nitrouspaul

I have a 5 psi kit i want to install and dont want to tune the way procharger suggests so i will buy a tuner but am looking for advise on someone who has done this. I have used hp tuners on my corvette for a number of years so I understand maps,mafs, ve tables etc. I am in the ft myers area have a 26 ft powerquest with a 7.4 mpi. Also i have a new fuel pump and return regulator and needed some proven set ups for the fuel, I have read all the posts but no one seems to do mefi tunes on their own, seems like black art.I will need to decrease my ipw at idle so i dont load up the plugs but want to richen under boost. I was also thinking of using a wide band to read afr and tune this way as i do with the car but am unclear how to install it in a wet exhaust.

sutphen 30

which mefi computer do you have?
its not that hard but when your by yourself,,it gets a little trickier.

nitrouspaul

its a mefi 2

abmotorman

Talk to Bob who sells the MEFIburn. I have the same computer and recently did a cam and head change that require adjusting so i purchased his system. You will need to add AFR's gauges to your exhaust though. I highly recommend installing bungs on both and even reading both at the same time. I believe you will need to change the map sensor to read over 1 bar. If you running the cool fuel system, the regulator will have to go. This will cause a increase in fuel pressure under 13lbs. of vacuum. All of your Run Fuel vs. MAP vs. RPM will need to be reduced. Which are typically very rich from MERC already. The MEFI 2 computer is really easy and should be able to adapt to a boost application easily. Again, confirm with Bob. Just be ready with your questions.

Andy

4bus

iTrader: (4)

I thought you had to jump to MEFI3 for boost applications? I am not sure, but yes Bob is the guy to talk to.

If you already have experience tuning it will be a breeze. MEFI Burn is just the upload software and the ALDL cable. You will use TunerPro RT software to write the maps and collect live data. Tunerpro is widely used, and has a huge forum support beyond just boats.

I see no reason for bungs on both sides, the odd side 1-7 will always be leaner. You can't tune one side different than the other, so why bother reading both sides?

ezstriper

Eddie Young on here can help with that as well...probably need a few more mods to make it good...

tunertech

mefi 2 will support 2 BAR map

Enable Load Anticipate (no Shift Interrupt) Not Set
Single Inj TBI (Off = Dbl Inj TBI) Not Set
Two Atm MAP Sensor Present Not Set

Trash

Agreed on above.

I did my own MEFI tuning cold, with nothing other than a few calls to Bob and a lot of study. In the end it isn't difficult but it is daunting at first.

Make small changes and only make one change at a time until you can control the variables and not get caught up chasing your tail.

Make many copies of your stock bin file! Every time you change a parameter save it as a new file. This allows comparison at a later date should you find yourself chasing your tail. Log your data. Different props help load the motor to tune different cells. Low pitch props tend to skew the operating band towards the lighter MAP side while higher pitch props to the opposite for a given RPM.

MOST items don't need to be changed except the BPW/RPM/MAP table and timing table. There may be some exceptions but concentrate there. No load idle on the trailer with a hose is a great place to easily and safely play with the fuel table to get used to things.

Wide band is a must. Install spacer between manifold and elbow to accept O2 sensor or have a bung welded into the dry section.

I'm positive TunerTech, Bob and a few others would have sage advice.

abmotorman

I found an injector not flowing properly this way. Read a plug afterwords and sure enough. Still worked, just to lean.

nitrouspaul

thanks to every one for the support