here too

They've got the VA's also.

 

yea, absolutely. me too! I don't mean to be a pest here -- my only point is that torque isn't really the end objective. That would be like saying you want to push your stalled truck to the dealer for service, and you can push on your back bumber with 100 lbs of force. that doesn't express how quickly you'll make it there.

Horspower is your real objective, because horsepower is what pulls you up the hill (remember, 'rate of doing work'). an increase in torque is just [b]one[/] means of obtaining additional horsepower. But note that once you say "torque at 1800-2300 rpm" then you have just described rate of doing work, which is horsepower! so in THAT sense, yes, I fully agree and support the use of term, torque, when in the same breath you state the rpm of interest. Because when you do that, you are really describing horsepower.

Well, yes, the classic trucking optimization of a diesel engine is an engine with moderate (or even low) peak horsepower, but a high torque rise -- the torque curve has that classic peak at the low end, falling as rpm increases. the big rig engines are even rated for torque rise -- where peak torque at low rpm is expressed as a percent increase over torque at the top end. This of course results in flat horsepower curve. the result is that the driver does not have to shift down to gain additional horsepower (via an rpm increase). the high torque rise engine pulls just as well at 1600 as 2000, for that reason.

the desireability of this behavior is the interesting point. From a theoretical standpoint, what harm would there be in raising the right-hand portion of the torque curve so that peak torque is maintained throughout the power band? nothing really, except that as a practical matter, long stroke diesels tend to fly apart at and make high EGTs at high rpms, and prefer to grunt and pull at the low end. So you have the natural optimization of a diesel engine's abillity to make power is a flat horsepower curve, obtained from a torque curve with high torque rise.

ahh, we are in vigorous agreement!

LROD: I only recommend that you try before you commit. It is monumentally instructive to drive these boxes. You'll see the classic tension between high end power (passing, acceleration while empty but at the expense of EGTs) and low end power (optimized for towing and cruising stability)

As for a source for the VA boxes, check out Precision Diesel in New York. As for Danny. Also, Piers sells them I believe. I've never heard of a Van Aaken "CPC".

 

doug, if you would give an explanation. The VA smartbox adjusts the quanity of fuel delivered, without putting pressure on the fuel pump. With this addtional quanity of fuel, why do some users report additional fuel economy. ie. more mpg?
Thanks for any help on this.

 

Just like the other pressure boxes, the VA does put more pressure on the rail, but only a few hundred pounds. I think some of the boxes have hit on an improvement in efficiency, probably because the spray pattern or plume has been changed.

What's funny is there seems to be just as many folks out there with EZ's that are getting better milaege as those that aren't. I'm betting it's individual driving habits, and maybe a little bit of dumb luck.

So you any closer on picking which box?

 

I want to install the X-Monitor before I put in a box. Should be tomorrow.
Just doing my homework right now as far as the box goes.
Those two boxes look pretty good at the moment.

 

rmb: VA claims that the C3.1 pressure box raises rail pressure by only a few [on edit: hundred] pounds, yes. Based on the small increase in peak horsepower, I'm inclined to believe them, although I expect on the order of 1000 psi per 25-30 HP gain at the rear wheels, which would put the increase at or just under 1,000 psi. I haven't measured it yet though.

spray pattern or plume improvements is a Predator claim that has not be validated with any statistically meaningful rigor. its a theory suggesting that with elevated pressure reduces the required duration to acheive the same fueling. As to whether or not thats true or matches its claims we don't know. Your comment about fuel economy is spot on.

LRod: There is another possibility that could explain fuel efficiency and that is with the increased amount of fueling at lower rpms, the engine itself might be a tad more efficient if the result of the box is less time spent at the higher rpms. this particular effect would apply more to the VA box than others because thats where it makes its power gains

I'm still convinced some guys believe the overhead trip computer...

 

I am looking for HP not necessarily torque. My towing plans that I bought the truck for fell through. Now I want to see how fast that 7400lbs will go in the 1/4 mile.

I have gauges installed. Putting on the aFe Mangnum Force Air Intake with torque tube Saturday. Trying to decide to straight pipe or AeroTurbine/Donaldson muffler.

Want to start simple and conservative to see how mods affect engine conditions(EGTs, Boost).

I really like the simplicity of the Predator Stage II. I don't think I can damage anything if I watch what I am doing.

Don't want to get radical until I can afford the Trans upgrade.

I have a PredatorPower dealer in town. Going there today to talk and probably buy.

I will let you know what impact it has from a racing performance perspective.

I really appreciate all of the information that I have gained from this thread, though I am not sure that all of this knowledge will lead me in the right direction.

Thanks guys

 

I'm always comparing the computer to the calculator and most of the time they're pretty close! IF I stay out of the throttle most of the time.

Ram, you don't necessarily have to give up one to get the other. I'm happy with the towing improvements the Predator gave me. I think though, if you're really after all-out maximum power, boxes like the TST are in order. Check out Dougs box summary, because there's other fueling boxes that are more top end than the predator or the VA.

 

I have a stage 1 and really like it, I was told I can upgrade for the diff. in price. Should I do it? Can I still tow heavy without EGT issues? I have exhaust and intake already and EGT's are not an issue at all with the stage one. Does the stage two connect to the MAP also? My stage one only connects to the fuel pressure sensor.(no boost fooling) How much boost does the Stage two run max?

 

I now own an aFe Magnum Force Stage II air intake, aFe Torques Tube and Predator Stage II for 2004.5 Cummins 325/600. Will install Saturday.

They almost talked me into Banks Monster Exhaust System for 325/600 with tip installed for about 500.

Or I just add AeroTurbine 4040 in place of stock muffler.

Starting BOMBs conservatively. Cant afford to break anything major until spring time.

 

I'm sure my SO reacts different to the HO, but yes I tow 9000+ no problem. On steep hills I can pull about 60-65 without getting too hot. I know, that doesn't sound like much, but I couldn't hit 50 before the box. I think only the stage 3's and 4's connect to boost, mine doesn't. I don't have the boost gage yet, don't know how much I'm getting.

 

So yours only connects to the fuel pressure sensor?

 

I have the 2018 in mine and works very well, never hit over 1250 while pulling 32' fifth wheel in the mountains,does nothing for mileage though, still around 16ish highway.

 

Yep, mine only conects to the fuel rail. The video clip they show for says it also has a MAP connection. But when I called them they said not on this stage 2.

 

That is funny. The 04.5 stage II that I saw had the map connection. Only the stage I seemed to have the single connection. Something sounds funny.