Marine Intake

[Supercharged111]

The 80E is rated for less torque. The more I read the more I think the failures are from PWM slip of the torque converter. Get a low mileage unit, change the filter and fluid. Ditch the PWM partial lockup and it should live. My worry is lack of torque management killing it though. I think a newer shift lever would go right on after grinding a flat spot on it, giving tap shift.

I've also heard that, despite its lower rating, the 4L80 holds up better due at least in part to a simpler design. The timing of releasing and applying those clutches is crucial, 2nd overruns 1st but the rest are clutch off/on.

 

[Supercharged111]

@Supercharged111

Also felt like mentioning. I drove this thing with a cold start showing 34F this morning. Never made it hesitate. With any luck the marine intake is tamed. I will say it dumps a ton of fuel though when it is cold. When it is that cold the PCM is dumping as much pulsewidth or more at 1,500-2,500 rpm under half throttle than it does hot, foot on the floor from 3,500-5,500. My open loop air/fuel adder vs coolant vs map table has values as high as 1.75. Actually borrowed the table from a LS6 Vette to richen it up. The L31 values were much lower, 1.30-1.40ish and actually had a spot where they commanded leaner than stoich from GM. Substituting the Vette table really made it happier. Commanded air/fuel ratios are in the 9s and 10s on non ethanol 93 when it is cold. Marine manifold really wants the fuel when it is cold.

Yes it does. Adding some open loop fueling really made mine a lot happier. The 454 doesn't even act the way the marine intake does on the 350.

 

[L31MaxExpress]

Yes it does. Adding some open loop fueling really made mine a lot happier. The 454 doesn't even act the way the marine intake does on the 350.

Imagine feeding a 383 with good heads, lol.

FWIW my 8.1 did not act like the marine on a 350 or 383 either. I looked at the 8.1 transient fueling and the 350 was already higher values than the 8.1L despite its tiny OE injectors.

 

[L31MaxExpress]

WOT 1st gear pull with it fully up to temp. Running a bit sluggish with the fan clutch locked. Fan clutch wiring changes are on the top of the list of things to do now that I know the P59 can fully control the EV Clutch.

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[L31MaxExpress]

Also noticed in this datalog that the PCM did not command any shift torque reduction on this upshift for some reason, despite having already done it several other times and being programmed for a 30% reduction at that torque value. Shifted pretty darn firm under full power.

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[0xDEADBEEF]

I would use the PCS controller. I do not want to go back to CNP. My van eats those coils for breakfast, lunch and dinner.

Can you get the tow-haul mode with that controller? I found there was no need for the manual mode while towing.

You could relocate the coils.

 

[L31MaxExpress]

Can you get the tow-haul mode with that controller? I found there was no need for the manual mode while towing.

You could relocate the coils.

I do not know if it can access the OEM calibration. However it can apparently be programmed for up to 3 shift patterns including lockup patterns. If that is the case.

1. Normal
2. Tow/Haul or Haul A$$
3. Economy/Rain/Snow

I would have a 3rd map with the shifts tamed way back and keeping the converter locked most of the time. Idea would be to reduce rpm and torque multiplcation in situations that did not need more aggressive shifting.

I have also discovered that it is possible to use the 8L90E stand alone as well. Not sure if I would go with the 6L90E or the 8L90E. The 8L90 has an impressive ratio spread. First gear is approaching what my M56S had and my mom's 2019 Titan has. A 4.78 first gear makes for a strong launch and that was in a car that had a 2.62:1 rear gear.

 

[Supercharged111]

The 8 speeds seem more hit and miss than the 6 or 10, don't they?

 

[L31MaxExpress]

The 8 speeds seem more hit and miss than the 6 or 10, don't they?

Well I looked at a gearing calculator. An 8 spd, in normal driving with a 3.73 gear and a 30.5" tall tire, shifting at 2,000 rpm the shifts would look like this.

1-2 @ 11 mph
2-3 @ 16 mph
3-4 @ 22 mph

I have enough grunt that the extra 2 gears probably would not really be worth much compared to a 6L90E.

I am not sure why some people are saying a diesel 6L90E will not work behind a SBC. My understanding is that a Duramax has the same flexplate spacing relative to the bellhousing as a Gen1 engine and the converter pattern is the same as a 4L80E. For some reason it seems that the 6L80E requires a spacer or custom converter. More research needed.

 

[0xDEADBEEF]

I think the ZF 8 speed is the best of the >6 speed automatics. I liked it a lot better than Ford 10 speed although that may be down to programming.

I know someone makes an adapter for ZF to the LS.