Tuned 1.5t non si gas mileage

[boydboyer]

Hello,
I recently installed an OTS pre-able tune on my 1.5T non-SI, and I absolutely love it! However, the gas mileage is another story. Wow, I'm averaging only about 200 miles per tank, which translates to around 18-20 mpg. Maybe I have a heavy foot, but even with cruise control set at 65 mph, I'm not getting the fuel efficiency I used to. I could easily hit 40+ mpg on long drives before. Has anyone else dealt with this issue?

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[PangziXin]

flash back to stock and compare

 

[Cueyo]

When that happened on my 24 sport I had a bad downpipe cat. Tunes usually reduce your mileage, but it should never be something that extreme I don't think.

 

[Bald Wonder]

'24 OTS tuned Si here, and I'm averaging 37mpg when I drive moderately. My average mpg on a fresh tank when all I've done all day is autocross is still about 24ish. I don't know what's going on, but I think you're right to question it.

 

[Cueyo]

I highly suggest checking your downpipe if you can, do you notice any smells too?

 

[AZCWTypeR]

I've tuned 2 motorcycles, going from factory 14.7:1 to 13.5:1 air/fuel ratios and observed fuel economy was unchanged.
It sounds like you're running way rich and if you don't have a downpipe problem, you will soon.

 

[danielbl]

OP, did you resolve the issue? I know you're looking for non-Si replies, but something's for sure amiss. '23 Si on the Hondata 240 CARB tune here, and overall MPG is the same as before. I've also reached a best highway MPG of 41 MPG after tuning as documented in my Fuelly log. Hope your issue gets fixed if it hasn't been fixed already.

 

[Bald Wonder]

OP, did you resolve the issue? I know you're looking for non-Si replies, but something's for sure amiss. '23 Si on the Hondata 240 CARB tune here, and overall MPG is the same as before. I've also reached a best highway MPG of 41 MPG after tuning as documented in my Fuelly log. Hope your issue gets fixed if it hasn't been fixed already.

"Nice! Tell me your secrets!" he said, clearly hijacking the thread for his own gain.

 

[BoostBlooFL1]

I have a tuned 2024 non si 1.5T, also been noticing the same thing. I assumed mine was due to extra idling since it’s winter and I take my lunch in my car or a heavy foot but seeing this makes me second guess.. did you ever figure anything out?

 

[Shankmeyster]

Had a custom tuned Si and was seeing 40+ on the highway at 70-80. Either you want to do a trim relearn or flash back to stock and see if your mpg comes back. Are you only running the tune or do you have mods as well?

 

[BoostBlooFL1]

Had a custom tuned Si and was seeing 40+ on the highway at 70-80. Either you want to do a trim relearn or flash back to stock and see if your mpg comes back. Are you only running the tune or do you have mods as well?

Excuse my ignorance but trim relearn as in fuel trim? Is this something that must be done after switching from 89 to 93 octane? I have the K&N Cold Air Intake and a Remark Catback exhaust.

 

[Shankmeyster]

You disconnect the negative terminal for like 30 mins to let it discharge and then reconnect it and drive. Let's the ECU relearn how to fuel the car after you install mods.

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