$10 dollar fuel pressure regulator w/ long explaination

[killerquake]

ok guys,

i have been doing some research on fuel pressure regulators lately. mainly because im gonna need one. anyways, this is what i have came up with.

the way a fuel pressure regulator works is it controlls the amount of fuel allowed to flow back to the tank (from the return line). the less flow back to the tank the more pressure in the rail.

so, in order to increase the pressure in the rail all you have to do is simply decrease the flow back to the tank. so i got to looking at all the fuel pressure regulators offered out ther and came up with this....

the ones that allow you to lower pressure are the way to go. but if you buy the ones that cut off the top of your stock one, or just raise pressure you are getting ripped off bad!!! sure they look nice, but all they are doing is putting more pressure on the stock valve.

to achive the same exact results as one of these all you need is a bleeder style valve. i got mine at diamond hardware. i put on a 1/4 inch barb on each side and spliced into my fuel return line. clamped it all off and went out to test it.

what i found..... at an idle it you close the valve all the way i will idle up about 500 rpms. the reason is pretty obvious. no fuel returning. so i cracked it open just a little so my idle returned to normal. i then took it for a drive. i was able to run more boost and run with lower egt's. 20c degrees lower with 2 more psi. also my a/f read richer in the higher rpms. so i know it worked.

the reason i even considered doing this is because right now im saving up for a few things and dont have the money to spend. also i was getting too much knock at 6000 rpms and above. now i am running alot better, and only for 10 bucks.

of course its not a permanent mod, its just somthing that i will use to get me by untill i can afford the "good" fpr. its a cheap solution that will work safely. i think it may reduce gas mileage though.

anyways, if you have any questions just ask. ill try and post a pic tomorrow.


Brent

 

[crankbender]

could you explain a little more? did you remvoe your stock fpr? if you did did you compensate for the increase in pressure inside the cylinder during boost? if you didn't then all you did is change the ammount that the stock fpr allows back into the tank and eventually that may bite you in the butt (if say the stock fpr is trying to close off the return completely). You don't want to decrease the fp you want to increase it...i donno why you would want to go the other way.

 

[killerquake]

stock fpr is still there. all i did is tap into the return line. the only reason you would want to adjust a fpr lower is if you had a 255lph fuel pump. those will overrun your stock fpr and really mess up your fuel curve. all i was doing with this valve is closing off the return line a little more so that i build up more pressure in the fuel rail. with the added pressure it helps me not to lean out at the higher rpms.

 

[OMN_DSM]

That is exactly what I was looking for! do you have a pic. of the piece you are talking about, so I know what to look for? Thanks

Mike

 

[OMN_DSM]

It works!!! I went down to Home Depot and picked up a few brass fittings and made a little valve. But be extremely cautious as there will be allot more fuel pressure in that line and it is not made to handle that. I blew the line off twice before I double hose clamped it and now I have to find a stronger fuel hose because mine swells up so bad when I close it a little that I'm afraid of it bursting. That’s all any of us need is a fire to start with fuel spraying every where. But it defiantly works.


Mike

 

[killerquake]

cool!

and yes you defintately have to clamp it down. my stock line worked great for me but looks like you will need a piece of high pressure line for that little section to the fpr. anyways, glad to hear somone else tried it and had a success. i know i was really stoked when it worked for me. sorry i didnt get back to you in time for the pic. i was gone. and besides its raining like hell over here. just be careful not to close it all the way. i did that and my idle jumped 500rpms immediatley. i think that would be bad if i left it that way.

 

[OMN_DSM]

Mabye the reason my hose is weaker is I hade to replace it last time my car caught on fire. I'm going to try and find some Hydraulic hose tommorow for it. I know that won't break. Thanks again for the tip!

Do you think I will be o/k to run 18psi with this mod and about 100 octane?

Mike

 

[killerquake]

ya i would say that you shouldnt have any problem with it at 18psi. just make sure you have that extra octane in there. you know west coast gas sucks. it would be good if you have some guages though to monitor your engine too. (a/f, egt.)

 

[OMN_DSM]

I don't have gauges yet (end of this month) but, I pull my plugs almost every time I stop, even at grocery stores and what not. Thats how I know I was running lean.

Mike

 

[killerquake]

not having guages is kinda dangerous, your really gonna have to feel and listen to your car. im sure you wont have any problems, but you never know. i take it you have a boost guage though? anyways, just be careful.

 

[OMN_DSM]

Of course i've got the boost gauge. And your right you never know, with my luck with this car who knows what will happen next. Well I will post how I do with the new part in it on Wed., if I do bad it was your idea, if I do good it was all my idea. J/k.

Mike

 

[killerquake]

haha funny! good luck man. what do you normally run?

 

[OMN_DSM]

In the quarter? Well I ran it for the first time with mods on it last week and I went 13.8 @98. I ran a 15.0 stock. So we shall see.

Mike

 

[killerquake]

i guess a 13.5@101 mph. let us know what you get.

 

[killerquake]

ok i got a couple pics of my lil invention here. hope this helps a little. the barbs i used were 1/4" barbs with a threaded male connection. the center valve has a threaded female connection. i just put a little plumbers tape on the threads of the barbs and screwed them into the valve section. torqued them down a little with a wrench and i was done. the barbs are the same size as the hose so it was a little difficult to get the hose to go on. took me about 3 minutes. just make sure to clamp the hose down good that goes to the stock fpr.

 

[killerquake]

and here's another view of it. like the view of the turbo in the background. that sits right beside me at my computer desk. its my little friend.

 

[OMN_DSM]

Mines a little different than that, I will try and get pics up a little later. Same idea though. I replaced my hose with some stainless braided fuel line .6an And it work pretty good, doesn't even swell up when you shut the line totally off.

Mike

 

[killerquake]

ya i would like to see pics of yours. then people who read this thread will have an idea to go by. did you notice when you shut your valve completely off that your idle goes up quite a bit? mine sure did.