Low RPM Vibration - 2005 NV5600

[HBarlow]

Cee,

I would probably not upgrade the clutch at all but if you do my recommendation would be to use Southbend Clutch's mildest offering. Cummins and Dodge spent a lot of time and money determining the best compromise when they chose the Luk clutch disc and pressure plate. Any aftermarket product involves a different set of compromises. The higher the clutch rating the more difficult it will be to use. Stronger springs in the pressure plate and material offering increased friction in the clutch disc create clutches that engage abruptly. The factory Luk products served me very well. The secret to long life with a clutch is a skilled driver. If you already know and practice this method I apologize for writing it - never raise the engine rpm above idle when engaging the clutch from a stop. Gently engage the clutch and increase engine rpm only after the clutch is fully engaged.

I am not a believer in modifying HPCR engines with aftermarket turbochargers, air filters, or magic black boxes. Earlier 12 valve and 24 valve engines were a different situation. A modified engine gives up service life and may be subject to early catastrophic failure. Injectors in hpcr engines are already highly stressed and increasing performance further increases stress. An injector that fails often fails open, overfuels that cylinder, and melts the top out of the piston. Increasing power output creates new problems like excessive exhaust gas temps that shorten engine life, excessive boost that causes blown head gaskets, and more. To me accelerating faster when unloaded is simply not worth it.

The factory air box and filter is not a hindrance to power development until power output exceeds about 450 hp. PM Joe Donnelly and ask him. The OEM filter is as good as money can buy for protecting the engine from dust and grit while developing full rated hp. If you insist on increased air flow potential (not increased air flow) remove the factory filter and use an appropriately sized section of door screen. It won't do a thing for power output but will be cheaper to buy than an expensive aftermarket air intake and filter almost as well. Either way you'll be buying an engine sooner than if you leave it stock.

Your engine's rated hp and torque will do a completely satisfactory job of pulling your very heavy trailer. Increasing engine output to 650 hp and 1200 ft. lbs. of torque will not allow you to pull grades significantly faster but will allow climbing grades in higher gears including sixth overdrive. Doing this will guarantee transmission and driveline failure. Except for drag racing or impressing friends who are following you in Furds on long steep grades power mods are not very practical in a towing motor. My advice is leave it alone. Not too many years ago eighteen wheel OTR drivers were climbing the Rockies out west or in the Appalachians with less hp and torque. They were slower on the grades but always made it to their destinations and their engines lasted a long time.

Many will disagree with me but those who use their trucks primarily for heavy towing will be more likely to agree. It's your truck, your money, and your choice.

 

[AH64ID]

I am not a believer in modifying HPCR engines with aftermarket turbochargers, air filters, or magic black boxes. Earlier 12 valve and 24 valve engines were a different situation. A modified engine gives up service life and may be subject to early catastrophic failure. Injectors in hpcr engines are already highly stressed and increasing performance further increases stress. An injector that fails often fails open, overfuels that cylinder, and melts the top out of the piston. Increasing power output creates new problems like excessive exhaust gas temps that shorten engine life, excessive boost that causes blown head gaskets, and more. To me accelerating faster when unloaded is simply not worth it.

Statements like show that you don't have a full understanding of what Dodge/Cummins did to meet emissions with the HPCR, specifically the 04. 5-07.

The factory timing is very retarded to meet emissions, this reduces efficiency and power for a given fueling rate. Advancing timing (I like the Smarty Jr) provides for increased economy, power, and lower exhaust gas temps. It does all of that without effecting the rail pressure, or anything else that would shorten injector life. In fact it disables the 3rd injection event which reduces injector wear.

The factory turbo is a quick spooling and strong unit. It has a compressor wheel capable of enough air for 450 rwhp; however, its turbine section was chosen for emissions and doesn't match the flow of the compressor. Many have great luck with the stock turbo, but there is room for improvement without sacrificing spool, low speed performance, or longevity. The stock turbo is more than capable of running 2x as much exhaust pressure as boost, which reduces airflow thru the cylinder and increases EGTs, decreases economy, and runs more boost than needed. As an example I would see 25 psi of boost and 40-45 psi of exhaust pressure towing up a 6% grade at 55 with the stock turbo, now I see 23 psi of boost and 16-18 psi of exhaust pressure up the same grades at 55, with lower EGTs. Which one do you think is better for the motor?

The stock motor is great, and has plenty of power but there is room for improvement without sacrificing anything. It also works just fine left alone. Its up to the owner, but some educated modifications can be good.

I dyno just over 100hp and 250 ft/lbs more than stock, with lower boost, lower exhaust pressure, lower EGTs, fewer injection events and better fuel economy. Whats not to love!

The HPCR actually leaves the most room for improvement on the stock motor/turbo because of the timing profile. You can correct the timing and gain 60-90hp on stock fueling, and moderate timing. Older trucks were setup closer to peak timing/fueling for the turbo and thus easier to fuel/time beyond their capability. What the older trucks lacked was a 5 minute tune that could be excessive, and that's why the HPCR's are easier to destruct. It's not because the motor is weaker, but there are too many people doing too much with the stock setup because it's cheaper/faster/easier than on older motors.

 

[boonhauler]

Is the vibration tied into the engine rpm or the truck's speed? Put another way, if you push in the clutch and increase the engine rpm with the truck moving, does the vibration go away?



John L.

Yes, once the the clutch is engaged the vibration / growling stops

 

[boonhauler]

Cee,



The secret to long life with a clutch is a skilled driver. If you already know and practice this method I apologize for writing it - never raise the engine rpm above idle when engaging the clutch from a stop. Gently engage the clutch and increase engine rpm only after the clutch is fully engaged.



.

I never raise the engine RPM while dis-engaging the clutch, no thottle just release the clutch. I most often start in 2nd gear. I mostly double clutch while shifting.



I did ride the clutch a little but not for sometime now... ... . At stops I shift into neutral and really make an effort to stay off the clutch.

 

[HBarlow]

Cee,

Okay, sounds like you are doing things right.