MPG Down after Cobra CAI Install

dank82

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Hey guys,

So I've had the PRL Cobra CAI installed on my 2018 Civic Sport Hatch MT for about a month now and am definitely liking the part. At first I was mashing around quite a bit but then decided to start driving normally on a new tank of gas. I've noticed even after resetting my MPG, and driving the car as normal as possible, nothing too spirited--MPG has gone way down.

I was averaging anywhere from 36-39 MPG with the stock airbox, and now I'm consistently down to 26-27 MPG with regular driving. Is a 10 MPG cut to be expected? I remember reading a few MPG posts and I don't recall too many people having that much of a cut in MPG after install. Same route to work and stops like usual.

BTW, I do run the Hondata FlashPro +6 and decided to use the app for it to look at STFT and LTFT. I noticed STFT is at times cutting all the way to -14, and adds up to around 6. LTFT looks to be going +-5 or so with regular driving.

I did run a handful of data logs although I'm having trouble updating the FlashPro software and pulling the data logs to post them. I'll try to get those up as soon as I can.

My understanding is STFT shouldn't ever be more than +-10, and Long Term should not be more than +-3 on these cars.

I know it's premature to say without looking at the logs, but is there anything to possibly change/check to improve my MPG, or is this what I have to live with when running this part?



 

2018Si_NY

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Sounds like your driving I have tsp stage 1 and when I use the lowest setting for the tune I still get phenomenal mpg like 35 area and with the highest tune and spirited driving I get like 15 mph
 
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dank82

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Sounds like your driving I have tsp stage 1 and when I use the lowest setting for the tune I still get phenomenal mpg like 35 area and with the highest tune and spirited driving I get like 15 mph
I'm guessing you also have a Cobra CAI? I've been running the +6 tune for close to a couple years and my MPG has never been that low.

Like I said, I've been driving normally, and it still stays in the sub-30 range. Just wondering if there's anyone else who has experienced the same thing after putting in the CAI.
 

fenix-silver

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STFTs will certainly swing +/- 15% or more. STFT really swings a lot under sudden throttle transitions. It sounds like your LTFTs are fine. For reference, on my stock intake, during colder weather my LTFTs are around 0, but during hot/humid summer weather I'm typically around -6%. Do you have the Race MAF or standard?
 

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