Yeah, I'm wondering that myself. And about what benefits, if any.

 

Hot Rod VP is basically taking the HO head and rotor and putting it in an SO pump that has the larger plungers. Like .5 MM difference i think. To sum it up in simple terms you are getting the higher injection pressure of an HO pump and the amount of fuel of an SO pump. Its really not worth the extra money if you are not looking for extra numbers on the dyno or faster times at the track. You wont gain a whole lot on a street truck.

 

what color smoke?

if its black, probably due to the warmer weather that comes this time of year...not the pump.


Pat

 

It is black smoke, but I havent changed anything fuel wise on this truck in a couple of years now and other than the white smoke in winter I couldn't make it smoke until a few weeks ago, but I'm still up for any suggestions. I sure can't afford a new pump, but can't afford to be broke down either.

 

black smoke = too much fuel to be burned completely for the amount of air entering the engine.

warm air is less dense than colder air, therefore less fuel will be burned and it will smoke as a result. also, check for a dirty air filty and loose intercooler boots.

Pat

 

Still alot of open questions through this thread, hopefully there is more help out there.

 

A lttle out of the way, but there is a Cummins shop right on I-44 on the east side of Tulsa. I am sure they could do the pump swap for you.


Roman

 

I believe the Hotrod VP44 can also be a HO pump with the SO head. Hotroding the HO will give it 16% more volume.

Besides programming and volume differences, the HO pump works at much higher pressures. With the Hotrod you get the pressure of the HO pump and the volume of the SO.

The SO pump will not work on the HO.

 

When you guys swap SO pumps onto HO motors I assume you're swapping the matching ECM with it? Otherwise it won't work for sure, but I am wondering if anyone has done this and had it work (will the ECM be incompatible with the PCM?).

The HO VP44 was designed for faster fuel delivery during injection.

Vaughn

 

If it helps any I have a HO pump on my 98.5, runs fine.

 

The Hot Rod VP doesn't make any addition peak HP than a SO pump, but they do broaden the rpm range that the power is made. This is kinda like a lot of the aftermarket cams out there, they don't make any more peak HP than the stock cam but they do broaden the power band (OK they also lower egts...).

All of this would help you out in everyday driving, drag racing, or sledpulling. The guys that I have known that have switched to a Hot Rod pump all seem to be happy.

Doug

 

There are different PLC's (Programable Logic Controllers) in the HO and SO pumps. They will run if swapped ie: SO on an HO but the engine is sluggish and has no power. Been there done that - one example - an engine swap was done at one of the local used truck lots (01HO engine lunched #6 piston). They put a 99SO salvage yard engine in a 2001HO truck with the 01 ECM and a 99SO VP44 there were numerous other electronic/cam issues that would take forever to explain .... I changed out the VP44SO to an 028 pump and they were back in business.

Doug is correct .... the HR pumps broaden the range and are quite nice for those that are serious about playing .... but usually not needed for most of the population - unless they just gotta have it!

 

So if the SO pump will not work with the HO, does that mean that there is no Hot Rod pump for the Ho? Maybe I understood it wrong, but that is how it sounds to me.

 

Think what is being said is
1. The head is different betwwen -27 & -28
2. The plungers in -27 head are 7.5mm & -28 is 7mm
3. You can put the head from a -27 into a -28 more flow
4. You should not take the head from -28 to-27 less flow
5. There is programing differences between the two
6. The cam rings are different also

 

i'll be doing the swap....... hard enough to swallow the purchase

any how-to's on the swap?

get the hotrod pump from Pierce? 1300 for it?