Check to see if your MAP and MAF sensor are clean and connected well.
Also make sure anything related to air flow is tight and hooked up right.
judging by your other posts, whoever is doing the installations arnt doing the best job they can.
I currently have a JB4 and am thinking about doing a bef with MHD.
Is anyone here running this setup? Have you experienced any issues?
The main reason to doing this is because I have a catless dp and don’t want a cel thrown or even on the cars shadow coding of a prior one.
Would suggest to go under the car and look for a manufacture number then research it.
Im assuming the car is entirely BMW besides the body and badge.
there is also a 45 min long video on YouTube of a Supra being modded out to 1000whp. Maybe they may have a mention of it?
So I’m here getting my cam installed and the guy said that the setup is doable in the Supra.
however the mirror showing a display may not be in the Supra, he said an E class Mercedes did so it was all good (I don’t think we do).
but he said you can ship your rear view mirror.
in terms of DIY...
I was in the same boat OP. Knew little to nothing about cars. It’s sort of a blessing as I take extensive time out of my day to find the best of the best for the price, what a part can do for me, and compare and contrast.
In terms of piggyback. I went with the JB4. I usually have it on map 2...
I have the JB4 and notice that my AFR remains at about 14-15 but I see spikes to 25, it then settles back to 14-15
edit: I think it’s normalbetween shifts. I think fuel supply cuts off temporarily from each gear