Ford Powerstroke Diesel Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
I bought a 95' f250 a few months ago as a project for myself. I intend to try and get around 500 rwhp out of the 310,000km 7.3L. My plan is to do all the supporting mods first so as not to break anything while pushing it to the Max. I've already got alot of good advice and hints off this forum by reading other posts but haven't come across much talking about fuel system upgrades. The truck already has an AFE Stage 2 intake and a 4" turbo back exhaust and a super chip programer which I will be replacing promptly with a t wild custom chip soon. The next thing I was planning was a upgraded HPOP but I read that the stock fuel bowl is in the way. So now I will do the fuel system first. My question is will a system like the Air Dog II replace my stock system completely and relocate it to the frame rail or is that system just a secondary to feed my existing pump, filter, bowl assembly?
 

·
Premium Member
Joined
·
23,192 Posts
It will bypass it completely, but it needs to push more psi than the stocker.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3
The Air Dog II claims to be able to feed a constant 50psi and can be dialed back via a regulator which is included in the kit. Anyone know how that compares to the stock system?
 

·
Premium Member
Joined
·
23,192 Posts
I think stock is around 60 psi, don't quote me tho, but I think your gonna need more fuel.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #5
Ok, well maybe some who know what I need to do to relocate my fuel system can suggest a kit. I eventually plan on running stage 2 injector and a d66 or h2e turbo. Like I said though, supporting mods first.
 

·
Registered
Joined
·
999 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #7
The super duty 7.3 fuel pump definitely looks like the way to go. So does my 95' 7.3L only have a lift pump? It's my understanding that diesel fuel injectors run into the tens of thousands of psi. Am I mistaken about that or is there another injector pump that the 45psi lift pump feeds?
 

·
Registered
Joined
·
11,152 Posts
Read up on the HEUI system. The 'lift pump' is for diesel. There is only one for an OBS, which is mechanically driven in the valley. The SDs have an elec pump on the frame rail under the driver seat. They supply fuel to the injectors at 55-70PSI. The HPOP pressurizes oil up around 2500-3000PSI, which enters the injector, hits a plunger and intensifier and then injects the previously 55-70PSI diesel at around 20000PSI. (Not sure on the full diesel injection PSI, but that's how it works.)
 

·
Registered
Joined
·
6 Posts
Discussion Starter #9
That makes perfect sense now. I defiantly still have some homework to do but I'm getting alot of great info from this forum. Sounds like my plan of upgrading both the HPOP and fuel system will work better together then I initially realized. I really want to my this truck as strong as possible not nessisariely just high hp and torque number.
 

·
Registered
Joined
·
999 Posts
Actually the pump in the engine valley on a OBS 7.3 is a 2 stage lift pump and a high pressure pump.

The pump "lifts" the fuel out of the tanks and into the filter housing and then pressurizes it to 50-75 PSI to the injectors out of the fuel bowl.
 

·
Registered
Joined
·
11,152 Posts
Actually the pump in the engine valley on a OBS 7.3 is a 2 stage lift pump and a high pressure pump.

The pump "lifts" the fuel out of the tanks and into the filter housing and then pressurizes it to 50-75 PSI to the injectors out of the fuel bowl.
Well if you wanna get technical I guess it is. But that's most any pump. One side is negative pressure (suction) and one side is positive pressure.
 

·
Registered
Joined
·
999 Posts
Well if you wanna get technical I guess it is. But that's most any pump. One side is negative pressure (suction) and one side is positive pressure.
The stock OBS 7.3 pump is a 2 stage pump, it isn't like any normal single stage pump.

The top portion of the pump has a supply (suction) from the tank and a discharge to the fuel bowl at 3-5 PSI.

The lower portion of the pump has a feed (suction) from the fuel bowl after the fuel went through the filter and a discharge to the heads that is pressurizing the injectors at 50-75 PSI.

That makes it a 2 stage pump since it has 2 supplies and 2 discharges.
 

·
Registered
Joined
·
11,152 Posts
The stock OBS 7.3 pump is a 2 stage pump, it isn't like any normal single stage pump.

The top portion of the pump has a supply (suction) from the tank and a discharge to the fuel bowl at 3-5 PSI.

The lower portion of the pump has a feed (suction) from the fuel bowl after the fuel went through the filter and a discharge to the heads that is pressurizing the injectors at 50-75 PSI.

That makes it a 2 stage pump since it has 2 supplies and 2 discharges.
:doh:
gotcha
nevermind
 

·
Registered
Joined
·
6 Posts
Discussion Starter #14
This is all actually quite helpful for me to understand how it works, I am pretty green when it comes to diesel engines. Ultimately though I now seem to have a clearer understanding of what I need to do. Since the stock pump is mechanically driven it seem quite inferior to the electric upgrade not to mention the added protection of a better filtration system. Also the adrenaline HPOP upgrade I wish to do requires the fuel bowl be relocated. Exactly why I'm not sure.
 
1 - 14 of 14 Posts
Top