11pm Thursday, there will be little traffic, so hammer down.

75mph, cruise control, A/C on, halfway max miles 448 total miles. So, so far this trip lost 32 total miles due to the higher speed compared to last week.
I am still well above half a tank and just as long as I can make it home on 1 tank of fuel I am good. The faster speed did shorten the commute by 15 minutes, 2.5 hours vs 2.75 hours at 70mph.

**8/2/18- So finished the trip home at 75mph A/C on, max miles 410.
took 14.25 gallons and averaged 25.123mpg.

[CobraMarty]

A note on the blocked aFe air inlets. Power is noticeably less but mileage is up.

I got a 3" and 4" exhaust dump valve, butterfly valve thing. One is operated with a switch and the other is with a remote.

So I think that I will bolt it in and leave it open all the time and when I commute and get on the highway, just push the remote and close the butterfly valve and let the front air scoops build a little pressure in the air box and get better mileage.
And then when home, remote open it up and let it flow and sing.