Looking for info on VGT vs. non-VGT.

[swinky]

This is not true at all. Head pressure is simply the result in the difference in elevation from the fuel level in the tank to the inlet of the pump. Regardless of the path.

On a different note, Greg, are you able to achieve ICP of 4000 psi on your flow bench? all the flow benches I have dealt with are really only capable of 3000 psi. I am just curious if you have modified your flow bench, if you use a little math to correlate results to the higher pressures. That's what I've had to do.

Right but if the supply line is higher than the fuel level it will lose all head pressure. As soon as your supply line goes higher than the fuel level you won't have any type of pressure.

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[windrunner408]

No it won't.... I know it doesn't appear to be this way but Adam is correct. It is merely the relation of the two points that matters. As far as the path in between is concerned, you are really only concerned about the diameter of the tubing for flow and that's it.

 

[swinky]

Okay so say you have a water bottle 2ft in the air and another on the ground. Run a straw from the higher one to the lower one. It's going to need help to flow. I just don't understand not trying to argue.

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[TooMuch03]

Okay so say you have a water bottle 2ft in the air and another on the ground. Run a straw from the higher one to the lower one. It's going to need help to flow. I just don't understand not trying to argue.

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Yes it will. Now, fill the straw with water, it no longer needs help, you have created a syphon. That's what the fuel system is like. The line from the tank to the pump is full of fuel.

 

[william_ace]

Think of a siphon. It will take effort to get it going, but once the fluid is moving it creates a siphon of sorts. At least thats how I think of it.

Edit: ^^^ He beat me to it.

 

[Pizza pig]

This is not true at all. Head pressure is simply the result in the difference in elevation from the fuel level in the tank to the inlet of the pump. Regardless of the path.

On a different note, Greg, are you able to achieve ICP of 4000 psi on your flow bench? all the flow benches I have dealt with are really only capable of 3000 psi. I am just curious if you have modified your flow bench, if you use a little math to correlate results to the higher pressures. That's what I've had to do.

No, with the cost of this machine, and the warranty coverage, I've had to beat craig with a stick to not touch it, im surprised this thing isnt supercharged yet... LOL

Math my friend.

 

[swinky]

Yes it will. Now, fill the straw with water, it no longer needs help, you have created a syphon. That's what the fuel system is like. The line from the tank to the pump is full of fuel.

Got it. Thanks for clearing that up.

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[strokin6L]

Ever stick a hose in a fuel tank and try to syphon fuel out? I hate getting fuel in my mouth haha. A little sucking and the fuel is running lol!

 

[MrOneEyedBoh]

So guys, Im still undecided with injector size. First and foremost I know if you wanna play you gotta pay. Im considering me doing the studs, and supporting mods as me paying, so with that said...

Im debating on 175/75s or 190/75s. 175/75s seem to be a more "safe" option and not pushing the headgaskets as much, not pushing trans as much, easier to maintain ICP and FP all versus the 190s, which usually are matched. But as we know most def pushing the limit on some of those areas.

I do plan on getting a trans next year tax time and I think I can take it easy for a year. But what if ICP starts to fail and FP cant keep up. WIll those items show its face ASAP or would they come to light more gradually?

Also, I keep reading about people having to dig back into their engine 1-2 years later with bad gaskets. Is that mainly block prep?? I keep reading things all over the board, but nothing solid form any of the "big guys" ont he forums.... MPD O-rings the heads as we know, so from what Ive read on that its a big plus... The issue seem to be that the heads are being bowed up in the center of each cylinder head and not having the studs stretched as a lot think/thought. If thats the case, then no matter what we do, it will eventually happen.. no?

Power wise Id like to be around 600. BUT! I want to keep that 600 for years, I dont want to have to do this again in 3-4-5 years. I dont drive hard at all, Im just a weekened warrior IF that..

 

[Josh@DirtyDiesels]

So guys, Im still undecided with injector size. First and foremost I know if you wanna play you gotta pay. Im considering me doing the studs, and supporting mods as me paying, so with that said...

Im debating on 175/75s or 190/75s. 175/75s seem to be a more "safe" option and not pushing the headgaskets as much, not pushing trans as much, easier to maintain ICP and FP all versus the 190s, which usually are matched. But as we know most def pushing the limit on some of those areas.

I do plan on getting a trans next year tax time and I think I can take it easy for a year. But what if ICP starts to fail and FP cant keep up. WIll those items show its face ASAP or would they come to light more gradually?

Also, I keep reading about people having to dig back into their engine 1-2 years later with bad gaskets. Is that mainly block prep?? I keep reading things all over the board, but nothing solid form any of the "big guys" ont he forums.... MPD O-rings the heads as we know, so from what Ive read on that its a big plus... The issue seem to be that the heads are being bowed up in the center of each cylinder head and not having the studs stretched as a lot think/thought. If thats the case, then no matter what we do, it will eventually happen.. no?

Power wise Id like to be around 600. BUT! I want to keep that 600 for years, I dont want to have to do this again in 3-4-5 years. I dont drive hard at all, Im just a weekened warrior IF that..

I'm pretty confident in saying that if you take your truck to MPD and have them stud it with O-ringed heads you most likely WILL NOT be replacing headgaskets any time soon, if ever. IIRC Johnny and Kris's trucks both got sprayed to the high heavens last year at the track in VA. Johnny's went 11.6 in a CCLB and took enough of a beating to destroy the bottom end. Kris's also lost a bottom end and IIRC neither had blown headgaskets....

 

[Gearhead]

the intensifier springs wear out significantly with large modified injectors and the increased stroke.

springs don't much like being taken past 80% of their coil bind height.

 

[Josh@DirtyDiesels]

springs don't much like being taken past 80% of their coil bind height.

Here was a spring out of one of my injectors next to a brand new one.

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[MrOneEyedBoh]

Dzlpwr... So then with that being said, you're saying if anything ICP and FP will be the issue...

 

[Josh@DirtyDiesels]

Dzlpwr... So then with that being said, you're saying if anything ICP and FP will be the issue...

wait what?

 

[MrOneEyedBoh]

You basically said that the process MPD uses works pretty damn well. With that eliminated ( assuming here ) the next issue would be maintaining FP and ICP using 190/75s, right?

If the above was an issue, it would show asap correct? But even if Im having an ICP issue, I could get my tuner to just lessen the ms in the tune, thus not needing as much ICP then a full ms tune... no?

 

[swinky]

springs don't much like being taken past 80% of their coil bind height.

Any way around this?

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[Josh@DirtyDiesels]

You basically said that the process MPD uses works pretty damn well. With that eliminated ( assuming here ) the next issue would be maintaining FP and ICP using 190/75s, right?

If the above was an issue, it would show asap correct? But even if Im having an ICP issue, I could get my tuner to just lessen the ms in the tune, thus not needing as much ICP then a full ms tune... no?

Oh. Yes. I have full confidence in their ability to keep your headgaskets from blowing. As far as FP I couldn't tell you. The same day my truck got larger than stock injectors I ripped the stock fuel pump out and went for an A1000 setup. My FP gauge has never moved off of 60psi. As far as ICP you should talk to Greg as he can help you with this but with a 190 from mpd you should hold icp just fine. Unless you have a failing pump. I also can't really relate from experience with ICP because I have always had trouble holding ICP with the size injectors that I run.

 

[MrOneEyedBoh]

Thanks bro. My truck is still young at 51k miles. I can hold ICP fine now, ( doesnt say much though haha ) I also have the original HPOP fittings, so maybe the newer ones will ensure better ICP more-so

 

[Josh@DirtyDiesels]

Thanks bro. My truck is still young at 51k miles. I can hold ICP fine now, ( doesnt say much though haha ) I also have the original HPOP fittings, so maybe the newer ones will ensure better ICP more-so

Is your truck an 05-07? If you're talking about the STC fitting that isn't going to change ICP. But if you still have the original STC fitting get that taken care of asap. I had one fail on me and take out an hpop and crack the rear cover. $$$$$$$$$$

 

[MrOneEyedBoh]

Damn. I thought that they could be leaking and not giving you full ICP under full/heavy load?