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Discussion Starter #1 (Edited)
Had an interesting phone conversation with the owner of TST products today about the so vp44 fuel pump.
He was a Cummins employee and has worked on and has had access to testing the vp44 and prior fuel pumps.
He said that the high pressure side of the internal vane pump produces around 300 psi at 2200 rpm engine speed, and that the actual injection is done by a piston that creates the high pressure pulse and also directs it to the correct injector. This piston not only pushes the fuel to the injector but also rotates or spins to line up with the correct injector port in the VP44. He said that many of the pump failures are attributed to the piston ceasing from lack of adequate lubrication.
He also said that when the HP is pushed to high levels by programmers and oversize injectors (100 hp and up) or stacking programmers with the larger injectors, this piston can suffer from an inadequate fuel supply being able to fill the piston for every time it fires the injector(s). This can cause the power to come and go in quick spurts under heavy loading and higher rpms, even with the FASS or airdog pumps of 100 gpm flow. It's not about the fuel to the vp44 this he said can happen with 15+ psi at the vp44 fuel inlet.
He said that the hot-rod pumps that are built have different parts from Bosch that have a larger piston with more capacity, and that they (TST) no longer build them.
He also said that when a vp44 is rebuilt that the pump does not have to be put on a test bench and programmed, that the parts are all connected to the electronics and programmed when they get them from Bosch. They have even taken the internals from one pump and put them into another with no reprogramming as long as the electronics are not taken apart and reassembled. It's like taking non volatile memory out of a computer and putting it back into another computer of the same configuration.

So my question is how much hp have people been able to get from the stock so vp44 with injectors and stacked programmers without having apparent fuel starvation?

Thanks
Jim
 

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That is a good question I would like to know myself before I start adding stuff to my truck...
 

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Well Jimbowe I got over 100k (from me alone PO had put miles on her too) from my stock HO pump, with a powermax 3 and smarty stack, and injectors from 100 HP to ++300. Pump is still working fine, I just upgraded to the SO pump for its larger plungers, and better response to electronics. To answer your question, the SO is said to support 6 - 650 hp.
 

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i know a guy that just did 653 on fuel only with a stock output pump. Also another guy did 720 or 730 (i believe) on fuel and for sure 813 on the bottle with a stock pump with over 100k on it.
 

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no you'll need a good lift pump and maybe an upgraded torque converter--- Like matthews8pt said, There was recently a thread about a guy who made 729 on an sovp44. I'm guessing its kind of a luck of the draw. Some SO's can handle more than others..
 

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I made 640hp on my original SO VP with 275,000 miles. It gave up its life at 325,000 miles. It actually never died, but got a sticky timing plunger.
 

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325k off an original vp is rediculous..
 

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Discussion Starter #8
The reason I started this thread is because, with what I have on my truck (see sig), it was cutting out and coming back quite violently when using any PowerMax setting over 4 with the smarty on anything above stock. So I was thinking that they didn't play well together. As a result I called TST and had the discussion (first post) and was told that it's possible the plumger was running out of fuel. I had already checked everything else out.

Well, I started on my trip to Montana with about 8K in tow. I kept the PM turned off as it seemed to cause some problems. Leaving TOK Alaska (about 350 miles into the trip) I got the bright idea to try the PM one more time as all other problems had gone away (including the stalling when shifting into drive - I now believe that was caused by winter fuel). I turned on the PM and set it on 3 then started to give it a little fuel. As soon as the box started over fueling the pump (green light on the box came on) there was a loud BANG from under the hood and the truck died. I coasted to the side of the road and tried to restart, nothing, tried again, nothing. Turned the key off for several minutes wondering what to do next. I tries another restart, it stumbled a couple of revolutions and started. It seemed to run perfectly, and has so far into the trip, and i'm in FT StJohn 1200 miles down the road from then.
The PM has I've discovered quite literally lost it's mind. the displays of EGT and boost are erratic to say the least.
At least I can somewhat monitor the boost with the SG II MAP reading.

I'll let you know what and when I can.

Jim
 

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I made 600.2 on Tuesday with everything in my sig without any sputtering. I've never had a problem out of mine and it has been modded for the last 25k miles. Could someone post a link to the 729 thread. I would love to read up and see what that guy had. I knew that **** smile just did 653 which was very impressive but I didn't know anyone was over 700 with an SO pump.
 

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I made 600.2 on Tuesday with everything in my sig without any sputtering. I've never had a problem out of mine and it has been modded for the last 25k miles. Could someone post a link to the 729 thread. I would love to read up and see what that guy had. I knew that **** smile just did 653 which was very impressive but I didn't know anyone was over 700 with an SO pump.
There used to be more 700+ SO trucks back before everyone jumped on the p-pump conversion bandwagon.
 

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Wow Jimbowe with the exception of our injectors our setups are pretty similar and Ive never had that happen, even with the 150 s. Now if you turn the smarty up to 9, and using the revo turn timing AND duration way up strange things will happen.
 

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What is an SO pump?? And where can you get one?? Thanxs.
 

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What is an SO pump?? And where can you get one?? Thanxs.
SO = standard output. HO = high out put

SO pumps came factory on trucks from 1998.5 - 2002. HO pumps were installed on the later (2001-2002 I think) 2nd gen trucks with the 6 speed manual. The autos and 5 speeds got an SO pump.
 

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Well i have heard 500hp -600hp from SO pump, i also read, that when and if you are going to replace a vp, insist on having new electronics, otherwise, you could pay for a pump that has electronics with 200k miles of heat cycles on it. I have read alot of threads, and web pages about cutting out, stumbling after new pumps installed. Check the electronics.
If smokincummins got 325k out of his pump, i dont have too much to worry about at 150k
 

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Discussion Starter #18 (Edited)
Wow Jimbowe with the exception of our injectors our setups are pretty similar and Ive never had that happen, even with the 150 s. Now if you turn the smarty up to 9, and using the revo turn timing AND duration way up strange things will happen.
Haven't used the smarty to turn up timing and duration, I'm now certain that the PowerMax went out.
The display will not give accurate readings for boost and EGT. At times it will shut off altogether then come back on and work for five minutes or so then go way off again. I've checked and double checked all the connections in the harness to no avail.
Anyway I've made it to my destination in Montana, 2,400 miles of it (since the big BANG) without the PowerMax turned on and the truck is running fine. It just don't have the power I normally have with the PowerMax so I'm shifting out of OD a lot more than I usually do.

When I get back home I'm going to make some changes to the truck setup.
Before I left I put on a HX35/40 with a 14 CM2 exhaust housing. I'm finding it way to slow to spool and smokes like crazy when the engine rpm's are below 1500. so I'm going to put on the 12 CM2 housing and see how it works.
I also think that I'm going to replace the edge +80 stage II injectors with 275s to try and get back some of the lost mileage. I'm averaging about (haven't done the hand calcs yet) about 13-14 with the 8K load. That's down about 1.5 2 mpg from the trip last fall. Heck when I pulled the 17k trailer on one trip I was getting 12.5 mpg with the stock injectors and just the PowerMax when it was working, and I drove faster.
So I'm thinking that the +80 injectors and the smarty tuner and the HX35/40 are giving less mileage and less overall performance than the stock injectors with the HX35 and 14 CM2 housing and the smarty.
With the PowerMax (that works) I have the economy of the closer to stock setup but can add the power when I want it. It's more the best of both worlds for towing. Guess I'll find out for sure when I get back to Alaska and make the changes.
 

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SO = standard output. HO = high out put

SO pumps came factory on trucks from 1998.5 - 2002. HO pumps were installed on the later (2001-2002 I think) 2nd gen trucks with the 6 speed manual. The autos and 5 speeds got an SO pump.



SO's were in the auto trucks mainly, 235hp. HO's were in the manuals, 245hp. Nevermind, i just finished reading the last couple sentences. Mods can delete pretty much the same post.
 

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SO's were in the auto trucks mainly, 235hp. HO's were in the manuals, 245hp. Nevermind, i just finished reading the last couple sentences. Mods can delete pretty much the same post.


Like stated before only the six speed got the HO, all others had the SO :thumbsup:
 
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