adjustable fuel psi regulator need some pointers
12-23-2009, 01:58 PM
#22
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Yes, check it out. Look where the FPR used to be you will see a hole and some of the material poking out. Fuel that has been pumped by the fuel pump is now able to leak from here and enter the tank again. Which will make for a lean condition.
12-23-2009, 09:27 PM
#25
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Always more that one way to skin a cat
12-24-2009, 03:23 PM
#27
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It depends on how the kit is designed.
P-tuning uses a plug because they modify the sending unit as little as possible. Instead of giving you an improved feed line they have you cut the stock plastic line off the feed fitting from the sending unit, re-use the sending unit fitting and hose clamp a braided line onto the fitting you removed from the stock line ( i do not think this is safe, that is my opinion i would feel much better with an AN fitting) and then plug the regulator port so that you can use the feed solely as a feed line. Then you run the return into the sending unit and use the original feel line as your return line.
The only issues I have with doing something like this is that you don't actually get a full bolt on kit. If you ever want to return to stock or have to for some reason (ie state inspection, selling the car, trading in) you would have to go buy a new line from the dealer to fix the problem.
Another issue is using the stock feed port to supply fuel to the upgraded kit. The size of the feed on the stock sending unit is .2110" inner diameter which is roughly 7/32" allowed for the feed. You would see improvements if you used a -6an feed which is .375" or 3/8" continuous. The benefits of this would be less strain on the fuel pump which means less amperage draw and overall more output from your in tank fuel pump. Taking this attention to detail often times makes needing a second fuel pump unnecessary. If you upgraded the fuel feed side you would have to add a fuel filter inline but that is easy and what most people do anyhow. The stock fuel filter is super restrictive and with good cause as it was designed to flow enough fuel to make 200 hp. The factory fuel filter is located inside the sending unit and is not replaceable. I think this is stupid because if that filter plugs up you have to replace a $250 sending unit as opposed to a $12 dollar filter.
Not to mention if you look at where the FPR goes in the sending unit you will notice a passage to the filter media. That O ring on the stock sending unit prevents fuel from bypassing out of that cavity. The pump fills that cavity where the fuel filter resides before it leaves the sending unit. By removing the stock FPR completely you are allowing pumped fuel to bleed back to the tank. If it were that easy do you think that P tuning would have taken the time to make a plug?
The only way you can get around removing the plug completely is if you do not use the stock fuel filter and instead use a hose to connect directly from the fuel pump to the feed fitting you would have to add.
I have designed a sending unit that utilizes this and thus does not require a fuel plug. Any other way would cause problems. Maybe not something you would see at lower boost but higher boost for sure in the way of fuel starvation.
These statements are not meant to be antagonistic in any way shape or form. This is factual data, minus my opinions. Please take it as such.
P-tuning uses a plug because they modify the sending unit as little as possible. Instead of giving you an improved feed line they have you cut the stock plastic line off the feed fitting from the sending unit, re-use the sending unit fitting and hose clamp a braided line onto the fitting you removed from the stock line ( i do not think this is safe, that is my opinion i would feel much better with an AN fitting) and then plug the regulator port so that you can use the feed solely as a feed line. Then you run the return into the sending unit and use the original feel line as your return line.
The only issues I have with doing something like this is that you don't actually get a full bolt on kit. If you ever want to return to stock or have to for some reason (ie state inspection, selling the car, trading in) you would have to go buy a new line from the dealer to fix the problem.
Another issue is using the stock feed port to supply fuel to the upgraded kit. The size of the feed on the stock sending unit is .2110" inner diameter which is roughly 7/32" allowed for the feed. You would see improvements if you used a -6an feed which is .375" or 3/8" continuous. The benefits of this would be less strain on the fuel pump which means less amperage draw and overall more output from your in tank fuel pump. Taking this attention to detail often times makes needing a second fuel pump unnecessary. If you upgraded the fuel feed side you would have to add a fuel filter inline but that is easy and what most people do anyhow. The stock fuel filter is super restrictive and with good cause as it was designed to flow enough fuel to make 200 hp. The factory fuel filter is located inside the sending unit and is not replaceable. I think this is stupid because if that filter plugs up you have to replace a $250 sending unit as opposed to a $12 dollar filter.
Not to mention if you look at where the FPR goes in the sending unit you will notice a passage to the filter media. That O ring on the stock sending unit prevents fuel from bypassing out of that cavity. The pump fills that cavity where the fuel filter resides before it leaves the sending unit. By removing the stock FPR completely you are allowing pumped fuel to bleed back to the tank. If it were that easy do you think that P tuning would have taken the time to make a plug?
The only way you can get around removing the plug completely is if you do not use the stock fuel filter and instead use a hose to connect directly from the fuel pump to the feed fitting you would have to add.
I have designed a sending unit that utilizes this and thus does not require a fuel plug. Any other way would cause problems. Maybe not something you would see at lower boost but higher boost for sure in the way of fuel starvation.
These statements are not meant to be antagonistic in any way shape or form. This is factual data, minus my opinions. Please take it as such.
Having said that, when we set out to develop our entry-level spec-ss fuel system, we wanted to design it so that the system was affordable, upgradeable and most importantly offer a proven performance over the factory fuel system for forced induction applications. We feel that with the spec-ss fuel system, we've accomplished all of the above.
With regards to the factory siphon assembly, there's no way to build an affordable aftermarket return-style fuel system without modifying the factory siphon assembly or fuel tank. The only way anyone can create a return-style fuel system utlizing the factory fuel tank is to build a custom machined or injection molded siphon assembly--and that would increase the price of the fuel system significantly and pricing is always an issue with the majority of the scion community. If you want to be able to put it back to perfectly stock condition, save yourself the headache and don't mod it in the first place
We went to great lengths to build our spec-ss fuel system in a way that the average person can easily install our fuel system with minimal modifications to the factory fuel system. From the machined FPR bypass plug to the factory-style fuel line disconnect plugs. The only real modification needed is to drill a hole in the factory siphon for the fuel return fitting and cutting the plastic fuel feed line in order to connect our braided feed line. Everything else is a simple remove and replace with the components we supply.
In regards to the "restriction" with the factory fuel feed on the siphon assembly, what is the restriction. The path from the outlet of the included in-tank walbro 255 high pressure to the outlet of the feed neck on the siphon assembly is so short that it doesn't really introduce any real restriction to the -6AN feed line that we supply to connect the siphon assembly to our fuel rail. If there were any restriction at all, it would be at the outlet of the walbro pump. If you break the feed nozzle on a walbro in-tank pump, you would see that the opening is less than an 1/8", to be exact .1195" (3mm) (see picture below). But in this case the tiny opening on the pump does not cause any real restrictions. If we were running an 1/8" ID line from the siphon assembly to the fuel rail, yes, that would create a massive restriction to the fuel supply since the distance is so long, but that's not the case here.
We've already dyno tested our spec-ss fuel system over 400whp (dyno dynamics) without any fueling issues. There's no reason why someone could not run over 500whp with this setup with the proper size injectors. The in-tank walbro pump will probably reach it's flow capacity before the lines and connections in our fuel system reach it's limit.
So unless you're planning to build a 900hp daily driver tc, the spec-ss fuel system is all you'll need. And for those customers, we have our spec-rs and spec-rsII (dual external pump) fuel system. They're currently in use but not yet release--will announce it once we have the system finalized.
The bottom line is that there's more than one way to build an upgraded fuel system for forced induction tCs. We just happened to do it our way and that's not to say that it's the only way, but it meets all of our requirements for a simple bolt-on system.
The only thing we wanted to add to our spec-ss fuel system that we didn't do was to create a billet 90* feed adaptor with an AN flare end so that you could easily disconnect the factory feed line at the siphon assembly without having to cut the plastic feed line. But that would only add additional cost to the fuel system.
MrC
Last edited by MrC_Ptuning; 12-24-2009 at 06:23 PM.
12-24-2009, 04:22 PM
#28
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Join Date: Apr 2008
Location: Orlando, FL
Posts: 4,156
First off, there's no need to critic another vendor's product. If you have a better product, produce it and let the quality of your product speak for itself. There's nothing wrong with competition, but there's no need to put down another companies' product publicly, inorder to get ahead.
Having said that, when we set out to develop our entry-level spec-ss fuel system, we wanted to design it so that the system was affordable, upgradeable and most importantly offer a proven performance over the factory fuel system for forced induction applications. We feel that with the spec-ss fuel system, we've accomplished all of the above.
With regards to the factory siphon assembly, there's no way to build an affordable aftermarket return-style fuel system without modifying the factory siphon assembly or fuel tank. The only way anyone can create a return-style fuel system utlizing the factory fuel tank is to build a custom machined or injection molded siphon assembly--and that would increase the price of the fuel system significantly and pricing is always an issue with the majority of the scion community. If you want to be able to put it back to perfectly stock condition, save yourself the headache and don't mod it in the first place
We went to great lengths to build our spec-ss fuel system in a way that the average person can easily install our fuel system with minimal modifications to the factory fuel system. From the machined FPR bypass plug to the factory-style fuel line disconnect plugs. The only real modification needed is to drill a hole in the factory siphon for the fuel return fitting and cutting the plastic fuel feed line in order to connect our braided feed line. Everything else is a simple remove and replace with the components we supply.
In regards to the "restriction" with the factory fuel feed on the siphon assembly, what is the restriction. The path from the outlet of the included in-tank walbro 255 high pressure to the outlet of the feed neck on the siphon assembly is so short that it doesn't really introduce any real restriction to the -6AN feed line that we supply to connect the siphon assembly to our fuel rail. If there were any restriction at all, it would be at the outlet of the walbro pump. If you break the feed nozzle on a walbro in-tank pump, you would see that the opening is less than an 1/8", to be exact .1195" (3mm) (see picture below). But in this case the tiny opening on the pump does not cause any real restrictions. If we were running an 1/8" ID line from the siphon assembly to the fuel rail, yes, that would create a massive restriction to the fuel supply since the distance is so long, but that's not the case here.
We've already dyno tested our spec-ss fuel system over 400whp (dyno dynamics) without any fueling issues. There's no reason why someone could not run over 500whp with this setup with the proper size injectors. The in-tank walbro pump will probably reach it's flow capacity before the lines and connections in our fuel system reach it's limit.
So unless you're planning to build a 900hp daily driver tc, the spec-ss fuel system is all you'll need. And for those customers, we have our spec-rs and spec-rsII (dual external pump) fuel system. They're currently in use but not yet release--will announce it once we have the system finalized.
The bottom line is that there's more than one way to build an upgraded fuel system for forced induction tCs. We just happened to do it our way and that's not to say that it's the only way, but it meets all of our requirements for a simple bolt-on system.
The only thing we wanted to add to our spec-ss fuel system that we didn't do was to create a billet 90* feed adaptor with an AN flare end so that you could easily disconnect the factory feed line at the siphon assembly without having to cut the plastic feed line. But that would only add additional cost to the fuel system.
MrC
Having said that, when we set out to develop our entry-level spec-ss fuel system, we wanted to design it so that the system was affordable, upgradeable and most importantly offer a proven performance over the factory fuel system for forced induction applications. We feel that with the spec-ss fuel system, we've accomplished all of the above.
With regards to the factory siphon assembly, there's no way to build an affordable aftermarket return-style fuel system without modifying the factory siphon assembly or fuel tank. The only way anyone can create a return-style fuel system utlizing the factory fuel tank is to build a custom machined or injection molded siphon assembly--and that would increase the price of the fuel system significantly and pricing is always an issue with the majority of the scion community. If you want to be able to put it back to perfectly stock condition, save yourself the headache and don't mod it in the first place
We went to great lengths to build our spec-ss fuel system in a way that the average person can easily install our fuel system with minimal modifications to the factory fuel system. From the machined FPR bypass plug to the factory-style fuel line disconnect plugs. The only real modification needed is to drill a hole in the factory siphon for the fuel return fitting and cutting the plastic fuel feed line in order to connect our braided feed line. Everything else is a simple remove and replace with the components we supply.
In regards to the "restriction" with the factory fuel feed on the siphon assembly, what is the restriction. The path from the outlet of the included in-tank walbro 255 high pressure to the outlet of the feed neck on the siphon assembly is so short that it doesn't really introduce any real restriction to the -6AN feed line that we supply to connect the siphon assembly to our fuel rail. If there were any restriction at all, it would be at the outlet of the walbro pump. If you break the feed nozzle on a walbro in-tank pump, you would see that the opening is less than an 1/8", to be exact .1195" (3mm) (see picture below). But in this case the tiny opening on the pump does not cause any real restrictions. If we were running an 1/8" ID line from the siphon assembly to the fuel rail, yes, that would create a massive restriction to the fuel supply since the distance is so long, but that's not the case here.
We've already dyno tested our spec-ss fuel system over 400whp (dyno dynamics) without any fueling issues. There's no reason why someone could not run over 500whp with this setup with the proper size injectors. The in-tank walbro pump will probably reach it's flow capacity before the lines and connections in our fuel system reach it's limit.
So unless you're planning to build a 900hp daily driver tc, the spec-ss fuel system is all you'll need. And for those customers, we have our spec-rs and spec-rsII (dual external pump) fuel system. They're currently in use but not yet release--will announce it once we have the system finalized.
The bottom line is that there's more than one way to build an upgraded fuel system for forced induction tCs. We just happened to do it our way and that's not to say that it's the only way, but it meets all of our requirements for a simple bolt-on system.
The only thing we wanted to add to our spec-ss fuel system that we didn't do was to create a billet 90* feed adaptor with an AN flare end so that you could easily disconnect the factory feed line at the siphon assembly without having to cut the plastic feed line. But that would only add additional cost to the fuel system.
MrC
I will have this soon
12-25-2009, 03:59 PM
#29
Im very happy with the ptuning fuel system, very nice setup.. not only i got more fuel but the car runs smoother.. one thing i wished it came with is a wiring harness for the walbro fuel pump but really not biggy.. i'll be posting a review soon or a DIY im not even sure if necessary
12-25-2009, 04:33 PM
#30
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Im very happy with the ptuning fuel system, very nice setup.. not only i got more fuel but the car runs smoother.. one thing i wished it came with is a wiring harness for the walbro fuel pump but really not biggy.. i'll be posting a review soon or a DIY im not even sure if necessary
couldnt help but notice your not running the rear pcv to vac.., did u just plug the line ? ive been thinking of doing the same to prevent boost from entering the crankcase
12-26-2009, 01:38 AM
#33
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No offense but like Don said i would go with an fittings.
Not worth it in my opinion, but to each his own. The idea and design is nice just kinda throws me off with the lines and the stock fuel tree. I built my own custom return and feed set-up, with -6an lines/fittings, aeromotive FPR and a stainless steel fuel tree i made. Cost me maybe $500 max. Nice product none the less.
Not worth it in my opinion, but to each his own. The idea and design is nice just kinda throws me off with the lines and the stock fuel tree. I built my own custom return and feed set-up, with -6an lines/fittings, aeromotive FPR and a stainless steel fuel tree i made. Cost me maybe $500 max. Nice product none the less.
Last edited by GetIt; 12-26-2009 at 01:48 AM.
12-26-2009, 03:31 AM
#34
^^ you got pics of your setup? especially the feed line? the only non an fitting ptuning used is the for the feed line to the stock feed fitting and the 2 oem style quick disconnect clips, i think those make the kit pretty easy to install and the lines very well secured
12-26-2009, 02:46 PM
#35
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I don't have pics of it, but when i do head over to the shop when i get back from vacation i can get and post some pics. It's honestly really easy to do. The only real differences are.... my FPR is located against the firewall, used -an fittings, and my custom fuel tree. The tree i just swapped out the sending unit, welded feed and return fittings and there ya have it all you have to do is build the lines, run em (which i ran in the original stock location) and screw'd em on. One thing i do LIKE about the Ptuning is where you have the FPR located, i love the cosmetic look of the system. Hopefully no one thinks im bashing, and my bad if did.
12-26-2009, 02:59 PM
#36
oh no, really everyone has their opinion.. im just interested to see different setups, especially on the siphon assembly.. I ran the two -6 lines like the stock ones too, and its a really tight fit in there.. I have to drop the tank some to get it on top of the siphon assembly
12-28-2009, 04:22 PM
#37
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Location: Buffalo, NY
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First off, there's no need to critic another vendor's product. If you have a better product, produce it and let the quality of your product speak for itself. There's nothing wrong with competition, but there's no need to put down another companies' product publicly, inorder to get ahead.
My opinion and concern about the safety of putting a hose that was designed to seal in a compression like manner on the end of a fitting not designed to seal in that way and using a clamp, is that of my own (and probably most any racing tech inspection body). I'm sure you have tested it and found it to be adequate to your standards.
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