Fuel injected 525SC
 

I am considering building a fuel injection system for my 525SC. I am a novice on EFI systems in general, but have a basic understanding of them. The motivating factor is my boat uses twice the fuel and has half the HP of my friends EFI equipped boat.
-Will the Merc distributor work?
-Where would be the best place to inject fuel? (the area between the intercooler and head is only about 1 inch.
-I would only consider a MEFI controller. Should it be a 3 or 4?
Comments or first hand knowlege appreciated.

Fixx
 

consider this instead..

http://www.professional-products.com/EFI_3.php

mefi 4A AT crateenginedepot for $600is w/ harness. Great buy! Mefiburn software and you can tune yourself.

I have a MEFI 4A complete that I will be installing on my car. I plan to buy the MEFIBURN software thats why I am stuck on the MEFI. That Professional Products set up looks great though..

525SC's are thirsty and I doubt that making them EFI will help more than about 10%-15% in fuel economy.

They are set up rich and if you tune it with an O2 sensor and lean out the jetting, it will help some also.

[QUOTE=Old Navy;3482599]I am considering building a fuel injection system for my 525SC. I am a novice on EFI systems in general, but have a basic understanding of them. The motivating factor is my boat uses twice the fuel and has half the HP of my friends EFI equipped boat.
-Will the Merc distributor work?

With the mefi a mid 1980's to 1995 chevy truck tbi twin coil distributer works plug and play, yours won't
-Where would be the best place to inject fuel? (the area between the intercooler and head is only about 1 inch.

Wherever you can.
-I would only consider a MEFI controller. Should it be a 3 or 4?

You own a mefi 4 controller, it controls fuel a little better past 100 map/boost over the early ones, use it.


Hmmm!

"The motivating factor is my boat uses twice the fuel and has half the HP of my friends EFI equipped boat."

Maybe if you took your blower belt off you could beat your "friends" boat:evilb:

am i the only one here that thinks that if you have to ask these questions that there is no way on earth you have the necessary skill set to do this job ? i mean... you have a motor that is sensitive to combustion chamber temps to the point of disaster and you are going to cobble up some home built efi ?

i am really looking forward to reading this thread as this project evolves... the entertainment factor will be priceless...

Oldnavy isn't quite as dumb as he sounds in his post:evilb: although he will not gain the mileage his "friends" efi boat gets because his "friends" efi boat is lighter and is turning a procharger which has signifigantly less parasitic loss than his little, tiny , itty bitty, baby jesus, roots style blower motor (my phone will be ringing in 15 minutes).
As far as the efi conversion he could probably seek qualified help and advice from his "friend" with the efi boat that gets better mileage (when its not broken) than his.
Stevexsm, I am currently finishing a efi project using a mefi4a and ramjet 502 harness on a Pontiac 455 , it will be going to dyno soon and starts and runs pretty good so far, I will send you some pics when done as I know you were involved with some Pontiac projects in the past, Smitty

This is a tech forum. If you want to be such an azz, take it to the Bilge. It really makes me want to post here.....

i agree 100%...much easier to lean the overly rich mixture (might even get a couple of horses doing it) than reinvent the wheel

listen butthead...
you are correct. its a tech forum and part of the advice that you get from people that actually know what they are doing is that you recognize what the scope of the project is from a technical standpoint. you post a question indicating an absence of knowledge of the most basic configuration parameters of a very very complex system and don't expect someone to say " gee are you sure you want to take your expensive motor that you obviously can't fix the most basic problems with a carb on and invent an electronic fuel injection system that you know nothing about to solve problems that you aren't going to solve with efi anyway "?

welcome to the forum, forest.

your engine still requires X amount of fuel to run...weather it be from a carb or EFI so bottom line you are wasting your time and $$ whatever you gain....and will be small if any..you could buy a whole lot of fuel !! now maybe you need to look at what you have...go thru your carb, tune up ?? basic stuff..bet your friends boats are not a fair compairison...H/P vs weight etc...

Will, if you are more concerned about mileage than anything what ezstriper is saying holds alot of truth, although you have to jet your motor to be safe at all throttle settings and ultimately end up with some spots that can't help but be rich in order to noot melt down somewhere else lets look at the math:
Lets say everytime your boat hits the water it cost your 200$ in gas, you lean it out 15% (which would be my realistic guess) and you save 30$ every time you take boat out. I know you only take our boat out 10 times a year or so, you are talking a 300$ a year savings at best. To do your efi conversion (I just did this as you know) you will spend:
600$ mefi controller and harness
500$ for 8 appropriate sized injectors
150$ for regulator
500$ for throttle body
400$ for fuel pump
200$ fuel rails
200$ to get manifold machined for injectors
150$ for gm two plug coil connector tbi distributer
75$ msd 2 plug coil
750$ for fuel line/fittings
You will spend at least 3000$ if not 3500$ to do it and thats assuming you get your "friend" with the faster efi boat to tune it for you (Which I am sure "he" would do for free for a small favor from misses diet pepsi).
Your payback would take 10 years easily, if you still want to do it you I will help you make it happen, Smitty
If you want to see where your afr's really are get a o2 bung in them lightnings and jet it down using a 02 sensor and you will save some fuel.

how rich does your engine has to be to be ''safe''...too rich is almost as harmful as too lean...my definition of safe :find the ideal mixture,and go up ONE notch.....just sayin...