Like Tree1Likes
  • 1 Post By Griff

2015 Mercruiser 377 MPI Tuning? Changing Rocker arms?

Reply
Old 10-09-2017, 03:31 PM
  #1
Registered
Thread Starter
 
Join Date: Jan 2015
Location: Germany
My Boats: Wellcraft Nova II
Posts: 19
Default 2015 Mercruiser 377 MPI Tuning? Changing Rocker arms?

Hello,
I have two Mercruiser 377 Mag Mpi in my boat with imco Powerflow exhaust from 2015
Gived it opinium with little tuning this engine?

Can i change the rocker arms, from steel arm 1,5 to full rocker with 1,6 ratio? Will this work?
Or must i programming than my pcm?

Thanks
Patrick
nova2_excalibur is offline  
Reply With Quote
Old 10-09-2017, 09:57 PM
  #2
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha
My Boats: .......32............. ...............Active Thunder....
Posts: 15,710
Default

It is essentially the same as going to slightly larger cam.
I don't think you will see any significant gains in power. Maybe 10-15 hp at most which equals about 1 mph.

Most likely you would need to have the ECM tuned. If you installed a wide band O2 sensor and guage, you could check the readings.

Do you have a PCM555 or MEFI ???
Griff is offline  
Reply With Quote
Old 10-10-2017, 02:05 AM
  #3
Registered
Thread Starter
 
Join Date: Jan 2015
Location: Germany
My Boats: Wellcraft Nova II
Posts: 19
Default

Okay, i have a pcm555
nova2_excalibur is offline  
Reply With Quote
Old 10-10-2017, 02:49 AM
  #4
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha
My Boats: .......32............. ...............Active Thunder....
Posts: 15,710
Default

Quote:
Originally Posted by nova2_excalibur View Post
Okay, i have a pcm555
I'm pretty sure the only one who can even custom tune a PCM555 is Whipple. I would just leave the engines stock..
Ryan00TJ likes this.
Griff is offline  
Reply With Quote
Old 10-10-2017, 03:02 PM
  #5
BUP
Registered
Trade Score: (6)
 
Join Date: Jul 2011
Location: Ft. Worth TX
My Boats: 2017 - 29 Laveycraft Custom Build & SHE's Going to be a Bad Boy. www.laveycraft.com
Posts: 6,761
Default

He will have ECM 555

PCM 555 was for the 496 Mercruiser Non Cat engines

Last edited by BUP; 10-10-2017 at 03:08 PM.
BUP is offline  
Reply With Quote
Old 10-10-2017, 03:07 PM
  #6
BUP
Registered
Trade Score: (6)
 
Join Date: Jul 2011
Location: Ft. Worth TX
My Boats: 2017 - 29 Laveycraft Custom Build & SHE's Going to be a Bad Boy. www.laveycraft.com
Posts: 6,761
Default

Correct not worth doing anything to these stock 6.2 MPI and down MERC engines. one is longevity can be comprised and really sometimes no performance are gained either after all that time, effort and money.

I would play with props and take weight out of the boat if all possible. A very Clean bottom and clean water to the prop(s) plus a very straight skeg also helps as well.
BUP is offline  
Reply With Quote
Old 10-10-2017, 04:11 PM
  #7
Registered
Thread Starter
 
Join Date: Jan 2015
Location: Germany
My Boats: Wellcraft Nova II
Posts: 19
Default

Thanks to all. I Think the Stock Engines is than the best..
nova2_excalibur is offline  
Reply With Quote
Reply



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 07:13 AM.


Copyright 2011 OffShoreOnly. All rights reserved.