Mike do your research as I know you will however I spent a couple hours on the subject with dick from more power over the weekend on the subject. Guess that tells you what I had up my sleeve with new builds.

So what did you learn on the subject?

That was such a nebulous post that all I got out of it is that he likes dick. ;)

FiTech you can not run with out a 02 sensor, to me this is a deal breaker for marine.

I personally run Holley HP EFI on a GM ls twin turbo in a boat, the 02 sensor and self learned worked great to tune it in, actually was really easy, but after awhile it started reading lean(richened up the motor) I have since set my base tune back to what it first learned and turned self learn off. Seems to run just fine. This can not be done with FiTech.

My 02 sensor were pre-turbo and I have dry exhaust to the tips, and they still would get a tiny bit moisture.

I cant speak for FiTech cost, but Holley HP efi with the harness was $1500 and I use the 8" digtail dash which was another $750. Well worth the money. I think I have about 10-12 hrs into the tune and I bet half that was getting the idle quality right, so when it went in gear and lugged the motor down it wouldn't die, but wouldn't hunt when in neutral.

I'm not in any real hurry to do anything new. Seeing that the prices on these systems are beginning to become realistic I'm starting to consider them.

snake oil when comes to a boat setup, if you are getting ANY water near the 02 this is NOT going to help, we tried all kinds of stuff like this a while back, only cure was to move to a header tube which worked fine(how accurate no way to tell, but seemed fine) as far as the EFI really need to run with the 02 or at least do ALL tuning with one

Has anyone here had any good experience with running a closed loop system?

It is very difficult to run closed loop at idle. I run closed loop from 1800 rpm on up.

What's your experience with closed loop at idle. Looking to EFI a set of twin turbo motors and currently thinking closed loop.

I have 5 inch exhaust on my blower motors and you fight sucking back outside air at idle giving you false lean readings on the o2s. If your putting the o2s before the turbos the problem may not exist. I run the Holley Dominators systems with the new v4 software and it works great in closed loop above idle. Also the NTK o2 sensors are more durable than the bosch imo.