Solved the excess fuel pressure from the dual pumps

[turboglenn]

Just thought i'd share that i was easily able to get the pressure to be able to go as low as 20psi without vacum

All i did was ran some of that blue -6 hose from the AFPR outlet to the OEM feed at the firewall.. I cut the stock fitting ( the one that attaches to the OEM filter) off the feed and double hose clamped the -6 it to the rest of the old feed line...

Then at the rear i used the 14x1.25 to -6 AN adapter that had came with the filter kit from extremepsi to connect some -6 to the metal line at the chassis where it would normally change to rubber. I noticed the rubber part's coupling had a very small openings compared to the rest of the metal line it was supplying.

And eventhough i wanted to braze in a new return tube at the hanger, i was short on time and just gave it a shot at clamping the hose to the stock one, and it worked , but that's okay, next time it's warm and i want to mess with it i'll upgrade it.

There's several things i learned from completely re-working the fuel system this way instead of just replacing EVERYTHING with aeroquip stuff. I now feel i could get a lot better results from cars in the future off one pump by simply removing several of the main restrictions in both the OEM feed and return lines.

I"m actually thinking about now going back to ONE pump because i feel with the restrictions all gone that havenever even been brought up in any thread i've found, a 255 being able to do it's job without being overly stressed to provide the needed fuel through the stock lines...

Some say the filter's banjo bolt is the largest restriction in the OEM feed, but i would put a strong bet that the rubber hose from the pump hanger to the solid metal line at the chassis in the rear either equalls it in restriction or comes in a damn close second place.

 

[joyfil2001]

Just thought i'd share that i was easily able to get the pressure to be able to go as low as 20psi without vacum

All i did was ran some of that blue -6 hose from the AFPR outlet to the OEM feed at the firewall.. I cut the stock fitting ( the one that attaches to the OEM filter) off the feed and double hose clamped the -6 it to the rest of the old feed line...

Then at the rear i used the 14x1.25 to -6 AN adapter that had came with the filter kit from extremepsi to connect some -6 to the metal line at the chassis where it would normally change to rubber. I noticed the rubber part's coupling had a very small openings compared to the rest of the metal line it was supplying.

And eventhough i wanted to braze in a new return tube at the hanger, i was short on time and just gave it a shot at clamping the hose to the stock one, and it worked , but that's okay, next time it's warm and i want to mess with it i'll upgrade it.

There's several things i learned from completely re-working the fuel system this way instead of just replacing EVERYTHING with aeroquip stuff. I now feel i could get a lot better results from cars in the future off one pump by simply removing several of the main restrictions in both the OEM feed and return lines.

I"m actually thinking about now going back to ONE pump because i feel with the restrictions all gone that havenever even been brought up in any thread i've found, a 255 being able to do it's job without being overly stressed to provide the needed fuel through the stock lines...

Some say the filter's banjo bolt is the largest restriction in the OEM feed, but i would put a strong bet that the rubber hose from the pump hanger to the solid metal line at the chassis in the rear either equalls it in restriction or comes in a damn close second place.

So you are saying you replaced the feed line and lowered the pressure? I am still having high fuel pressure on my 2g. I have a SS -6an line going from the fuel pump to the rail. I am assuming my problem is the fuel return line going back to the tank.

 

[Weapon-X]

If I follow correctly, he did the same thing I was gonna do...............

You use the OEM feedline as your return line. Save money on materials, its all ready ran, and is larger then the"actual" OEM return line.

You just need to make the approriate connections at the tank because of the change and the obvious connections on the firewall.

I have a 99 GSX and have the over-priced Full Blown dual pump hanger. I have the OEM siphon opened up a bit and was gonna use my OEM feedline as my return line also.

In my case with being AWD though, I also have to put forth the additional effort to get the siphon area working properly also.

My system isn't in service yet, so I really cannot comment on any "real world" results just yet.

But I am glad to see this project take place and evolve for you.

 

[turboglenn]

Thanks Weapon-X, at least now you know for sure that it will work!


Joyfil - I did exactly what he described, I used the OEM feed line as the return line after upgrading my feedline to -6 stuff

 

[joyfil2001]

Thanks Weapon-X, at least now you know for sure that it will work!


Joyfil - I did exactly what he described, I used the OEM feed line as the return line after upgrading my feedline to -6 stuff

Please excuse my ignorance here, but how did you connect the hard line to the FPR return line? Did you just use regular fuel hose and clamp it down?

 

[turboglenn]

Yea, i just cut the fitting off, flared it a tad for grip and double hose clamped it. IN the rear i used a few metric to AN conversion fittings to adapt it to more -6 stuff then hose clamped that to the return port on the hanger

 

[joyfil2001]

Yea, i just cut the fitting off, flared it a tad for grip and double hose clamped it. IN the rear i used a few metric to AN conversion fittings to adapt it to more -6 stuff then hose clamped that to the return port on the hanger

What was your reason for doing this? You have a GST so you don't have the saddlebag fuel tank like the AWD. You were still having fuel pressure issues?

 

[Weapon-X]

Here's my take on this situation................I don't believe the OEM sized return can handle the volume from the dual pumps.

Since the line "backs-up" because of this it causes an increase in fuel pressure. Unfortunately it causes it to raise to a point that is not in our favor.

Yes turboglenn is a GST so he does not have to combat extra issues with the siphon like I do being that I'm AWD, but it still does not change the fact that the OEM return just can't handle the return volume of the dual pumps.

So an economical approach is to use the OEM feedline as the return. Like I said above, it's all ready there, it saves time and additional cost, and as far as I know it's just enough of an increase in size to handle the return flow of the dual pumps.

I'm gonna run a -6 return from my FPR to the OEM feedline. I'm just gonna use and adapter/fitting combo to connect my -6 directly to the feedline though. I will be using a -8 for my feedline.

Since I'm AWD I have my siphon opened up to 1/8 to see if that helps open things up in the tank. I can go up a size......possibly 2 yet before I need to figure out if I need to completely build a new siphon piece myself or try something different if I experience troublesome pressure issues.

 

[turboglenn]

Yea, Weapon-X is right, i had to much pressure from dual pumps and the factorty feed line makes a perfect larger return.

I'm going back to one pump just for a test to see if the change in tune is due more to the dual pumps and how the charachteristics change when doublling them up, or if the change is from the enlarged feed line alone.

Anyone see any harn in leaving a plug dangling in hte tank not hooked to the 2nd pump? I mean there's +12v exposed to gasoline and it's vapors from the factory so i'm thinking a loose plug should be fine as long as it can't get to touch anything that might make a spark..anyone else thing differently befoer i do this tomorrow?

 

[joyfil2001]

Here's my take on this situation................I don't believe the OEM sized return can handle the volume from the dual pumps.

Since the line "backs-up" because of this it causes an increase in fuel pressure. Unfortunately it causes it to raise to a point that is not in our favor.

Yes turboglenn is a GST so he does not have to combat extra issues with the siphon like I do being that I'm AWD, but it still does not change the fact that the OEM return just can't handle the return volume of the dual pumps.

So an economical approach is to use the OEM feedline as the return. Like I said above, it's all ready there, it saves time and additional cost, and as far as I know it's just enough of an increase in size to handle the return flow of the dual pumps.

I'm gonna run a -6 return from my FPR to the OEM feedline. I'm just gonna use and adapter/fitting combo to connect my -6 directly to the feedline though. I will be using a -8 for my feedline.

Since I'm AWD I have my siphon opened up to 1/8 to see if that helps open things up in the tank. I can go up a size......possibly 2 yet before I need to figure out if I need to completely build a new siphon piece myself or try something different if I experience troublesome pressure issues.

Yea that is my issue. Since I am AWD I can not lower the fuel pressure below 45-50psi. So I am constantly running rich.

Yea, Weapon-X is right, i had to much pressure from dual pumps and the factorty feed line makes a perfect larger return.

I'm going back to one pump just for a test to see if the change in tune is due more to the dual pumps and how the charachteristics change when doublling them up, or if the change is from the enlarged feed line alone.

Anyone see any harn in leaving a plug dangling in hte tank not hooked to the 2nd pump? I mean there's +12v exposed to gasoline and it's vapors from the factory so i'm thinking a loose plug should be fine as long as it can't get to touch anything that might make a spark..anyone else thing differently befoer i do this tomorrow?

I don't see an issue with leaving one of the pumps unplugged. I would, however, tape up the exposed end.

 

[turboglenn]

i thought about taping it off, the realized as soon as gas hits it the tape will fall off becoming a piece of tracsh in the tank, of course i can't recall electrical tape's reaction to gas, but i'm pretty sure it softens it up *shrugs*

 

[joyfil2001]

i thought about taping it off, the realized as soon as gas hits it the tape will fall off becoming a piece of tracsh in the tank, of course i can't recall electrical tape's reaction to gas, but i'm pretty sure it softens it up *shrugs*

I was thinking more along the lines of duct tape. It is pretty resistant to water. I'm not sure how gas would effect it. But it's not like you have to do it. You should be fine. (crosses fingers)

 

[4g64GST]

add a zip tie around the tape to hold the tape on if it becomes loose.

 

[Weapon-X]

You should be fine with out any tape. The gasoline will take car of stripping off the adhesive on electrical tape or duct tape in short order.

I wouldn't worry as gasoline is not conductive. It actually has more insulating properties then it does conductive properties.

Your fuel is constantly in contact between the positive and negative connections inside the fuel tank.

Nothing to worry about.

 

[Weapon-X]

Yea that is my issue. Since I am AWD I can not lower the fuel pressure below 45-50psi. So I am constantly running rich.

Sorry, I'm not familiar with your exact set-up....................... But..............

Have you modified your siphon at all?

If not, you may want to do exactly what I have done.

You will need to open up the orifice in the siphon using an 1/8" drill bit.

Make sure its clean then re-install.

Are you using dual pumps?

If so, your return might be doing what I explained in the posts above.

Your volume of fuel is "over-running" your return line............... "backing up" causing a raise in your fuel pressure.

The raise in fuel pressure is the negative effect of the line not being able to handle the return volume. Once the flow limit of the line is reached the pressure rises.

If you are 1000% sure..............yes I said 1 thousand percent sure, your return line is sufficient then your problem is in the siphon.

 

[turboglenn]

Well, I came home for lunch and decided to unhook one pump and see what would happen. Strangely enough the AFR's came back in check (for the most part, there was still a few spots that hadn't been tuned)

I'm thinking that the one 255HP was overpowering the the old regular(non HP) 255. I've had had for around 8 years or more. I think that instead of pushing the fuel through the injectors when the pressure raised, i believe some of it might have been going back through the old pump

One thing for sure is, at least now i have a great feed and return setup going and a dual pump kit just waiting for a matching 255hp to go with the current one

I can't wait to get this thing dialed in..money is coming slower than ever this month though I still need to buy a damn turbo from the guy who's got it before some one else gets it.

 

[joyfil2001]

Sorry, I'm not familiar with your exact set-up....................... But..............

Have you modified your siphon at all?

If not, you may want to do exactly what I have done.

You will need to open up the orifice in the siphon using an 1/8" drill bit.

Make sure its clean then re-install.

Are you using dual pumps?

If so, your return might be doing what I explained in the posts above.

Your volume of fuel is "over-running" your return line............... "backing up" causing a raise in your fuel pressure.

The raise in fuel pressure is the negative effect of the line not being able to handle the return volume. Once the flow limit of the line is reached the pressure rises.

If you are 1000% sure..............yes I said 1 thousand percent sure, your return line is sufficient then your problem is in the siphon.

I have not modified the siphon yet and I am still using the factory return line. Everything else is upgraded. I just can't set the base fuel pressure low enough. I was hoping that by upgrading the return line I wouldn't have to mess with the siphon. By the way, where is the siphon located?

 

[Weapon-X]

I have not modified the siphon yet and I am still using the factory return line. Everything else is upgraded. I just can't set the base fuel pressure low enough. I was hoping that by upgrading the return line I wouldn't have to mess with the siphon. By the way, where is the siphon located?

The siphon is located on the fuel assembly in the tank.

It's a white piece of plastic with 3 ports on it.......... 2 on the top 1 on the bottom.

I will be experimenting with mine.

I have it modded with a portion cut-off of it, and the addition of a barbed fitting.

Its also opened up to an 1/8"

I "believe" you can safely go up to 7/32" if need be, but not 100% sure though.

You need to be careful though because I'm not sure if opening it up to large will cause problems with the function of the siphon.

The 3 ports are sized to function as they are from the factory with a specific ratio in mind, changing the sizes affects the fluid siphoning functions.

I am starting small and will work my way up if need be.

I'm hoping that with using my OEM feedline as my return and the combination of my modded siphon I will have my fuel pressures under control.

I can't give any results as of yet, cause I'm not ready to run right now. Sorry.

 

[gsxtasy]

I have not modified the siphon yet and I am still using the factory return line. Everything else is upgraded. I just can't set the base fuel pressure low enough. I was hoping that by upgrading the return line I wouldn't have to mess with the siphon. By the way, where is the siphon located?

http://www.dsmtuners.com/forums/bol...nstalling-new-wally-255-hp.html#post151534165


There ya go .

 

[Weapon-X]

http://www.dsmtuners.com/forums/bol...nstalling-new-wally-255-hp.html#post151534165


There ya go .

Nice......................... !!!!!

I feel better about what I have done so far.

This is turning out to be a nice, informative thread.

 

[turboglenn]

Now i've got a quesion about inline pumps (duals again). I'm getting a brand new bosch 044 pump from a friend for 50 bucks and it's even still in the box! He was going to convert his 510 to fuel injection, then decided on a set of webers instead (yey for me! ) So the 044 pump has never even been in gasoline. I was thinking about just putting the 044 in place of the 255 as a single pump since it flows much better anyway, but something tells me from the one time i saw it that it's an "inline" not an "in-tank" design.

So i may end up having to feed the 044 with the 255HP.. Would that work or would the 255 become a restriction in the 044's pull when it's outflowing the 255?

I've seen/found plenty of info/talk on inline dual pumps, but when it came to this combo the same question i asked was raised and never answered (in the threads i read anyway..just searched "dual in-line pumps")

 

[DoyoFCT]

Jayracing makes a nice sock-filter adapter for 044 pump intank installs. I think i'm probably going to do a single 044 in the tank for my setup.

You must be logged in to view this image or video.

He also makes a nice check valve, if you decide to run it as a dual pump / inline.

You must be logged in to view this image or video.

 

[joyfil2001]

http://www.dsmtuners.com/forums/bol...nstalling-new-wally-255-hp.html#post151534165


There ya go .

I am going to have to do this when I can free up some time. Right now the high fuel pressure isn't effecting my driving other than the fact that I am running rich and pissing away gas.

 

[gsxtasy]

Now i've got a quesion about inline pumps (duals again). I'm getting a brand new bosch 044 pump from a friend for 50 bucks and it's even still in the box! He was going to convert his 510 to fuel injection, then decided on a set of webers instead (yey for me! ) So the 044 pump has never even been in gasoline. I was thinking about just putting the 044 in place of the 255 as a single pump since it flows much better anyway, but something tells me from the one time i saw it that it's an "inline" not an "in-tank" design.

So i may end up having to feed the 044 with the 255HP.. Would that work or would the 255 become a restriction in the 044's pull when it's outflowing the 255?

I've seen/found plenty of info/talk on inline dual pumps, but when it came to this combo the same question i asked was raised and never answered (in the threads i read anyway..just searched "dual in-line pumps")

Glenn, the 255 won't be a restriction, as it will be feeding at zero pressure. This means it can flow a TON of fuel, it's only job will be to keep fuel at the mouth of the 044, and it will act as a booster pump more than a restriction. I wouldn't worry about it, with the 044 being the main pump, it will flow even more than the 044 by it self, and it will be able to sustain much higher fuel pressure's. That in itself, is one of the main benefits of running inline pumps. You can run much higher fuel pressures without loosing flow. So when your pumpin out 40lbs of boost at 40psi BFP, you'll still have fuel!

 

[turboglenn]

Glenn, the 255 won't be a restriction, as it will be feeding at zero pressure. This means it can flow a TON of fuel, it's only job will be to keep fuel at the mouth of the 044, and it will act as a booster pump more than a restriction. I wouldn't worry about it, with the 044 being the main pump, it will flow even more than the 044 by it self, and it will be able to sustain much higher fuel pressure's. That in itself, is one of the main benefits of running inline pumps. You can run much higher fuel pressures without loosing flow. So when your pumpin out 40lbs of boost at 40psi BFP, you'll still have fuel!

Cool, thanks for the info! Unless i end up needing a part or something like in the pics above i might try putting it in this weekend. I have to get out to his house to pick it up then come home and slap her in Too bad he livesd like 40 minutes away

I also need to change the oil in my car this weekend and cut the filter apart to see how much stuff got built up in this one. THe first one hardly had anything in it as far as metal flakes and the like, and upon pulling the pan i found very little silicone that made it's way inside the motor.

Now i'm back to chasing a PK source, i am getting great pulls with great power but every now and then something hits loud right in the gated time that the J&S is sampling and it retards the hell out of one cylinder It's almost like a mildly modded 2g where you get 5 great pulls then one where it feels like there's no power. I've double checked all suspension pieces, CV's, bearings, sub-frame bolts, etc and nothing has "cured" it. THe last thing i have that might be causing it would be the AC compressor again, which when i do the oil change i'll pull the belt and see if it goes away.