Hello All,
I'm seeing VERY poor mpg in my RX8-LFX swapped car. Poor being around 10-11mpg where others with the swap are able to see high 20's while not tracking it. It should semi-obviously not get worse mpg than the Camaro it came out of. I've had the car running up on quick-jacks and see/smell no obvious leaks. No obvious leaks on the back side of the engine where all the high pressure lines are. I've had others suggest logging O2 sensor data and from what I've been told/found out, the data seems fine, meaning the O2 sensors are working properly. O2 trims are not out of line. I'm a little bit at a loss. I was hoping that it was going to be something obvious. Anyone have any LFX specific ideas that I haven't checked yet? Anything with the injectors? This is my first gasoline DI car experience. Looking forward to any thoughts. Thank you in advance for your time!
Is this a stock tune? Have you made any changes since? Are you running factory cats or high-flow cats or no cats? The last log shows your post-cat O2's pegged at 1280 mV - believe these should be steady at ~450 mV with factory cats, or ~750 with high-flows.
Can you log the injector pulse widths and injector flow rate? If you can, maybe go for a drive on a highway, maintain constant speed as best you can for a few minutes, and I can compare to mine where I'm getting 20+ mpg (I do most of my logging on the highway, where I can keep a constant speed for several minutes or even hours). I also have my cams set to 0/0 while cruising, to dial in my VVE, so I imagine I could probably get better mileage by creating more overlap, but I'll get to that one day.
Not a stock tune. Was done by an unknown company prior to my ownership. I have downpipes that are catted which are made specifically for lfx-rx8 swap and assume that they would be considered, high-flow.
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