More RPM's

[jstabilka]

does anyone know how to get a few more (300 or 400 more) rpm's out of the motor?

 

[realsquash]

I was just pondering what the effect of increasing the RPM range (and thus moving the defueling up) would be on the Cummins' short/long block. I wouldn't use it for anything other than competition, however.



Does anyone know if the big truck pullers and such run higher RPM's than the gen 3?



Andy

 

[Digger]

There are some that run well above 5000.

 

[realsquash]

There are some that run well above 5000.

That's crazy! I was thinking 4000 RPM would be really nice to have I wonder how that's done?



Andy

 

[RabidRam]

Blue Chip just released a new plug-n-play box that gives you 4K rpm. Not sure if it works on 3rd gens or not, but it might be worth checking into. There is a thread on here about it. I think it's called the "Redline" or something along those lines.



HTH,



Dave

 

[silver03]

I would pay big money to have 500 rpm increase. The 12V can run big rpm but no one up to this point can change RPM on 24v or gen 03'. Please let us know if that is possiable.

 

[RankRam]

There are some that run well above 5000.

It's my understanding that the B series will start to self destruct at 4250 rpms is this not correct?

 

[realsquash]

I know that the ECM on the 03+ is what limits the RPM. I don't know if it does it by simply defueling to the point of no fuel or what. Are there any other common rail Cummins'ss's'ss's that operate over a wider RPM band? Marine? Industrial?



I know for a fact the engine in my truck has hit 3400 RPM during shifting, I bet it would run to 4k with the right electronic mods.



Whatever does it's magic on the previous trucks won't apply to the 03+



Andy



EDIT: I have driven my truck at 3400 rpms with the EZ on 4 and no other mods so I'm quite sure we can push it higher with the right stuff.

 

[Vaughn MacKenzie]

It's my understanding that the B series will start to self destruct at 4250 rpms is this not correct?

Rankram you're right about 4250 RPM, but the Cummins won't fly apart. It's at that RPM that "destructive harmonics" occur which means it's damaging (at least potentially damaging) to the bearings. I think if you go past that RPM then you are OK, but of course given the weight of the rods and pistons running higher is hell on rod bearings.



From all the looking I have done on Cummins' website, the majority of applications run considerably lower RPM than in the Ram, typically 2600 - 2800.



Vaughn

 

[FDavid]

i just reved my truck to 4000 rpm. whats the big deal

 

[realsquash]

i just reved my truck to 4000 rpm. whats the big deal

Did you try doing it with a load?



Andy

 

[XcumminsX]

Yeah id pay a nice chunk of change to get my motor to 3600 - 3800 rpm. Then i wouldnt have to change my 4. 10's out for drag racing ...



You said something about load... . what if i never tow? Or do you mean load as in the trans? This has never dawned on me before... . I wonder what the egts would be at 3750 rpm

 

[KatDiesel]

By load he means the clutch engaged or the auto truck in gear... ... ... ... ... meaning not in neutral or park.

 

[XcumminsX]

Ok see here is what i want to do... .



I want to run these tires. .



http://www.tirerack.com/tires/tires...rch=true&partnum=745WR9AVSST&fromCompare1=yes



265/60/17 = 29. 52 DIA.



w/ 4. 10 gears...



47RE/48RE 4 Speed Automatic

Gear 1 2 3 4

RPM 2. 45 1. 45 1 0. 69

1000 9 15 21 31

1100 10 16 24 34

1200 10 18 26 37

1300 11 19 28 40

1400 12 21 30 43

1500 13 22 32 47

1600 14 24 34 50

1700 15 25 36 53

1800 16 27 39 56

1900 17 28 41 59

2000 17 30 43 62

2100 18 31 45 65

2200 19 32 47 68

2300 20 34 49 71

2400 21 35 51 75

2500 22 37 54 78

2600 23 38 56 81

2700 24 40 58 84

2800 24 41 60 87

2900 25 43 62 90

3000 26 44 64 93

3100 27 46 66 96

3200 28 47 69 99

3300 29 49 71 102

3400 30 51 73 105

3500 31 53 75 107

3600 32 55 77 110

3700 33 57 79 113



Now the max i plan to go is 110.....



I need 3600 rpm... ..... HOW?



Its gotta be cheaper than adding new gears (3:73 ) quote = $1950 whole job



P. S. So no one asks..... Yes i know the truck would look retarded with these tires and the level kit..... Level kit is coming off and rear is getting lowered

 

[XcumminsX]

Bump Bump Bump

 

[SRadke]

Nick, why not a slightly taller tire to make the speed you want at a lower rpm? 1/2' of tire height would be several mph at that rpm and cost you very little in rotational mass. Of course, you'll have to make a few more mods to pull a 110 out of a quarter anyhow.



-Scott

 

[Vaughn MacKenzie]

One thing to consider, especially on the 600s, is injection duration relative to RPM. Since the common rail extends the injection event well into the power stroke, revving it high will have you still injecting fuel when the piston is close to the bottom of the cylinder, and what good is that besides wasting fuel and making needless heat? Point is there's more benefit to making power at lower RPM instead of revving like mad.

 

[Floor It]

The ECM starts to defuel at 2950 and it falls off fast! You can rev it higher but it will not be making power. No one has gotten around this yet but I know are working on it.



John

 

[XcumminsX]

I was doing some research last night and at 3500 rpms you start getting floating valves if your boost is high enough... .