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Discussion Starter #1
Long story short I removed the little valve in the stock filter head to install an adapter to mount a Racor 660 in place of the stock filter. The adapter threads weren't quite right so I reinstalled the stock filter leaving the check valve out.


Now here's the thing. MY TST comp box dosen't burst any more!!! I drive with it at 4 and 3 and it usually bursts. I have tried it now at 9 and 9 and no bursting. I roll into it at 15 MPH as I have a stock tranny, smoke like hell and the EGT goes above 1700 before I get through 3rd gear (limiter set at 1700) but no bursting. I think the little valve is a restriction to fuel flow. To remove it all you have to do is remove the filter head (2 12 mm bolts) unplug the positive wire to the filter head (it just pulls off, no tools) turn the head upside down and remove the two torx screws (T12, I think). the black plastic cover is then removed and the spring with the nylon ball is then easily removed. Then just put the thing back together. Easy. The only function that I can see that it might have is to prevent fuel leaking from the head when you remove the filter. I intend to drain the filter prior to un screwing it to prevent fuel spillage. I would like independant confirmation that you can really increase fuel flow just by removing this little valve. Is there anyone out there with a Tech II that has a high enough power program that can monitor actual fuel pressure vs desired to see if this really works and I'm not just smoking crack? I don't have access to a Tech II, I'm just a poor underpaid test pilot.
 

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sounds like genius to me
 

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Smoking crack is an altogether separate issue!



I am sure you did increase fuel flow. You mentioned the little ball only serving the purpose of not letting fuel leak when changing the filter. I am curious to see if you now have any hard starting issues do to loss of prime?Edited by: Bronco
 

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Discussion Starter #4
Bronco, I haven't yet. I'm pretty sure that the ball is unseated by the filter, so it is not a "check valve". If you have a filter handy look in the very center of it. The X in the middle unseats the ball, I think. Anyway the spring is WAY too strong to be sucked open by vacuum, so I'm pretty sure it's not a check valve that prevents back flow of fuel into the tank. Probably is one in the system somewhere, but I don't think this is it.
 

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a64pilot,


I will try to take mine apart this weekend and check it out. I will see if it makes a difference on the fuel pressure with my Tech II.
 

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Well it was a good find but we just finished testing with and without the valve in place. It did not affect fuel pressure with a fuel pump in the system. Don't get me wrong on this as I had high hopes for it but it just didn't do anything in our test. This was an Xtreme program with a fuel pump set to 6 psi. We still have a pressure drop with the valve removed. Still searching.........................................
 

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Grass...I believe that's what he ment with 6 PSI, well it was a lift pump the way I read it. That is indeed a very interesting find.



Lenny
 

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Discussion Starter #11
IF it works it would be almost too good to be true, but it's worth a shot. It definately made a difference in My truck.Edited by: a64pilot
 

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Im still dumping mine
 

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check valve
 

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I wouldn't be surprised if it does help on a stock fuel system.


There are a lot of little things that add restriction to the fuel system. I'm still amazed at how small the fuel line is, but I suppose GM really isn't in the business of making 600hp diesels.
 

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grasshopper said:
WHAT?????




His truck. He wants a Hemi. Seriously.
 

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This could be some of the best news I've heard in along time. I can't wait to see if someone without a lift pump can prove or dis-prove this with a tech II or Kent-Moore gauge under load.
 

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Yes, we have a lift pump. It's a Holley black pump with regulator set at 6 psi. Problem is pressure in the line drops to <1 psi at WOT with the Xtreme program. Would like to get it stable at 5 psi if possible. Still searching ....................................


Removing the valve may help when running lower performance but we were not test at that level. So wait and see if one of the other guys has better luck.
 

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What does WOT stand for?
 
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