Aftermarket EFI

[Viper]

For the benefit of others that have reached the same conclusions as yourself, document the conversion on a new thread with pictures. It'll be a good place for folks to see what's involved. They'll appreciate hardware sources, costs, test results, etc. Should be a fun project. Keep us posted.

[tomschauer]

I have never tried it, but I would think a 1980's gm TBI set up could be easily adapted to use on the 350 motors. very simple computer and I think only two sensors. Should be super cheap at a local salvage yard.

[bud37]

Qr Bbpost I have never tried it, but I would think a 1980's gm TBI set up could be easily adapted to use on the 350 motors. very simple computer and I think only two sensors. Should be super cheap at a local salvage yard.

Interesting, but for me the same question, what do you do with the o2 sensor? Have an idea that maybe that was the problem to overcome for them in the first place..

[Viper]

Qr Bbpost I have never tried it, but I would think a 1980's gm TBI set up could be easily adapted to use on the 350 motors. very simple computer and I think only two sensors. Should be super cheap at a local salvage yard.

I trust you mean marine salvage yard otherwise the reference data/table will not suite a marine application.

[Viper]

Qr Bbpost

Qr Bbpost I have never tried it, but I would think a 1980's gm TBI set up could be easily adapted to use on the 350 motors. very simple computer and I think only two sensors. Should be super cheap at a local salvage yard.

Interesting, but for me the same question, what do you do with the o2 sensor? Have an idea that maybe that was the problem to overcome for them in the first place..

If it were off a marine application you wouldn't have to worry about O2 sensors until a much more recent vintage as they didn't get incorporated into marine use until recently with the introduction of catalyst engines. If you go with a new EFI retrofit that incorporates O2 sensors on a non catalyst engine, you'd have to turn the O2 input/option off or the engine will run in with default parameters.

[bud37]

Exactly.....the problem as I see it ,is when trying to convert auto to marine...you gotta have some way to trim the mixture other than mapping.....it seems it has taken quite some time for the marine sector to come up with a cost effective dry O2 sensor installation on a wet exhaust.....next question would be , when a boat is now refitted( up-dated ), do you have to comply with the new regs as far as pollution control goes like the hot rod side in some areas????......

[Viper]

It's not that the marine sector couldn't come up with a way, they simply weren't required to until recently but that's not yet the case in our neck of the woods. The exhaust doesn't get wet until the elbow so plenty of room to install O2 sensors in dry sections of the exhaust. The catalyst manifolds are designed differently but basically the same principle applies.

[bud37]

I wonder if the sensor would be far enough away from the wet section to avoid reversion problems.I still think any retrofit would need a special design manifold to be efficient if you want to use the o2 trim effectively.

[dcrahn]

Water reversion can be a death sentence for an o2 sensor, so placement has to be carefully considered. Another problem is that camshaft overlap can play a big part in water reversion, so cam selection needs to carefully considered for your application. Being a retired Sr. Master Craftsman for a prominent cooperate aircraft company and a car fabricator for better part of 42 years, I have and idea I'm working on to eliminate that problem. I can't say anything now until I test and verify and if it works then apply for a patent. I've been bitten before about posting ideas on forums and have learned my lesson.

Big companies do cruise the web looking for other peoples ideas. Years ago I came up with an idea for drag cars and posted photos on a forum to help other drag racers. Several months later a friend contacted me and said, "Doug you need to go on so and so's web page, they took you idea and now offering it to the public". Never again!

[bud37]

Yes, a very real problem....there were some engine assembly techniques I used to minimize that problem, worked on the intake side but with these marine exhausts you are kind of limited with the distance from the last exhaust valve. Hey, good luck with it and keep it quiet this time........