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Improving power 5.9 cummins diesel

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Little Mouse
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Improving power 5.9 cummins diesel

Post by Little Mouse »

My cousin has bought a 2001 36 ft rv with what should be a 5.9 ISB, 24 valve. In a pickup i think that engine is rated at 460 ft lbs at 1700 rpm, 235 hp not exactly much good at pulling grades. What can he do to get say at least another 200 to 250 lbs of ft tq and be reliable. Can the stock turbo do that with bigger injectors and change to the computer. What would you do if you had it.
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Re: Improving power 5.9 cummins diesel

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Little Mouse wrote: Fri Jul 31, 2020 9:04 pm My cousin has bought a 2001 36 ft rv with what should be a 5.9 ISB, 24 valve. In a pickup i think that engine is rated at 460 ft lbs at 1700 rpm, 235 hp not exactly much good at pulling grades. What can he do to get say at least another 200 to 250 lbs of ft tq and be reliable. Can the stock turbo do that with bigger injectors and change to the computer. What would you do if you had it.
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Any upgrades need the head to be studded. Some guys say not needed but it will loose a head gasket if the power is boosted to the level you looking at. While its easy to do 1 at a time it will keep the head gasket it it.
Unless the head is coming of for valve springs anyway.
Injectors will help and the pump can be tuned if you can find a shop to do it.
They will not do it up here so its harder with sending the pump away to get done. A computer tune will also help.
An updated cam is the biggest gain but the most work. Stage II grind cams can also be done on stock core if not worn bad but you must limit the valve springs regardless.Don't go over board or use a cheap copy like the spring kits for the 4 cyl. twin cam Neon that are out there on ebay.
Is it std. or auto trans?? the std. trans turbo offers more boost then the auto trans turbo but they can also be had very reasonable now as well..

There is much more but those are the basic's
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Rick!
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Re: Improving power 5.9 cummins diesel

Post by Rick! »

This little gizmo was all the rage before the EPA squashed the diesel aftermarket.
https://www.dieselpowerproducts.com/sma ... 02-cummins

Call up DPP and see if they still carry it and if it would be applicable to your rig.
One would assume it has an OBDII port but you might need to check.

Other than that, it's like ProPower said: injectors, then more air (turbo), VP44 tuning/mods.
A 4" downpipe and " exhaust is requisite before any of the above are applied.

Good luck.
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Re: Improving power 5.9 cummins diesel

Post by Little Mouse »

This rv my cousin bought looks to be close as new as far how well the inside out side were kept up. He lives in so-cal but has registered it in montana. He has complained to me that besides low power to pull grades it is overheating something that has to be fixed for sure, on flat ground no heating problems. Yes the head studs do sound like a good plan to modify it. The extra tq figures i threw out was just a guess by me what it would really need to make it a good hill pulling RV he pulls an suv behind it. From what i can find out the 2001 version of this engine has a less desiresable rotary fuel pump think its called R44, around 2003 they changed to a full rail system and fuel pump change. My cousin has owned an insurance agency for 35 years and fairly well off, but he can be a tight wad on spending money to the point of messing himself up. Far as i know this modern day rv has an auto trans which one i do not know yet or what it can stand in extra power. Thanks for all the info provided i may need to go by and talk with cummins on what can be done about its power after i come up with a fix on cooling issue.
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Re: Improving power 5.9 cummins diesel

Post by CamKing »

We regrind the cams to 210/210 with .300"/,300" lobe lift, and widen the LSA 4 degrees
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Re: Improving power 5.9 cummins diesel

Post by rebelrouser »

I have a 1998 1/2 the first year of the second generation Dodge diesel, which is also what you have I believe. It has a VP44 electronic injection pump. and regular hydraulic controlled injectors. Mine now has 350,000 miles, and has pulled my 14,000 lb car trailer for many years with no issues. I bought mine with 185,000 miles on it.
I can tell you what modifications I made, lots of them are available. Some available I did not due to the issues with possible damage to the engine or electronics.

1st I installed bigger injectors, don't remember the part number, but I remember they had one extra hole in the nozzle. The main reason for replacement was that I pop tested my stock injectors and they were 500psi weak. The pop point of the injectors is when the fuel is injected, so a weak injector is like changing the ignition timing on a gas engine.
2nd I ported the exhaust manifold, and the right angle air horn that bolts to the top of the intake. I think Banks makes a nice replacement for the air horn. On my flow bench I picked up a bunch on the air horn, I do know that after those two modifications, the truck set an overboost code climbing a steep hill, so something picked up the air into the engine.
3rd I installed what they called a 50 HP chip, which what it basically does is fool the engine computer that the intake air is always below 30 degrees, which richens the fuel and advances the pump timing. It is just a plastic box with a resistor in it.

Then the weak point of this truck is the transmission, which is basically a 727 with an overdrive bolted to it. Everybody thinks the transmissions are junk, that is not the case. The issue is the lockup torque converter. The engine has so much torque that the lock up will slip and it takes the lining off of the lock up clutch, that material then stops up the filter, and burns up the transmission. So while the transmission is burnt, the root cause of the issue is not the transmission. I rebuilt the transmission with a dual disc towing converter, and a trans go shift kit. The lockup hits so hard most people think it is another gear shifting. I also changed the stock 4.11 gears to 3.54 gears. I can tow in OD at 70 MPH less than 2,000 rpm. Truck gets 20 MPG empty, and fully loaded trailer 12 to 13 MPG. I have to downshift on steep hills, but most interstate driving I set the cruise and it just goes down the road.

I will tell you that the aftermarket chips available for the VP44 that pierce the wire at the pump, while they do make a lot of power, are hard on the pump, and the pump is expensive. If you hop them up to the point that you need to stud the heads, the life of the engine is reduced, and I personally would not want to haul down the road on long trips with such modifications. Usually they fire ring the heads, along with the studs, and the Cummins heads are prone to cracking when you hop them up as well. I know one guy who warned me when I worked on his truck not to give it full throttle until in warmed up because it would blow a head gasket cold, for example.

The third generation Cummins Dodge Diesel has the Bosh common rail, fully electronic system, which is much quieter running, and the tuning or chips, are a lot more controllable for what power levels you want. To my thinking the 2003 to 2005 Dodges before they put catalytic converters and DEF injection, are just about the best light duty diesel trucks ever made. If you look at what prices the used ones bring, a lot of other people must feel the same way.
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Re: Improving power 5.9 cummins diesel

Post by Rick! »

Little Mouse wrote: Sat Aug 01, 2020 8:32 pm This rv my cousin bought looks to be close as new as far how well the inside out side were kept up. He lives in so-cal but has registered it in montana. He has complained to me that besides low power to pull grades it is overheating something that has to be fixed for sure, on flat ground no heating problems. Yes the head studs do sound like a good plan to modify it. The extra tq figures i threw out was just a guess by me what it would really need to make it a good hill pulling RV he pulls an suv behind it. From what i can find out the 2001 version of this engine has a less desiresable rotary fuel pump think its called R44, around 2003 they changed to a full rail system and fuel pump change. My cousin has owned an insurance agency for 35 years and fairly well off, but he can be a tight wad on spending money to the point of messing himself up. Far as i know this modern day rv has an auto trans which one i do not know yet or what it can stand in extra power. Thanks for all the info provided i may need to go by and talk with cummins on what can be done about its power after i come up with a fix on cooling issue.
The cooling system issue may not be trivial. I have a relative that owns big motor coaches and he usually fixes overheating issues by trading them off.
Maybe hanging out on an RV forum or two might lead to some nuggets of info to address the issues of low power and overheating.

https://www.irv2.com/forums/f26/5-9-cum ... 35971.html
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Re: Improving power 5.9 cummins diesel

Post by ProPower engines »

Little Mouse wrote: Sat Aug 01, 2020 8:32 pm This rv my cousin bought looks to be close as new as far how well the inside out side were kept up. He lives in so-cal but has registered it in montana. He has complained to me that besides low power to pull grades it is overheating something that has to be fixed for sure, on flat ground no heating problems. Yes the head studs do sound like a good plan to modify it. The extra tq figures i threw out was just a guess by me what it would really need to make it a good hill pulling RV he pulls an suv behind it. From what i can find out the 2001 version of this engine has a less desiresable rotary fuel pump think its called R44, around 2003 they changed to a full rail system and fuel pump change. My cousin has owned an insurance agency for 35 years and fairly well off, but he can be a tight wad on spending money to the point of messing himself up. Far as i know this modern day rv has an auto trans which one i do not know yet or what it can stand in extra power. Thanks for all the info provided i may need to go by and talk with cummins on what can be done about its power after i come up with a fix on cooling issue.
Cummins deals are not willing to boost power levels beyond stock configurations. There is a liability issue they don't want to have to get into.
You best bet is to talk to a speciality shop near you that does speciality diesel mods as the 5.9 is the most popular diesel engine going these days but the injection pump is the big issue to get updated as they are electronically controlled.
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Re: Improving power 5.9 cummins diesel

Post by englertracing »

Uncle had n overheating issue I think his is a cat not a Cummins.

Turbine inlet flange was leaking and blowing nice warm exhaust through the radiator at all times
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