2010 VLX- 350 to 383..

[mgb1974]

22 hours ago, justgary said:

It isn't lost power you should worry about.  I would think that running lean would risk burning a piston or rubbing it dry against a cylinder wall.  If you are running lean and getting away with it, maybe it is only in a part of the throttle range where you just don't run the engine much. 

I would think it is worth either flashing the ECM or raising the fuel pressure to make sure you aren't lean.

I have diacom and I was monitoring it the first season.  The boat seems to run on the richer side. I also flow checked all my injectors before reinstalling them. 

I think I’m over 200 hours on the motor. 
 

 

[LXRBarefooter]

Running lean is a pretty big concern of mine. Did you have to increase your fuel rail pressures @mgb1974

I barefoot a lot, before I bought my boat I spent a long time looking for a 409 LXR, but they’re almost non existent here in Australia. I was talking to Malibu Aus about a TXR with a M6di, but they canned the production line before I put an order in. Long story short I ended up with a 2014 LXR with low hours and a Monsoon 350 in it instead.
 

With a 449 prop it maxes out at 4800rpm and 47mph, but with me footing it is running at WOT, and a fair bit slower than that. Dropping a 400 or 450hp 383 long block in would be unreal, the extra power would also let me run a 425 prop, which is better for barefooting. 
 

@Brap20 I’ve spoken to John Todd at Indmar and it sounds like the 2014 E-Controls ECU is not compatible with the Hammerhead tune (from the E-Control ECU circa 2009), which is disappointing because they both have the extcat style exhaust and O2 sensors, and the 2014 350 Monsoon has an improved intake and fuel system over the 2009 340 Monsoon and 383 Hammerhead. What year was your ECU?

Edited February 4 by LXRBarefooter
Tagged people.

[Woodski]

@LXRBarefooter - More important than the added displacement to provide the power you are looking for so WOT is not mandatory for footing speeds is the added airflow via camshaft change.  A GM ZZ4 cam + a set of GM fast burn heads will wake things up nicely.  That does the hardware side.  Fuel delivery can be a challenge depending on what components you have to trigger the injectors.  Add in 383 ci and the 425 prop works great.

[LXRBarefooter]

Yep that’s right Woodski, the extra power and tq will let me run a 425, thus bringing the engine rpm for a given speed down. But it will give me the overhead to run the motor harder if we foot two up, or with more people/fuel in the boat. 
 

I’ve followed your 350 build with the ZZ4 cam and fastburn heads, and it’s a nice build. Not sure how it would work out with the stock ecu tune for the vortec heads and tamer cam.  
 

Oh the joys on Indmar E-Controls ECUs locked down harder than Fort Knox. If someone opened them up and made them tuneable they’d have a monopoly for sure. 

Edited February 3 by LXRBarefooter

[Woodski]

The whole marine ECU business model for us tinkerers is really annoying.  There is so much available on the automotive / hot rod market which makes it more annoying.  Perhaps an ECU conversion to a MEFI unit is an option.  Or a good old fashion carburetor 😂

My little Echy loafs along dragging me around the lake at 41, half throttle does it.  I would guess 3 footers would be a WOT event.  36 mph / 58 kph is 3250 rpm.  My boat is light, so that helps.

[Nick55]

@LXRBarefooter, I know you’re down under, but may be worth talking to these guys about the ECU tuning.  I have a hard time believing a Delco ECM (unless I’m wrong and it’s not a Delco) is locked to the point it can’t be tuned.  There may be a matter where the hammerhead tune can’t simply be “placed” on the ECM but a tuner should be able to look at both map and match it up on your ECM.  
 

https://obd2allinone.com/mefituning.asp

[LXRBarefooter]

14 hours ago, Nick55 said:

@LXRBarefooter, I know you’re down under, but may be worth talking to these guys about the ECU tuning.  I have a hard time believing a Delco ECM (unless I’m wrong and it’s not a Delco) is locked to the point it can’t be tuned.  There may be a matter where the hammerhead tune can’t simply be “placed” on the ECM but a tuner should be able to look at both map and match it up on your ECM.  
 

https://obd2allinone.com/mefituning.asp

@Nick55 My understanding is that MEFIBurn from OBD Online is compatible up to MEFI 6, but not the newer E-Controls ECU. More than happy to be proven wrong. Last time I spoke to Bob he hadn’t opened up the single plug ECMs.

Edited February 4 by LXRBarefooter
Tagged Nick55

[justgary]

2 hours ago, LXRBarefooter said:

My understanding is that MEFIBurn from OBD Online is compatible up to MEFI 6, but not the newer E-Controls ECU. More than happy to be proven wrong. 

What year engine do you have?

[LXRBarefooter]

6 minutes ago, justgary said:

What year engine do you have?

It’s a 2014 Monsoon 350ss (with the new style black and red intake), fundamentally it’s the same block as OPs 340 Monsoon hence why I chimed in to see how he went after a few seasons. 

[justgary]

6 minutes ago, LXRBarefooter said:

It’s a 2014 Monsoon 350ss (with the new style black and red intake), fundamentally it’s the same block as OPs 340 Monsoon hence why I chimed in to see how he went after a few seasons. 

Thanks.

I would think that bumping up your fuel pressure by the ratio of new to old displacement should take you a long way toward success.  383/350 = 9.4% more displacement.

On the other hand, a 2014 in here the states would have O2 sensors.  If you indeed have O2 sensors, I would think that your ECM would learn the values you need to fuel your new displacement fairly quickly.  10% extra fuel should be within the range available, but I am guessing about that.

[LXRBarefooter]

5 hours ago, justgary said:

Thanks.

I would think that bumping up your fuel pressure by the ratio of new to old displacement should take you a long way toward success.  383/350 = 9.4% more displacement.

On the other hand, a 2014 in here the states would have O2 sensors.  If you indeed have O2 sensors, I would think that your ECM would learn the values you need to fuel your new displacement fairly quickly.  10% extra fuel should be within the range available, but I am guessing about that.

@justgary I’m hoping for a solution that is closer to ‘factory’ per se. The plan is to either get a SP383 crate engine or have a local engine builder build a 383 that’s close to the same spec (ideally a little warmer).

Both of these engines should be close enough to the factory hammerhead tune for the ECM to work. I’ve still got the ETXCAT Exhaust manifolds and O2 sensors etc for AFR adjustments with the closed loop ECM (same as @mgb1974 and @Brap20).

I’d prefer not to ‘cheat’ the system by just bumping fuel rail pressure, but if I can’t load the Hamerhead tune it may be my only option, it’s also an option if for what ever reason the Hamerhead tune is too lean. 

 

[justgary]

8 hours ago, LXRBarefooter said:

@justgary I’m hoping for a solution that is closer to ‘factory’ per se. The plan is to either get a SP383 crate engine or have a local engine builder build a 383 that’s close to the same spec (ideally a little warmer).

Both of these engines should be close enough to the factory hammerhead tune for the ECM to work. I’ve still got the ETXCAT Exhaust manifolds and O2 sensors etc for AFR adjustments with the closed loop ECM (same as @mgb1974 and @Brap20).

I’d prefer not to ‘cheat’ the system by just bumping fuel rail pressure, but if I can’t load the Hamerhead tune it may be my only option, it’s also an option if for what ever reason the Hamerhead tune is too lean.

The "factory" solution is how I would go as well if possible.  Some of my comments were based on remembering that at least one of the people here that tried it had an older open loop MEFI system.  I just went back and reviewed the thread and saw that the unit was reflashed with the Hammerhead tune. 

It does look like @mgb1974 has shown that the e-Controls ECM does have plenty of capacity to learn the new injector map needed to fuel the 383.  He did not yet specifically state that he did or did not increase the fuel pressure.

[mgb1974]

On 2/4/2024 at 11:00 AM, justgary said:

The "factory" solution is how I would go as well if possible.  Some of my comments were based on remembering that at least one of the people here that tried it had an older open loop MEFI system.  I just went back and reviewed the thread and saw that the unit was reflashed with the Hammerhead tune. 

It does look like @mgb1974 has shown that the e-Controls ECM does have plenty of capacity to learn the new injector map needed to fuel the 383.  He did not yet specifically state that he did or did not increase the fuel pressure.

Sorry for the delay in posting a replay, I did not mess with fuel pressure(In the end changed nothing). I took the approach of engine swap and monitoring it to see what I need to do. From my past of messing with 5.0 Mustangs I thought I would be ok. 

If I had knocking(Pre-ignition) or lean conditions I would then make changes.