# more power out of fl70 with cummins



## grosser397

hey guys i just bought a new freightliner fl70 dump truck with a 5.9 cummins 12v and eaton fuller 6 speed manual. the truck has air brakes and glad hands out the back so im hopping to buy a air break deck over but i feel a little extra horse power would be nice


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## snowpro44

take it too cummins!!dont buy aftermaket junk...let a good cummins guy tune it!!might need overhead,injectors set up!!should need more power..cant be tuned right.


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## 90plow

Your goi g to have a hard time. Thats a small motor in a big truck if you turn it up youll lose reliability. Hp isnt the key its torque my mack has 275 hp but 1,100 ftlb of torque.


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## Mark Oomkes

90plow;1659928 said:


> Your goi g to have a hard time. Thats a small motor in a big truck if you turn it up youll lose reliability. Hp isnt the key its torque my mack has 275 hp but 1,100 ftlb of torque.


You don't know much about the 5.9, do you?

Where's JDip when you need him?

There's a million things that can be done to get more power\torque out of the 5.9, just depends on how mulch you want to spend. Fuel plate for starters. Injectors, turbos, cams etc.

I went with a Stage 3 cam in my F350 and turbo lag is gone. Completely. Nada. Zip. Zero.


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## Dogplow Dodge

Is it a P-pumped motor, or VE ?

Either way, you can do the mods yourself. The VE is the easier of the two to work on, and power increases can be as simple as increasing the power screw, smoke screw, advancing the timing, etc. If you want even more power, it can easily be had with injectors and such. one of the easier upgrades is changing out the turbo to a more efficient unit with a smaller diameter turbine housing.

Since your truck is in a heavier vehicle, you may wish to consult with the guys on DTR to see where to take this..

http://www.dieseltruckresource.com/dev/


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## grosser397

I know a fair share as far as turning up the pump goes and bigger injectors that stuff but like some one said I don't want to effect the reliability of the truck , the nice part about this truck it's really easy on fuel when your just spreading salt.


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## Mark Oomkes

If 5.9's are unreliable after modding, there are going to be thousands and maybe millions of surprised as well as pissed off 5.9 owners.


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## grosser397

I know there reliable in a pick up but in a medium duty application you could over work the small motor


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## Mark Oomkes

The 5.9 is a medium duty diesel. The only true medium duty diesel in a pickup.


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## 1olddogtwo

Mark Oomkes;1660109 said:


> The 5.9 is a medium duty diesel. The only true medium duty diesel in a pickup.


The C is a workhorse. Mark is 100% right. Ford even offers them in the larger F series.


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## grosser397

I suppose your right! I had a 06 5.9 dodge I just got rid of I but I am a big C fan when it comes to diesels!


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## 90plow

I've had three cummins. I also had a cat in an f 650 no matter how you look at it its only 5.9 liters its a small motor for a big truck. Turn it up all you want in a pickup they dont see the weight and rpms a med duty truck will. I know you can turn them up its still small displacement motor.


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## 2COR517

90plow;1659928 said:


> Your goi g to have a hard time. Thats a small motor in a big truck if you turn it up youll lose reliability. Hp isnt the key its torque my mack has 275 hp but 1,100 ftlb of torque.


Which one of those numbers gets you up the hill fully loaded?


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## 2COR517

90plow;1660196 said:


> I've had three cummins. I also had a cat in an f 650 no matter how you look at it its only 5.9 liters its a small motor for a big truck. Turn it up all you want in a pickup they dont see the weight and rpms a med duty truck will. I know you can turn them up its still small displacement motor.


A 5.9 turns faster in a Med duty than a Light duty?


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## 90plow

No but in a med duty truck your rpms remain higher due to gearing and load (in most situations) When your on the highway pulling a load that engine will be near red line for hours trying to maintain speed. Im not trying to start a war i tried to turn up my small cat which was a 7.2 liter and the three dealers i approached warned against it for those reasons. You can do whatever you want but ive been warned against it just passing on the same advice. Some people are way to touchy and closed to other opinions. Notice how many fail to mention along with engine upgrades etc transmissions need to follow suite. Go turn up your dodge see how long the trans lasts same applies to med duty trucks. Many medium duty trucks will have lower hp ratings than their pickup counter parts just for the reasons i listed above. Flame suit on.


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## 2COR517

So you didn't actually experience a failure with a turned up 5.9 in an FL70?

And is it Horsepower or torque that gets you up the hill?


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## 90plow

Now your just being a ball buster. Im giving actual advice against tuning a truck you use for work. I had a tuned up 5.9 for play and i plowed with it and anytime i plowed with it i de tuned (high egts trans temps etc). Horsepower wars aregreat in pickups but when you step out side of that if you dont have a big displacement motor your still only going to get so much. Hp is no doubt the number you need to go up hill on the highway and maintain 65mph. Take that same hill and a stop light at the bottom you need torque so its two different situations. If your theory on hp being the sole need in a big truck why dont the use a 6.7 powerstroke in my mack?


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## Mark Oomkes

Pretty sure 2COR is not saying high HP is the theory he is after. 

AS for high EGT's and tranny temps, it all depends on the setup. My tranny temps have dropped significantly in my F350 with the Cummins compared to the 6.0. EGT's are higher, but not dangerously so and really only when I put a big load on it. 

As an aside, why is it when someone's statements are challenged they are called names, such as: ball buster; touchy, closed to other's opinions. Yet the person making that statement is touchy about having his statements questioned as well as closed to the possibility of someone else knowing more than him?


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## SnowFakers

I really dont think that its cranking up HP that destroys reliability in trucks, I attribute it to people who beat the daylights out of their truck since they are turned up. Go easy and anything will last. Cranking it up wont make the engine go any less miles, it just doesnt help for sure.


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## bcramblit

First off... Tuning a med. duty truck for work is a totally different ballgame than tuning a pickup. The weight of these trucks will burn little 5.9's alive (when loaded) and not properly tuned. Most people with advice on this matter have never felt the burden of being loaded at 30,000lbs or better. If they have, most will tell you to leave it alone. 
The first thing you need is a pyrometer. After that, the best and cheapest mod you can do is make sure your engine is governed at 3200rpm. If its not, change the governor springs. Its a must. 
You need to find the CPL# of your Cummins. You have to know where your starting from. I'm guessing its a #1552 rated at 210HP. These were tuned for Med. duty trucks, motorhomes, buses, equipment. You can tune it to your liking. You will be limited to EGTs at that point. If you pull heavy it won't take much more than stock to max EGTs. If you don't pull heavy it will take a bigger tune. Either way you will be glued to the pyro. If you have employees you have to ''idiot proof'' so just the governor springs will do most good. As little gains as you will use for this, the reliability is not a factor.
Also, it is a 94' so if it has a lot of miles or exposed to harsh conditions it may not be performing to its stock rating. The fuel shutoffs go bad and restrict flow cause they don't open fully. If that is the case none of these mods will do any good so might want to start by checking that all systems are up to par before moving forward. 

P.S. Its nice to have power, but its a burden at the same time. 
Good Luck...


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## 2COR517

90plow;1660436 said:


> Now your just being a ball buster. Im giving actual advice against tuning a truck you use for work. I had a tuned up 5.9 for play and i plowed with it and anytime i plowed with it i de tuned (high egts trans temps etc). Horsepower wars aregreat in pickups but when you step out side of that if you dont have a big displacement motor your still only going to get so much. Hp is no doubt the number you need to go up hill on the highway and maintain 65mph. Take that same hill and a stop light at the bottom you need torque so its two different situations. If your theory on hp being the sole need in a big truck why dont the use a 6.7 powerstroke in my mack?


You're the one giving "advice" on a subject you don't really have any personal experience with. So I will label your comments as opinions. I'm questioning some of your opinions that don't seem logical to me.

And nice back pedal on the hp vs torque argument.

What is the displacement of the engine in your Mack?


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## jhenderson9196

That year truck doesn't have valve spring enough to safely run 3200. Im not sure, but I think that motor runs a P pump, not VE. Either way, a set of marine injectors and minor pump adjustments will improve low RPM performance. As previously mentioned, a pyrometer is mandatory to gauge your driving style vs engine performance.


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## 90plow

Its a 12 liter engine. im not speaking without experience. I stated that i had a similar lack of power problem in my f650 with the cat 3116 similar truck platform similar engine size same class truck. I didnt say hop up your cummins like a pick up truck i didnt say the motor would blow up i said you would lose reliability. That could be in the form of your rear end, transmission, turbo over heating, not enough cooling or anything else. I had my truck at the shop they ran the vin and said given the clutch, turbo, injectors, and rear end youd be lucky to have this truck last much longer after turning it up. Before selling my f 650 i looked at a. Sterling with a mercedes motor it was only around 8 liters it had bigger hp numbers than the mack but the torque and displacement numbers were lower. How many medium duty dump trucks do you run 2 cor and mr ommes? How many have you turned up and run? How many with a cummins? Original poster asked a question I stated nothing claiming it was all fact everything on this forum is assumed to be opinion unless you back it with quotes or sources.


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## grosser397

bcramblit;1660596 said:


> First off... Tuning a med. duty truck for work is a totally different ballgame than tuning a pickup. The weight of these trucks will burn little 5.9's alive (when loaded) and not properly tuned. Most people with advice on this matter have never felt the burden of being loaded at 30,000lbs or better. If they have, most will tell you to leave it alone.
> The first thing you need is a pyrometer. After that, the best and cheapest mod you can do is make sure your engine is governed at 3200rpm. If its not, change the governor springs. Its a must.
> You need to find the CPL# of your Cummins. You have to know where your starting from. I'm guessing its a #1552 rated at 210HP. These were tuned for Med. duty trucks, motorhomes, buses, equipment. You can tune it to your liking. You will be limited to EGTs at that point. If you pull heavy it won't take much more than stock to max EGTs. If you don't pull heavy it will take a bigger tune. Either way you will be glued to the pyro. If you have employees you have to ''idiot proof'' so just the governor springs will do most good. As little gains as you will use for this, the reliability is not a factor.
> Also, it is a 94' so if it has a lot of miles or exposed to harsh conditions it may not be performing to its stock rating. The fuel shutoffs go bad and restrict flow cause they don't open fully. If that is the case none of these mods will do any good so might want to start by checking that all systems are up to par before moving forward.
> 
> P.S. Its nice to have power, but its a burden at the same time.
> Good Luck...[/
> 
> well said, i think you have very valid points


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## grosser397

i think im going start by turning up the pump, but to give everyone a little more info about the truck, i will be the only one really who ever drives it (for now) the truck is a 97, has a eaton fuller 6 speed manual transmission that is brand new along with the clutch, truck only has 107,000 miles on it so i think as far as the motor goes it should be very strong still. I plan on pulling a dual tire tandem deck over trailer with a case 580 ( or something similar) and probably wont be alot of highway driving


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## grosser397

and yes a egt gauge will be first thing installed!


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## bcramblit

jhenderson9196;1660716 said:


> That year truck doesn't have valve spring enough to safely run 3200. Im not sure, but I think that motor runs a P pump, not VE. Either way, a set of marine injectors and minor pump adjustments will improve low RPM performance. As previously mentioned, a pyrometer is mandatory to gauge your driving style vs engine performance.


Anyone who knows these pumps will know that with 2500rpm springs the pump starts defueling at 2200rpm. So the engine pulls hard to 2200 then fuel starts tapering off to almost nothing at 2500rpm. You can get it to turn 2800rpm but not making much power. The 3200rpm spring kit will allow full fuel up 3000rpm. No need to turn it that fast but allows full fuel where you need it most. This is the most noticeable mod for the p-pump.


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## bcramblit

grosser397;1660834 said:


> i think im going start by turning up the pump, but to give everyone a little more info about the truck, i will be the only one really who ever drives it (for now) the truck is a 97, has a eaton fuller 6 speed manual transmission that is brand new along with the clutch, truck only has 107,000 miles on it so i think as far as the motor goes it should be very strong still. I plan on pulling a dual tire tandem deck over trailer with a case 580 ( or something similar) and probably wont be alot of highway driving


Sounds like a pretty sweet unit. That thing should do you some good for a some time. Tune it right and you will enjoy it for along time.ussmileyflag


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## Mark Oomkes

90plow;1660803 said:


> How many medium duty dump trucks do you run 2 cor and mr ommes? How many have you turned up and run? How many with a cummins?





bcramblit;1660844 said:


> Anyone who knows these pumps will know that with 2500rpm springs the pump starts defueling at 2200rpm. So the engine pulls hard to 2200 then fuel starts tapering off to almost nothing at 2500rpm. You can get it to turn 2800rpm but not making much power. The 3200rpm spring kit will allow full fuel up 3000rpm. No need to turn it that fast but allows full fuel where you need it most. This is the most noticeable mod for the p-pump.


Interesting info, thanks. And you are correct, top end is where the 5.9s are lacking in medium duties. I will have to look into. Will the intake and\or exhaust springs need replacement if the engine has a few miles on it? Reason I ask is I had mine overhauled and just replaced the springs since they were $88 a set and turns out that what was needed for the 4,000 RPM governor springs.

Other than adjusting the fuel plate and timing, I have not done anything with my other 2 5.9s in F800s. Same with the 8.3 in my L8000.

PS One can always tell when one is winning a debate when the other party starts calling names.


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## Dogplow Dodge

I have the 5.9 VE in my Brick. The engine ran fine and then I put the 3200 spring in. Now it runs great.

Realty is that I never see RPM's over 2200 anyway, as it's never beaten on by anyone other than myself. The spring just gave it more of an improved drivability, as it responds better to the accelerator pedal than it used to. I'm also able to now go over 75MPH, where previously, The truck was maxed out there. Best mod.... and really the only one I did other than tweaking the pump a little. The P-Pump is supposedly more flexible when it comes to increasing HP, but since I don't own one, I can't confirm this other than what I've read.


Pyrometer I purchased also has a Fuel pressure and boost gauge built in. I'm glad I spent the time installing those, as I can now have a better idea of what's happening under the hood, and not damage my ride without "knowing". Tachometer was a nice addition as well.


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## mnglocker

The money best spent upfront will be on a better/bigger intercooler. With any extra fuel going in, your EGT's will climb. If the truck is used in summer months, you'll really need the extra air charge cooling capacity if you want to be able to use it after you've bumped the fuel levels. 

Without something to help lower the EGT's the new found power will be unusable without burning up your valves.


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## clark lawn

That is too small of an engine for what you want. I see them all the time at the truck dealership I work at. I'd be willing to bet that truck started life as a box truck. To make big power you need big cylinders. That 5.9 is tiny, turn it up all you want but the truth us that it is not enough engine.


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## grosser397

clark lawn;1661555 said:


> That is too small of an engine for what you want. I see them all the time at the truck dealership I work at. I'd be willing to bet that truck started life as a box truck. To make big power you need big cylinders. That 5.9 is tiny, turn it up all you want but the truth us that it is not enough engine.


Nope I'm got it from a guy I have know and he got it from the guy who set it up new, I wouldn't of chose that either if I was building a new truck but I'm going to turn it up and going to try it , I don't plan on using it for ever to tow big loads but until I can afford a quad or quint I think it will work for what I want to do


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## grosser397

Next question and this seems dumb to me but there is no grid heater on this truck, this common and how do I go abouts putting one in


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## Blizzard1980

Dogplow Dodge;1660926 said:


> I have the 5.9 VE in my Brick. The engine ran fine and then I put the 3200 spring in. Now it runs great.
> 
> Realty is that I never see RPM's over 2200 anyway, as it's never beaten on by anyone other than myself. The spring just gave it more of an improved drivability, as it responds better to the accelerator pedal than it used to. I'm also able to now go over 75MPH, where previously, The truck was maxed out there. Best mod.... and really the only one I did other than tweaking the pump a little. The P-Pump is supposedly more flexible when it comes to increasing HP, but since I don't own one, I can't confirm this other than what I've read.
> 
> Pyrometer I purchased also has a Fuel pressure and boost gauge built in. I'm glad I spent the time installing those, as I can now have a better idea of what's happening under the hood, and not damage my ride without "knowing". Tachometer was a nice addition as well.


GLOW SHIFT you went with i see. Good choice. I have triple gauges set up on my pillar. Between price and ease of installation of all sensors it's no brainer.


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## Dogplow Dodge

Blizzard1980;1663032 said:


> GLOW SHIFT you went with i see. Good choice. I have triple gauges set up on my pillar. Between price and ease of installation of all sensors it's no brainer.


I like it (the glowshift triple in one), but I've heard lots on the net about others who absolutely hate them. I cannot tell you why, other than my own personal experience has been pretty much nothing but good. The light is a little bright at night, even with the dimmer set to come on with the lights, but if I just alter to a less bright color, it's no longer a problem.


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## grosser397

Anyone know if a grid heater off a 99 24v from a dodge truck will work on the 96 5.9?


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## SnowFakers

Im almost positive its 94-98 and then 98.5-02 for the grid heater splits atleast for those years. So in that case it will not work.


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## pinepointe

If your lookin for power do the gauges and intercooler, next the turbo and inectors along with upgrading the pump. If you are looking for power get the heater grid out of the intake all together. I have run everything from 5.9 to the mighty 600 cummins, the cummins will start just fine with out the grid and if it's that cold just plug the olg girl in. I would talk to industrial injection they are on the web and leaders in upgraded diesel everything. Oh yeah while your at it go ahead and get the head ported and fire ringed


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## cl733

As bcramblit said, that little cummins was an awesome motor, its has had so many fuel delivery changes to it in its life span, cummins never wanted to see that motor go past 245 hp for long term reliability, chrysler took it to 305 hp in 03, and kept turning it up into 07,add a few more hp with after market parts and start beating them up in the hills and look at the damages that were happening, probably live for ever at a factory setting, but turn up the heat and you never know,


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## jhenderson9196

Chrysler doesn't touch these motors. Cummins does. Never designed for more than 245 HP? 275 HP in RVs and up to 375 in marine applications, and those were 12 valve motors.


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