Bad MPGs?

[Danny]

The mods are surely contributing to it a little, but there's probably something else at play here.
Could be any number of things.

clogged cat
bad spark plug
fuel filter
low fuel pressure
intake filter
...

How many miles are on the s50? You should do a compression test.

Cat could be a choke point, I realistically need to redo my whole exhaust, its pretty bad. Spark plugs have less than 10k on them, fuel filter I'll have to check, fuel pressure is where it should be I believe, and the intake is just a cone filter on the end of the MAF. O2 has around 10k miles as well.

S50 is unknown but I believe has less than 100k on it. I should do a compression test.

Yeah, I'd say that's a tad on the low side. I get around 18-19 in town, and 23-24 highway, with the same engine, and same mods--21.5lb/hr injectors, 3.5" MAF, BW air boot, TRM tune. I don't have a lightweight flywheel, but I do have fairly high gearing--1:1 5th gear with an S3.46.

I'm running the G260 with a S3.73 with 235/40/17 tires, if it matters.

[10Toes]

Are your brakes sticking at all? I get like 26mpg mix of city-freeway and 30+ all freeway.

[Danny]

I don't believe so, I mean the car runs fine. Pulls hard, kicks a lot of ass.

[328ijunkie]

Somethings up. I get 26-30. OBD2 M52.

[ak-]

Well that is a pretty short gear ratio for an s50.
Not saying that the econometer is super accurate, but when I had short gearing no matter how lightly I was on the gas it moved the needle below 25mpg.

My 3.46 was a noticeable difference in gas mileage.

[LJ851]

I'm guessing that your hair is causing massive aerodynamic drag.

[10Toes]

I'm guessing that your hair is causing massive aerodynamic drag.

and the basketball shorts.

[Danny]

I'm guessing that your hair is causing massive aerodynamic drag.

and the basketball shorts.

:rofl:

Slight update.

I have a check engine light at high rpms so I did a stomp test, pulled up a 1215 code which is points to a bad MAF. Could a bad MAF be causing these bad MPGs?

[giantkeeper]

:rofl:

Slight update.

I have a check engine light at high rpms so I did a stomp test, pulled up a 1215 code which is points to a bad MAF. Could a bad MAF be causing these bad MPGs?

Good luck with that, I've been wrestling with this for almost a year. I've replaced and test fitted MAF's, checked wiring with no luck!

[Danny]

Are you getting shitty MPG too?

[giantkeeper]

Are you getting shitty MPG too?

20-21 avg mixed driving.....I have a lead foot though

[Danny]

Well that kicks my ass.

[Adrian_Visser]

I also have a MAF code at high RPMS, have the exact same setup as you Danny and am getting shitty gas mileage, actually almost the same shitty mileage as you. I was guessing that it is the universal O2 sensor I have or the fact that the cone filter being straight onto my MAF is causing turbulance at the sensor. I have since snapped the driveshaft in my swapped car so it is sitting in my driveway while I drive my other e30.

[Danny]

I also have a MAF code at high RPMS, have the exact same setup as you Danny and am getting shitty gas mileage, actually almost the same shitty mileage as you. I was guessing that it is the universal O2 sensor I have or the fact that the cone filter being straight onto my MAF is causing turbulance at the sensor. I have since snapped the driveshaft in my swapped car so it is sitting in my driveway while I drive my other e30.

I just dropped off my car to have the A/C put in and my friend said he thinks its the tune, he thinks TRM sent me the tune for 24lb/hr injectors instead of 21.5lb/hr injectors and that's why there is a check engine light at high rpms.

[Adrian_Visser]

But if you had the tune for 24lb'ers wouldn't the initial tune be too lean with 21.5's? This same thought crossed my mind as well early on.