Topic: Fuel Pressure Regulators

[chrisfranklin]

I'm interested in the results on this

I was talking about the adjustable FPR in general.  Guess its sop

[dwtaylorpdx]

For extra safety...
If you want to run a in dash gauge, there is an Isolator gadget your supposed to use
if the hose enters the passenger area, It prevents fuel from flowing if the gauge fails
or the line gets pulled off the gauge. Otherwise electric fuel gauges are available too.

Dave

[Jeffy]

you can buy a brass elbow 1/8'' female to 1/8'' female at a h/w store for $2 (i saw one yesterday) - that would make it a grand total of $27

there's really no results, it just works and will show the fuel pressure in the rail. I have a permanent install with a teflon braided hose and the gauge in the dash

But then it looks like I built it at a hardware store.    The gauge you show say's it's not meant for a permanent mount.  The 0-100psi is though.  I've thought about using a braided hose and running it to the fender then being able to move it outside the hood when testing but that seemed pointless since I can't really see that part of the hood anyway.  Not sure about running a mechanical into the cab.  Might as well go electrical.  I don't really like the idea of fuel in my lap on on my feet.   

[dwtaylorpdx]

Ive usually just run the gauge out to the top of the hood and tied it to
the little hoop thing that supports the windshield when you fold it down... If its temporary....

I've often thought a idiot light that turns on at 30 PSI would be the ticket.... Just so you know if the pump is stalling.

Dave

[Jeffy]

Ive usually just run the gauge out to the top of the hood and tied it to
the little hoop thing that supports the windshield when you fold it down... If its temporary....

I've often thought a idiot light that turns on at 30 PSI would be the ticket.... Just so you know if the pump is stalling.

Dave

I'd like to be able to monitor what the FPR is doing.  I've been thinking a wide-band O2 might be in the plans too.  Them maybe a boost gauge for later.

So anyway, I drove it on the highway.  Seems to pull a lot better in the low and medium range.  On the stratch of highway, it's a slight grade for several miles.  Usually I'm in 4/5 doing 60-65mph but this time I'm in 5th and cruising at 65mph.  The last part of this stretch has a sweeping bend which goes up a steeper grade and the wind shifts to directly at your face.  For the hill, I'm usually in 4th at around 50-55mph floored.  Now I'm 60-65mph floored.

So there is definitely a torque increase.  Once floored, the difference isn't as noticeable.  I'm thinking that it's still running lean at WOT but without a wide-band O2, it's hard to say.  Could have been that, I didn't rev the engint high enough as it was only around 3000rpm and I probably should have pushed it to 40000rpm.

Overall though, I think the FPR made the biggest single difference with all of the engine stuff that I have BUT I don't think it would have helped nearly as much if I didn't have all of the other stuff.

Before I did the FPR, I tuned the intake so it was making more HP at the high-end at the cost of low-end torque.  This FPR seems to have fixed that issue.  So, maybe it needs even more air...

I'll definitely have to play around with the setup some more to tune to where I like it.  This, like all of the other mods will be different for each and every Jeep as mine is tuned differently with the aftermarket parts. So YMMV is assured but if you put the time in to tinker with adjusting your intake and exhaust then you'll probably like this mod.

I might tune the intake so it gives me the lower end torque and see what that feels like with the FPR.

[FourbangerYJ]

Glad to hear you have had good results. Looking forward to see how others will do.
How does one tune the intake?

[Jeffy]

Glad to hear you have had good results. Looking forward to see how others will do.
How does one tune the intake?

You can adjust the overall length and play around with CFM a little bit.  Even removing the front turn down on the box will change how the engine runs.  On mine, I notice the loss of low-end but I pick up HP on the high end.  The opposite happens when I put it back on.  I might see what happens if I route the box better so it has direct access to cold air and see what that does.  But you have to keep in mind that if you go with a larger tube you lose pressure while gaining volume.  The key is to maintain pressure while gaining volume.  Also, you can tune the engine the same way with the exhaust.  Less restriction will give you more HP at the high-end while losing low-end torque.  You have to sort of try to keep this in balances or else you'll just end up countering what you did on one end.

Small adjustments can make big changes.

[Jeffy]

SO I did a long trip.  I reset the computer again, since all of the other driving was short.  So I found that the Jeeps sweet spot is 60mph.  I can drive in 5th and still accelerate up some slopes without too much trouble.  Shift down to 4th when a steeper hill comes and rev it up.  Although, I could easily do 65-70mph and be around 3000rpm but I've got a sail bolted to the top  (roof rack) and I could tell the extra weight as well as wind resistance.  Still it wasn't bad and actually.  Quite pleasant actually since I was tailing a big rig so he was cutting a huge hole for me and I was able to cruise in 5th all the way back.  I'm still curious to see what happens if I put the turn down for the air box back on.

[Jeffy]

Purchase requests should be made here:  http://4bangerjp.com/forums/index.php/topic,8262.msg66424.htm

[FourbangerYJ]

SO I did a long trip.  I reset the computer again, since all of the other driving was short.  So I found that the Jeeps sweet spot is 60mph.  I can drive in 5th and still accelerate up some slopes without too much trouble.  Shift down to 4th when a steeper hill comes and rev it up.  Although, I could easily do 65-70mph and be around 3000rpm but I've got a sail bolted to the top  (roof rack) and I could tell the extra weight as well as wind resistance.  Still it wasn't bad and actually.  Quite pleasant actually since I was tailing a big rig so he was cutting a huge hole for me and I was able to cruise in 5th all the way back.  I'm still curious to see what happens if I put the turn down for the air box back on.

As the system gets more used to the new FPR do you think performance will improve?
Sounds like its a bit of an improvement. Would be curious to see how mileage is affected.

[sharpxmen]

As the system gets more used to the new FPR do you think performance will improve?
Sounds like its a bit of an improvement. Would be curious to see how mileage is affected.

will respond a bit better in closed loop as the trims get re-learned (so the mpg would get better once that is narrowed down).

[Jeffy]

will respond a bit better in closed loop as the trims get re-learned (so the mpg would get better once that is narrowed down).

Yeah, it's running a bit rich right now.

[sharpxmen]

Yeah, it's running a bit rich right now.

one thing i remember i forgot to do on yours (rushed to get it done) is to seal the adjusting screw - it might reduce the vacuum so there's more fuel at idle. if you have some teflon tape you can twist it so it makes it like a string and roll it around the screw, loosen the locking nut first and wrap that around the screw between the nut and the billet cap, and then tighten it back - it will seal the screw and give it more vacuum in the FPR - I did all the other ones like this but I remember i meant to do yours and forgot. Make sure you don't move the position of the screw when you do all this.

If it's still too rich after 50 starts you could lower the pressure 1 psi, that should do it.

also, you have only a 4.0 t/b, i hope to get your 64mm shipped on Tue as well when i send out the other 2 FPRs - that will give it a bit more air - i got the  t/b bored out but i need to get the butterfly finished - had some issues with the core, it cracked when i was boring it so i had to pick another one out.

[chrisfranklin]

I got the adjustable FPR installed today.  The rough idle, low rpm problems I'd been having for a long time basically disappeared.  I had a chance to wind it out in 3rd from about 2000 something to 5000 on an on ramp and it seemed strong throughout the range. 
So seems good so far Sharp    Will keep you posted. 

[Jeffy]

one thing i remember i forgot to do on yours (rushed to get it done) is to seal the adjusting screw - it might reduce the vacuum so there's more fuel at idle. if you have some teflon tape you can twist it so it makes it like a string and roll it around the screw, loosen the locking nut first and wrap that around the screw between the nut and the billet cap, and then tighten it back - it will seal the screw and give it more vacuum in the FPR - I did all the other ones like this but I remember i meant to do yours and forgot. Make sure you don't move the position of the screw when you do all this.

If it's still too rich after 50 starts you could lower the pressure 1 psi, that should do it.

also, you have only a 4.0 t/b, i hope to get your 64mm shipped on Tue as well when i send out the other 2 FPRs - that will give it a bit more air - i got the  t/b bored out but i need to get the butterfly finished - had some issues with the core, it cracked when i was boring it so i had to pick another one out.

I'll check it for leaks.  Probably won't take it apart though.  If you want to send me another, I won't complain, LOL.  I don't have a gauge yet so I'm a bit weary on taking the screw off.  I suspect it's not leaking and that the richness is from the trim not being adjusted since I just reset the PCM again.