Honda D Series Forum banner

1 - 20 of 35 Posts

·
Registered
Joined
·
305 Posts
Discussion Starter #1
I just want to start by thanking all of you that post on here I got 210hp out of my first turbo build.

I want to make sure I got the full understanding of how to change out my FPR to an aftermarket one. Ive seen a bunch of posts that state that this basically helps control the fuel and returns the unnecessary back to the tank. When swapping one out you take the vac of the top and get it to read about 44PSI then when you put it back on it should be between 32-36 PSI or so. I just want to make sure im understanding this right as ive already been tuned and dont want to go back.

My problem with the stock one is that im having problems starting the car as well as idle and when i let off the throttle.
 

·
Registered
Joined
·
137 Posts
The way I understand it the adjustable FPR is the old school way of changing the fuel trims so that you're not too lean after doing airflow mods NA. With the tuning solutions we have now, I've not seen any reason to change to an aftermarket FPR ever except for the bling factor. If the car was fine before, startup issues are due to a faulty tune.
 

·
Registered
Joined
·
6,365 Posts
x2 ^ sounds more like a bad tune then FPR.

If your reg has fail and your are out putting more psi of fuel at idle then yes it can cause a problem.
The higher the fuel pressure the more the injectors will flow.

And yes the manual says to adjust fuel pressure to 43.something or 44 psi with the vacuum line off. Then ad idle the pressure should be around 32-35psi
 

·
Registered
Joined
·
681 Posts
It could be the fuel map. He may have upped the fuel on the bottom. From what ive read the HP 255lph fuel pumps require an aftermarket FRP. Just want to make sure all my bases are covered. The tune up top is mint around 12 AFR the whole time.
the reason they say that is so you can adjust the psi back down to normal levels the upgraded fuel pumps are going to pump at a higher pressure then the stock unit if you were tuned on the new pump then you should be fine if you are replacing the pump after the tune then you will run alil on the richer side if you do decide to go with an aftermarket unit in order to lower the psi back to stock then stay away from the b&m command flo mod as it will not go down low enough without further modification of the fuel return orifice
 

·
Registered
Joined
·
305 Posts
Discussion Starter #11
No I haven't replaced it yet. It doesn't seem like its being starved. It seems like its getting to much at times. I'm going to try and adjust the TB to see if I can close it some more and see if any change happens. If that doesn't help ill try out the P08 to see how it idles and starts and take it from there.
 

·
Registered
Joined
·
681 Posts
No I haven't replaced it yet. It doesn't seem like its being starved. It seems like its getting to much at times. I'm going to try and adjust the TB to see if I can close it some more and see if any change happens. If that doesn't help ill try out the P08 to see how it idles and starts and take it from there.
this is possible if you have access to the tools look into the return orifice mod for the b&m units i will see if i can find a link i had it saved on my old computer but it burnt up in a house fire last year
 

·
Registered
Joined
·
681 Posts
that's all fine and dandy but I not saying to buy the b&m unit (i have it and so far i haven't had any issues) all i am saying is to try the mod on your exsiting stock unit to see if it helps but if you are concerned about riging up any of the fuel components i can understand your hesitation but the link i posted up is from endyn i don't think he would condone it if wasn't safe to do
 

·
Registered
Joined
·
3,714 Posts
found it here you go should take less then an hour of you time if you have the proper size bit
The Old One - Energy Dynamics : Articles
I had to do this with mine after my Walbro pump swap, after the swap I had 75 psi, drilled the hole and got 50 psi, then installed the B&M regulator and now it's down to good 38-44 psi. I heard 55psi is the ideal pressure for fuel atomization, curious what you guys think.

Its a good thought to drill it out but then fuel will run threw the vac line and back into the IM. Im sure thats where the B&M one comes in but id still rather have one with good results.
It doesn't do that, you aren't drilling the hole by the diaphram where the vacuum line goes in. It's so that more fuel will go to the return line, because the regulator has a spring with same tension and you can't adjust that without doing a B&M or Blox fuel pressure modifier.
 

·
Registered
Joined
·
3,866 Posts
I had to do this with mine after my Walbro pump swap, after the swap I had 75 psi, drilled the hole and got 50 psi, then installed the B&M regulator and now it's down to good 38-44 psi. I heard 55psi is the ideal pressure for fuel atomization, curious what you guys think.
I've read this too in my browsing. I tried it once, but I was still chip burning and couldn't get it dialed in well, so I went back to stock pressure. I may try this when I swap injectors out before I turbo, seeing as I just got my tune dialed in.
 
1 - 20 of 35 Posts
Top