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Dual Carbs vs MPI on Blown motor?????

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Dual Carbs vs MPI on Blown motor?????

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Old 05-10-2005, 12:30 PM
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Question Dual Carbs vs MPI on Blown motor?????

I currently own a 29.9 magic wizard with a blown 540 stroker. My dilema is that a single 1050 dominator is not enough fuel delivery pass 4,000 RPM's. This is the second season for this motor and a new set of valves for #8 due to a leaned out condition. I have a 1/2" fuel pick up line now and a consistent fuel pressure of 8-9 lbs. She lays down at around 4000 rpms. I know it is a fuel problem and that a single dominator for a blown motor is not doing the job.

I had the boat out for a week where we changed jets etcc adjusted the circuits you name it, in fact we even had the holley computer out telling us what humidity, elevation etc and what size jets the motor should use. So I have done whats possible with this setup.

I have spoken with Nickerson and he agrees that two carbs are necessary with the horsepower in my boat.

My question is this for another grand i could get the MPI kit and not have to deal with the guess work and adjust the baby via a computer. I am looking for real input on the pros and cons of setting up a blown injection system from people that currently have some experience.

I have access to pros who can assist with the install and configuration, but no marine experince other than drag boats and the strip. Any help will certainly be appreciated.


Gen VI block
Edelbrock Performer Heads Rectangular Ports
TBS 250 blower
Isky cam
Direct Drive Gear
Comp Rollers
JE Pistons 9:1

Hope that helps


by the way a brand new boost referenced 1050 Dominator will be ready for sale soon.
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Old 05-10-2005, 08:34 PM
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Default Re: Dual Carbs vs MPI on Blown motor?????

I'm a big fan of EFI, but you might want to research the conversion. Big fuel pump, good regulator, throttle bodies, injectors, ECU with wide band O2, custom wiring harness.
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Old 05-10-2005, 10:11 PM
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Default Re: Dual Carbs vs MPI on Blown motor?????

Isn't that a pretty small blower for a 540?
I am running a single 1090 King Demon RS jetted 94 square on a Whipplecharged HP500 @ 9lbs. boost on 100LL. I did the Carter seawater pump mod. and -10 lines and pickups, still wasn't enough pump. Went to an Aeromotive bypass setup and it's all good now. Stock c/r, 5600rpm, 111gps. (22 Stoker)
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Old 05-10-2005, 11:00 PM
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Default Re: Dual Carbs vs MPI on Blown motor?????

I also think the blower is too small for a 540ci.

Should go to a 671 or more and dual carbs.
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Old 05-10-2005, 11:34 PM
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Default Re: Dual Carbs vs MPI on Blown motor?????

I would talk to Gordy at Pfaff's.

Dave
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Old 05-11-2005, 03:27 AM
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Default Re: Dual Carbs vs MPI on Blown motor?????

Originally Posted by HP350SC
Isn't that a pretty small blower for a 540?
I am running a single 1090 King Demon RS jetted 94 square on a Whipplecharged HP500 @ 9lbs. boost on 100LL. I did the Carter seawater pump mod. and -10 lines and pickups, still wasn't enough pump. Went to an Aeromotive bypass setup and it's all good now. Stock c/r, 5600rpm, 111gps. (22 Stoker)

I am only running 3lbs of boost so the blower size is a good match. I am also running the Aeromotive bypass setup directly back into the fuel tank so far no problems.

thx
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Old 05-11-2005, 08:54 AM
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Default Re: Dual Carbs vs MPI on Blown motor?????

Originally Posted by Krumbsnatcher
I currently own a 29.9 magic wizard with a blown 540 stroker. My dilema is that a single 1050 dominator is not enough fuel delivery pass 4,000 RPM's. This is the second season for this motor and a new set of valves for #8 due to a leaned out condition. I have a 1/2" fuel pick up line now and a consistent fuel pressure of 8-9 lbs. She lays down at around 4000 rpms. I know it is a fuel problem and that a single dominator for a blown motor is not doing the job.

I had the boat out for a week where we changed jets etcc adjusted the circuits you name it, in fact we even had the holley computer out telling us what humidity, elevation etc and what size jets the motor should use. So I have done whats possible with this setup.

I have spoken with Nickerson and he agrees that two carbs are necessary with the horsepower in my boat.

My question is this for another grand i could get the MPI kit and not have to deal with the guess work and adjust the baby via a computer. I am looking for real input on the pros and cons of setting up a blown injection system from people that currently have some experience.

I have access to pros who can assist with the install and configuration, but no marine experince other than drag boats and the strip. Any help will certainly be appreciated.


Gen VI block
Edelbrock Performer Heads Rectangular Ports
TBS 250 blower
Isky cam
Direct Drive Gear
Comp Rollers
JE Pistons 9:1

Hope that helps


by the way a brand new boost referenced 1050 Dominator will be ready for sale soon.
Before you give up on the carb give CandS Specialties a call at 636-723-4996 and ask for Roger. They have all kinds of creative ways to get fuel to your engine. You're not the only one with this problem and he can tell you if theirs a problem with your carb or if you need carb mods.
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Old 05-11-2005, 11:40 AM
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Default Re: Dual Carbs vs MPI on Blown motor?????

I can't believe anyone would still consider using a carbonater in this day and age. I mean this is like opting for an old Curtis Mathis 19" B/W TV instead of an HD plasma screen. PLEASE you carburator guys; move forward to at least the 80s!

Roby
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Old 05-11-2005, 11:42 PM
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Default Re: Dual Carbs vs MPI on Blown motor?????

Originally Posted by robyw1
I can't believe anyone would still consider using a carbonater in this day and age. I mean this is like opting for an old Curtis Mathis 19" B/W TV instead of an HD plasma screen. PLEASE you carburator guys; move forward to at least the 80s!

Roby
Didn't consider myself a (CARB) guy. Just trying to help the guy out. Maybe you could post some more intelligent stuff so I won't be so stupid!
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Old 05-12-2005, 09:28 AM
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Default Re: Dual Carbs vs MPI on Blown motor?????

Originally Posted by NOBODY
Didn't consider myself a (CARB) guy. Just trying to help the guy out. Maybe you could post some more intelligent stuff so I won't be so stupid!
I'm Sorry if you think I directed my comment at you. If I did I would have quoted you like I did here. As far as "Stupid" goes those are your words not mine.

EFIs are the way to go. they offer more performance in every aspect. In my opinion they are as easy to learn as carburetors without the headaches. There is so much literature on EFI systems all one has to do is buy a book and read.

Carburetors are a thing of the past. Yes there was a time when carburetors could hold their own against a throttle-body injection system (TBI) but even the TBI is gone.. forever. Nowadays EFI systems are so far ahead of carburetors that you have to build a lot larger more powerful engine with a carburetor just to stay up with the smaller injected engines. I really wish I could take the time to sit here and list why everyone should choose an EFI over a carburetor engine build but I don't have time. I once was a carburetor guy too. But when I learned all about EFI systems, how to program them, how easy they really were to work with, how many tons of more horsepower they can make, I now laugh at my carburetor days. I find it extremely funny that some people still try to improve on them. Other than NASCAR and museums carburetors really have no reason to exist today. yes that is my opinion. I can tell you that it is an educated opinion. I have had many years experience with both. When I compare tuning carburetors to tuning B/W TVs I just expressing the resemblance not trying to personally insult anyone.

again sorry if anyone took it that way.
Roby
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