It’s time to replace the VP44 on my 01 HO 6 speed. I’ve been doing a lot of research on different pumps and suppliers. 
I’m taking the advice of Mopar Man and have decided to go with a DAP remanded pump. 
my question is are the “Hot Rod” pumps worth the extra coin?

I will be upgrading my injections to 7x.010’s from DAP at the same time. 
I do not have any tuners on the truck. 

No. Don't bother with a hot rod pump. Only roughly  20 HP gain. Makes a problem for tuning being the hot rod pump mechanically advanced internally. Better of with stock SO pump 

Why the SO pump? 
I have seen where they use that one instead of the HO. 

The Bosch part numbers for the SO vs. HO injectors are different, but I do not know if there are differences in pop pressure, nozzle spray setup, etc.

 

Don't the HO units ramp up injection faster? Do they inject later (retarded) when there would be higher cylinder pressure and temperature? That could lead to NOx issues with emissions but give better performance - were HOs available in California? Also a louder rattle, which maybe they wanted to avoid in SO motors for noise and harshness reasons... just thinking "out loud" here.  DAP, Me78569, and AH64ID (along with others) would likely be some of the best equipped to answer these questions.

 

EDIT: just confirmed that he pop pressures are the same, at 300 BAR, -0, +14 BAR.  Per BOSCH Application Guide 15091457 I have (dated October 2015).  HO injector number is 0 432 193 581.  SO injectors numbers end with 629 (manual trans) or 630 (auto trans).  This is regardless of year.  275 HP injectors are 0 432 193 635, same pop pressure.

Edited March 3, 20223 yr by LorenS

HO pumps have a more aggressive ramp up of fueling via the pump ring, but the ho also has smaller diameter plungers causing total fuel per stroke to be less than a SO pump.  

 

Generally people run a SO pump because they want the larger plungers and their tuner makes up for the slight bump in timing a ho pump gives.   

 

either ho or so will be fine for under 500 hp.  if you are running no tuner and don't plan on running a tuner then the HO might be the better choice.  however without some sort of boost fooling on the ecm to allow boost higher than 18 psi your setup with the 7 x .010's wont really be that great.   

I can second getting a SOVP. I came from a dragon flow vp44, now a SOVP on a HO truck. DFVP44 is one of the biggest vp44's out there, made a TON of HP, but man they are a pain to deal with. Same goes with the hrvp44. Stay away from hrvp44's and go with the highly suggested sovp44. 

 

Edit/side note: HO trucks can use a SO pump but a SO truck can't use a HO pump.

Edited March 5, 20223 yr by Stanley