Fuel Injection on a blower
 

Has anybody utilized fuel injection on top of an 8:71 blower? Did you use injectors with air only throttle bodies?

When needing Brain surgery go to a Brain Surgeon!
 

Its been done hundreds of times both ways!

Talk to:

Kieth Eikert
Dean Gellner
Eddie Young
Potter
Mer Performance
Zul
Cobra
Larry's
the list goes on and on........

One of these guys is very capable of gettingan 871 equipped marine performance engine properly fuel injected,
Don't re-invent the wheel!

Best Of Luck

Regards,
Ray @ raylar

I've just placed an order for a pair of 1000's built with 1471's and EFI on top. Bill Lawson at Ateco is building them, and is conferring with Keith Eickert on them. We are looking at using 2x FAST 4150 throttle bodies, each having 4x 85lb/hr injectors. We are also seeing what BigSuff and Accel's latest offerings before we commit.

This topic has come up before, and everyone was quick to point out the Merc 575SC was built like this. I am DIY'ing everything else but the engines, including drive change to SSM V's on extension boxes, but fiddling with four carbs just doesn't seem like a good use of my limited free time.

I actually make my own injector plate (and fuel rails) to go on top of the blower between the blower and the carb adapter. On top of the carb adapter goes the throttle bodies. Depending on the blower size and the hp, I may use (2) 1000 cfm or (2) 2000 CFM throttle bodies.
I started making my own because I couldn't find one that would accept 10 or 12 injectors. I use Mefi ecms and they only work with high impedence injectors. The problem is that the largest high impedence injectors (until recently) are 65 lb/hr. (8) 65lb injectors is only good enough for a little over 1000 hp. Any more than that needs more injectors. So, I had to improvise. Let me know if I can help. Thanks
Eddie

If you are thinking about using your existing 575 throttle boddies it can be done. Steve Zuckerman has did this with success. The 575 throttle boddies are a little small and have been told they act like a ristrictor plate. There is a couple shops that can improve the flow on them.

Have yourstock head gaskets been replaced? That definately needs to be done and when you do that you might as well pull the motor and replace the cam with something that is more worthy of a SC. If your heads need to be done you may want to consider just going with a set of aluminum edelbrocks. You have to have your ECM remapped anyway so this is the time to do it. What you will find is that your drive will be up to the task after all this.

at this hp level I would skip the Edelbrocks & go brodix, afr etc

http://www.offshoreonly.com/forums/g...opinion-3.html

This is a great thread. I would much rather have the AFRs that the Edelbrocks. But for the price, the Edelbrocks are hard to beat and the drive is will still not handle the power. Another reason for the Edelbrocks on my app. is the stock exaust port height. My CMIs are literally rubbing on my hatch with the stock heads.

The biggest problem with the 575 throttle body injection is the injectors. They are not very reliable when you raise the pulsewidth. When you start asking them to work hard, they don't like it. You also are limited to injector size. I'm not sure what the largest available ones are, but it's not very big. So that will limit power potential.
In stock form, the 575 setup is good for about 650 hp tops. It will work fine if that's the power you're looking for. Any more than that, I would look for something else.
Eddie

What about using the stock throttle boddies with your custom injector plate and ditch the stock injectors?

fixx
 

Eddie we may have talked about thease already? have you checked into mike moraans injectors yet?

http://www.moranmotorsports.com/prod...ce66480eaf2dfb

Yeah, he has huge ones...I think like 500lb/hr. The problem is that they are low impedance. They have just recently come out with some 80lb high impedence injectors. I just verified yesterday that they are available. You could run a piggyback driver to fire the low impedance injectors, but it is a pain.

JRider,
I don't see why you couldn't do that. Those throttle bodies aren't very big, so it would depend on the power goals as to if they would be big enough. You would have to have them or get them real cheap to make it worth it. The aftermarket ones aren't that expensive.

Eddie

It's never a good thing when you have an impotent injector!

thanks for all the info. My stock 575 SCI came from Advantage with a superchiller and 3" pulley. Also came equipped with an exhaust pyrometer. And from experience with the set-up, it stated to run lean at 4600 RPM. To me that is proof the factory throttle bodies lack flow and adequate fuel delivery. Talked to FAST since they offer 4-barrell high impedance injectors, but they do not recommend them on blower engines. currently looking at injectors mounted in a throttle plate with air only throttle bodies.
Currently rebuilding total motor with Hyd. roller, Dat Pro 1's and good gaskets. Will multiple injectors work with factory ECU?

I was just thinking that all the merc linkage is good, the IAC is there, and the arrester looks good and is already there. Why not make use of it? ditching the stock injectors would most likely help the TBs flow.

I'm going to look into using the stock throttle bodies as air only. But i keep hearing they do not have enough air CFM above 5000 RPM. What is the CFM on the stock throttle bodies?

I Think 670 each but without the stock injectors in the way they should flow better. How much better...I dont know. I know Steve Zuckerman sent his out to have some mods done so the would flow more.

Adavantage_575. I am in the process of doing the same thing as you. I have a Littlefield 871 that is stripped and the whipple intercooler that is ready to go in. I have talked with Steve quite a lot along with Eric his motor man and EFI tuner. I will try and find more info the the TBs

Eddie,
have you looked at a driver box for the low Z injectors? Depending on the output of the MEFI.. (switched to ground?) to fire the stock injectors a driver box can open up the injector world to much bigger squirts!!

Dick

JRider, let me know what you find out. I think 1340 CFM is a little shy for an 871 Blower in the upper RPM band.

I have. I mentioned it in post 11. It is just a pain and something else to go wrong. The 80# er's are available now, so it's no longer an issue. (8) of them will support over 1400 hp.

The way to get the 575 injectors to flow adequately at a pulse width that doesn't burn them up is to install an adjustable fuel pressure regulator. Turn up the FP, turn down the pulse width.
The guys that modified my throttle bodies say they are Merc/GM rated at 670CFM, but on their flow bench they only flow 640, probably because of the big injector sitting right above the bores. Mine now flow 740 each (with the stock injectors) for a total of 1480. I think side mount injection and removing the TB injectors would result in a big flow increase too. Hmmmmm. Maybe get that missing 30CFM back or even more?
Eric did have to completely remap my injection after this but, knock on wood it's run great ever since, evidenced by my repeatedly broken drive :eek:.
Here's a pic. Eric has my program stored if you guys want to do this upgrade. Oh yeah, Eric also upgraded my manual fuel pump to an Eickert, and went to bigger lines.
EB Marine #615-714-2944.
Best Regards,
Steve

Steve, what cam and heads did you use?

Dart Pro 1s with a little hand grinding.
For the hydraulic roller cam, which I would buy through Eric, or have him install, just give him a call. It has worked very well in several 502/509/540/575 buildups he's done.
My motor spins freely to 5800/6000, and pulls hard across the RPM band.
BTW, your throttle bodies, with our mods can easily handle your current project. I'm at 509", and now that we have the flow figured out, I am seriously considering going to 540".
That's actually how this project started out. My TBI system was "done" at a modified 502, and we were trying to figure out if there was enough left (CFM/fuel delivery) to go further, without going to carbs or an aftermarket EFI system, and having to start from scratch.
Then there's the drive issue..................
Is there an aftermarket EFI system that will out perform the stock (or modified) TBI system? I'm sure there is, and if you spend the $$$ to find it and make it work, let us know.
Regards,
Steve