Topic: Adjustable fuel regulators

[sharpxmen]

this is what i use, is taken off since i am routing the intercooler pipes and it was in the way, i need to relocate it once i finish the intake manifold side piping so i'll post some updates then.

this is the Mallory 4305M adjustable FPR, 30-100psi, it is at $100 about everywhere i looked


It comes with AN-8 fittings, however i got AN-4 as that is what the schraeder valve is. I used a braided hose to connect the schraeder valve to the FPR with both ends AN-4
I needed to take the valve out first


I used a return end from another fuel rail to connect the bypass port from the Mallory FPR to the return line on the Jeep


And i used a stock FPR to block the return port on the fuel rail - i threaded the output and put in a screw with teflon paste or tape (can't remember) and i rounded the end so it will fit in the mounting hole. I believe the screw i used was a Metric 6



I also have another port on the FPR that is used to connect to an in-dash pressure gauge (autometer) using another braided hose with AN-4 ends - it is good to monitor the pressure while driving in case the pump failsor has problems, i used it when i was boosting the pressure while testing my supercharger but now that's my gas reserve warning as it will drop on a turn when it's close to the bottom :)

EDIT: instructions for this FPR can be found here http://www.malloryperformance.com/pdf/4305M.pdf
also, the price is $100, however with the fittings and adapters, braided hose and gauge it came to $150 if not more, so the ones on eBay are still a great deal (some come with the gauge already), but since i never used one i can't speak for their quality

[dwtaylorpdx]

For inside the vehicle mounting you should also have a isolator in the line so if it comes unhooked etc it wont fill the cab with fuel...

Dave

[sharpxmen]

For inside the vehicle mounting you should also have a isolator in the line so if it comes unhooked etc it wont fill the cab with fuel...

Dave

it's teflon steel braided hose with crimped an-4 fittings at both ends

[dwtaylorpdx]

You should maybe still have the isolator, its not uncommon for the
diaphragm in the gauge to let go and spray fuel. Or if something
weird happens and the hose gets yanked off the gauge, at least make
sure that if your in a bad wreck there is sufficient slack to allow the
hose to move if the engine does..

I play at the track on race cars about 30 weekends a year
and I've put out two cars with gauge leaks from oil pressure lines
(Aeroquipe swedged lines) and I've seen a fair number of -4 fittings break,
between the swedge and the fitting, Heck I've broke a few trying to
tighten them up, they can be delicate. The AL ones break really easy the
stainless ends not near as often, they are way stronger.
Probably because they use them on brakes... :) We have to use the
isolators or an electric gauge to pass tech.

Good Luck!

Dave

[sharpxmen]

You should maybe still have the isolator

yeah, you're right - it should have an isolator.

[dwtaylorpdx]

Lets just say that once youve been in one race car on fire its not something you want to repeat! 

"When your on fire ,,, People get out of your way!" - Richard Pryor

Dave

[FourbangerYJ]

Seems like the Hesco one would be the easiest to install. It is pricey at $179.
http://www.hesco.us/shop.asp?action=details&inventoryID=43022&catId=7973
It say's its pre-set to 44# so I guess there is no adjusting it.
Does the 5 extra psi make that much of a change?
How much pressure does the stock fuel pump put out?

[Jeffy]

Seems like the Hesco one would be the easiest to install. It is pricey at $179.
http://www.hesco.us/shop.asp?action=details&inventoryID=43022&catId=7973
It say's its pre-set to 44# so I guess there is no adjusting it.
Does the 5 extra psi make that much of a change?
How much pressure does the stock fuel pump put out?

It's adjustable but preset so you don't have to adjust it.  Stock is 31# at idle and 39# with no vacuum.

[sharpxmen]

Seems like the Hesco one would be the easiest to install. It is pricey at $179.
http://www.hesco.us/shop.asp?action=details&inventoryID=43022&catId=7973
It say's its pre-set to 44# so I guess there is no adjusting it.
Does the 5 extra psi make that much of a change?
How much pressure does the stock fuel pump put out?

44psi will give you 18.5lb/hr compared to stock 17.4 - would be like installing 19.5# injectors at stock pressure (which would give you the same 18.5# flow at the stock 39psi)

[Bounty Hunter]

I've got an extra stock FPR here, I think I'll take it to my machinist and we will see what we can come up with.  Will surely be cheaper than Hesco.

[FourbangerYJ]

I've got an extra stock FPR here, I think I'll take it to my machinist and we will see what we can come up with.  Will surely be cheaper than Hesco.

That would be cool if they can modify one for less money. Keep us updated if you get around to it.

[sharpxmen]

I've got an extra stock FPR here, I think I'll take it to my machinist and we will see what we can come up with.  Will surely be cheaper than Hesco.

if there's a disk on top of the spring inside you could potentially do it w/o cutting it with a screw in the center where the vac port goes - i think someone mentioned it before and also that you can only go higher (i believe was dwtaylor who said it) - downside is that you can't go lower but unless you have larger injectors and need to reduce the fuel flow you don't really need it. You'll need a vac port thru the screw or relocated on the side. otherwise you might be able to use a pipe threader on the outside of the housing and make a cap for it.

[FourbangerYJ]

I saw on another forum that a FPR from a 93-97 3.5L Concord,Imperial, or New Yorker or 90-95 3.3L Caravan or Dynasty put out between 41-50 PSI. It would not be adjustable but sounds like it would put out more pressure. Anyone know the PSI those really put out?

[FourbangerYJ]

I did a bit of reasearch on those FPR from the Dodge/Chrysler. Near as I can tell they are set up for 43-44 PSI. Still they are not adjustable but there is more pressure. I saw some brand new on Ebay for $40.00 Not sure it the PICS are generic but when I compared them to the Jeep FPR they looked the same.

[TahoeYJ]

Great thread! 

So if you've got a fair amount of performance mods done on the 2.5, is it worth the money/time to slap one in? With a wideband o2 sensor I imagine you'd be able to get a pretty good idea of where to set it for the most gains? Sorry for my ignorance, but this has got me thinking about it for the future...