Engine/Transmission (1998.5 - 2002) Rasp

[TDIdog]

If you need the stock lift pump to start, what good is that! That means you are still reliant on the POS stock lift pump. I thought that the whole point was to "not have to carry a spare lift pump in your tool box". Perhaps the better system is the FASS as it eliminates the stock pump completely. I don't mind keeping the stock pump for stand by(what good that is) , but to have to rely on it to get the thing started doesn't make sense.

 

[Supermod56]

The stock pump will only run for a few seconds during start up, filter change, etc. So I think it will last quite a long time. The RASP can't build pressure unless it's at a certain RPM, so you need the initial "boost" to the 44 to get it lit. The beauty of the RASP is reliability, it will never leave you stuck on the road, unless the belt breaks, and they supply you with a spare. No wiring/fuse problems either. The most important feature is fuel VOLUME increases with engine RPM, which is the way it's supposed to work. I like it, but the price is a little steep with all the plumbing you need. I still might get one though.



Tom

 

[rmrc]

The most important feature is fuel VOLUME increases with engine RPM, which is the way it's supposed to work. I like it, but the price is a little steep with all the plumbing you need. I still might get one though.



Tom

I fully agree regarding the flow of fuel increasing with the RPM... . I,,, ALSO agree as to the price being excessive when taking into consideration the,,, "plumbing" needed to complete the installation!



The price is the only factor that might make the difference in going with the FASS over RASP,,, unfortunately!!!

 

[TDIdog]

Never leave you stuck on the road, as long as you leave your truck idleing!

 

[Double J]

If you need the stock lift pump to start, what good is that! That means you are still reliant on the POS stock lift pump. I thought that the whole point was to "not have to carry a spare lift pump in your tool box". Perhaps the better system is the FASS as it eliminates the stock pump completely.

Your right, the better pump for you is the FASS. Good luck.

 

[snowracer69]

Wow, little bit of bashing going on here by guys who have no idea how this thing actually works.



There is only one way to prime a system like this in a decent amount of time, and that is to leave the stock LP in line and let it do the work... otherwise it would take HOURS to get the thing going after a filter change or whatever.



Here is how I have mine plumbed:



#ad




Notice my return fuel doesn't go back to the tank, but rather back into the "fuel log"... there are many different ways of returning fuel, this one just saved some braided line and the theory seemed right to me. Works fine. You will however probably have to use a different spring in the bypass valve in order to get the pressure correct (mine originally was ~9 psi at idle, and we tried 3 different springs before we found the one to give me ~14 psi at idle).



Now, the stock LP runs off the pressure switch. When the pressure in the system is below 8 psi, the stocker turns on. This means that first thing in the morning when I turn my key on it runs for ~6 seconds, and for a split instant as you start the engine it runs, just until the RASP is up to speed and takes over. I also have a switch in the cab to override and MAKE the RASP pump whenever I want. When I turn it on in conjunction w/ the RASP my idle pressure goes to ~15. 5... I've never ran at WOT w/ both pumps as I feel I would starve one of them for fuel w/ the small line coming from the tank. Also, the stock pump will only run when the ECM is telling it to. All you do is cut one wire going to the pump and put the hobbes switch in the middle of it (and then of course you also "jump" the hobbes with the bypass switch from inside the cab so you can override anytime you want). I also have an LED in my cab, right next to my FP gauge, so I know if/when the LP is running.



With the load and rather short time the stock pump is being used, it should last forever. I had my last stocker put on ~3000 miles before going to the RASP and now have ~7000 miles on the RASP with no problems (I did have a small leak in a fitting at one time, but that was my fault). Bill K gave me his cell number the day I was installing mine so he knew I got it done and was back on the road. It was a full 8 hour day of work to get the thing on by myself, but in the end, it was worth it.



If anyone wants actual pics of my system, let me know.



RASP it and forget about it. The only thing that can go wrong is if you break a belt. There is absolutely nothing inside the pump that can fail... and even if the belt breaks, flip a switch and drive to your nearest NAPA and buy a new one.



Josh



EDIT: Just noticed there is an error in my plumbing diagram. The 90* fitting coming out the pressure side of the RASP should be "to 1/4 NPT" and not to 1/8 NPT (I'm pretty sure it's 1/4... I know it's NOT 1/8).

 

[GKinney]

Looks like a great system... . shouldn't be too hard to install other than the actual mounting of the pump I presume. Mechanical pumps are just that wether they are driven by a belt off the crank or an electric motor, they are not indestructible no doubt. But that is a sweet looking system,,,the only bad thing is the weakest link, getting fuel to it... . aka fuel modules are lousy not to mention the small 1/4" fuel lines and flimsy quick connectors. I think I will stick to my Fass and 1/2" suction in the tank for now. Too bad Dodge doesn't pick up on some of these ideas out there and make the Cummins rock solid like it used to be!!!

 

[snowracer69]

Actual mounting of the pump takes ~10 minutes, and yes, that includes positioning of the belt. The part that takes the longest time is running all the lines, with the cutting and routing and etc.



I do not know if you're talking about the RASP system when saying "flimsy quick connectors" but I only used -6AN stainless braided line and good solid connectors. Nothing quick or cheap about my setup.



It's the internals of the RASP that make it a superior pump design. Stefan can elaborate more, but it's not the same type of pump as is being electrically by the FASS or other pusher type systems.

 

[GKinney]

connectors

No I was referring to the oem garb quick connectors that are installed on the tank fittings from the factory. Guess they are alright if you never have to dis-connect them ... ... and then try to re-connect then. I also used all stainless braided hose from the fass to the injector pump... . the only way to go I think... . never wear a hole through that stuff!! I think Russell and Earls is about the best money can buy when it comes to hose and connectors... if you want to spend the money that is.

 

[Stefan Kondolay]

The RASP pump is similar to a mechanical oil pump , basically it uses 2 straight cut gears. There is no thrust , there is no load. It will be a long time before one of these things wear out. We have been handling this product with retail sales for about a year now. Not one single pump has come back or for that matter not even a belt has been changed out or broken. While guys may complain about the price, when you get the package it actually gives you the means to run 2 complete fuel systems independent of each other . It comes with a Hobbs switch , comes with fuel regulator system, and a one way flow valve. So in essence you have 2 complete independent fuel systems when you are done. As far as the mounting hardware is concerned, it is a dream. Undo the four front bolts on the engine oil pan and bolt the mounting bracket on, it is self alligning. You dont have to worry about the pump not being square. if this process takes you more than 10 minutes you have had way too much beer.



The plumbing system can be as expensive or in-expensive as you want to make it , you can do it with brass fittings and rubber lines for a couple hundred bucks or with braided line and aeroquip fittings for about $ 350 bucks.



As far as guys saying that the rasp pump will not work without the factory lift pump, that is definately not true. It can work without the oem lift pump. The initial two months of testing we did was without the oem factory lift pump so I know that for a fact. The electrical fuel pump stays in place as a back up for fuel filter changes to prime the system and also serves as a back up should the belt break. Your oem lift pump probably doesnt run for more than 20 seconds a day after you install this RASP pump. You guys may not mind paying over and over for these electrical pumps but I did, so we went back to our drag racing background and found a solution that made sense.

 

[TDIdog]

Well I do mind paying over & over for factory lift pumps! Thats why I needed to know if the RASP would run with out the LP. I just replaced one & the simptom was no start. So if the RASP needs the LP to start, then you are still reliant on the LP, even if for only 20 seconds(enough to not start). I trust what you are saying, Stefan, is that with the RASP the truck will start with or with out the factory LP. If thats the case then this is the system is for me. Stefan thank you very much for shedding light & setting us straight on this subject.

jack

 

[BLACKRAM]

Yes the truck will start without the LP. I had DTT install mine yesterday.

 

[jpmutt]

What kind of fuel pressures do you see at idle and wot, under a load, etc. ?

 

[snowracer69]

After getting the right spring installed in my regulator I see ~14 psi at idle. At WOT w/ Comp on 5x5 I can pull it all the way down to 13 psi! And that is with a dirty fuel filter (dirty to me is 8000 miles on it... I change mine every 10k). Cruise between 60-75 MPH is ~14-14. 5 psi. At 80 MPH and up it climbs to 15-16 psi since the revs are high.



The one line I haven't replaced yet is from the filter to the VP-44, and I should probably do that soon... just one more restriction. However, my FP gauge is post-filter.

 

[John]

I think Russell and Earls is about the best money can buy when it comes to hose and connectors... if you want to spend the money that is.

In my experience over the years I have found the quality of braided stainless steel hose and (especially) fittings in order of quality as follows:



1 Aeroquip



2 Russell



3 Earl's



Summit Racing as well as Jeg's carries the complete line of all three hose/fitting manufacturers.

 

[paulb]

I ran my RASP pump for about the first 3K with the stock lift pump unplugged. Worked without a problem.

 

[Augie]

The RASP fires my rig up daily with no help from the LP, but I'll keep it for back up.