4.3 to Fuel Injection mercruiser conversion.
11-28-2005, 08:41 PM
#1
How do I change this text
Thread Starter
iTrader: (26)
Join Date: Jan 2005
Location: Behind the TIG welder
Posts: 7,279
Likes: 0
Received 0 Likes
on
0 Posts
4.3 to Fuel Injection mercruiser conversion. I just bought a a Tahoe bout with a 4.3L I want to do a Fuel injection conversion on it anyone got any ideas where to start or if it even worth it? The boat is brand new so I'd like to stay away from engine removel (sp). I have HPtuner (if that helps) would any ECM run it, or how does the vortec 4.3 MPI work.
Thanks for any input .
Thanks for any input .
11-29-2005, 09:00 AM
#2
TECH Resident
You need to consider the whole MPI setup for a 4.3 from a wrecking yard, from a late model (2000-2001) old style s-10 blazer or pickup, utilizing the upgraded MPI setup that has the "mini injectors" at the port ends of the tubes. These run really well and should make a good conversion. I've seen several done on older 4.3 V-6s.
11-30-2005, 10:18 AM
#5
How do I change this text
Thread Starter
iTrader: (26)
Join Date: Jan 2005
Location: Behind the TIG welder
Posts: 7,279
Likes: 0
Received 0 Likes
on
0 Posts
I'm in Reno, lts10, have you done/seen this conversion in a boat before? and are the 4.3l marine blocks the same as the ones chevy uses in there pickups?
Oscar Will, So what about 02 sensors? and all other sensors for that matter? will the ones off 00-01 s10 work in the block?
Oscar Will, So what about 02 sensors? and all other sensors for that matter? will the ones off 00-01 s10 work in the block?
12-05-2005, 11:02 AM
#7
TECH Resident
Join Date: Dec 2004
Location: Baltimore, MD.
Posts: 841
Likes: 0
Received 0 Likes
on
0 Posts
I've got a couple of thoughts / questions....
1.) Why switch to EFI? Is there a particular problem you're trying to solve?
2.) The MPFI system GM uses on the 4.3l has limited fueling capability. It does not use replaceable injectors, instead using what is referred to as a "spider". Basically, its 1 main injector assembly with 6 hoses & nozzles. In order to get more fuel, you have to jack up the pressure and injector duty cycles (and you still max out around 270 to 300 hp MAX). So, keep that in mind.
3.) The coast guard has a bunch of requirements that you're supposed to meet. Flash suppression, special treatment of alternators, starters, etc. I'm sure EFI equipment needs some special treatment, just don't know what.
4.) Have you though about how you'd provide high pressure fuel to the fuel rail? Depending upon your fuel tank shape, you may need to have 2 fuel pumps, a low pressure pump to push fuel to a canister that contains some fuel (maybe 2 or 3 quarts) and a high pressure pump. That way, as fuel sloshes around in the tank when you get low on fuel, you don't have stalling / fuel starvation issues.
Personally, it seems like a fair bit of work for very little potential reward. I don't think you'll see a significant performance advantage out of it. It might idle a little better, maybe burn a little less gas, and done right might tolerate bumps a little better.
'JustDreamin'
1.) Why switch to EFI? Is there a particular problem you're trying to solve?
2.) The MPFI system GM uses on the 4.3l has limited fueling capability. It does not use replaceable injectors, instead using what is referred to as a "spider". Basically, its 1 main injector assembly with 6 hoses & nozzles. In order to get more fuel, you have to jack up the pressure and injector duty cycles (and you still max out around 270 to 300 hp MAX). So, keep that in mind.
3.) The coast guard has a bunch of requirements that you're supposed to meet. Flash suppression, special treatment of alternators, starters, etc. I'm sure EFI equipment needs some special treatment, just don't know what.
4.) Have you though about how you'd provide high pressure fuel to the fuel rail? Depending upon your fuel tank shape, you may need to have 2 fuel pumps, a low pressure pump to push fuel to a canister that contains some fuel (maybe 2 or 3 quarts) and a high pressure pump. That way, as fuel sloshes around in the tank when you get low on fuel, you don't have stalling / fuel starvation issues.
Personally, it seems like a fair bit of work for very little potential reward. I don't think you'll see a significant performance advantage out of it. It might idle a little better, maybe burn a little less gas, and done right might tolerate bumps a little better.
'JustDreamin'
Trending Topics
12-05-2005, 12:51 PM
#8
How do I change this text
Thread Starter
iTrader: (26)
Join Date: Jan 2005
Location: Behind the TIG welder
Posts: 7,279
Likes: 0
Received 0 Likes
on
0 Posts
I did'nt think of the fuel tank proble,. The boat comes with MPI or a carb. so I thought the tank would be fine, but if it is different, you are right I don't think it would be worth it. I guess I need to know everything that is different between a MPI boat and a carb boat.
The only reasons I want MPI is the better perfomance, altitude compinsating (sp), and because I can't leave anything alone.
The only reasons I want MPI is the better perfomance, altitude compinsating (sp), and because I can't leave anything alone.
12-05-2005, 03:28 PM
#9
TECH Resident
Join Date: Dec 2004
Location: Baltimore, MD.
Posts: 841
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Wilde Racing
The only reasons I want MPI is the better perfomance, altitude compensation, and because I can't leave anything alone.
I doubt that a 30hp power gain (220hp for the MPI, 190hp for the carb) is made strictly through the use of MPI over the carb. A good carb setup should make just as much power as an EFI setup. I'd check to make certain that the cylinder heads don't change (later model Vortec heads are light years better than the older stuff and make a considerable bit more power) between the two. Because if they did, you'd need to swap them too in order to pick up the extra ponies.
'JustDreamin'
12-05-2005, 04:01 PM
#10
TECH Resident
Just a side note on this. I installed a better cam and heads (late model Vortec) with a good intake and carb on my old 4.3 V-6........instead of fuel injection, it would outrun alot of V-8s.
12-06-2005, 12:41 PM
#12
TECH Resident
When I mentioned the MPI setup I wasn't referrring to the old "spider" setup, it has been replaced by a central fuel block, tubes to each port and little tiny electronic injectors at each port. This setup is being retrofitted into the 1996-2001 4.3 V-6 and the "R" 350 (old style) V-8s. In California it's being done by GM as a "Special Policy". This new system works very well, and I suppose it would be the best conversion if you were looking for "off the shelf" parts. At least it has individual injectors and decent fuel control.
