gunracer1

i have read his post 4 times and i never found out what the problem is. it sounds like he has spent a lot of time and money. but i still don't see what the problem is. how can a 7100 run fine on a 12v and not a 24v? the valves can't account for all his troubles. what has caused him all the head aches?
i have a buddie that has spent a butt load of money fixing his kdp when it let go, and he still doesn't have it back right yet. i did mine for less than 200 bucks and it runs like a champ. now he did do about everything wrong that he could do wrong,dropped a lifter,messed up a dv, had the pump run away with him. and hurt the pump with the run away. had to change the pump after that. but he brought all these problems on himself. he caused all his problems. i am trying to find out what problems will travis run into. no one has giving me 1 real problem. except that it is hard to tune in for the miss match of injection pressures. and i have pretty much learned that it will in fact just advance the timing a bit..

travjrath

i have been told that something was to hard , to much trouble , and that it plain wouldn't work , i love a challenge i just got done putting a cummins and drivetrain under a jeep wrangler with rockwell axles custom everything and it looks great , and it works awesome (ask gunracer ,he's seen it ) everyone told me its immpossible ,it won't work... but i did it . i am looking forward to this conversion and will share every thing i learn.
thanks , travis

p.s if you want to see that cummins powered rock crawler ... it is the one with the stack out the hood , and a camo body

http://www.4x4offroadphotos.com/Rock...ect%20Page.htm

MCummings

Hey Mike,

I'm not tryig to put you down.

I have a '98 24V and a '98 12V. They are modded about equally, and although I'm not in a perfect situation to say how they both perform now (my 24V is slowly getting a new motor), The 24V was a much more streetable truck.

The P-7100 is a great pump, but is outdated.

The VP44 is a good pump also,,, able to easily put out more than a P-7100. (no "tuning" required)

The reason I have stuck with my 12V this far, is the fact, that I have big HP goals,, where a 24V couldn't reach. But, in turn, this makes the truck run "bad" on the street.

My 24V can make it's own timing advance, and retard.

My 12V is stuck at running optimal timing for 4,000RPM at 800RPM.

The P-7100 is a good pump,, I think that is not disputed, but the VP44 has more manners. I've been around High HP long enough to say that,, for all out HP, the P-7100 is The Pump to get,, but for a combination truck,, that pulls, and drives on teh streets,, a VP44 is much more mannered, and sophisticated.

I went 20,000 miles on my VP44 and killed a few Lift Pumps, and it's still going strong. I credit that to my Edge COMP that wasn't fueling very hard. We'll see what it does with a special COMP from Edge.


I think it coes down to this,,,

A VP44 is plug and play,, it adapts to current RPM, throttle position, and Boost. Add more fuel, and it will adjust to it.

The P-7100 is a stupid pump, governed by springs and levers.
It can fall out of tune easily,, if you change altitude, it is no longer tuned,, if you want more power, or change a turbo, it's no longer tuned.

Although the P-7100 pump can deliver more fuel, the VP44 matches the motors current setup better, taking less fuel, to make the same HP.
The VP44 is more emissions friendly, and this can lead to lower MPG when cruising because of timing, where the P-7100 isn't emissions friendly, and can be setup for insane MPG.

That's my $.02

Merrick

gunracer1

hey merrick, i am not saying the vp is not smart pump, it is just not a reliable one. i am willing to give up a bit of timing and put out some smoke to make sure it works. i have seen way too many vp's drop dead, even stock. for me to mess with one. heck i keep checking the auctions for a 2001 or 2002 ho 6 speed truck to replace mine. i hope to find one that need a pump. the first thing i will do is p pump it. i don't want any thing to do with a vp44. and travis has had his fill of his. so here goes nothin.

Dr. Evil

Ive been following this thread......when you have it working, give us an update so we can find out how things went....

gsdog1

I am with the good Doctor on this. Let us know when it is done, and how it went - please refer to my last post on the topic....

Matt

John_P

gunracer1:

I agree with what you have said about the P7100 pump!!
IMO, it is way ahead of ANY VP-44 in toughness and
durability!! No doubt about it!! What is funny to me is
that Dodge/Cummins changed to the VP-44 in about mid-
year 1998, and during the time of that run (1998.5-2002)
owners of those 24 valve trucks have been "fighting" with
the fuel systems (inadequate fuel system causing failures
of lift pumps and the VP-44 fuel pumps)!!! Now,......here
comes the 2003-2004 Dodge CTD (Common Rail) Engine
with that "new" fuel system!! Guess what???? They are
finding out already that you can pull the fuel pressure on
those to "0" with just the low H.P. boxes!!! So, what
is the answer to that??? Install a "pusher pump" or
auxiliary fuel pump to "up" that pressure!! Several
companies are already offering them!! So we are having
to do the same basic things on the CR engines that we
had to do on the 98.5-02' 24 valve VP-44 engines!!

My old tired 96' has NEVER had a "pusher" pump of
any kind on it!! I am a little over 500 RWHP and as
everyone knows I run the truck very hard but also take
care of it! My fuel pressure on that P7100 pump is still
32-35 at idle and around 25-28 underway and the truck
has over 230,000 miles on it now. The ONLY thing I have
to do on that P7100 pump is replace the small "overflow"
valve twice after Scheid said they were not working right
and at around 200,000 Scheid did do some minor work
to the governor from normal wear!

I would like to know how many lift pumps and VP-44's
have been replaced versus whole or partial P7100's and
their associated mechanical lift pump. I still have my
"stock" mechanical lift pump too along with the fuel
"heater".

---------
John_P

John_P

Dr. Evil:

Shane I tried to send you a reply (P.M.) reference to your questions on the 12V etc. but it said "your box is full!!"
Try to delete some of your messages and I will send my
message again!!

--------
John_P

DeereDiesel

qoute from gunracer1
i have read his post 4 times and i never found out what the problem is. it sounds like he has spent a lot of time and money. but i still don't see what the problem is. how can a 7100 run fine on a 12v and not a 24v? the valves can't account for all his troubles. what has caused him all the head aches?

IMHO, the 24v engine was designed for electronic injection, not mechanical. That is why these guys are making you aware of tuning problems that may occur with your project. All of the different senors the vp corresponds with will have no message to them with a mechanical pump. I have no experiance with this conversion and have been very interested since the first time I saw Jetpilot's sig sometime ago and have seen other conversions to the "p".

But, I do see that the guys that converted to the 7100 have done so for horsepower purposes that the vp cant cut, not for reliability reasons. I have done A LOT of research on this conversion and in my opinion, there is alot more to it than just slappin a housing on there and setting timing and your done with it. Im not saying it cant be done for all harmony but I think there are always alternatives. Not trying to dampen your spirits, just want to help weigh the outcomes/potentiol problems.
Lets us know how it turns out.
carty

travjrath

well i started my conversion last nite and i am now 1/2-1/3 done its been going unusaly smooth no big F up's to speak of . WOW it felt good to get that insult of a injection pump out ( yes, i need therapy for this ) . Alot of the parts i have resused in a different application , so far i have been having fun doing this. i will repost later with updates ( like if it starts ) . MMMMMM... i can see the smoke now

travjrath

I GOT SMOKE NOW !!!!! well i got it in , fired it up at bout 9pm sounds good , runs better than tst comp'ed VP hunk o junk, had a little prob with the kill arm at first ( it ran like crap ) then i figured it out ,BLAM!! ... hot rod . All dash gauges work , cruise is still an issue , im workn on that. i forgot one bolt ...in lift pump bracket , of course it had to be one that went through to the crank area (oil leak!) Ive got a few more bugs to work out , then i will get it up to the hp that i want (its close now ) i learned alot doing this , more than i can type about , because i suck at typing

BigBlue

Wow. That's impressive. If you don't mind me asking, how much did it all end up costing you? Would you do it again?

gunracer1

i am pretty sure it cost him less than a grand, he swapped the leakin vp44 for the p pump. the lines were around 400.

John_P

travjrath:

Glad to hear you got the pump on!!

--------
John_P

travjrath

yes, i would do it again with vp's the way they are ..but IF they could make a vp more reliable that would have been easier... but i think that is wishful thinking . I had no major problems during this swap. it cost me bout 1200 ( i did buy all parts new from cummins though ) i am happy to answer any questions