383 mpi package

[Dream Wet]

Trying to do some serious research on repower options before making a choice.Has anyone heard or know of any pros or cons on the fairly new program from Merc.I am replacing a tired 1988 350 mag 270 hp.alpha 1. will go to bravo 1 with change. Thanks in advance foor your time. Rory

 

[QC]

Re: 383 mpi package

Well I have the 377 (6.2MX 320) which is the new version of that repower platform. I believe the 383 is a bored over version. I love it. Strong as an Ox and I run the snot out of it. I cruise it above 4000 RPM most of time and it'll pull 5200 as it is propped right now. It doesn't use any oil and I have 325 hours on it. I've changed the plugs and dist. cap once, never touched anything else on the engine but pump impeller, filters and oil.

 

[HT32BSX115]

Re: 383 mpi package

If you have a 270hp now, the 320 hp 383 would run pretty good. It'll have to be EFI to get that HP though. It doesn't appear that you can get that sort of HP out of a small block with a carb unless you do a little supercharging.

I'm replacing a 460 OMC King Cobra with a '97 454/Bravo III combo.

I've had more than one person tell me that "there is NO substitute for cubic inches"!



Regards,

Rick

 

[180shabah]

Re: 383 mpi package

It doesn't appear that you can get that sort of HP out of a small block with a carb unless you do a little supercharging.

Sort of true.

Mercruiser and Volvo Penta do not use carbs on thier 300hp + engines. That decision is pure marketing and does not mean it is not possible. The biggest reason for the difference in power between the carb and EFI engines has nothing to do with the EFI it's self. It is mostly a function of intake efficiency. One of the newer Vortec engines would have no problem making 300+ HP using a 4bbl carb a good intake manifold.

Cheaper too!

 

[QC]

Re: 383 mpi package

Mercruiser and Volvo Penta do not use carbs on thier 300hp + engines. That decision is pure marketing

Sorta true They also use MPI on the V6 and 5.0 260 bhp. Also, there are other benefits to MPI than marketing. Like better starting, troubleshooting, warm-up strategies, sexy timing stuff, fuel economy (can't guarantee which hole the fuel goes down with a carb . . . ), closed loop knock sensing stuff, closed loop O2 sensors, and ultimately emissions tweaking is very much enhanced by MPI.

 

[180shabah]

Re: 383 mpi package

Didn't mean to come accross as "anti-EFI" just wanted to let him know that it was possible to get the same kind of power without paying the $1500-$2000 premium of an injection system.

I know there will be a difference in emmissions, and economy will be slightly lower( 5-10% is not nearly as noticable at 3mpg as it is at 30mpg)

I have never had a boat with one, but doesn't the TB V system incorporate a knock sensor?

Most starting problems are either poor/no maintainence or incorrect procedure. Mine starts on the first try(if I remeber to out the @%^$ saftey lanyard in) 15 seconds or so at fast idle and she's ready to go( usually before I am). It is not as simple as turn the key and out it in gear, but not exactly the end of the world either.

As for the 260hp 5.0, there are a few 4.3's out there (in boats) that are making that power reliably with carbs. Mine will be getting the buildup soon, there is not much too it(Cam, intake manifold and Vortec heads)

One last comment, I love your signature QC.

My boat used to have a stingray on it, and it was downright scary at speed. It created too much stern lift forcing the bow down, made steering very twitchy. I took it off, so there is more bow rise when planing, but handling is much more stable now.