4bangerjp.com
General Forums => The Mess Hall => Topic started by: FourbangerYJ on November 10, 2009, 05:21:41 PM
-
How about a crash course about them. Lets start by pretending I know nothing about them. :lol:
-
Hesco sells them advertised for the '91-'95, often considered one for my 2.5L. I used to have a site bookmarked where a guy made his own and marketed them, requiring a core charge. Makes me wonder if I could make my own. I need to take one apart and discuss with my machinist.
-
Hesco sells them advertised for the '91-'95, often considered one for my 2.5L. I used to have a site bookmarked where a guy made his own and marketed them, requiring a core charge. Makes me wonder if I could make my own. I need to take one apart and discuss with my machinist.
you can make your own out of a stock one - I had a guy back in the day (about 15 years ago) that would make bmw FPRs out of the stock ones, he was cutting them on a lathe (the top part where the vac port goes) and made a housing for them out of aluminum and relocate the vac port on the side and had a screw in the center with a plate inside to adjust the spring pressure. Of course there was also the cheap and dirty way of pressing the top of the housing inwards, but you can only go higher pressure, can't really bring it back out.
I think the way you could make one for Jeep is to create a thread on the outside of the housing and make a matching housing to go on top (if they are thick enough)- not sure how the brace would go over that but i'm sure you can come up with something.
i use a mallory performance one for the Jeep but they're not cheap, they do look nice and work well. There are some cheap alternatives on ebay, for testing i believe they're ok but i'm not sure in the long run if you want to rely on something that is not high quality and risk of not being able to get back to base camp or home - but you can always carry the stock as a spare for emergencies.
-
At what point in building up your motor would one of these become necessary? Like I have the PD kit, 4.0 throttle body, the 19lb injectors, and cat back exhaust. Would this be something that I would notice a difference with or would be beneficial to me
-
I've seen a picture where someone threaded the barb that comes off the center of the
regulator where the current vac line connects and put a machine screw in then added a
new hole on the side tapped it and put a new barb for the vacum line there...
It only allows increasing the pressure as I recall. I decided to fiddle elsewhere first.
Dave
-
At what point in building up your motor would one of these become necessary? Like I have the PD kit, 4.0 throttle body, the 19lb injectors, and cat back exhaust. Would this be something that I would notice a difference with or would be beneficial to me
you can give it a bit more gas for open loop (same as with larger injectors) so your max power will increase a bit. For close loop won't make a difference as the PCM will readjust. It can also be used to reduce the pressure if you got injectors that are too big.
-
you can give it a bit more gas for open loop (same as with larger injectors) so your max power will increase a bit. For close loop won't make a difference as the PCM will readjust. It can also be used to reduce the pressure if you got injectors that are too big.
How easy is it to tune with the Adj. FPR?
Where is it on the Jeep?
-
How easy is it to tune with the Adj. FPR?
Where is it on the Jeep?
if you use a hesco it goes in where the stock one is installed. if you have a generic one (the route i took) then you need to somehow replace the stock one - what i did was to use a stock FPR and plug the return port (threaded and put a screw in with teflon tape on it) and then use the schraeder valve to connect to the new FPR - hesco makes a plug disc as well, i had a spare stock FPR so that didn't cost anything. I'll post some pics of these 2 when i have some time to take them - it's pretty straight forward and would work with any generic adjustable FPR that has a high pressure port, a return port and a vac port (you want that as that's the way the stock one is).
On my Mallory as well as most of the generic ones on ebay there's a gauge port on which you can have a gauge to see the pressure - easiest way to tune it is to start the engine, let it idle, unplug the vac port and adjust the pressure and monitor the gauge - stock pressure uncorrected by vacuum is 39 psi. Sometimes the gauge is off so first thing i would do is to verify what the stock pressure shows at on the gauge - for that you can connect the new FPR to the schraeder valve and have the adjusting screw in quite a bit to prevent the fuel come out on the return port of the new FPR - you still have your stock one installed - let the engine idle and take note of the pressure that is displayed - can be 38psi for example which means that is your starting point. From there remove the stock FPR, install the blocking one or the blocking disk and put the contact a few times to build pressure in the rail - adjust the screw until you are close to what the stock pressure was. Start the engine and let it idle (you can also jump the Fuel Pump relay) and with the vac port unplugged set your target pressure - let's say you are targeting your injector static flow to 18.5lb/hr, that is an increase of 1.1lb/hr compared to the stock flow - you need 5psi more final pressure so your gauge should show 44psi (or in case it's off like in the example above 43 psi). Put the vac port back and take it for a test drive (try to hit wot and get a feel for it, best if you do a run with the stock pressure before the change so you can compare) - you can go lower or higher and compare the runs, i was up in the 49s or 50s at some point when in boost but that was corrected by the boost pressure thru the vac and i think that would be too much. For 18lb/hr static flow compared to 17.4lb/hr stock you need an increase of 3psi in the fuel rail and i would say that's the best place to start and then go up or down from there.
Best case scenario is to have some logging capabilites to monitor your AFR via a wideband o2 but if your Jeep is not smoking black and your spark plugs keep their nice color you're good. Of course there's a downside with the mpg, but if you drive it normally in closed loop (you don't hit wot too often and accelerate mildly) there shouldn't be any penalty on that once the PCM relearns the trims. I'll try and post some pics of the adjustable FPR and modified stock one with the plug when i get a chance.
-
How easy is it to tune with the Adj. FPR?
Where is it on the Jeep?
It's on the fuel rail at the front. It had a vacuum port on it.
-
Youll find some 2.5's with a pulse damper instead of the regulator on the fuel rail.
Looks the same but no vacuum connection. Those have a reg down on/by the pump.
I have yet to figure out how and when jeep moved this around.... I've found this on
94 and 95 YJ and a lot of 96 and up Cherokees.
Dave
-
Youll find some 2.5's with a pulse damper instead of the regulator on the fuel rail.
Looks the same but no vacuum connection. Those have a reg down on/by the pump.
I have yet to figure out how and when jeep moved this around.... I've found this on
94 and 95 YJ and a lot of 96 and up Cherokees.
Dave
my 95 YJ 2.5 has a return type on the fuel rail - same is shown in the FSM for 94/95 XJ and YJ 4.0 and 2.5 engines (the one on this site). I believe TJs came with the regulator in the fuel tank but those run at 49psi, so i believe that 96 was the changeover, but like the brakes on late 95 YJs maybe there was a transition model or something.
EDIT: never had my hands on a TJ FPR so i assume they are in the tank since there is no return line, just to clarify in case it's outside the tank somewhere.
-
My theory is they were doing lines of coke off the toolboxes on the assembly line.... ::)
Just like my weird distributor in my 94, I have to ask for a 92 to get the right cap and rotor...
Dave
-
EDIT: never had my hands on a TJ FPR so i assume they are in the tank since there is no return line, just to clarify in case it's outside the tank somewhere.
They sit on the tank like most of the newer Jeeps. The change-over happened in 1996 in the wranglers. Generally XJ's and ZJ's see changed a few years prior to the Wranglers.
-
What pressure are the 4.0's set at? Will these bolt on the 2.5?
-
What pressure are the 4.0's set at? Will these bolt on the 2.5?
same pressure as the 2.5L (39psi) and they are the same as the 4 banger ones (they will bolt on).
-
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
(http://i57.photobucket.com/albums/g222/sharpxmen/Misc/FPR_Mallory_4305M.jpg) (http://i57.photobucket.com/albums/g222/sharpxmen/Misc/FPR_Mallory_4305M_Box.jpg)
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
(http://i57.photobucket.com/albums/g222/sharpxmen/Misc/FPR_Schraeder_Valve_Tool.jpg)
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
(http://i57.photobucket.com/albums/g222/sharpxmen/Misc/FPR_Mallory_Return_Hose.jpg)
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
(http://i57.photobucket.com/albums/g222/sharpxmen/Misc/FPR_Stock_Plugged_1.jpg) (http://i57.photobucket.com/albums/g222/sharpxmen/Misc/FPR_Stock_Plugged_2.jpg)
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
-
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
-
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
-
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
-
You should maybe still have the isolator
yeah, you're right - it should have an isolator.
-
Lets just say that once youve been in one race car on fire its not something you want to repeat! :yikes:
"When your on fire ,,, People get out of your way!" - Richard Pryor
Dave
-
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?
-
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.
-
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)
-
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.
-
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.
-
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.
-
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?
-
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.
-
Great thread! :thumbsup:
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...
-
How does the FPR work on a OB1 system? Does the fuel pressure vary as the vaccume varies?
-
How does the FPR work on a OB1 system? Does the fuel pressure vary as the vaccume varies?
you mean OBD 1? it's unrelated, there are obd2 vehicles that have a vac port on the FPR. The FPR vac port decreases the pressure in the fuel rail proportional with the vacuum in the manifold (which is the difference in pressure between the manifold and outside atmospheric pressure) - for YJ 91-95 closed throttle you should be at 31psi, wide open throttle at 39psi and in between for various stages of the vaccum level. The main goal for the vac port is to lower the flow when not needed so the duty cycle of the injectors is higher - some injectors have a limitation on low duty cycle, it is recommended to avoid something that is too low and lowering the fuel pressure is one way to address this (atomization is better above certain level of the duty cycle and if too low there could be a negative result).
-
Ya I meant OBD1, I was in a hurry.
So how do you think a FPR that starts at 41 PSI and tops at 48 PSI would work? To much?
-
Ya I meant OBD1, I was in a hurry.
So how do you think a FPR that starts at 41 PSI and tops at 48 PSI would work? To much?
it's all based on what you target - in your case i say it's too much - you'd end up around 19.3 static flow on the stock injectors and around 12.2 AFR which i'd say it's too low, but if it's a direct fit (if it's the same as the jeep one) and you want to test and see how it works you could, long term i don't recommend it.
-
it's all based on what you target - in your case i say it's too much - you'd end up around 19.3 static flow on the stock injectors and around 12.2 AFR which i'd say it's too low, but if it's a direct fit (if it's the same as the jeep one) and you want to test and see how it works you could, long term i don't recommend it.
I had a feeling it would be a bit much. The Dodge/Chrysler ones I mentioned earlier in the tread look to be a direct fit. I am looking for long term so I guess it's out.
This had been a good learning deal for me. Thanks for the advice!
-
I had a feeling it would be a bit much. The Dodge/Chrysler ones I mentioned earlier in the tread look to be a direct fit. I am looking for long term so I guess it's out.
This had been a good learning deal for me. Thanks for the advice!
if i get a weekend without rain i'll try to do a little writeup on my FPR and the wideband O2 install , just need some sunshine (been raining like crazy here the last couple of weeks and it's getting frustrating - forecast is not positive, rain till Tuesday next week and who knows what after that, hope we don't get snowed on)
-
if i get a weekend without rain i'll try to do a little writeup on my FPR and the wideband O2 install , just need some sunshine (been raining like crazy here the last couple of weeks and it's getting frustrating - forecast is not positive, rain till Tuesday next week and who knows what after that, hope we don't get snowed on)
I keep telling the Mrs. she would not like living up there. We have so much sunshine here it's getting old. At least it's cooling down some. It feels sorta like fall.
That write up would be cool. Where are you working on this, outside?
With a higher pressure FPR I would think that atomazation (sp) would be a bit better. How about the 41-48 PSI FPR with a smaller # injector?
Like the 0280155703 or 705, or 706?