Procharging and boost referencing?
 

I understand that a fuel injected 509 mpi motor with a procharger starts with let's say a 40 pound base line fuel pressure. And ends up making around a 20 pound rise by the time full boost is achieved. But why does that happen when we are using a 1:1 boost reference regulater? If the boat makes 5 pounds of boost at wot, then should it not be making about 45 pounds of fuel pressure. One pound of fuel pressure for every pound of boost. I want to add my smaller pulley which should make 7/8 pounds of boost up from 5, and want to make sure I have enough fuel. Running the a1000 pump with areomotive boost reference regulater. Fuel rail is fed from both ends and has a custom return from the regulater to the fuel fill neck. All larger fuel lines to match. I am assuming stock injectors....... Am I safe to toss the smaller pulley on. And if so, should I bump up the base fuel pressure to put more pressure on the injectors at wot? What's everyone think? By the way m3 charger With the 504 cooler.

where is your regulator? b4 or after the injectors..

The regulator that comes with a Procharger kit is not linear. It has "gain". Bumping the fuel pressure as the boost goes up is a crude but workable way to use the stock injectors and ECU. Tuning can be tricky.

The ideal way is to reprogram the ECU and change injectors as needed.

Agree. This is a normal and acceptable practice in a blow thru carb setup. Not so much to provide more fuel, but to keep the added psi from the blower not to overcome the floats in the carbs and close them off, starving the engine for fuel. Since the bowls are no longer seeing normal atmospheric pressure resistance. If you raise the psi at the carb 7psi, you need 7psi more fuel pressure so the floats behave normally. Thats really where the 1:1 idea comes from. If you think about it, adding 3 lbs of boost on your setup might produce an additional 100HP(guessing). 3psi more fuel psi on a port injected setup, isnt gonna support the extra 100HP alone.

With injection, Id want the proper LB injectors with a good tune. A 02 sensor would probably be a worthy investment.

The regulater is before the injectors. This is not the regulater that comes with the procharger setup. The boat has a complete big line,big pump, good regulater setup. Not the half ass stuff procharger supplies. I have had a hard time finding different injectors for this motor. What should I be searching for? Can the mefi3 just be sent out and tuned to my boost and fuel requirements, or does that all have to happen on a dyno or in the boat with tuners? Sorry I am new to all this Efi stuff. Just trying to learn.......

Maybe the regulater is the procharger one. Did they use a aeromotive boost reference unit? Is that why you see a 20 pound gain from off boost to full boost. Prochargers way of dealing with stock tune and stock injectors? Again sorry for the ignorance, just don't want to blow anything up, but do it the correct way!

the correct way is to ditch that boost-referenced regulator and get the thing tuned. What ecu are you running?

It's a 99, so that should be the mefi3 if I am not mistaken.

Okay, I brought this boat home last Saturday after purchasing it. I had a chance to go over it some more this am, and can speak with some more accuracy. The boat does have the procharger regulater on it. It also has what appears to be a custom pickup from the tank (bigger) and it get returned to the tank as well. It's all big lines not sure on exact size, I am going to try to figure that out. They are earls fittings. I am going to attach some pics of this as well. The computer is definitely the mefi3. Also found a small procharger module that taps into a temp sensor and the factory harness as well. It called a ect signal conditioner. Would I unhook this module if I had ecu tuned for bigger injectors and the 7/8 pounds of boost? Which regulater should I be running on this setup with the tuned ecu and bigger injectors? Are is the rest of my fuel system up the task? My 5 pound pulley measures 4.25, and the other pulley that came Withe the boat measures 3.75. Will that smaller pulley put be into the 7/8 pound range? Photos coming!

Here's a few more

I watched the fuel pressure gauge at idle while I winterized this afternoon, and it was reading 48 pounds.

Rob, I am going to call you, half that stuff is just garbage. The signal conditioner is a big bandaid that needs to go in the trash along with that POS regulator. The reason for the signal conditioner is when you don't run a stat and motor is running at 100-120 degrees (which helps your ability to run more boost and timing on less octane) it tricks motor into thing its warmed up so the ecu doesn't stay in warm up enrichment mode. The boost compenasting regulator from procharger is a terible pos, seems like no one can ever get one to work the same twice, they are bandaids that were popular 12 years ago but there are much better ways to do things nowadays (put proper size injectors in motor and tune for it at a linear fuel pressure, reprogram ecu to quit adding fuel at table below temp yolur boat runs w/o a stat in it), Smitty

Is your M-3 a self contained? If your crank pulley is around 8" your 509 should have about 15 psi of boost with a 3.750 top pulley , if its a regular m-3 ignore what I said as I am only familar with the m-3sc, Smitty

Rob, you may want to remove that pickup and check it. It looks as though it's the stock pickup with a different adapter fitting installed. That pickup should have a plastic pickup tube. The problem is the hole that connects that aluminum piece at the top to the tube is pretty small. On top of that, when the blue adapter is screwed in, it ends up blocking off part of the hole. I have seen them where the hole is only about 3/16" after the adapter fitting is installed.

It depends on which version of fuel rail you have as to if the injector change is easy or not. If it's the later version and uses the shorty injectors, then no problem installing larger ones. If it's the earlier one that uses the Kiehin injectors, then it's a little more involved. The rail and manifold can be drilled out to accept long Mototron injectors. I've done quite a few of them. Give me a shout if I can help.

Also, as mentioned, get rid of the POS regulator and tune it correctly on the dyno. Smitty can certianly help you out. LEt me know if I can help in any way.
Eddie

accel makes injectors that will fit and come in diff lb applications..

http://www.summitracing.com/search/B...FexAMgodLxkAKQ

match the body and ohme out your's for the correct ohm impedance and 50lb? 60 lb ?

I have had a couple great conversation with Smitty today. He really knows his stuff!!! Anyways, when I look at my current rail and injectors there is only about an inch maybe a touch more of injector body showing between rail and intake manifold. I am pretty sure these would be the shorty. Smitty has already directed me on to the correct injector to run in its place. Also Eddie I will be changing the regulater ASAP as well. I will be running a steady fuel psi, and letting the larger injectors and new mefi3 tune do its thing. Smitty is thinking dropping from my current 4.25 pulley at 5 pounds boost to the 3.75 pulley should make around 7-9 pounds.

Eddie, the fittings appear to be -10 through out the fuel system, maybe -12 not 100 percent sure. Some one defiantly welded in a larger pickup, and or larger fitting for the -10/12 Earl fitting. Seeing as its all welded into the tank I am not real sure how I could tell if it was just a fitting welded on top of a stock pickup? Either way can I provide enough volume for 750hp? After the new regulater and injectors of course.

It's hard to tell from the pics if the pickup tube is welded into the tank or if it's part of the fitting. The best bet is to pull it out and have a look. If the tube is welded in the tank, then there is nothing to do. Just make sure the aluminum fitting on top has a large enough hole in it. If it has the plastic pickup tube attached to that aluminum fitting, it needs to be change. Just pull it out and see what you have. It should only take a few minutes. And that is -10 hose.
Eddie

as Eddie says you need to pull off the fitting and make sure. it could be as small as 3/8" or even 1/4" plastic tubing on the fitting or if you are lucky they welded in a 1/2" or bigger tube and it is just a fitting. if it is just a fitting I would throw it out and put a straight fitting in the tank and a sweep 90 hose end on the hose. those drilled 90 degree fittings knock the heck out of the flow rate.

So what you guys are saying is unscrew the 90 degree fitting from the welded on tube/adapter and I should be able to tell from how large that opening is if I am good or not? Would the stock plastic pick up tube thread right onto the bottom of that welded in fitting, if it is in fact not a complete larger pickup tube.

Just curious if I had to install a new larger pickup, how do you go about cutting a new hole and welding in a new pickup tube with the tank in the boat, with fuel in it!!!?

Okay here are some pictuers of the pickup tube, and 90 degree elbow. The smallest part of the whole assembly is the long pickup tube section with the screen on it. It measures 1/2 inch O.D. Should I have a larger pickup butt welded to the bottom of the 90 degree fitting. Everything else it pretty big.

fixx
 

you will want to get away from the alunimum tube and go with a nylon one..those will break at the threads and fall in the tank and leave you floating..seen it many times..

A couple more..... is this big enough?

Look at the hole inside of the aluminum square piece at the top of the tube. How big is that hole? That will be the smallest part. Also, when the blue adapter piece screws into the aluminum square, how much of the hole does it block off?

We just make our own from SS. I use a 3/8" NPT x #10 adapter and weld a SS tube to it that is 1/2" ID.

fixx
 

USCG dont want any type of metal near the fuel tank..just saying..

Why? The tank is metal. The existing fitting attached to the tube is metal. I've seen tanks with metal tubes welded in them. I don't understand??? I'm certainly not trying to argue, but I just don't understand what you are saying. Do you have a link to a USCG reg where it states that? I would like to know since every boat I have ever worked on has had some type of metal on the tank pickup, so that means they are all going against CG regs.
Eddie

I believe my Fountain and buddys Cigs came with metal pickup tubes in the tank.

I do know that stainless braided fuel line is not USCG approved.

That is true about the braided hose. I either use Push Loc or braided nylon hose. I'm not aware of the other part.
Eddie

my 253 checkmate looks to have the same aluminum pickup he is showing....not sure if it came that way(procharger as well) but looks the same...

The problem with that standard fitting is that the tube cracks at the threads. The fuel is constantly beating on it and the root of the thread is a stress point. I cannot tell you how long it took to figure out the first time I ran into a cracked one - just enough to leak air.

I used to drill the fitting to slighty under the OD of the tube and use a piece of tubing with no threads. Made it a light press fit (polish the end of the tube if needed) and either loctite or epoxy the tube in. I am a firm believer in better living through chemistry (and I do not mean the mind altering kind) :)

I figured that was the best way to avoid any stress concentration. Never had one of those break. Ever

Eddie, how much for one of your pickup's? And do you put a screen on the bottom, or just leave them open. I figure by the time I source all the pieces and pay someone to weld it, I may as well just order one from you. Thanks Rob.