Excellent explanation and thank you very much. I see it now.

So Eddie........whatcha got so far

I am on the fence of having my current injectors cleaned and checked, or just going your route. Would also be interested to see where the AFRs fall on the stock tune, if it is safe to use as a base line

I hae one completed. I haven't had a chance to run it on an engine yet, as I don't currently have one. Instead, I decided to take the time to digitize the injector plate on the CNC so that I can make several of them. I am hoping to have a few made in the next couple of weeks. Here is a pic of it with the harness installed on it.
Let me know what you think.
Eddie

I am interested, I can see this changing my cam selection with availability of larger in injectors.

Eddie, how's the project coming? Any updates??

It's still moving along, albeit somewhat slowly. After I made the first one, I realized that I wanted to change up a few things. That required me to make a completely new injector drill bit, which took some time. I just got enough material to make about 25 of them and have the base completely digitized in the 5 axis CNC. The only part that isn't digitized yet is the injector holes. That's where I wanted to make most of the changes. So, I'm going to try to get one cut out this week. I'll then have to drill the injector holes on a manual mill. Once I'm happy with it, I'll digitize the rest of it and we can start cutting some. That entire process should only be another 2 weeks or so.

In the meantime, I did get a chance to run the new EV1 injectors at the stock 30 psi. They worked just fine at that pressure. So, for the guys with stock engines and stock fuel systems, we won't need to make any changes to the Cool Fuel setup. I was a little worried about that, since most Cool Fuel setups aren't accessible, but it worked out great. Obviously, the injectors won't flow what they are rated at, but that's OK since they are way bigger than we need anyway.

Also, I didn't have a 575 setup in the shop anymore. But, I just got 2 of them here. That has been a big part of the holdup. I have them now so I can continue making progress with them. I'll keep you guys posted on the progress. Thanks for your interest.
Eddie

just asking if you did any wideband / 02 readings using the Bosch EV1 injectors as they are (3 bar) 43.5 psi rated, I understand that they are regulated at 30 psi currently in the build.

Also wonder about how much the fuel pressure regulator is going to have to by pass and or keep up with it ? I know you by pass back to the gas tank in which is way better than the stock set up being returned back into the filter head or intake or TB.

This particular plate is a cost effective way to replace the crappy stock injectors in a 575 SCI. I am trying to put out a bolt on deal for guys with 575's, that's why it needs to run at 30 psi. In most boats, the Cool Fuel Module is not accessible with the engine installed. If they have to get to it to install a regulator (which are available), then it isn't really a bolt on kit any more, for most. It would require lifting the engine, which is not possible for most. It won't be bypassing any more fuel than it does now since the fuel system will all remain stock. It will retain the stock throttle bodies and flame arrestor as well.

However, it can be used on modified engines as well. You will still be limited at some point by the throttle bodies, but that should be about the same time that you run out of supercharger and fuel pump. I'm making this plate so that the stock throttle bodies (with the injectors removed) will bolt right up. There are already injector plates commercially available to house 8 injectors and run a standard carb adapter on top. But, that adds significant cost. You would need the plate and injectors, carb adapter, throttle bodies, flame arrestor, fuel plumbing, etc. It could easily add up to 3-4K. You will gain some power, but you will have way more throttle body than supercharger.

If guys want to change the fuel system, or already have, then we will run at a higher fuel pressure. That would be ideal. However, I wanted to be sure that the injectors would work and still have a nice spray pattern at 30 psi, which they did. Distribution will really not change since all of the fuel is still going through the blower.

Everyone that either owns a 575 or has owned one, has probably had some issue with the injectors.....they fail, they drip, they go static and dump fuel, etc. I'm just trying to come up with a cost effective way to remedy that with commonly available parts. It will also have the added benefit of allowing a ton more air through the throttle bodies once the injectors are removed from the throat. If I had to guess, I would think that each throttle body would flow at least another 100 cfm. I don't have any hard data on that as it's just a guess. But it has to help since the injectors completely clog up the throat of the throttle body.

Hope that answers your questions BUP.
Eddie

I understand what you are doing and totally agree about any TBI injectors in use especially currently plus access to Merc GEN II cool fuel systems. I have been in all these cool fuels more than I ever count from most marine engines .

TBI injectors spray patterns are very poor for complete fuel atomization as it can run and or drip down the throttle body walls and can be even worst during hard corning (puddling) among other problems including notorious to leak after shutdown.

just asking about fuel pressure / fuel pressure regulator possible not to by pass correctly especially the way the Gen II cool fuel is designed and the stock regulator . I bring this up because I seen fuel injection systems retrofitted in apps like this and others. I had a couple engines that were changed over from TBI to MPI plus remapped ECM's using the stock lower psi rated fuel pressure regulator that could not by pass correctly from the builder.

The fuel pressure is regulated in the Cool Fuel Module, so the fuel going up to the throttle bodies is already regulated. I don't think that it's the ideal way to do it, but that's how the 575 is done. The injectors type and style won't have any effect of fuel pressure since it is pre-regulated.
Eddie