Direct injection in gasoline engines is good for about a 25% increase in power unless more stringent emissions are included. Then it might drop to 5 to 10% power improvement. Also improves economy.
Back around 1992 or so was working for Ford engine design as a design engineer and was trying to push for direct injection and turbos.

So you are the one that designed those fine gems!

I'm with you Randy... although I never expected to gain hp, I can't even believe how much better my fuel economy is with my MPFI systems. We machined our higher flowing intake manifolds and calculated the injector bung angles to shoot right at the back of the valves. No loss in performance across the board. I went with the Holley HP EFI setup and can't say enough about how easy it is to tune on the fly. With all the extra programmable inputs/outputs, I've also easily added driveability aids like an IAC kick for shifting in and out of gear. My 540's used to be a little tricky around the docks at low idle, now my wife can operate the boat like it's her car.

I started out keeping my MSD systems, but later found that the Holley DIS (distributorless ignition system) is another step in the right direction and is daily driver reliable... no more MSD box failures. Improved the idle and you can't beat the simplicity of removing the distributor from the spark distribution equation (no more cap and rotor changes).

The other major improvement is the ability to add guardian features. If I ever lose oil pressure, if the ECM detects fuel pressure issues, knock sensor issues, etc.., I can program an immediate automated response (however I want). It takes some of the pressure off driving - I still watch gauges, but I feel better about keeping my eyes on the lake.

Tibbstoy2 - Was that the Holley Dominator system? That is what I am looking at.

he stated holley hp.it is a great unit for marine.the dominator is overkill for performance marine.

but thats how week like to roll. overkill racing.

HP EFI, not the Dominator. I have plenty of spare inputs available and the only advantage of the dominator is extra inputs/outputs beyond what is ever needed in a boat. The dominator has more for fan controls, AC compressor control, stuff like that. The dominator ECM is also a bit larger, harder to mount/hide in the engine compartment.

Thanks for the input.
Did you get it from Haxby?

The last paragraph is where its at!
Wonder what your ROI on the system would be fuel wise. Wish these systems came down in price.

I got my system through Competition Marine Center - they gave me a dealer discount that was pretty good compared to Summit. PM me and I'll give you more information about them.

I didn't really do my change just from an ROI standpoint...

A few years ago, pre EFI - I was starting to have serious plug fouling and cylinder wash down issues even after completely rebuilding my carbs. Whether I went EFI or not, I was replacing my tired mechanical fuel pumps. So the fuel system change is an investment, but not as painful as replacing a good system. The other part that is optional that I upgraded was the distributorless igntion and crank trigger setup. I've had been wanting to go with a crank trigger for a while and get rid of my MSD pro-billet distributor that was rotting inside (cap and rotor every year and it still looked like a biology experiment inside).

My engines in particular ran fantastic carbureted for about 3 years. I ran wideband O2 sensors in my tailpipes to check A/F ratio. Boating in Grand Haven means your idling for almost a half-hour before getting to lake Michigan. In that idle time, I would start the boat having the carbs tuned on the lean side (at idle), by the time the engines were warmed up after a good run on the lake, I'd be coming back with the carbs running slightly rich. In 3 years, this condition was my "happy medium". The boat ran fine and I wasn't going through plugs. A couple years ago, it was getting to the point where my wife would idle us out the channel and I was changing 4 plugs at a time. Obviously an unacceptable scenario. The EFI system was easy to program to account for idle fuel at startup vs, warm-up, vs. fully warmed up. I get ideal A/F ratio at all times (on command). The system has learned well enough by now that the O2 sensors are optional.

The ROI specifically based on fuel consumption is looking around 4-5 years for me. From a budget standpoint, I've spent about half as much money per year with similar usage. That said, I know I'm not burning half the fuel I was!!! The engines were better tuned that that.