That piece in the top pic is exactly what I was describing. What psi are we trying to dump excess fuel at?
Frps
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Factory goes for 67psi +/-7psi in the PPRV. So ~67psi blow off sounds good to me. At 67psi with a delta pressure of 39psi, that would give a user up to 28psi before having delta pressure related problems. But at that point, I don't think someone will be keeping a mostly stock fuel system. :lol:
So how do you know if you blew the frps?
Very true. I'm going to keep my brain working on this one also, though I have not had to remove my pumps from the tank and still have the PPRV installed in stock form. Here is another idea. What about a piece of steel fuel line that is welded shut on one end and goes from the pump, down to bottom of the tank and back up forming a trap filled with air. The top of the trap that is closed could even be larger to contain more air. As the fuel pressure spikes for a very short period of time. The fuel will compress the air in the tube taking the "shock" out of the fuel line. A very small hole can even be drilled in the bottom part of the trap to let off excess fuel and pressure. These are used in homes in the water lines by the shut off valves in sinks and toilets to absorb the "shock" that creates pipe knocking. Figured this might be cheap and easy. No parts to brake and adjustments to make. Also it can be made to be compact.
The problem with the "air hammer" is they eventually fail just like in homes. I have see the use of these and not sure if they would apply in the fuel tank situation. Not sure how they fail but with proper explaination, they do work for a time. The amount of air needed may be more than you think to properly absorb the shock. The knocking sound in the home water system is normally caused by a valve in the system being slightly shut.Just my 2 cents.
I like the idea of the PPRV being used only as the bleed valve in the above drawing. Simple yet effective. Keeping the check ball side from being a problem is of the biggest concern. Repeated high pressures and jb weld while submerged in fuel?
More info please.
My thought was that the "air hammer" would last longer than the fuel lines in the tank. The other thought was that currently the "fix" is an orfice near the FRPS. The orfice is designed to delay the surge to the switch long enough for the pressure to fall below the piont of damage so it only has to absorb pressure for a split second. The air hammer in the tank would give a lot more time because not only is it going to absorb the shock but will give more time because the entire fuel line will have to see the increased pressure after the air hammer has before the FRPS blows. This would probably double the time the spike would need to destroy the FRPS. The air hammer along with the restriction orfice in the FRPS and you would probably never blow the switch. In this theory, I'm assuming the spike in fuel pressure only lasts less than a second. Though it is just a theory....
The thought is good. I just dont think the air hammer will be a long lasting fix. I think it will eventually fail and you would be back in the same boat.How long to fail I dont know.
The spike if fuel pressure should only last as long as there is no demand for fuel at the injector and the duration of the pump still feeding the rail. As explained earlier the pump still is running for a short time after the throttle is closed to keep the fuel pressure at the set rail pressure. Minimal at best.
The spike if fuel pressure should only last as long as there is no demand for fuel at the injector and the duration of the pump still feeding the rail. As explained earlier the pump still is running for a short time after the throttle is closed to keep the fuel pressure at the set rail pressure. Minimal at best.
Ah, got it. Yes, if the pump still runs for even a short period then the air hammer will not work. I'm guessing the only thing that will work is something that can bleed of pressure for a short extended period of time : regulator, blow off valve, etc...
Any new ideas??
I have to say that with the addition of the PPRV delete i added the Kenne Bell pressure disc under the FPRS. I was worried about the possible failure and didnt want to be stranded. I would like to see an alternative to that disc. Would like to see if the PPRV delete and FPRS could live happily ever after.
I have to say that with the addition of the PPRV delete i added the Kenne Bell pressure disc under the FPRS. I was worried about the possible failure and didnt want to be stranded. I would like to see an alternative to that disc. Would like to see if the PPRV delete and FPRS could live happily ever after.
As I expected, the blow off valve in the PPRV does nothing to protect the FRPS, its the small hole in the small nipple that does it. Unfortunately, I haven't found an easy way to install 2 PPRVs yet. The stock-like hose is surprisingly hard to find in 3" and 5" lengths. Even if I find it, I think the size difference between the fittings (pumps and hat are 5/16" while the PPRV and stock "Y" fitting are 3/8") is going to pose a problem when installing the hose. I'm assuming that the stock hoses were designed for 5/16" fittings, cause I can find the same hose 8" and longer, and they are designed for 5/16" fittings. With the stock hose you (sweet88gt) sent me, I tried installing the uncut ends onto a 3/8" fitting.....no luck. How the factory did it, I'm not sure. Since the hose is significantly stretched over the 3/8" fittings, I'm guessing that's why there are no clamps; the hoses hold on by themselves. I tried the same thing with 5/16" 30R10 hose onto a 3/8" fitting.....without a clamp, I couldn't blow it off with 100+psi of pressure and I couldn't even pull off the hose with my hands. My big concern would be the affects of being submersed in fuel (ie slight hose expansion/contraction and its affects on grip). Another concern are kinks. Even with 5/16 hose, I don't like how the 30R10 hose starts to kink right on top of the pumps. If we can find a supplier for 3"/5" corrugated fuel line that will work with the 5/16" and 3/8" fittings, we'll be in business.
Right now, my plan is to actually go with a Fore hat and possibly a combo of a check valve and Aeromotive FPR. With the stock hat, I don't like the idea that Gates hose start to bend due to the tight radii. I also used steel hardline for the bends, but even the hardline begins to kink. Plus, all the clamps bug me (call me anal). Another bonus is that I have room to grow if I decide to go for ~600rwhp. Couple GT pumps, dual FPDMs, and wire upgrade is all I'll need.
Right now, my plan is to actually go with a Fore hat and possibly a combo of a check valve and Aeromotive FPR. With the stock hat, I don't like the idea that Gates hose start to bend due to the tight radii. I also used steel hardline for the bends, but even the hardline begins to kink. Plus, all the clamps bug me (call me anal). Another bonus is that I have room to grow if I decide to go for ~600rwhp. Couple GT pumps, dual FPDMs, and wire upgrade is all I'll need.
The stock hose must be installed with heat at the factory. Heat end of fuel line and install on pump. I couldnt get the hose off of the pump and just cut into it to get it off. I cant think of an easy way to get the stock lines with spending some cash. I will do some searching of my own on the correct fuel lines.
As far as the kink of the 3/8 line. I took an extra set of clamps and slighty closed down on the area when the kink started. Seems to be doing fine for now. I agree that the line is kinked but went ahead with the project as planned.
The Fore setup deletes the PPRV internally correct?
As far as the kink of the 3/8 line. I took an extra set of clamps and slighty closed down on the area when the kink started. Seems to be doing fine for now. I agree that the line is kinked but went ahead with the project as planned.
The Fore setup deletes the PPRV internally correct?
Yup. There is a short distance between the pump and the top of the hat. Unfortunately, not enough for a PPRV. The "Y" is built into the top of the hat.
I've had thoughts about drilling a small hole (similar in size to the hole in the small nipple of the PPRV) on the underside of the Fore hat. Another thought is to buy a 3-pump hat and install a PPRV on the 3rd pump location.
Like I've said, I've thought about this too much. :lol:
Side note: Personally, I'm surprised no one has come out with a stamp steel (or other low cost) version similar to the factory hat where the lines come straight out the top with a "Y" fitting used externally. This could even allow the use of 2 factory style fuel filters (suggesting reduced restriction) since the "Y" fitting could be used after the filters. Using billet aluminum seems like an unnecessarily expensive way to do it, IMO.
I was looking at the 3 pump hat and wondering the same thing. Using that port for something other than fuel feed.
Could that 3 line be used for the return for your Aeromotive idea of a pressure reg installed somewhere close to the hat loaction and run the return line back to this port?? Thinking out loud:shrug:
Could that 3 line be used for the return for your Aeromotive idea of a pressure reg installed somewhere close to the hat loaction and run the return line back to this port?? Thinking out loud:shrug:
Yes, it would work. But it wouldn't need a 3-pump hat, simply a 2-pump designed for a return-style system. The return port could be used for the discharge of the FPR.
Is there a how to on changing/checking your FPRS?? I think mine is out, but I'll find out if it was the faulty battery(charging as I type), alternator, or the FPRS!!! Any pics of the FPRS? Where do I check and pull/disconnect?? Visuals would help a lot w/ a circle to show me where the FPRS is located? Thanks...
I fixed my fuel pressure spikes (cause of the dreaded hesitation... after a 2.93" pulley swap) by performing the following major programming changes:
-Nail the MAF x-fer (used in determining load) function
-Correct the returnless fuel pump voltage table (feed forward voltage table)
-Update the Load with Failed MAF table (the big fix...)
Doing the above caused my returnless fuel line pressure reading to never exceed 62 psi. I was seeing 74 psi before that.
This worked out great until I needed to change my MAF when I went to a 2.8" upper. I went with a SCT2400BA.
The MAF change and SCT's "tweaks" to the tuning skewed how the load is calculated. I then believed the "Load with Failed MAF" table was no longer valid. You could tell, my fuel pressure was spiking again!
Doesn't matter anymore. I no longer own the Cobra, I now drive a Range Rover Sport...
-Nail the MAF x-fer (used in determining load) function
-Correct the returnless fuel pump voltage table (feed forward voltage table)
-Update the Load with Failed MAF table (the big fix...)
Doing the above caused my returnless fuel line pressure reading to never exceed 62 psi. I was seeing 74 psi before that.
This worked out great until I needed to change my MAF when I went to a 2.8" upper. I went with a SCT2400BA.
The MAF change and SCT's "tweaks" to the tuning skewed how the load is calculated. I then believed the "Load with Failed MAF" table was no longer valid. You could tell, my fuel pressure was spiking again!
Doesn't matter anymore. I no longer own the Cobra, I now drive a Range Rover Sport...
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the frps is on the end of the fuel rail, it has an electrical connector as well as a vacuum line attached to it.
Thanks... I saw a clear picture of it on page 2. I appreciate the help... I don't think it's my FRPS. My alternator died out on me @ only 20k on the car. :dw: I'm starting to think if getting this Cobra was a good move. Hell, my V6 has had no problems and it has 95K miles on it. V6 = 0; V8 = 1.
It can be done and it fixed my problems. I was constantly setting off the FRPS Code (though I wasn't actually ruining the sensor itself). Once the duration was extended on startup, my problem went away
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