Injection or Carb.

[SSTahoe]

I'm rebuilding both motor's right now and they are being Injected. The problem I have is the computor, it seems to me their could be alot of things that could go wrong with this computor. I mainly boat at Lake Tahoe it ran fine with the mer. 800SC but I wanted more power. It has the 572 tall deck blown. My Question is should i run the Injection and maybe deal with computor problems or stick with the dual carb's.

[jackpunx]

I'm rebuilding both motor's right now and they are being Injected. The problem I have is the computor, it seems to me their could be alot of things that could go wrong with this computor. I mainly boat at Lake Tahoe it ran fine with the mer. 800SC but I wanted more power. It has the 572 tall deck blown. My Question is should i run the Injection and maybe deal with computor problems or stick with the dual carb's.
There are a few people out there that have the computer parts of it down. I run carbs and love them. but with the altitude changes you may be better off running the EFI set up.
for me the EFI is just more moving parts that are out of my control.
Good luck..
Call Gary Teague.. or Info
Mark

[HighRoller]

You might PM Infomaniac as well. He has started selling EFI versions of his engines and he knows his stuff. BTW, is it still a roots setup?

[SSTahoe]

It has the B&M 420 blower with Mercrusiers tag on them I would like to get 8-71's but these only have 101.0 hrs. on them and are really good shape.........unless anybody know's of some one who would like to buy them as a set!!

[Infomaniac]

What injection do you intend to run on top of a roots blower? Selection is limited.
The B&M 420 will only accept throttle bodies on top. No top plate like every other roots blower. Will be very tough to put injection there.

[SSTahoe]

Mr. Gasket was going to install the throttlebodys on top and drill and tap manifold and install the bosch injectors. There is boss's in the manifold at each intake port, they have the intake and said that will work fine.. if you have any info on a better way let me know. Infomaniac if you can offer a better system let me know.

[Infomaniac]

That sounds like a decent set up to me. A lot of blower manifolds will not accept EFI injectors.
What computer are you going to run?

[SSTahoe]

The computor is going to made by Accel who is owned by MR. Gasket it's a DFI System. you stated that this would be OK what do you think of the computor I'm a little worried about the moisture getting to the computor and its Componets but they should know that. This is the system you can connect a laptop and down load info and program the computors for performance. have you had any experiance with this system??

[oknozelman]

The Accel is what I'm going to use on mine. The rep @ Accel said the computer was sealed and would work fine in a marine application. I was going w/ a 6-71 and an injection plate under a bug catcher but now I have decited to go w/ a B&M intake {w/ port injectors} and chiller and pipe twin turbos through throttle bodys into the chiller. How are you going to run the blower w/out fuel to cool it? I thought you had to run some fuel through the blower, even if you did the port injection? :confused:

[SSTahoe]

The Accel is what I'm going to use on mine. The rep @ Accel said the computer was sealed and would work fine in a marine application. I was going w/ a 6-71 and an injection plate under a bug catcher but now I have decited to go w/ a B&M intake {w/ port injectors} and chiller and pipe twin turbos through throttle bodys into the chiller. How are you going to run the blower w/out fuel to cool it? I thought you had to run some fuel through the blower, even if you did the port injection? :confused:
That's a good question?? Don't know if they thought of the cooling of the blower that could cause some major problems. I wil call MR. Gasket and ask about that, thanks for the info!!

[cdog]

I'm runnin the Holley Commander system with the 2000cfm throttle body. So far i'm real happy with it. Starts right up and idels down when it's warmed up. It's on a 540 with 570 hp. I set it up to add a procharger in the future so it only has 8.5 compression. What I like about the efi is now that all of the noise restrictions are now in place I can launch the boat, start it cold and not have to rev untill it's warm. It starts like a brand new truck. The Holley efi computer is water resistant and is made for marine use.

[SSTahoe]

who carries the complete holley system for marine use. Is it approved by the USCG??

[SSTahoe]

The Accel is what I'm going to use on mine. The rep @ Accel said the computer was sealed and would work fine in a marine application. I was going w/ a 6-71 and an injection plate under a bug catcher but now I have decited to go w/ a B&M intake {w/ port injectors} and chiller and pipe twin turbos through throttle bodys into the chiller. How are you going to run the blower w/out fuel to cool it? I thought you had to run some fuel through the blower, even if you did the port injection? :confused:
I talked With the guys at Mr. Gasket and they said they will have a injector on top in the throttle body to just to cool the blowers. don't know if that will or not..

[oknozelman]

The injector in the throttle body should work fine, it won't take mutch to lube and cool the blower. Do you have chillers on your set up?

[oknozelman]

I'm runnin the Holley Commander system with the 2000cfm throttle body. So far i'm real happy with it. Starts right up and idels down when it's warmed up. It's on a 540 with 570 hp. I set it up to add a procharger in the future so it only has 8.5 compression. What I like about the efi is now that all of the noise restrictions are now in place I can launch the boat, start it cold and not have to rev untill it's warm. It starts like a brand new truck. The Holley efi computer is water resistant and is made for marine use.
Holly, and Accel are owned by the same people so maybe the same? But I've been told the Accel VII is te best set up but I don't know.

[SSTahoe]

The injector in the throttle body should work fine, it won't take mutch to lube and cool the blower. Do you have chillers on your set up?
I'm going with the traditional Intercoolers made by Whipple.

[hulshot]

Ok I also have some questions about this subject. I am looking at some ideas on my next project. I may do a roots blower with EFI by 2000autotronics. I was looking into the direct port EFI in the manifold but no one I found makes one for EFI except indy Manifolds. I am also worried about the rotors burning up from heat and then I talked with Pfaff and they make a EFI adapter that goes under the throttle bodies. What set up works, who can get a base program for a motor like this, and is it better to run the injectors on top or bottom?? Also Infomaniac, I am looking for a manifold and cooler perferably used but will buy new if price is right. Pm me with any and all info. Thanks

[Unchained]

There's no question that its more desireable to have the injectors as close to the cylinder as possible.
A dyno shop owner told me that roots blown engines with intercoolers have a tenedency to have fuel settling out at idle speeds after the mixture has gone through the intercooler which can cause rough idling.
I ran a blower for several years and wasn't aware that they considered that the fuel mixture was lubing the blower rotors. That sounds pretty crude.
I rememeber the blower I had used a single teflon strip on each rotor and it would get so hot even at cruise speeds that you couldn't touch it anywhere.
It was like it was working against itself.
There's a clue here...........
I remember looking into using a blower manifold and installing the injectors in the ports but there just wasn't enough room.
I ended up using a single dominator manifold to weld the bungs into.
The fuel rail that holds the injectors in can be mounted real easy to the center manifold bolts.
http://www.***boat.com/image_center/data/504/220DSC01623-med.JPG

[oknozelman]

Boostpower USA makes a intake that has port injecters but it is for the B&M style blowers{I'm looing for one, and the chiller that fits it} I don't know of one for a 6-71 to 14-71 flange?

[cdog]

Holly, and Accel are owned by the same people so maybe the same? But I've been told the Accel VII is te best set up but I don't know.
I believe Accel is a mr. gasket product/ or company.
Here's a link to the holley marine site. http://www.holley.com/marine/index.html

[Havasu47]

Holly, and Accel are owned by the same people so maybe the same? But I've been told the Accel VII is te best set up but I don't know.
CDOG is right. Mr Gasket owns Accel, two complete different parent companies. I am a Mr Gasket, and Holley W.D. We have built many engines with the Accel Gen VII and like it alot. We have done blown engines with it also. Good stuff, a little complicated to learn but worth it.