Hey guys, my car was dyno tuned a few years ago and I was really happy with the results. But there is always room for improvement. I have been itching to do the BBMAF for a while now. I finally have a version I am 100% happy with and will be installing on my car in a few weeks. I will obviously be going to retune when this is done.

But in the last few weeks I decided to do a tune up on the car. In preparation for the BBMAF I wanted to increase the injector size because I was close to maxing out the stock injectors. (75-80% duty IIRC). Now I know this isn;t too big a deal, but I figure if they are that close to maxing out, the z33 injectors certainly wouldn't hurt. I found a set for 30 bucks shipped.

So for my tune up I put in a set of lightly used coils from an 07 low mileage Murano. I put one step colder iridium plugs in the car. I also put in a ceramic coated lower intake manifold. And I installed the z33 injectors.

The car is tuned with an emanage blue, so before I started the car i told the amanage that my injector size changed from 315 to 335 cc. I started the car and it was idling and running way too lean. So I undid the change in the emanage setup for the injector size setup.

The car runs better but it still doesn't feel quite right. I know one problem I have to fix is my TB is not setup properly (wont accept the idle air relearn so I am breaking down and paying the dealership to fix that with the consult.)

So my question is, why did my AFR not change after putting in the larger injectors? I know the increase was minor but I was expecting the car to relearn the AFR at idle, and be a little too rich for normal driving. But just cruising around at 50kmh, the AFR was reading about 16 when I adjusted the injector size in emanage. After putting it back it is 14.7 but it is rather jumpy compared to before. Did the colder plugs affect the AFR? or are the injectors just not a big enough difference (6%) to change anything?


Here's the BBMAF that will be going in, 14" long with 80MM id and a 3.5" velocity stack goes with it.

 

I put in DE-K injectors about 2 weeks ago and AFR cruising bounces around 14.7. My idle was already on the rich side (13's) and the injectors put me in the 12's. I do recall the AFR being a little more jumpy after the injectors but nothing that made me worry.

Last week I finally put in the BBMAF I bought off you and thats a whole different monster. It idled perfectly at 14.7 but most of the time right after a shift it would get super lean and the car would bog. After some tuning and a slight change in drive style everything seems to be almost perfect.

I personally don't think the injectors are big enough to make to much of a difference. At WOT they richened up my AFR by about 0.5. The ECU will adjust AFR to 14.7 in closed loop, or at least try.