• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Feed the Beast pics

There is no one or two ways to do this mod. Someone will next invent the 1/2" FTB mod. I can't claim to be the first to raise their filter manager out from the valley either, but maybe I can claim to be first to use a door hinge to mount a pre-LP filter. You saw it here first ):h

What was mysterious to me when performing this was the lower IP fitting part, was not good general understanding on that part of the mod, and it goes undone on most FTB jobs. Because its a PITA boring out those 4 small holes.
 
buddy said:
There is no one or two ways to do this mod. Someone will next invent the 1/2" FTB mod. I can't claim to be the first to raise their filter manager out from the valley either, but maybe I can claim to be first to use a door hinge to mount a pre-LP filter. You saw it here first ):h

What was mysterious to me when performing this was the lower IP fitting part, was not good general understanding on that part of the mod, and it goes undone on most FTB jobs. Because its a PITA boring out those 4 small holes.
Click to expand...


I agree. Now that I have a backup IP I will mod that units inlet. I will do it on my vice with my cordless.

Buddy, can you do the math of the comparison between 3/8 ID fuel line volume, and the volume of the 4 holes at factory size (1/8"?) And the new larger size?.
 
Anyone tapped the FFM with a 1/4" pipe tap as opposed to an 1/8"? Just wondering if theres enough material there.
 
Matt said:
Buddy, can you do the math of the comparison between 3/8 ID fuel line volume, and the volume of the 4 holes at factory size (1/8"?) And the new larger size?.
Click to expand...

The way it sits (before the mod), the 4x 1/8" holes have 4/9 the x/c area of the 3/8" line...

Means the little holes cannot flow the amount of fuel coming through the line. Stock.

If you want to maximize the amount of throughput, you need to open them up.
 
Last edited:
If you bore the holes to 3/16 diameter, you have the same x/c area as the inlet line...
 
JiFaire said:
If you bore the holes to 3/16 diameter, you have the same x/c area as the inlet line...
Click to expand...

So no reason to go larger, even if there was meat left. I've never had it off yet, but why not an open shot? why the restriction? The screen is a good idea there though for sure! I do like that.
 
I would tend to think the reason for the restriction would be to maintain a constant flow of fuel... even if things hiccuped on the outside, it shouldn't affect the inside. That's the normal reason for orficing a flow line.

That might not have anything to do with Stanadyne's thinking here, though...
 
IDK but something I did notice was this. My Dually sprung a leak in the return line along the chassis(Have another thread on all that) and one thing I noticed was that the fuel/return line was Hot and that was halfway down the chassis which makes me wonder why GM thought this would cool the PMD. The fuel was very hot in the return line. I know this cause it was dripping on me...:D
 
The fuel in the IP is fairly cool... but then it goes through the return lines, along the heads, before collecting and going back to the tank.

Bet it warms up pretty good while moving along that path...
 
yeah something cause let me tell you it was hot which I suppose in the winter is a good thing by warming up the fuel in the tank but in 90 deg heat I question how good that is.
 
buddy said:
What was mysterious to me when performing this was the lower IP fitting part, was not good general understanding on that part of the mod, and it goes undone on most FTB jobs. Because its a PITA boring out those 4 small holes.
Click to expand...
IIRC TD tested the FP up to the inlet fitting and showed a vacuum before FTB came to be . There is no way to my knowledge to test if a vacuum remains at those four little holes so no one really knows whether or not that is still a choking point. It seems it could be but the world may never know. If I had a spare fitting I'd give it a shot but I'm not gonna take a drill to my only one....:eek:
 
4 x 3/16 holes = .11 sq in
4 x 1/8 holes = .05 sq in

1/4" fuel line = .05 sq in
3/8" fuel line = .11 sq in

So you see, stock they lined up exactly equal in cross sectional area. Probably why you have 1/4" lines and why the mod is not complete until you bore them out.

When you upgrade to 3/8" line you have doubled the cross sectional area so you need to go to 3/16" holes to match up again. This is also a reason it would be harder to maintain high fuel pressure at high fuel demand. There is more cross sectional area with 3/8" line, multiply that by 18" of line from FFM and youre pushing 2 cubic inches of fuel vs 0.9 cubic inches with 1/4" line.

Why an aftermarket lift pump is good idea after doing this.

Put in a time and pressure variable and you can caluclate flow.

The fuel in the IP is hot, the thermistor I have had on the side of the IP puts my IP as one of the hottest things in the engine bay. Thats the face where the PMD would have originally been mounted, other parts of the IP are cooler though. Driving around scanner shows about 100F fuel temp and it cool outside here and thats 180F engine temps. IP reads about 140-160F.
 
Thats a good point about the line. So the additional 18" 3/8 hose going to my fuel pressure gauge sender probably keep active pressures a tad lower, but also acting as an expansion chamber/stabilizer. Would reducing this to 1/4" hose and/or shortening this be a good idea and would it effect my at the IP reading??
 
Ace, maybe your pmd is heating up your return line fuel as it bleeds off heat. Never thought about the warmed fuel being sent back to the tank to help keep it fluid during cold temps. I always figured the fuel manager heater thingy was what kept my truck from gelling up and freezing solid like everything else around when it got seriously cold. Yet I wondered how the tank didnt freeze up. So now I know. Well, except that I havent had the return-line-fuel-preheater-box (PMD) on there for many years...

Maybe we're onto something here. We could design a ftb style mod to route return line fuel back to the tank to keep tanks from gelling on commercial rigs. When I was towing, we were out nonstop fixing or towing commercial rigs with gelled fuel when it got real cold. Course those were usually trucks that fueled up down south and drove north without local winter blend...and southern trucks wouldn't likely want to buy something for the occasional trip north.
 
This lower IP fitting that everyone should drill out the 4 holes on. I took it out and was having a look at it. From what I've seen there is a check ball in there...anyone know what this is for? And has anyone tried not running this fitting at all and just getting the right sized fitting to go in there instead of this stock fitting that seems to be pretty restrictive?
Thanks
 
That should be self explanatory... If your increasing the fuel flow to the engine more than likely you will be increasing power. Upsizing the fitting into the injection pump at least makes it so more fuel is available to be used if need be and then the excess will be cycled back to the tank... You can get those fittings you need to do this for way cheaper than what the kit is sold for and at the same time get rid of the stock fuel filter for an aftermarket spin on unit and make the line sizes according to what you need... The fitting into the IP is 11/16" O-ring boss threaded if that helps you....
 
You must log in or register to reply here.
Back
Top