LMTV power increase

[Smike740]

Hello,

I searched and found a few threads but nothing with all the details.

I am looking to increase the HP of my Cat 3116 powered LMTV.

The engine is currently rated at 225HP and I want to upgrade to the 290HP level of the FMTV.

I did some comparison of the parts manuals etc between the two engines and have found the difference in parts are the turbo and governor.

The turbo for the 290 HP version is part number 4R-8915, I was able to find a NOS one for a good price.

The Governor is basically the same between the two HP ratings with the exception of the Torque cam and Control AS ratio.

The way I understand it the Control AS ratio retards the fuel rack under low boost pressure and the torque cam adjusts the fuel rack movement under load, as I am not a diesel mechanic I may be wrong.

The fuel setting for the 290hp is a bit higher and the injector timing dimension only slightly different, the details can be found on the engine spec plate.

I plan to install the bigger turbo soon and make the corresponding fuel and timing adjustments per the spec plate for a 3116 with 290HP.

I am still considering whether the governor parts need changed and or any governor adjustment is needed.

Some sources advise to adjust the governor air ratio screw out a turn.

If anyone here has advise regarding the governor needing changed/ adjusted I would appreciate it.

I plan to install a boost gauge and pyro before the turbo swap.

 

[wheelspinner]

I did just this on mine. No change to the governor parts, but we did take the android valve out of the equation. Turbo change and fuel pressure/timing was all that was needed. And it is SO worth it. Huge difference!

 

[Smike740]

Hi Wheelspinner,

Thanks for the feedback, I am happy to hear the governor doesn't need adjusted.

The android valve you are referring to is it the valve on the governor that has the line that runs to the front top of the engine which senses the intake boost pressure?
Did you just disconnect the line and plug the port on the manifold.

 

[wheelspinner]

Hi Wheelspinner,

Thanks for the feedback, I am happy to hear the governor doesn't need adjusted.

The android valve you are referring to is it the valve on the governor that has the line that runs to the front top of the engine which senses the intake boost pressure?
Did you just disconnect the line and plug the port on the manifold.

That's the valve. Honestly the internal workings are just voodoo to me. I have a local independent shop that specializes in CAT and the only thing he told me was that he had the tool to remove it from the loop. All it does is retard the fuel pressure until the boost is there. If I hit the throttle hard it blows some smoke. I would worry about that last. Get the rest done, you will love it.

 

[Smike740]

Thanks again, I can't wait to getting the turbo swapped. High speed gears will be next.

 

[Awesomeness]

I put a 290HP engine in mine, and the difference is subtle at best, definitely nothing I would describe as "SO worth it". I pretty much forget it's in there. Basically, you can go up slightly steeper hills without it downshifting into 6th. Depending on how much the parts cost you, and how many other things your truck needs worked on, this is an upgrade I would recommend waiting on until last (after stuff like new air dryer, high speed gears, etc.).

There's no downside to doing it, there just isn't much reward for the effort either. I did it "by accident" - I had to swap out a broken engine and the one I found was 290HP - but if I bought another LMTV I wouldn't even bother looking into making it 290HP. It's still a big slow truck, and the engine upgrade didn't change that at all.

If you do it though, it would help others if you can whip up a clear How-To on exactly what parts (part numbers) you need, and the process, to complete the job.

 

[scottmandu]

4 turns of the rack limiting screw and a custom S300 turbo capable of flowing enough air for about 700hp and my 3116 screams. I also put some of the 3.07 gears in it and will surprise people when the stop light turns green.

 

[coachgeo]

4 turns of the rack limiting screw and a custom S300 turbo capable of flowing enough air for about 700hp and my 3116 screams. I also put some of the 3.07 gears in it and will surprise people when the stop light turns green.

Have you driven it enough to be able to do a comparison on MPG with OEM set up?

 

[Smike740]

4 turns of the rack limiting screw and a custom S300 turbo capable of flowing enough air for about 700hp and my 3116 screams. I also put some of the 3.07 gears in it and will surprise people when the stop light turns green.

Sound like a nice setup, any idea on the HP you are achieving? I would expect with the fuel turned up that much a significant increase. Did you need to also make any changes on the governor?

 

[scottmandu]

Have you driven it enough to be able to do a comparison on MPG with OEM set up?

Seems to get similar MPG which is dismal.

Sound like a nice setup, any idea on the HP you are achieving? I would expect with the fuel turned up that much a significant increase. Did you need to also make any changes on the governor?

I had to back off the idle screw almost to the stop.

 

[Aernan]

4 turns of the rack limiting screw and a custom S300 turbo capable of flowing enough air for about 700hp and my 3116 screams. I also put some of the 3.07 gears in it and will surprise people when the stop light turns green.

Can you share any info on the custom turbo?

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[wandering neurons]

The turbo and the "android valve" and the mods to that please!

 

[scottmandu]

Can you share any info on the custom turbo?
Sent from my SAMSUNG-SM-G930A using Tapatalk

Not yet.. I'd like to get some miles on it.

 

[Smike740]

Ok I have attached a couple of pages showing how the governor works. I believe what is being called the “android valve” is called the fuel ratio control and is #3 in the attached pic.

The purpose of the fuel ratio control is to limit the fuel under low boost conditions.

If I understand correctly as boost pressure increases the plunger of the fuel ratio control moves to the right allowing the output shaft to move further to the right thus allowing more rack travel and more fuel.

Backing out the FRC setscrew #8 will add more fuel, not sure how much it should be backed out if using the 290 hp turbo.

Probably best to adjust 1/2 to 1 turn at a time and then confirm the EGT is not too high.

 

[wandering neurons]

Thanks for the info, something to add to potential mods on my truck!

Ok I have attached a couple of pages showing how the governor works. I believe what is being called the “android valve” is called the fuel ratio control and is #3 in the attached pic.

The purpose of the fuel ratio control is to limit the fuel under low boost conditions.

If I understand correctly as boost pressure increases the plunger of the fuel ratio control moves to the right allowing the output shaft to move further to the right thus allowing more rack travel and more fuel.

Backing out the FRC setscrew #8 will add more fuel, not sure how much it should be backed out if using the 290 hp turbo.

Probably best to adjust 1/2 to 1 turn at a time and then confirm the EGT is not too high.

 

[scottmandu]

I believe what is being called the “android valve”

I belive it's called an aneroid, aneroid valve, or boost compensator.

 

[wandering neurons]

aneroid makes sense. Pressure sensing valve. Thanks much!

I belive it's called an aneroid, aneroid valve, or boost compensator.

 

[wandering neurons]

Update: Searching for "3116 aneroid governor" I found a decent writeup on turning up the fuel on the Caterpillar 3116:
https://www.justanswer.com/heavy-equipment/1xedq-3116-cat-engine-dump-truck-turn-power.html

There's three things to do:
1. Block the aneroid line that feeds air pressure into the governor
2. Turn up the fuel screw under the valve cover
3. Turn up the fuel screw inside the governor

Recommended one turn CCW on each screw.

Now, for that uprated turbo...

aneroid makes sense. Pressure sensing valve. Thanks much!

 

[Pointman0853]

Can we ask who helped you with the turbo? Any overheating issues so far?

Pointman

 

[snowtrac nome]

I am looking at a mechanical vgt turbo called a switchblade turbo I think it will be just what I need to improve off the line performance and top end. It should work as good as compounds with out the bulk heat and expence.