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Hood Latch

FASS DDRP: Why not????

78 posts in this topic

Some folk's are saying that this pump is fine for a stock motor, and some are saying it is only good for target practice or an expensive paper weight. It is my understanding that it comes with two different springs (to adjust for more pressure if desired) , that it is a relatively easy install in the oem position, and that it is an option to install it down on the frame close to the tank with the required relocation kit. It comes with a four year warranty from the same folks that make the higher end FASS systems. So, for a stock motor, why not use this pump? Thank's for your time and attention............Hood Latch

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Hood Latch, Opinions will vary but, I have read enough accounts of the DDRP either failing, not performing properly, or not being much better than the factor pump that I personally could not justify the $275 cost of this pump. Some have had good luck with them, more than a few have not. It is your call. The price alone for me would justify paying another $225 and get the Air Dog or spend $162 and go with the Airtex 7153 pump. There is a saying about pursuing a "middle of the road approach" Those in the middle of the road are the first to get run over. I recommend going one way or the other and closely monitor the fuel pressure gauge.

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Problem with it its only a 40 GPH pump compared to AirDog, Raptor, or Full FASS at 100/150 GPH. Then by the time you add the relocation kit to it you got a price very very close to a Raptor but still the Raptor is lifetime warranty and comes with relocation and doesn't require ording from a second supplier for parts.

so comparing... FASS DDRP to Raptor you end up paying just as much for a limited warranty, sub standard pump, that still barely meets the requires of ONLY a stock truck... So with a Raptor it good for at least 500 HP of toys...

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Hood Latch, Opinions will vary but, I have read enough accounts of the DDRP either failing, not performing properly, or not being much better than the factor pump that I personally could not justify the $275 cost of this pump. Some have had good luck with them, more than a few have not. It is your call. The price alone for me would justify paying another $225 and get the Air Dog or spend $162 and go with the Airtex 7153 pump. There is a saying about pursuing a "middle of the road approach" Those in the middle of the road are the first to get run over. I recommend going one way or the other and closely monitor the fuel pressure gauge.

Live Oak, Thank's for the come back. A new mechanial pressure gauge will be going in first. Can't know if I am making any improvement if I don't know where I've been. I guess the reason I am sort of leaning toward the fass ddrp is the warranty, and if I understand correctly, it is a gear type pump as opposed to the airtex being a rotary vane type pump. Over the years I have found that there are two different schools of thought on which is the better design. I think, that it depends on the application and desired outcome of the pump. I think, they both have their place and probably in some applications, one could be as good as the other. In this particular application, (oem on the side of the block) I personally believe that a gear type pump has a better chance of longevity. I believe they are perhaps inherently more robust. Maybe I am wrong about this, and if I decide to go with the fass ddrp and I have problems, I will have no one to blame but myself. I have certainly been forwarned. If do install the fass ddrp, and then decide I need to go with something better, I will be looking to install one of the better pumps on the frame close to the tank. I would then mount the fass ddrp on a piece of plywood, plumb it with hose, and wire it for use as a fuel transfer pump to fuel tractors and such. I have a cheap one of these set up now and it is about wore out. Which ever way I go, I will report back with my results. Thanks.......Hood Latch

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Problem with it its only a 40 GPH pump compared to AirDog, Raptor, or Full FASS at 100/150 GPH. Then by the time you add the relocation kit to it you got a price very very close to a Raptor but still the Raptor is lifetime warranty and comes with relocation and doesn't require ording from a second supplier for parts.

so comparing... FASS DDRP to Raptor you end up paying just as much for a limited warranty, sub standard pump, that still barely meets the requires of ONLY a stock truck... So with a Raptor it good for at least 500 HP of toys...

Mopar Man, Thank's for the come back. I will not deny , that the logic of your thought is SOUND WISDOM. Either way I go, I will report back when the job is done and give my results and thoughts. Thank' again......Hood Latch

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The bad thing about a DDRp pump in the stock location is that the pump has to suck the fuel from the tank, the other pumps push the fuel from the tank. Try sucking the water from a garden hose for 6' compared trying to push the water from the hose. Which is easier? Plus, you are using your stock lines for the DDRP. All of the other pumps you get all the lines (1/2") and fittings to get you going. Good luck with what ever you choose.

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the vp44 is designed to only use 30% of the fuel pumped to it. the other 70% is returned to tank for cooling purposes. 40 gallons/hour is 40 gallons/hour, no matter what pressure it gets there. that is one reason i spent the extra on airdog. heat and lube is what kills/saves pumps and motors....

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Live Oak, Thank's for the come back. A new mechanial pressure gauge will be going in first. Can't know if I am making any improvement if I don't know where I've been. I guess the reason I am sort of leaning toward the fass ddrp is the warranty, and if I understand correctly, it is a gear type pump as opposed to the airtex being a rotary vane type pump. Over the years I have found that there are two different schools of thought on which is the better design. I think, that it depends on the application and desired outcome of the pump. I think, they both have their place and probably in some applications, one could be as good as the other. In this particular application, (oem on the side of the block) I personally believe that a gear type pump has a better chance of longevity. I believe they are perhaps inherently more robust. Maybe I am wrong about this, and if I decide to go with the fass ddrp and I have problems, I will have no one to blame but myself. I have certainly been forwarned. If do install the fass ddrp, and then decide I need to go with something better, I will be looking to install one of the better pumps on the frame close to the tank. I would then mount the fass ddrp on a piece of plywood, plumb it with hose, and wire it for use as a fuel transfer pump to fuel tractors and such. I have a cheap one of these set up now and it is about wore out. Which ever way I go, I will report back with my results. Thanks.......Hood Latch

About a month ago my stock lift pump failed. It was before I was a member of this site so I bought another lift pump from the Cummins dealer and installed it. Then Michael Nelson on here told me that the plastic insert in the stock pumps rotor fails and causes breakdowns so I had a guy at an EDM shop make me a rotor for the stock lift pump out of P20 steel with a solid drive slot instead of a plastic bushing for a coupling to the armature shaft that drives it. It's been in my truck for about 3 weeks and I don't have to worry about it stripping out now until I can change the fuel lift pump system in the summer. It is $200 for the rotor but it was a drop-in install and kept everything in the stock location for now. If anybody wanted one of those rotors for a stock pump I think he will be making two more on the week of Jan 18th.

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If the fass ddrp is 225 bucks you are only looking at another 175 bucks for an airdog with a lifetime warranty.Luke

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the vp44 is designed to only use 30% of the fuel pumped to it. the other 70% is returned to tank for cooling purposes. 40 gallons/hour is 40 gallons/hour, no matter what pressure it gets there. that is one reason i spent the extra on airdog. heat and lube is what kills/saves pumps and motors....

I am assuming, your point is that: "40 GALLONS PER HOUR" is KNOWN not to be enough flow in order to properly lube and cool the vp44 on a stock motor? I am not asking the question in an argumentative way, I am just trying to learn all I can about required fuel flow and pressure for the vp44 (in order to make it live) on a stock motor. Thank's for the comeback and your patience...........Hood Latch

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I am assuming, your point is that: "40 GALLONS PER HOUR" is KNOWN not to be enough flow in order to properly lube and cool the vp44 on a stock motor? I am not asking the question in an argumentative way, I am just trying to learn all I can about required fuel flow and pressure for the vp44 (in order to make it live) on a stock motor. Thank's for the comeback and your patience...........Hood Latch

Yeap... The fact is Bosch requirements is 70% to be returned and 30% to be burned. So if the supply is under rate the the cooling and lubing is cut to keep the engine going...

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Yeap... The fact is Bosch requirements is 70% to be returned and 30% to be burned. So if the supply is under rate the the cooling and lubing is cut to keep the engine going...

Thank you. I understand that the Bosch requirement is for "70% to be returned and 30%" to be burned. I guess what I am trying to establish is wether or not there is conclusive evidence that 40 G.P.H. is in fact under the needed G.P.H. supply rate to burn 30% and return 70% on a stock motor. If 40 G.P.H. is not enough, what would be the minimum G.P.H. number needed for a stock motor. If it sounds like I am being bull headed about this subject, I apologize. I am just trying to understand what the minimum G.P.H. number should be for a stock application. Thanks for your patience......Hood Latch

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Well here is simple data given from my ScanGauge II for comsumption rate... On my stock truck I remember seeing 18-20 GPH consumption rate with mt RV275 and Edge Comp on 5x5 I'm seeing 30 or so now... 20 GPH Demand / 40 GPH supply = 50% consumption rate (50% left ofr cooling lubing) 20 GPH Demand / 30% Requirement = 66.6 GPH needed to meet Bosch 30 GPH Demand / 40 GPH supply = 75% consumption rate (25% left fo cooling/lubing) 30 GPH Demand / 30% Requirement = 100 GPH needed to meet Bosch So for stock setup you would need at least 66.6 GPH to meet the bosch requirement... Since the closest pump to that is the FASS 95... Once again it proves that Dodge cut corners on the fuel system... So now with my AD 150... 30 GPH Demand / (AirDog) 150 GPH supply = 20% consumption rate (80% left fo cooling/lubing) Remember this is simple math figuring it out but real world loading and demands is way different...

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Well here is simple data given from my ScanGauge II for comsumption rate... On my stock truck I remember seeing 18-20 GPH consumption rate with mt RV275 and Edge Comp on 5x5 I'm seeing 30 or so now... 20 GPH Demand / 40 GPH supply = 50% consumption rate (50% left ofr cooling lubing) 20 GPH Demand / 30% Requirement = 66.6 GPH needed to meet Bosch 30 GPH Demand / 40 GPH supply = 75% consumption rate (25% left fo cooling/lubing) 30 GPH Demand / 30% Requirement = 100 GPH needed to meet Bosch So for stock setup you would need at least 66.6 GPH to meet the bosch requirement... Since the closest pump to that is the FASS 95... Once again it proves that Dodge cut corners on the fuel system... So now with my AD 150... 30 GPH Demand / (AirDog) 150 GPH supply = 20% consumption rate (80% left fo cooling/lubing) Remember this is simple math figuring it out but real world loading and demands is way different...

Thank you sir. Know I have some idea of what is required, as per. G.P.H., for the Bosch requirement. As to the question of what is required for reliable P.S.I. needed, at this time, I also am thinking that if a minimum of 5 P.S.I. under any condition is believed to be enough by some folks, I can see nothing wrong with maintaning a minimum of 10 P.S.I. I (being new to this question) have still not come to any conclusion as to what to think about a maximum P.S.I. before any possible adverse affects to the vp44. I have a better understanding now (thank's to you and others on this forumn) as to why you are in favor of the pusher pumps of at least 95 G.P.H. I can see why you could have a more confident feeling as to the higher G.P.H. flow rate. Again, the Bosch G.P.H. flow rate required, that you have shown here, is welcome knowledge. Thanks.........Hood Latch

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Personally I prefer a fuel pressure between 14-17 PSI as a normal. Reason being is above 14 PSI now the overflow valve is opened and excessive fuel is now flowing from theVP44 pump. This increase volume flow around the VP44 thus cooling it greatly. But as for maximum pressure documented by Bosch there is none as far as I can find. But as for safe and relible pressure I would hold a span of 10-20 with a normal of 15-17 PSI. Now there is a few pioneers out there with 12V mechanical fuel pump pushing 35-45 PSI into a VP44... But there is no long term results on this yet. So you got some at one extreme saying 5 PSI is fine... Then at the other end of the spectrum there another group saying extremely high pressure is good. I use common sense at this point that ther overflow valve is designed for 14 PSi to open. so if you want to increase cooling ability you got to get just enough pressure to open and hold open the overflow valve to increase fuel flow around the VP44. So going to full extremes and pump beyond 20 PSI is a waste and below 10 PSI and the valve is shut and most times out of ten cant meet the requirements of VP44 at WOT...

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Personally I prefer a fuel pressure between 14-17 PSI as a normal. Reason being is above 14 PSI now the overflow valve is opened and excessive fuel is now flowing from theVP44 pump. This increase volume flow around the VP44 thus cooling it greatly. But as for maximum pressure documented by Bosch there is none as far as I can find. But as for safe and relible pressure I would hold a span of 10-20 with a normal of 15-17 PSI. Now there is a few pioneers out there with 12V mechanical fuel pump pushing 35-45 PSI into a VP44... But there is no long term results on this yet.

So you got some at one extreme saying 5 PSI is fine... Then at the other end of the spectrum there another group saying extremely high pressure is good.

I use common sense at this point that ther overflow valve is designed for 14 PSi to open. so if you want to increase cooling ability you got to get just enough pressure to open and hold open the overflow valve to increase fuel flow around the VP44. So going to full extremes and pump beyond 20 PSI is a waste and below 10 PSI and the valve is shut and most times out of ten cant meet the requirements of VP44 at WOT...[/QUOTe I would think, that if there are no known problems with keeping the overflow valve open at all times, then (with what very little I know about it) I can see the wisdom of the constant flow of fuel in, thru, and out of the pump providing a better cooling of the pump, and therefore the computer bolted to it. Your common sense approach of (more fuel volume at a known adequate pressure) to my mind, has plenty of merit. I am learning. Thank's for your time...............Hood Latch

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I got my Fass 95GPH mounted to the frame today, and I have the wiring run, tomorrow I will connect to the fuel tank, hopefully that is all big blue is going to need. I agree that DDRP at 40GPH is only putting out the same amount as the OEM pump. The math comes to 1.11 quarts in 25 seconds, even less then the OEM puts out per specs of the pump test. Correct me if I am wrong? http://mopar.mopar1973man.com/cummins/2ndgen24v/lift-pump-diag/lift-pump-diag.htm

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Update: Installed new DiPricol mechanical fuel pressure gauge. Isolator is not here yet, so ran the tube from new banjo bolt (the one that had the shreader valve) directly to the gauge (after bleeding the line first). No leaks so far (that's the only good news). Bad news is that the stock carter lift pump is only making 8 p.s.i. @ idle. Under load (and I mean just pulling up an incline of not much) it dropped to 4 p.s.i. Well boys and girls, there ain't no warm and fuzzy feeling with that kind of pressure. I put her back in the shop and she will stay there until the new lift pump is installed. By the way, that was (banjo bolt with the shreader valve) the correct place to tap in the gauge, is it not? Thanks......Hood Latch

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I think you got it all hooked up correctly. From what I can dig up searching and looking at pictures and all anyways lol. If it's hooked into #1 thats the supply line so that would be right. Posted Image Yeah that pressure doesn't inspire me either :lol3:

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I think you got it all hooked up correctly. From what I can dig up searching and looking at pictures and all anyways lol. If it's hooked into #1 thats the supply line so that would be right. Posted Image Yeah that pressure doesn't inspire me either :lol3:

Thank you ISX. Yes sir, that's where I got her plumbed up at. Hood Latch

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Update: Installed new DiPricol mechanical fuel pressure gauge. Isolator is not here yet, so ran the tube from new banjo bolt (the one that had the shreader valve) directly to the gauge (after bleeding the line first). No leaks so far (that's the only good news). Bad news is that the stock carter lift pump is only making 8 p.s.i. @ idle. Under load (and I mean just pulling up an incline of not much) it dropped to 4 p.s.i. Well boys and girls, there ain't no warm and fuzzy feeling with that kind of pressure. I put her back in the shop and she will stay there until the new lift pump is installed. By the way, that was (banjo bolt with the shreader valve) the correct place to tap in the gauge, is it not? Thanks......Hood Latch

Is the fuel filter a new filter? A restricted fuel filter can cause low pressure like this.

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Is the fuel filter a new filter? A restricted fuel filter can cause low pressure like this.

Live Oak, No, it is not new. I must of had a brain fart or something cause I did'nt think of that, whew!!! I have new filters here, I'll give that a try next. Thanks for the reminder. Hood Latch

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I think you got it all hooked up correctly. From what I can dig up searching and looking at pictures and all anyways lol. If it's hooked into #1 thats the supply line so that would be right. Posted Image Yeah that pressure doesn't inspire me either :lol3:

I have mine hooked into the banjo at the return/outlet fitting of the VP44, should I maybe move it upstream to #1?

You can see it just below the sticker on the VP44.

http://forum.mopar1973man.com/attachment.php?attachmentid=439&stc=1&thumb=1&d=1263600058

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I didn't think you could get a pressure reading from a fuel line going back to the tank. I would most definitely move it to #1. If your getting normal pressure readings then maybe there is something I don't know about these things and their return system. Wait for someone else to confirm it..

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Yeah it got to be on the line to the #1 in that pic... The return line is not going to see pressure unless you pumping excessive amounts like about 20 on the supply side... So switch it around...

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