Krumbsnatcher

Update on the choice

Going with a custom FAST Racing injection system. It turns out that my father inlaw who is an ex drag boat racer knows I believe his name was Norm Grimes who is going to give me the parts for about a grand. Then his other buddy who is currently building the wiring for these FAST systems is going to build the wire harness and etc. They are also going to build a custom fuel map for the unit for my driving conditions which is programmable via a laptop.

Should be a interesting project, my only road block is that i have to mount an 02 sensor somewhere near dry exhaust. I currently have the IMCO Powerflows and stainless elbows that the water exits at the rear.

Any ideas guys.

robyw1

I know of this road block. Somehow it seems like spacers could be manufactured to go between the manifold and the riser that does not allow water to flow through. Most HP manifolds have this flange closed to water anyway. An O2 sensor could go there but might need to be lengthened in order to ensure it is well into the exhaust flow. You only need to do this to one side unless you want to use 2 just for looks and or possibly install an EGT in the other side. Either way unless your using dry pipes (which should make for easy mounting anywhere) this is the only solution I know.

No Question though; You Made the right choice

Roby

zt260

While I was waiting for my Stellings dry pipes, I had EMI thunders with long risers. They make the spacer that fits between the manifold and riser with an O2 sensor. Worked great and we removed it after programming. The only other way is to have a bung welded into the riser and insert an O2 sensor there. Unfortunately I had to do this as well. When the new tailpipes were ordered they forgot to ask for the bung. Its not that bad if you know a good welder.

Brad Zastrow

The upcharge for fuel injection is very large compared to carbs. I personally like the carbs. You can make a heck of lot of hp with carbs just like EFI. Biggest difference may be idle quality if the carb is not dialed in right.

jdnca1

Have not seen a fuel injection system yet that can make more power than a PROPERLY matched and tuned carb for the package. Don't get me wrong the fuel injection stuff has come a long ways and for the "average" person a better overall program.....but it comes with a big cost.

If you tune your carb (s) on the dyno with wideband O2 on every cylinder you can get it dead on.....exactly whats needed for an EFI system if you want it to be right and live.

Before I get jumped by the EFI croud I'll only say this.....I'll be convinced that EFI is the new deal when I see it outrun carbs in NHRA pro stock.....

I may be wrong, but I think the advantage of carbs over EFI still is the fact that nothing atomizes fuel like a carb.

tomcat

I know you're already moving into EFI but I am just curious. Could someone explain why this engine's problem (laying down at 4000 RPM) is due to carb capacity?

A 540 can only take in 625 CFM at 4000 RPM. At 3 psi boost the blower is cramming 750 actual CFM into that same volume, less if you calculate how much of that boost pressure is just due to the temperature increase. How is a 1050 carb not able to supply this engine to way beyond 4000 CFM? Is there something about how the rotors move under the carb that prevents it from flowing it's rated capacity?

hillbilly24

plenty of air, not enough fuel for the application. I can't beleive you guys are even arguing over EFI VS Carbs. They both have there places and can make good power when set up right.They both have upsides and downsides. For turn key power EFI is the way to go, for big HP blower motors, I'll still take a carb. Neither is better then the other, they just have different applications, It's like comparing a Ferrari to a 1 ton pick up truck.

jdnca1

Tomcat my thoughts exactly on why the laydown? A 1050 should be plenty of carb for a 540 and small blower. Hell I know people running 8-71's on 540's @9 pounds of boost with single 1150 Dominators with no problems. Not ideal, but no delivery problems.

Could be a lot of things on the delivery...fuel pump? float level? pick-up problem? etc, etc,........But a 1050 dominator should keep that motor well supplied.

Tomcat interesting point on the rotor possibility.. ? ? ?

NOBODY

This is not a CFM problem.
This happens alot with single carb apps with a supercharger, and this problem may not be fuel delivery to the carb, but the fuel delivery through the carb via (jet size, needle and seat size, power valve orifice size, booster size and style, float drop, air bleed size, ect., ect. This is where a talented carb guy can come in and give you good idle quality and cruise, but with the ability to have WOT fuel delivery. This is alot easier to accomplish with two carbs because you have double the amount of orifices and reservoirs for the same amount of air to move.

Attack

Gone old school --- I had EFI's on my last boat and had too many nagging issues like, electrical grounding, IAC's failing, injectors clogging, failing fuel pumps, and too much wiring to trace. I had to buy expensive test equipment to trouble shoot and spend many weekends in the bildge. I have 1050 Dominators in my new boat dialed in by Nickerson and love them. Just start and go play.... I think computers and sensitive electrical systems are fine in my car, but not in my boat.