I just found out that the HO version of the VP will bolt right on the standard output motor giving around a 30-40 hp increase! Reason is the HO runs at a higher fuel pressure but has smaller injectors to keep the numbers down. Thats why they dont respond as well to boxs like the standard motor but wake up to larger injectors. So I thought that if anyone out there was interested in buying a VP you might want to look into getting the HO version and get a few ponies while at it. Just sharing if anyone cares. If anyone has already done this please let me know.

 

Yes you can do that, but if your going to modify the truck with injectors and a fueling box, it is not the way to go. If you are staying stock then yes you will gain some hp. Theres internal differences in the injection pump as well, which is why they can't show the same hp with a fueling box and injectors as an ETC motor.

 

I do know the HO pump will run out of fuel faster than the SO pump will once you begin the climb to higher HP. If max power is in your future. Stick with the SO.
Yep, the HO can deliver more of a punch at near stock levels, but will begin to fall behind at 450HP.

Main differences are the HO pump uses 7mm plungers, but ramps them to pressure faster. The SO uses 7.5mm plungers and ramps them to pressure slower. More volume with less pressure.

The injector size differnce is there, but its not a bunch either. About 4% more flow on the SO engines.

Don~

 

Interesting! Then whats with the after market pumps you can buy? Like from Piers. What makes them so good?

 

They don't melt,,

I've got a VP44 from Piers, and it hasn't broke yet.

Merrick Cummings Jr

 

A couple of years ago the hot idea was to put an ETC pump on an ETH when it was discovered the ETH doesn't fuel as good as the ETC. I checked with Lawrance form DD about the swap. He had tried putting an ETH pump on an ETC and it didn't run well at all. There's a timing difference between the two VP44s.