injectors vs fuel box wrt vp44 workload

[Sean Flanagan]

GWS,
I have heard that larger Injectors actually put less of a strain on the injector pump. Although, I think all of it is just speculation. Nobody really knows, except maybe Bosch.

The only problem with the Fueling boxes that use the fuel pump wire to connect is the tell tale nick in the wire that could void your engine warranty. Other than that, they give you more bang for your buck.

I tried DD3's here in Colorado. The cold wasn't the problem, it was the altitude. Less air means more smoke.

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98. 5 2500 QC LB 4x4 5spd, white. BFG 285x75x16
Cummins 24v w/ TST PowerMAX w/EGT and Boost gauges on A-Pillar. VanAaken CPC. K&N In the factory air box. Stock Injectors, Stock Exhaust (Geno's Muffler Eliminator). Re-routed breather stink tube, 2WD-low kit, SnugTop, JJ Stainless Running boards, Tow Hooks, Bushwacker Street Flares, and a Cup Smoothie.
83,000 miles (1/10/01)

 

[GWS]

We often read posts discussing the relative merits of injectors vs fueling boxes as performance enhancements. When I made my choices, I decided to go with mild (275's) injectors, since I was worried anything larger would cause smoke problems especially up here where winters are long and cold. But as I play with my PE I wonder how the injector pump is holding out, which leads to the question of whether larger injectors put a strain on the pump. It seems injectors work all by themselves while allowing the fuel pump to operate according to the oem programming. If this is true, and given the wide range of injectors available, I suggest that the best (as far as vp44 is concerned) method of bombing is to use injectors plus a timing box (VA or EZ) and stay away from the fueling boxes that wire to the pump. Any experience with large (ie DD3's) injectors and cold climates?

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98. 5 24V QC 4X4 AUTO, 275'S VA, PE, DTT TC AND VB, PSYCHOTTY AIR, BOOST AND PYRO GUAGES, AEROQUIP
FUEL LINES BY V. M. , ESPAR HEATER, 2" SUSP. LEVEL, 255/855 DUNLOPS, AMSOIL FLUIDS.

 

[Bart Timothy]

I used to believe and preech the fact that injectors are easier on the VP44 than a fueling box based upon information given me by knowledgable people I trust. On one thread a few weeks back the discussion got on this very subject and Mark from TST stated that their experience from pump failure stats suggested that boxes didn't significantly increase pump failures. It's hard to argue with someone like Mark because of his vast knowledge of the inner working of these engines and him having the statistics to back it up. I know that in the SLC area at one time there was a rash of failures attributed to the many Blue Box installations here. It scared many people off the Blue Box. By the very nature of how a fueling box adds to the signals already coming out of the VP44's cpu to the fueling solenoid one would think that a box places mare strain on the pump than at least stock fueling does. So I don't know what to think anymore and maybe only a Bosch engineer would know for sure.

 

[Archive]

Lets see. An alteration is made to the fuel pump control signal that results in increased fuel delivery rates from the fuel pump. Could someone please explain how the fuel pump can accomplish this increased fueling task, without ANY increase in mechanical "stress". (I am not referring to a timing only signal alteration. )

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1999 White SLT Dually Auto 4:10 Posi. NOT BOMBED... ... ... ... (very much) 28,000 miles

 

[Brandon]

FUEL PRESS GAUGE AND GO ON WITH IT

B
also check out the lift pump thread that is running everyday


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Danelle's Dodge

 

[Archive]

We are discussing the VP-44 injection pump service life when it's operating with an altered signal from the ECM. The question in my mind is what IF ANY affect the electronic add on boxes would have concerning the VP-44's expected $ervice life. (We are assuming that the lift pump pressures are within specs to eliminate any obvious "lack of lubrication" failures. ) QUESTION: Which do you TDR members believe would last longer; a Boosted VP-44 that operates on a diet of lubricity enhanced fuel, or a Stock VP-44 running untreated #2 straight from the nozzle. (sorry... ... . this past weekend I had a lot of time on my hands to meditate about this kind of stuff)

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1999 White SLT Dually Auto 4:10 Posi. NOT BOMBED... ... ... ... (very much) 28,000 miles

 

[Archive]

Bart, thank you for a concise very well written post. I really enjoy this kind of brain candy. It would sure be nice if someone who was involved with the R&D of these boxes would step up to the plate and de-mystify the process. It COULD happen. Just look at the knowledge everyone here has gained about the auto trans from Bill K. 's posting. What I want is a Bill K. "clone" from a box manufacturer. I'm not asking for proprietary programming information. I just want a factual explaination of how their system operates and how well it integrates with the factory electronics. Is that too much to ask? I think Bart's posting ^^^ is the best most accurate description of the process I've read to date. I'm learning.

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1999 White SLT Dually Auto 4:10 Posi. NOT BOMBED... ... ... ... (very much) 28,000 miles

 

[Bart Timothy]

I'm still learning but here's how I think it all works.

When you use a box such as the PE you're sort of bypassing the ECM and definately bypassing the VP44 cpu.

The PE, or boxes simular, actually sends signals directly to the fueling soleniod, which usually gets its siganls from the VP44 cpu. Because it ties parallel into the soleniod line it has the ability to increase what ever signal is there but not to decrease it. I believe the signal must be analog, probably voltage.

The ECM talks to the VP44 cpu thru the Can-bus (which simply stated is a set of communication protocols). They talk digital. The VP44 cpu does have an upper limit - send it too big of a number and it interpets that number to be zero. Boxes like the EZ tie into the Can-bus and capture the signals sent from the ECM, modify them, then send them on down to the VP44 cpu. So the EZ has the ability to control fueling, but only to the limit of what ever the VP44 cpu will accept, and by definition doesn't fuel as much as the PE can.

There is a "latency factor" in using these timing boxes because of the capturing, processing, then sending on the siganls to the VP44. I believe the Can-bus operates at something like 20k bps and the EZ has a 20 Mhz cpu doing the number crunching, so there probably isn't very much latency. This all has to do with how precise the fueling is in relation the mechanicals of the engine.

I would think that the engineers designing the VP44 would have in mind the safe operating range of the fueling solenoid when they programed how large a number the cpu would accept. Because fueling boxes bypass the cpu they are, at the least, not considering what ever limits were programed there for the VP44 structural reasons.

Someone set my thinking straight if I'm wrong.

Bart