SO vp44 for HO

dipapadakis

dipapadakis

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Jan 20, 2011
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swapped out my ho vp44 for an so with expectations of loss on bottom end and gains on top end, i noticed less power on bottom end less smoke and less power on top end and less boost. with a near stock setup will you notice a difference or do you really need a hotter setup to notice a difference? i also heard when swapping you need to reprogram your truck as an etc in the ecm and that may be why i have loss of power overall? never heard of this before so just curious...
 
Shouldn't notice much difference till you get to the 500 hp mark which is roughly how much the HO pump can support...
 
That's kind of what i was guessing but i wasnt sure, any clue on reflashing the ecm from the eth to etc programming?
 
I have an HO on an SO truck. If you drove the HO truck without the Power Puck & the SO with the power puck in just timing mode (I think they can do that like the Edge EZ), they would seem identical.
Now, with my HO on the SO truck with the Quadzilla & COMP2 tune, I had to pull timing advance out of it in custom tuning to keep it from having a bucking at cruise.
Also, you have swapped your VP. I would suggest building a " Boost leak tester Cummins " to ensure that something isn't loose.
When doing your VP, you pulled bolts from the intake manifold plate. If it is the stock gasket, it is extremely brittle & may have cracked. Also, when putting ALL of those bracket, fuel filter bolts back in, you MUST use sealant, as they go into the intake plenum & WILL leak. If you haven't already done so, I would suggest pulling the 1st 3 or 4 lines (Look up intake gasket tutorial) & all bracketry to pull your intake plate. The 3rd Gen gasket is better. What I did was use the fatory gasket from NAPA & Permatex#2 gasket maker & glue the new gasket on the cover after FULLY cleaning & inspecting with a mirror for debris, put all of the bolts in the intake plate with the gasket tacked on & weighted down for 1 hour. Slide it back in. Bolt it back down woth the black or grey RTV (just a thin line down t a side of the bolt & reassemble. Also, you may notice (With said boost fooler) that you have leaks at the boots. See if tightening will help, or call Silicone Intakes for dirt heap priing.

Ed
 
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The ECM sends desired signals to the FPCM located on top of the VP44. THAT computer then decides what to do. Also, the HO pump has .5MM smaller plungers & cannot support the high end HP of heavy mods. Bolting on the SO VP , it gets the exact same signals from the ECM.

Ed
 
Farily certain that is not correct since there are different ECM programs for SO and HO pumps.
 
I swapped a SO vp on to a HO truck and it ran awesome no problems. I didn't need to flash the ecm.
 
i've put an SO on a HO truck without flashing the ecm. truck runs fine.
 
I have done the same (SO pump on HO engine) with both the orignal HO ECM program and the SO program. Both worked fine for me too; however, there was definitely a lower rpm power loss with the SO pump.

Before that, I programmed the ECM with the SO software while the HO pump was still on the engine and it worked OK, but there was the occasional rough running / stumble that could be "cured" by shutting the pickup off and restarting.

Since there are different ECM programs for the two pumps and since the HO pump did not like the SO ECM program on the '01.5 or on the current '02, there must be a difference.....right?
 
I actually have Ghostman's (Thanks again) HO on my SO truck. I will check later, but I beleive that the difference is in the VP & FPCU itself. Now, when you reprogram the ECM, it may have changed values in the FPCU.
I am studying some info from back in the day about the FPCU to see what can be done with it.

Ed
 
Stock for stock, HO's make more power. Put an edge ez on an SO and they'll be pretty close. HO's have different electronics. SO's have bigger plungers and barrels for more fuel. Combine the two and you have a hotrod pump. HO's have more timing stock which is why they feel better on the bottom end. They respond better to fueling boxes up to around 500hp. Above that, an SO wins.
 
The Quad with the COMP2 tune was too much timing for the HO. I had to back it off to I think 70% in the custom tuning.

Ed
 
Ol Blue said:
So you have a Smarty?
Click to expand...

Don't have a smarty, otherwise i'd just try it and see what it does, someone with a smarty said I had to program it.

The truck runs smooth, doesn't miss, just seems like it has less power and makes less boost (due to lack of fuel no smoke at all is visable any more), the gaskets are new and boost tubes are tight, just trying to figure out if reprogramming the thing would help any on driveability or power or that with such little mods to the truck theres just really no benefit of the sovp
 
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For a stocker, or close to it, the drivability of the HO is definitely Butt dynoable. Can you get a live data tool of any sort on it to check all of the readings? Do you have a turnbuckle on your turbo? With the mods you have it would help all around, as the PP does do boost fooling.

Ed
 
If you want to change the ECM program, and get access to a Smarty let me know. If you do and don't like the change, you can go back to the HO software too.
 
yankneck696 said:
For a stocker, or close to it, the drivability of the HO is definitely Butt dynoable. Can you get a live data tool of any sort on it to check all of the readings? Do you have a turnbuckle on your turbo? With the mods you have it would help all around, as the PP does do boost fooling.

Ed
Click to expand...

Have a turnbuckle on there now, haven't messed with it as i dont want to add another variable just want to see the pump only differences, and yes I think one of the guys at work has a obdII scanner, i suppose i should hook it up!
 
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