Mav

Will a hrvp pump be an increase of power over an So pump with 200+ hp injectors an a drag comp?? Im trying to learn a little about 24v im a cr dude. Also at what point is a lift pump needed? Also someone said with a hrvp any injector over mach 4s dont make a difference....... is this true? THANKS GUYS

Mav

Also on these trucks what does it take to break into 12s? THANKS

zulusafari

In a nutshell, no.

The Drag Comp takes over the electronics anyway, negating the HRVP horsepower increase. Get the SO, which will fuel just as hard with your mods, and save the coin for more goodies!!

Mav

Thanks so a SO pumped truck with a drag comp will outrun a Ho pumped with a drag comp? Or no

pmtg

HO's dont need anything more than a Mach 4. HRVP is not the same as the HO VP.

at what point is a lift pump needed? stock levels ! adding HPs demands a strong setup...you cant get away with the stock LP when wanting more HPs. walbro, fass, rasp, holley, etc etc

i dont have experience with a HRVP but if a drag comp is being connected, i dont believe a HRVP is worth the extra money. meaning, it wont gain you anymore HPs...well, on the top end.

in the competition/sled pulling section on this website is a list of 1/4 mile times with the mods that got the owners there.

zulusafari

Our trucks always need a lift pump. The stock unit is junk. Either relocate the stocker away from heat and vibration, or go with a Walbro or other high pressure and capacity pump. I have consistent pressure and supply to the VP44 with my Walbro and bypass setup, where my stock LP would lose pressure over time. If you don't have a fuel pressure gauge or a low fuel pressure light (I have both) then you probably should get one. Not that the gauge will save the VP, but it definitely will show when your lift pump is dying. Any fuel pressure below 5-6 psi is considered dangerous. I ran at 5 psi and less for fewer than 15 miles, but the VP44 was damaged anyway.

pmtg

that is correct

zulusafari

OK, I see a bit of confusion here. The SO pump is for Standard Output Dodges. The HO is for High Output Dodges, and has different internal parts to give a stock truck 10 more horsepower over stock SO's. HO trucks had different engine controls, I believe, to make use of the electronics on the HO pumps. If I am incorrect, someone with more details will chime in.

The HRVP is the Hot Rod VP44 sold by some performance vendors, and it is a souped up electronic version of the SO pump, with some difference in the internals.

One interesting fact is that the SO pump is actually capable of flowing more fuel than a HO pump. I have read that the HRVP and SO pumps flow pretty much equal, but it is the way they are controlled that akes the difference in power. Therefore, if you add a fueling box to a SO, you can get more power increase than the same box added to the HRVP. Notice I said Increase! The HRVP and the SO will make pretty much the same power with the box, but the HRVP will make more power than the SO will, on their own.

Don M has a really good explanation of the cutoff points where a HRVP makes more sense than an SO. Basically to me, it was cheaper to put another SO pump on my truck and add a fueling module than to install the HRVP. Plus, as I add even more to my truck, the SO becomes the better choice over the added initial cost of the HRVP, which is no longer any advantage to me.

RickCJ

I don't know about all that! but my SHOVP makes a lot more power with a regular Comp and 100hp injectors than the stock SO pump did! I haven't dyno'd with the SHO but it feels like at least 75 more hp.

The Comp increases the signal to the computer so if the SHO signal is higher than the SO signal wouldn't that show a higher increase? plus the higher pressure.

Mav

Thanks its somewhat clear now

Mav

Looking at the tst comp whats the difference between the 1999 manuel and automatic version, why should it matter as long as its for the correct pump??

99globalwarmer

wait for the new line of vp44 to come out then buy a injection pump.

Mav

whats new about them or what are they supposed to do better? Also whos going to make them

inline6power

look for a thread on hear that i have going called MONSTER VP!!!!!!!!!

NoSeeUm

From what I understand it is both.

The HO pump comes standard with longer stroke and smaller bore than a SO pump. This increases the rate of rise in fuel pressure to the injectors, but also limits the maximum fuel flow rate below that of the SO. The HRVP combines both, with a longer stroke of the HO and the larger bore of the SO. So as far as pumping ability it gets the best of both.

The HRVP also comes with tweaked electronics. Basically adding timing. Because the pump is only capable of a given amount of additional timing due to mechincal restraints that is the reason a timing box like the Comp don't have as much effect. Think of trying to stack two timing boxes, is more or less the problem. This is also the reason less Hp gain results from a HO truck over a SO truck for the same timing box. The stock HO electronics already have more timing.

From my understanding a HRVP and a fueling only box works pretty well. It also fuels harder at low RPM, I guessing due to the electronics on the pump.

Jim