When to upgrade to larger injectors?
Record Breaker
Joined: Feb 2006
Posts: 1,567
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From: Richmond, Va
RE: When to upgrade to larger injectors?
Stock injectors are rated 23.2 lbs/hr @ 49psi. You can kind oftell if you need largerinjectors with a scanner. If you observe high positivenumbers on your long term fuel trim then that means that the duty cycle on your injectors is too high at idle, cruise etc. This wont tell you if you are fueling properly at wot though. There is a formula that is used to determine injector flow based on horsepower. Google it. Typing formulas are a pita. The trick is to get just the bare minimum for your top end requirements so that the pcm doesn't struggle so bad at idle and cruise to keep your fuel trims correct and throw codes.
Record Breaker
Joined: Feb 2006
Posts: 1,567
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From: Richmond, Va
RE: When to upgrade to larger injectors?
ORIGINAL: OlsenG_360
some have noticed better mileage/response from switching to the 3 or 4 hole injectors of the same lb/hr rating over the 1-hole stockers...Ford Motor Sport injectors can be had pretty cheap on eBay, i picked up a set of 24 lb/hr FMS injectors with a rebuild kit (o-rings, spacers, filters, and pintle caps) for about $50 a couple weeks ago.
some have noticed better mileage/response from switching to the 3 or 4 hole injectors of the same lb/hr rating over the 1-hole stockers...Ford Motor Sport injectors can be had pretty cheap on eBay, i picked up a set of 24 lb/hr FMS injectors with a rebuild kit (o-rings, spacers, filters, and pintle caps) for about $50 a couple weeks ago.
Captain
Joined: Jun 2007
Posts: 730
Likes: 1
From: Columbus, GA USA
RE: When to upgrade to larger injectors?
With all that said a stand alone fuel managment system is the way to go, like a Haltech F10X.
I used that on my Turbo'd 3 and it worked something awesome.
I used that on my Turbo'd 3 and it worked something awesome.
Record Breaker
Joined: Feb 2006
Posts: 1,567
Likes: 0
From: Richmond, Va
RE: When to upgrade to larger injectors?
ORIGINAL: Fox Fader
With all that said a stand alone fuel managment system is the way to go, like a Haltech F10X.
I used that on my Turbo'd 3 and it worked something awesome.
With all that said a stand alone fuel managment system is the way to go, like a Haltech F10X.
I used that on my Turbo'd 3 and it worked something awesome.
FAST or Megasquirt
Either that or the new SCT stuff if you can find a tuner in your are willing to drop the cash on the software.
Professional
Joined: Mar 2007
Posts: 242
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From:
RE: When to upgrade to larger injectors?
ORIGINAL: mopowar
Ford injectors are rated @ 39psi. Those 24lb'ers will deliver 27lbs @ your 49psi. If your bottom end is stock, you will be WAAAAyyy rich. I'll bet money that within 50 miles you start getting rich codes.
ORIGINAL: OlsenG_360
some have noticed better mileage/response from switching to the 3 or 4 hole injectors of the same lb/hr rating over the 1-hole stockers...Ford Motor Sport injectors can be had pretty cheap on eBay, i picked up a set of 24 lb/hr FMS injectors with a rebuild kit (o-rings, spacers, filters, and pintle caps) for about $50 a couple weeks ago.
some have noticed better mileage/response from switching to the 3 or 4 hole injectors of the same lb/hr rating over the 1-hole stockers...Ford Motor Sport injectors can be had pretty cheap on eBay, i picked up a set of 24 lb/hr FMS injectors with a rebuild kit (o-rings, spacers, filters, and pintle caps) for about $50 a couple weeks ago.
Those 24 lb injectors aren't being installed on a stock anything, my turbo project is in the works as we type. and with the FMU and inline fuel pumpplumbed in...the pressure will be raised quite a bit under boost (a few guys out there are pushing over 100psi through these FMS injectors under boost without issue)
mopowar is right, i just forgot to mention that most injector replacements you'll find are for Fords, 19lb/hr to them is 23.2 for us (or 21'ish because of the shoddy 1-hole pintle design and some trucks just don't maintain 49psi)
Record Breaker
Joined: Feb 2006
Posts: 1,567
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From: Richmond, Va
RE: When to upgrade to larger injectors?
Doing the math, the fms 19's would flow 21.3@ 49psi. If ford made a 21 (which I was dissapointed to find out that they do not) it would be a perfect 23.2 lb replacement for the stockers. A lot of people say that the standard for flow ratings is 42.5 psi, but ford does 39, DC does 49, Accel (and alot of other manufacturers) actually do 42.5.....and then I'm on Holleys site and they use 43.5???? I guess you always have to check. BTW, KRC sent stockers out to have them flow tested and they came back at 22lbs. If they were tested at the standard of 42.5psi that would work out to 23.6 which is not too far off.
Where didyou pick up the return system, and how much did it run you? (if you don't mind me asking)
KRC has a nice kit, but it seems kind of pricey. Are you piecing the turbo together yourself?
Where didyou pick up the return system, and how much did it run you? (if you don't mind me asking)
KRC has a nice kit, but it seems kind of pricey. Are you piecing the turbo together yourself?
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Champion
Joined: Nov 2006
Posts: 2,902
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From:
RE: When to upgrade to larger injectors?
ORIGINAL: mopowar
Doing the math, the fms 19's would flow 21.3@ 49psi. If ford made a 21 (which I was dissapointed to find out that they do not) it would be a perfect 23.2 lb replacement for the stockers. A lot of people say that the standard for flow ratings is 42.5 psi, but ford does 39, DC does 49, Accel (and alot of other manufacturers) actually do 42.5.....and then I'm on Holleys site and they use 43.5???? I guess you always have to check. BTW, KRC sent stockers out to have them flow tested and they came back at 22lbs. If they were tested at the standard of 42.5psi that would work out to 23.6 which is not too far off.
Where didyou pick up the return system, and how much did it run you? (if you don't mind me asking)
KRC has a nice kit, but it seems kind of pricey. Are you piecing the turbo together yourself?
Doing the math, the fms 19's would flow 21.3@ 49psi. If ford made a 21 (which I was dissapointed to find out that they do not) it would be a perfect 23.2 lb replacement for the stockers. A lot of people say that the standard for flow ratings is 42.5 psi, but ford does 39, DC does 49, Accel (and alot of other manufacturers) actually do 42.5.....and then I'm on Holleys site and they use 43.5???? I guess you always have to check. BTW, KRC sent stockers out to have them flow tested and they came back at 22lbs. If they were tested at the standard of 42.5psi that would work out to 23.6 which is not too far off.
Where didyou pick up the return system, and how much did it run you? (if you don't mind me asking)
KRC has a nice kit, but it seems kind of pricey. Are you piecing the turbo together yourself?
Record Breaker
Joined: Feb 2006
Posts: 1,567
Likes: 0
From: Richmond, Va
RE: When to upgrade to larger injectors?
ford injectors are rated at 39psi. That what fords run.
Here goes:
actual flow = rated flow x (the square root of the actual pressure/rated pressure)
feels like doing word problems again
for a ford 19 lb'er
actual flow = 19 x (square root of 49/39)
= 19 x (1.12)
= 21.28
Here goes:
actual flow = rated flow x (the square root of the actual pressure/rated pressure)
feels like doing word problems again
for a ford 19 lb'er
actual flow = 19 x (square root of 49/39)
= 19 x (1.12)
= 21.28
Champion
Joined: Aug 2005
Posts: 3,313
Likes: 8
RE: When to upgrade to larger injectors?
It is worth considering to hook up a fuel pressure gauge to the fuel rail and check the psi at full throttle and 4000-5200 rpm.
After seeing the 'sock filter' at the bottom of the fuel pump assembly submerged in the Ram pickup's fuel tank...it is easy for me to suspect that it could quickly choke full throttle fuel rail pressure with as little as one bad tank of gasoline.
I haven't done the research
but I suspect that the fuel pump held in the assembly with hose clamps could be substituted with other Chrysler fuel pumps whose internal pressure regulator is different.
It is really not a big job to get at the fuel pump assembly by jacking up the cargo box....not nearly the hassle of dropping the tank to the ground.
After seeing the 'sock filter' at the bottom of the fuel pump assembly submerged in the Ram pickup's fuel tank...it is easy for me to suspect that it could quickly choke full throttle fuel rail pressure with as little as one bad tank of gasoline.
I haven't done the research
but I suspect that the fuel pump held in the assembly with hose clamps could be substituted with other Chrysler fuel pumps whose internal pressure regulator is different.
It is really not a big job to get at the fuel pump assembly by jacking up the cargo box....not nearly the hassle of dropping the tank to the ground.
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Champion
Joined: Nov 2006
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From:
RE: When to upgrade to larger injectors?
ORIGINAL: HankL
It is worth considering to hook up a fuel pressure gauge to the fuel rail and check the psi at full throttle and 4000-5200 rpm.
After seeing the 'sock filter' at the bottom of the fuel pump assembly submerged in the Ram pickup's fuel tank...it is easy for me to suspect that it could quickly choke full throttle fuel rail pressure with as little as one bad tank of gasoline.
I haven't done the research
but I suspect that the fuel pump held in the assembly with hose clamps could be substituted with other Chrysler fuel pumps whose internal pressure regulator is different.
It is really not a big job to get at the fuel pump assembly by jacking up the cargo box....not nearly the hassle of dropping the tank to the ground.
It is worth considering to hook up a fuel pressure gauge to the fuel rail and check the psi at full throttle and 4000-5200 rpm.
After seeing the 'sock filter' at the bottom of the fuel pump assembly submerged in the Ram pickup's fuel tank...it is easy for me to suspect that it could quickly choke full throttle fuel rail pressure with as little as one bad tank of gasoline.
I haven't done the research
but I suspect that the fuel pump held in the assembly with hose clamps could be substituted with other Chrysler fuel pumps whose internal pressure regulator is different.
It is really not a big job to get at the fuel pump assembly by jacking up the cargo box....not nearly the hassle of dropping the tank to the ground.