new fueling box summary includes new VA box

[Marco]

90 Volt

That's the reason. The injectors need 90 Volt to open. The electrical system only works @ 12.....



Hey I don't want to hold a complete course about the Cummins CR system here.



I guess you should get a technical manual from DCX or Cummins then you'll understand.





Marco

 

[Jeff_K]

If it takes 90V to fire an injector and the electrical system only has 12V, how does the truck run now? The Van Aaken duration box uses the existing electircal system and through the digital domain tells the ECM to extend the injection event. There already is an injection event, it's just told to stay open longer. I am an automation engineer and program control systems for a living. I am extensively involved in fuel mapping and combustion controls for GE LM2500 turbines (35000hp). It's not rocket science, but it is similar to what the box programmers are doing. I have no doubt that ALL parameters involving the injections timing, duration and pressure can be modified through the ECM. How do you think Cummins added a third injecton event to the 600? All programming. In fact the common rail cummins engine has many different fuel/injection maps depending on the application it is used in (Dodge, motorhomes, marine, industrial, etc. ). Each of these applications have different HP and Torque curves all achieved by modifying the injection maps.

 

[Blakers]

Originally posted by DLeno

I understand that for engine dynos. so brake horsepower does not refer to power measured by the braking device on a chassis dyno?



If these dyno runs are in fact engine HP, then they cannot be trusted because we don't know what correction factor they assumed.

These runs all apear to be measuring rear wheel horsepower. I was not sure about that when the charts first started circulating.



The definition of brake horsepower is just a technicality - it does not really matter here. There are a lot of different types of horsepower - brake, net, SAE, indicated, belt, pto, drawbar, and rear wheel. Probably a lot more if we dig.



Take care and thanks for a good job Doug!

 

[Jeff_K]

DLeno,



Looking closely at the Van Aaken dyno you posted a couple pages back, the "peak to peak" HP for the new duration box is only ~60HP, NOT 115HP as in your chart. Their best gain HP may be 115HP, but if we are going to compare those numbers, the TST has a best gain of 184HP from their dyno. It looks as though they start reducing the duration as the RPM climbs probably to keep EGT's in check. This still looks like an awesome box with huge midrange HP / TQ gains (where most people drive). I just want to make sure your chart was accurate (apples to apples) .

 

[Matt400]

Re: 90 Volt

Originally posted by Marco

I guess you should get a technical manual from DCX or Cummins then you'll understand.

Actually that is a big help having the factory manual in understanding what the aftermarket is up to.



I am very interested to know so when my VA level 1 showed up the first thing I did was look at what pins on the ECM were being used.

The fuel injector drivers are on that same 60 way connector and while I don't have a level 2 box I am sure they will intercept the outgoing signal from the ECM much the same way they do for the level one box. Seems very doable to me.

 

[Matt400]

Originally posted by DLeno

timing is conspicuously absent from the VA box.

I am thinking this was done for a reason. .



The level 2 box already provides a very respectable gain without over stressing other drive train components and it should be the same simple install at the single 60 pin connector.



Adding timing would call for another connection at the crank sensor and provide power levels requiring much more (owner) modifications to make use of.

It would also IMO appeal to a smaller market.

 

[DLeno]

Jeff_K -- I have pulled the numbers on my chart pending a more thorough interpretation. I hope to get some independant dyno data from someone.



boy, when I saw Marco's first comment about duration being impossible I just decided to watch the show for a while. Marco, you'll want to note that the VA duration box makes fully 100% of its power WITHOUT raising fuel pressure They already have a pressure box that operates the same way everyone else's does (insert analog error into the fuel pressure feedback loop). This one is a duration only box. But they don't control the injectors directly like TST does. there's not even a high voltage wiring harness. they're tapping into the ECM control bus. DSP, man.



Matt -- are not the crank and cam sensor inputs also available at the ECM inputs? adding timing would only add 30-40 HP. But I expect VA will play in the digital domain if they intend to come out with a timing function. for all we know, they've architected this box so that only programming changes are necessary for it do accomplish digital timing changes. why not? Edge and others have done that for years on the 2nd gen trucks.



VA must be laughing their heads off. While some scoff at duration without a high voltage interface, VA is doing it. While everyone else is playing with analog fooling, VA is perfecting DSP. I bet Edge is working on DSP too.

 

[Matt400]

Originally posted by DLeno

are not the crank and cam sensor inputs also available at the ECM inputs?

Yes but that signal arrives on the ECM 50 way connector so this would add cost to the product in the way they tap into the harness with that nice splice they do on the 60 way.

If they were to add timing it would be more cost effective to do it at the sensor but I don't think they need to.

 

[JPalese]

Just saw an ad for a Predator box that claims to do timing.



Predator series performance modules



Wonder what you make of it and if you can add it to your fueling box summary chart?



Regards,

John

 

[bpenrod]

I looked at the web site and going by the connections to the engine this is a pressure only box. Watching the video install they make the same two conections as all the other pressure boxes do.

 

[Mathew Clausen]

more pressure = advanced timing ..?

At part loads, it seems like most boxes that enhances pressure would be shortening the duration of injection (at a given power level), therefore while the start injection timing might be the same, the end time will be advanced. Very similar to installing larger injectors? Food for thought.

 

[bpenrod]

Ya got me there! I always thought (usually hurts my head!) that on a pressure box the injectors would stay open the same amount of time but due to higher pressure more fuel would be delivered. The duration box would actually alter the amount of time an injector stays open and a timing box would change when in the cycle the injector opened. I could be all wrong but that is how I was (am) thinking about this.

 

[Greg Boardman-RIP]

Originally posted by bpenrod

Ya got me there! I always thought (usually hurts my head!) that on a pressure box the injectors would stay open the same amount of time but due to higher pressure more fuel would be delivered. The duration box would actually alter the amount of time an injector stays open and a timing box would change when in the cycle the injector opened. I could be all wrong but that is how I was (am) thinking about this.

Thats how I see it too... ... ... .

 

[Mathew Clausen]

I am only talking part load timing changes. Consider these scenerios:



At 2000 rpm if the maximum power stock was 200hp, this occurred at timing 0, pressure of say 2, with duration of 2 (whole numbers just to make a point). If you increase to 250hp with pressure only, then the timing and duration stay the same but pressure up to 3. This goes along with bpenrod's statement and I agree the timing likely doesn't get effected at all.



BUT ... at part load things are different (say cruising on freeway):



At 2000 rpm to make 100hp (just a wild guess of what it takes to go 70mph) stock takes timing 0, duration of 1 and pressure of 1. Now since I am just cruising, when I add a box, it still only takes 100hp, but I have upped the pressure to 1. 1 with the box so to end up with a similar amount of fuel I would back off on the pedal and the ecm would decrease duration to 0. 9 (and possible change start timing - dependin how that is effected by throttle position vs rpm).



Does that make any sense?



Mathew

 

[bpenrod]

Seems to make sense but I don't see where the timing got changed in either of your two scenarios. In the first the added pressure gave more fuel for more hp. In the second since you have more hp due to increased pressure you only need a shorter duration "squirt" to maintain the same speed.

 

[Mathew Clausen]

Yes - first scenerio was meant to show no timing change when making more than stock power.



Second scenerio - you've got it. Shorter duration for the same power (because when you are cruising the power stays the same). So, since shorter duration, the timing has changed - not start timing but end timing.



I am not sure what effect that has , but just wonder if that is where claims of timing changes with boxes that only check pressure and map come from.

 

[bpenrod]

Could be, you never know what the marketing types will do to the facts!

 

[Blakers]

Wouldn't the "end timing" change on any diesel, depending on the amount of fuel that's being injected. If the nozzel is the same size and the pressure remains contant, and more fuel is put in each shot, naturally the "durration" or legth of time the injection event is taking place is going to increase. Thus putting more degrees between when the injection event started and ended.



I believe VA holds the durration longer on purpose in order to get more fuel in.