Carb to EFI

[Alex-Bravo3]

Hi everybody, I m new, it is very nice to be here.
I want to convert a GM 454 bigblock with a Edelbrock carb to EFI
For a Mercruise Bravo3 with this engine I saw FAST, EFISYS, Howell,
with O2 sensor on a bung or O2 sensor on a plate...
Does anybody have any experience with this issue ?
Any tip will be highly appreciated. Thank you.

P.S.: I called Edelbrock, they said they dont do Marine EFI because of the wet exhauts.

 

[scoflaw]

Your going to need a lot of parts for that conversion. Forget about the O2, nothing but trouble.

 

[thumpar]

You need a marine setup not something for auto. Best solution would be getting all the parts from a donor merc. It is not going to be easy or cheap.

 

[Scott Danforth]

first question...... why?
EFI doesnt offer any more power (its actually less power)
EFI doesnt offer any better fuel economy
EFI does idle better when cold when you first start it.
EFI will require you to change the cam when going from carb to EFI.
aftermarket EFI is crazy expensive

best and cheapest way to add EFI to your boat is to sell your boat and buy what you want.

 

[Alex-Bravo3]

Hi all / tks

Scott, I thought it was gonna be better in all the aspect you mentioned.

My GM has an Edelbrock, time to time the carburator gets dirty with a kind of glue (lacquer like)
I was told it is because gas comes with bioalcohol and when you leave gas in the tanks for a couples of month
it gets decomposed (or something like that) and everythinh ends in a sticky mess.
I guess valves won't be free of it because EFI and injectors may be dirty as well.

 

[Bt Doctur]

Happens the same way to injectors, no salvation there

 

[Scott Danforth]

not to mention you can fix a carb on the water with basic tools. EFI requires a shop.

if you want the fuel to quit gumming up.....use the boat more often.

 

[thumpar]

I will say EFI is much better when it comes to starting. It is a no brainer. Turn the key is all, cold or warm. The maintenance, or lack of, is nice too. That’s about it. Given the choice I will stick with EFI but I would not pay to convert over.

 

[bman440440]

here is my 2c.... take it for what its worth.... my buddy put this system on his 7.4
----> https://www.ebay.com/itm/EFI-Comple...264826?hash=item4b193228ba:g:laQAAOSwtPhZivVd

he had a great running engine before with the carb... great power and great fuel economy (for a marine 7.4)... after the system was installed it was amazing that it could run even better but it did... great starting cold or hot and better (at least by seat of the pants feel) low and midrange power... as well as a SLIGHT increase in milage... the one thing that did happen he did lose 1 MPH off the top end... but the improvements everywhere else was well worth it.

 

[achris]

AND you get a free hat or tee-shirt.

 

[Alex-Bravo3]

https://www.ebay.com/itm/EFI-Complet...QAAOSwtPhZivVd
Your buddy installed it in a boat, right ?
It is two barrels, not four, is that OK ?
I dont care loosing a little bit of power,
I really would like efficient starting, which is said is ok.
and overall "fuel economy". Does it save fuel ?
It comes without LCD, is it needed or udefull ?

Regard gumming, does anybody know a way to prevent it appart from using the boat more often ?
I bought Liqui Moly gas stabilisator and carb cleaner, but I haven't tried yet cause my engine was under reparations.

 

[thumpar]

Throttle Body Injection uses 2 barrels. They don't need 4 like a carb. It is like a marine version of the system GM had on their trucks in the mid 90's. For EFI is it pretty basic and in the auto version has been used in millions of vehicles.

Personally I have found carbs will gum up but I haven't run into it with EFI. Carbs have a bowl that sits with fuel in it. That bowl can dry out if it sits. EFI systems don't need that bowl of fuel. The entire EFI fuel system is sealed and only open to air at the injector tip. You will hear others recommend it but I don't treat my fuel with anything, even over winter. I use top tier fuel.

 

[TurtleTamer]

That system was just about bulletproof in cars and trucks, but they are more complicated than a carb with more potential points of failure. Great in a car that you'd drive every day with the better mileage and starting but in a boat I'd stick to carb. You can't just pull over and hitch a ride to the parts store or wait for assistance from AAA and if you lose power over a bad temp sensor in rough seas it could get ugly real quick.

 

[alldodge]

Holley has some stuff which many have used building large power in boats, but they are not USCG certified. Tegue has this

https://teaguecustommarine.com/em0011/commander-950-1000-cfm.html

but you need to be able to program your own ECU and most use the MEFI-3 and 4

You can also get a TBI or MPI harness and parts for a MEFI 3 or 4 and then get MEFIBurn software and reprogram it to suit your needs. Can also get a stock 454 MPI setup and install on yours, just need 502 heads and intake plenum

 

[Bondo]

Ayuh,..... I Love the AFB carbs, 'n personally think convertin' to any Efi is the biggest waste of money possible,....

Unless yer swappin' in a take-out motor from another ole barge, that already has a runnin' Efi on it,....

The only Plus side is it allows unknowin' unexperienced operators to start the motor, no matter what,....
'n that ain't always a Good thing,.....

 

[bman440440]

https://www.ebay.com/itm/EFI-Complet...QAAOSwtPhZivVd
Your buddy installed it in a boat, right ?
It is two barrels, not four, is that OK ?
I dont care loosing a little bit of power,
I really would like efficient starting, which is said is ok.
and overall "fuel economy". Does it save fuel ?
It comes without LCD, is it needed or udefull ?

Regard gumming, does anybody know a way to prevent it appart from using the boat more often ?
I bought Liqui Moly gas stabilisator and carb cleaner, but I haven't tried yet cause my engine was under reparations.

1st yes on a boat
2nd yes its ok
3rd he got more power threw 99% of the RPM range... just lost 1 MPH off the top end
4th it starts great every time now hot or cold
5th yes he got slightly better mileage... he has a big heavy boat and was getting 1.2 MPG and it went to almost 1.4 MPG
6th... what LCD are you talking about??

 

[Alex-Bravo3]

Holley, Howell and other EFI brands come with a hand held LCD screen