3126 w/ABS vs 3116

[GeneralDisorder]

Actually what pencils in my head is HP and TQ vs long term reliability. Have you not had physics? I will take the reliability bonus. Why would they need to de-rate if the military expectations of a 35K life (to quote you)?

By the way, the Steyr 12m18 only has 177hp.

There's really zero evidence that reliability is significantly altered. That's an unsubstantiated claim. Where's your evidence for this? I have provided examples showing the manufacturer has no concerns with this engine at this power level pulling over 4x my weight in conditions I will (hopefully) never see.

The Steyr is a manual transmission and that immediately accounts for an additional 10-15% power at the wheels. Source: Just so happens I own a performance shop that builds race cars and I have an in-ground AWD chassis dynamometer (DynoJet 424XLC-2). I do this literally for a living. Also the Steyr trucks are from a different era of warfare and as they relate to the FMTV's they pretty much only share the cab design which is a superficial similarity only. The entire drivetrain, vehicle weight, and operational performance requirements are different. The Steyr weights about 12,500 lbs while the lowly M1078 A0 weighs around 17,500 lbs. Apples to Oranges comparison really.

As such I would like to think I have a decent "sense" for what additional power output one can reasonably and reliably expect out an engine beyond factory ratings - and this 370 HP tune is WITHIN factory ratings. I have ZERO concerns.

Throw all the rocks you want at it. I'll be driving it and reporting my experience with it. So if there's any issues I'll let the forum know. Till then - if you have ACTUAL evidence of your claim against it's reliability please post it!

 

[Reworked LMTV]

Scientists who understand the physics of engine momentum, heat, pressure, etc, know that the laws of physics are a give and take. Increase HP and TQ = increases wear and reduced MTBF, assuming all other things are held constant. These are basics facts. You don't need to study each engine, that's why there is a well understood science and framework to operate from.

I'm sure your engine will work. It's just not the approach that I would take. If I had a 3126 or C7, I would stay at a max of 330 hp. By the way, do you the second turbo that is required to make 370hp?

 

[GeneralDisorder]

Scientists who understand the physics of engine momentum, heat, pressure, etc, know that the laws of physics are a give and take. Increase HP and TQ = increases wear and reduced MTBF, assuming all other things are held constant. These are basics facts. You don't need to study each engine, that's why there is a well understood science and framework to operate from.

I'm sure your engine will work. It's just not the approach that I would take. If I had a 3126 or C7, I would stay at a max of 330 hp. By the way, do you the second turbo that is required to make 370hp?

I have ordered the water cooled turbo that is used by the 370 HP RMF engine if that is what you mean - that's the only difference I can find. The requested and delivered boost pressure is dead-on with the 370 map and my stock turbo.

I don't think in practice it will matter with the high quality Amsoil synthetic oil that has a higher sustained temperature capability but I do plan to swap out to the water cooled variant (Borg Warner S300CG versus S300C center housing rotating assembly [CHRA]) but I don't expect that to make any real difference in practice. The CHRA are the same just the higher power version is water cooled - which will only be an issue in very hot conditions under extreme load.

Sure - physics. I get that but it proves nothing empirically or practically. By that reasoning you should run your engine at 1 HP to reach maximum lifespan. The numbers don't work out - sure maybe in 250k miles I have shortened it's life. Does that matter? Doesn't for me.

 

[Ronmar]

Yea the engine is probably OK with that much HP if you can keep it cool… I think I would be more concerned with the transmission. The highest 3000 series spec I have seen is in the lower 300s…

 

[GeneralDisorder]

Yea the engine is probably OK with that much HP if you can keep it cool… I think I would be more concerned with the transmission. The highest 3000 series spec I have seen is in the lower 300s…

Torque is the important factor and that's why CAT charges for rerates based on torque not on horsepower.

Yes I am exceeding the torque rating by about 60 ft lbs. I concede that.

In the scheme of how these vehicles are used and what they are rated for - considering my example of the A1P2 wrecker with attached load - do you really think that extra 60 ft/lbs is going to break the transmission?

I leave that to the readers to consider.

The 3700SP transmission in my A1R truck is the piece in question. My sources in the military say these transmission are incredibly strong and the FMTV transmissions in general have a failure rate that is very close to zero. Most failures being traced back to severe abuse.

 

[Lostchain]

Scientists who understand the physics of engine momentum, heat, pressure, etc, know that the laws of physics are a give and take. Increase HP and TQ = increases wear and reduced MTBF, assuming all other things are held constant. These are basics facts. You don't need to study each engine, that's why there is a well understood science and framework to operate from.

Caterpillar engineered the C7 to output 370HP (as evidenced by the attached data-plate), are you saying their engineers were remiss in their duties and the C7 will perform less reliably at that output level?

I'm sure your engine will work. It's just not the approach that I would take. If I had a 3126 or C7, I would stay at a max of 330 hp. By the way, do you the second turbo that is required to make 370hp?

What data have you seen that would make you uncomfortable running the C7 at levels beyond 330HP, especially when Caterpillar themselves sell and warrant the engine at higher levels? Also on the subject of a second turbo, did you mean that a 370HP Rated C7 requires a bi-turbo setup? Attached is a picture from the the same 370HP rated C7 that is clearly a single turbo.

 

[Reworked LMTV]

Nice engine. Some are bi-turbo. Wonder how it runs on WMO. You think diesel has been expensive this year, wait until Q2-4 2023.

 

[TomTime]

So @Stratosurfer, your the OP, how are you feeling about your questions now?

 

[Reworked LMTV]

I have ordered the water cooled turbo that is used by the 370 HP RMF engine if that is what you mean - that's the only difference I can find. The requested and delivered boost pressure is dead-on with the 370 map and my stock turbo.

I don't think in practice it will matter with the high quality Amsoil synthetic oil that has a higher sustained temperature capability but I do plan to swap out to the water cooled variant (Borg Warner S300CG versus S300C center housing rotating assembly [CHRA]) but I don't expect that to make any real difference in practice. The CHRA are the same just the higher power version is water cooled - which will only be an issue in very hot conditions under extreme load.

Sure - physics. I get that but it proves nothing empirically or practically. By that reasoning you should run your engine at 1 HP to reach maximum lifespan. The numbers don't work out - sure maybe in 250k miles I have shortened it's life. Does that matter? Doesn't for me.

"Sure - physics. I get that but it proves nothing empirically or practically."

Any man can take a 370 hp CAT up a hill, but the real question is: "How long can he afford the diesel to do so, and who will clean up his CAT litter?"

 

[Stratosurfer]

So @Stratosurfer, your the OP, how are you feeling about your questions now?

I’m moving forward in a search for a 3126 1079A1. Possibly an A1 1083 if I can find one. You boys have been very helpful in this process for me. Thanks to all.

 

[Stratosurfer]

Has anyone used this tuner for a 3126?

2003 | CAT 3126 RV Motorhome | Power Chip Diesel Performance Chips

www.usdieselchips.com

S

 

[Lostchain]

Has anyone used this tuner for a 3126?

2003 | CAT 3126 RV Motorhome | Power Chip Diesel Performance Chips

www.usdieselchips.com

S

Just throwing this out there as another option to consider, I just had my 2003 M1078A1 re-rated to 330HP by a CAT dealership for about the same cost as that tuner. Basically two hours of shop time and a sensor. The nice part is its just a re-flash of the personality module in the ECM, no need for an external box, and its the CAT engineered tune for the engine.

 

[GeneralDisorder]

"Sure - physics. I get that but it proves nothing empirically or practically."

Any man can take a 370 hp CAT up a hill, but the real question is: "How long can he afford the diesel to do so, and who will clean up his CAT litter?"

Actually the point isn't to go fast or burn more diesel. The point is to increase fuel economy - in conjunction with the 3.07 differentials lowering the RPM closer to peak torque and also increasing peak torque the engine will not be working as hard at the same speed (50 - 55 mph). This will translate into increased economy.

 

[GeneralDisorder]

Has anyone used this tuner for a 3126?

2003 | CAT 3126 RV Motorhome | Power Chip Diesel Performance Chips

www.usdieselchips.com

S

As the owner of a performance shop with a chassis dyno I wouldn't buy anything from that type of web site. That's likely to blow your engine up or do nothing or next to nothing. It's a "piggyback" device that's going to take engine sensor inputs, alter them, and re-transmit the altered data to the ECU to attempt to fool it into giving more fuel and thus increasing power. BANKS does this and generally has a good reputation but that web site seems to be selling basically the exact same "box" for pretty much every diesel application on the planet. I guarantee they haven't tested that many applications so you are likely to get something that does nothing at all and relies on the placebo effect for results or something that is dangerous because it's essentially untested.

We get this a LOT in the tuning world. Especially the late model (by late I mean like last 20-30 years of fuel injection applications) naturally aspirated cars that people ask us to "tune". We explain to them there's really nothing to gain by doing this but sometimes they just insist and keep at us to do it so we relent and take their money. It usually goes like this - we get the car as hot as possible just idling for 30 minutes with no dyno bay fans on it (usually this is in the hot summer months too) and then we do the "baseline" pull. That will give us a pull that will be down usually 15-20 HP just due to lack of air density with the engine hot AF. Then we shut it down, put fans on it, and pull the ROM file. We go into the office to do our "tuning" - maybe we add a degree or two of timing and watch youtube for 20 minutes while the fans do their thing. We spray the intake manifold and radiator down with water, etc. We load the "tune", fire it up and do a cold pull - usually this will be up by 15-20 HP from the hot pull. Now we have our before and after dyno graphs showing how much "improvement" we got from tuning. Usually that extra 1-2 degrees of timing will light up the knock sensor so we have to end up pulling it back out anyway. The customer is STOKED that he made 15 more HP from "tuning" and usually comes back at a later date and expresses how pleased he is and how much faster it feels.

Not even kidding. This happens. Owning a dyno/performance shop is an interesting experiment in how the placebo effect works in practice.

 

[Reworked LMTV]

Actually the point isn't to go fast or burn more diesel. The point is to increase fuel economy - in conjunction with the 3.07 differentials lowering the RPM closer to peak torque and also increasing peak torque the engine will not be working as hard at the same speed (50 - 55 mph). This will translate into increased economy.

Oh please....Does anyone have a shovel he can borrow ?

 

[TomTime]

As the owner of a performance shop with a chassis dyno I wouldn't buy anything from that type of web site. That's likely to blow your engine up or do nothing or next to nothing. It's a "piggyback" device that's going to take engine sensor inputs, alter them, and re-transmit the altered data to the ECU to attempt to fool it into giving more fuel and thus increasing power. BANKS does this and generally has a good reputation but that web site seems to be selling basically the exact same "box" for pretty much every diesel application on the planet. I guarantee they haven't tested that many applications so you are likely to get something that does nothing at all and relies on the placebo effect for results or something that is dangerous because it's essentially untested.

We get this a LOT in the tuning world. Especially the late model (by late I mean like last 20-30 years of fuel injection applications) naturally aspirated cars that people ask us to "tune". We explain to them there's really nothing to gain by doing this but sometimes they just insist and keep at us to do it so we relent and take their money. It usually goes like this - we get the car as hot as possible just idling for 30 minutes with no dyno bay fans on it (usually this is in the hot summer months too) and then we do the "baseline" pull. That will give us a pull that will be down usually 15-20 HP just due to lack of air density with the engine hot AF. Then we shut it down, put fans on it, and pull the ROM file. We go into the office to do our "tuning" - maybe we add a degree or two of timing and watch youtube for 20 minutes while the fans do their thing. We spray the intake manifold and radiator down with water, etc. We load the "tune", fire it up and do a cold pull - usually this will be up by 15-20 HP from the hot pull. Now we have our before and after dyno graphs showing how much "improvement" we got from tuning. Usually that extra 1-2 degrees of timing will light up the knock sensor so we have to end up pulling it back out anyway. The customer is STOKED that he made 15 more HP from "tuning" and usually comes back at a later date and expresses how pleased he is and how much faster it feels.

Not even kidding. This happens. Owning a dyno/performance shop is an interesting experiment in how the placebo effect works in practice.

Funny and sad at the same time.

 

[GeneralDisorder]

Nice engine. Some are bi-turbo. Wonder how it runs on WMO. You think diesel has been expensive this year, wait until Q2-4 2023.

You'll have to prove that to us. I have seen no evidence to support the claim of a twin turbo C7 (not C7.1) existing as a production model.

 

[GeneralDisorder]

Oh please....Does anyone have a shovel he can borrow ?

You throw stones without explanation. Peak torque is peak efficiency. So exactly why would I NOT want to cruise at closer to peak efficiency? Please enlighten and please use science rather than emoji. Thank you.

 

[Reworked LMTV]

You throw stones without explanation. Peak torque is peak efficiency. So exactly why would I NOT want to cruise at closer to peak efficiency? Please enlighten and please use science rather than emoji. Thank you.

Actually, I have not thrown stones. I explained why I am satisfied with my 3116. You have tried every which way to defend your thinking, rather than taking the time to see someone else's approach, just to say you are right. You have gone off on tangents. Now you are talking gears. I have said that I am using a different approach based on my need, not yours.

 

[GeneralDisorder]

There's absolutely nothing wrong with being satisfied with the 3116. It is an acceptable (some might even say good) engine and if it meets your needs then there's no argument I can make against that.

And none of this discussion went off on tangents. The discussion is about the 3116 or the 3126 which pretty much comes down to a discussion of mechanical or EFI - they are very little different otherwise. And of course the C7 is another option the OP might want to be aware of since he's still looking. What can be done with each engine as relates to upgrades, etc (software or otherwise) is absolutely germane to the conversation along with discussions about reliability. And you questioned "how" I was able to create a spare ECU after your claim that if it died you would be the helpless victim at the mercy of the CAT dealership. I don't see how any of this is a "tangent"