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larger injectors

34255 Views 9 Replies 6 Participants Last post by  LPD111
If I installed larger injectors will the PCM automatically lean them out to work with my motor correctly, or will it bog and smoke?

what are stock # and what size bigger should i go with?

this will be done in conjunction with a fastman 50 or 52mm TB.

Found some universals for $97 a piece, is that a decent price?

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On 2005-12-05 13:54, chizzle1 wrote:
If I installed larger injectors will the PCM automatically lean them out to work with my motor correctly, or will it bog and smoke?

what are stock # and what size bigger should i go with?

this will be done in conjunction with a fastman 50 or 52mm TB.

Found some universals for $97 a piece, is that a decent price?


I got some 21LB injectors that will work great for you truck. Send me a PM if interested. They change the plug on the 01's so the ones that I got wont work but they should work on yours.
i got some aftermarket boschs on e bay for a good deal. check it out
Here's the problem with larger injectors: The PCM is key to all the air/fuel mixture. This is from more than one source, the stock PCM is programmed for 19 lb injectors, now when put larger 21, 23, etc. the fuel rate and curve can only correct itself so much. At idle the engine will most likely run rich, the fuel is cut back, now you step on the skinny pedal and your running lean and the cycle starts all over again. This is all controlled by the O2 sensors and PCM. Most stock PCM's cannot correct the larger injectors and never go into a closed loop.
save your money, instead of injectors go with a cam and an M-1 with the TB. You already have the ignition and exhuast. Still at that you won't have the stock injectors maxed out. Then get a PCM to take advantage of all the goodies you put on. The only reason to go with bigger injectors if you go with a big cam or supercharge or turbo.
Take a look at Peterson's 4Wheel & Offroad, June 2005 issue.

Page 98: "Milking The Ram For More Juice: MOPOWER"

This is their project "Jinxy" Ram, with the 5.9L V8. In this issue, they swapped out their 16pph stock injectors for some Holley Avenger 24pph injectors (on a motor with some very decent hp/tq mods).

I ran a set of FMS (Ford Motorsport) #19 injectors on my V6 Dakota and they did run a tad rich, but it did accelerate faster.

The FMS are nice because you can get an entire set for about $200, plus they are a matched set.

Normal Ford #19 injectors are NOT the same as Ford MotorSport #19 injectors. Summit Racing sells the FMS #19s new and you can also find them all over Ebay and Ford Mustang performance site, where owners have taken off their #19s for #21s and are selling them cheap.

Ok, sit back, and relax. Here is my archived info saved on fuel injectors:

Depends on the year of the truck though. '92-'99 use the Design-II FMS Injectors; '00+ use the Design-III style.

Here's the story on factory injectors starting from most current:
-1996 through 1999 - ALL 5.2's & 5.9's share the same injector ( Dak, Ram 1/2 & 3/4, SS/T, Durango, everything).

-1996 through 1999 - All 3.9's share the same injector (different than the above V-8's).

-1993 through 1995 - ALL 5.2's & 5.9's (MAGNUM'S) share the same injector, different than above.

- Magnum 5.2 was introduced in 1992/3.
- Magnum 5.9 was introduced in 1993/4 (some
books say different).

-1994 through 1995 - All 3.9's share the same injector (different than the above V-8's), different than above.

-1990 through 1993 - All 5.2's (NON-MAGNUM'S) share the same injector.

Once again, the Design-III injectors will only work on the 2001+ models. What I do know is this 94 through 96 318's and 360's have the same Dodge part numbers.

The bottom line, all Magnum engines (318, 360) from inception through 1995 take the same injector.

Depending on the size that came in them (19# I believe), the Ford Motorsports 19# Injectors works VERY well. P/N: M-9593-C302 (Summit Racing)
Remember: '92-'99 use the Design-II FMS Injectors. '00+ use the Design-III style.
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The Magnum engine was first put in 1992 Daks and Rams with the 318 and the 239. In 1993, they changed the 360 over to Magnum heads. Fram/autolite dosent recognize this either. For example, plug wires for a 92 Dak and Ram are p/n 86231 (think). This set has the short coil wire for the coil mounted on the firewall. If you want the one for the Mag. eng.(coil is up front), you have to get the 93 wires (86233). Same for the V6. So do the 92's have the same injectors as the 93-96? I would a$$ume so,
but not sure.

-94 through 96 318's and 360's have the
same Dodge part numbers. If the 97's and 98's do indeed have the same part #'s, then the BW
injectors would be applicable

Ford MotorSport #19 Injectors (Flow tested/matched sets) $99 from Five-O-Motorsports (Bruce Holt - really nice guy) or about $150-$200 from Summit Racing.
*Oddly enough, the Magnum 4.7L V8 uses stock #24 lb rated injectors
BWD (Borg Warner) has a replacement injector for the 318, 360 engines. If you need injector(s), you don't need to go to Dodge to get them. Part # 57135 and is applicable from 94 through 96, and it may be applicable to the 97's and 98's. Last time I checked, Borg Warner was not in the business of
manufacturing fuel injection components, they more then likely are just re-packaging.

Although big injectors dont slow you down (on the 360 magnum)... some saw a 6hp increase @ 4900rpm with big injectors 270cc @ 87% duty ccyle and 43psi, stock is 232cc @82% duty cycle (max)) no fuel pressure mods... 360s have the same injectors as the 318s. with that, the duty cycle on the 360 @ WOT is greater. With stock injector variations you can find a "weak" unit
that will not increase flow rate as it reaches the peak duty cycle allowed by the PCM (80%)... I agree with you re: 318s even a weak stock injector
should flow enough to supply a mildly modded 318. With a free flow exhaust and a 700cfm TB, some can feel their injectors potentially "hanging" at very extended WOT (would you buy a used truck from this man...). The Lucas disk injectors (p/n 03764aa) have much less injector to injector variations and help smooth out the idle as compared to an unmatched set of Si
emens or Bosch pintle style injectors.

Factory injector from a '98 5.9L Ram flows 234cc/min @ 3 bar or 43.5 psi Factory injector from a '02 5.9L Ram flows right at 200cc/min @ 3 bar or 43.5 psi.
~22.2# injectors used on the '99 and earlier and 19# used on the '00 and later 360s.

So the 21# that everyone has been a$$uming for the later 5.9 is in fact flow rates for the higher factory pressure of 49 psi at the rails. This would
also go far in explaining why Bernd might have used a later model injector in an earlier truck and saw a lean condition(I'm a$$uming that was open loop, you didn't say). You lopped 15+% out of the fuel effectively by going with the later style. Since the factory tune is somewhere less than 10% fat in open loop, yeah, you would be lean.

This should clearly show how unreliable some of the information that's out there is on these injectors. Judging a flow rate based on the color of the
plastic is just plain foolish and the part numbers for the factory pieces are not much better unless you have definitive data from someone having flowed one at a known and specified pressure.
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Most injectors are rated at 3 bar (43psi). It is a standard pressure to rate them at. Our trucks have a fuel pressure of 49psi. There are several different sized injectors above 19 pph. Easiest place to
start is to make sure you are looking at the correct connector type. Up to 99 was a gray injector (19pph) with 1 style of connector, 2000+ is a red (21pph?) with a different connector.

On my buddies '99 R/T, we actually got more useable power and better mileage from the Ford MotorSports 24# injectors. No computer reprogramming required.

You can't jump 50% up in injector size and expect the PCM to have any hope of controlling them in open loop mode. It will be difficult enough in closed loop with the O2 sensors helping out. Unless your 318 is blown and has heavy head port work, it's not likely you
need more than 24#. This is based on widely accepted fuel injector calculators. What are you measuring A/F with to suggest that it's lean? PS..The stock 19# injectors should be good to at least 250-260HP (FLYWHEEL) so unless you're going beyond that I'd consider injectors a good waste of money.

Whenever larger injectors are installed, the engine calibration MAY need to be changed to match the pulse width issued to the engine's needs.

A 19 lb/hr injector size at 43.5 psi with a fuel pressure of 50 (close to ours) will have a flow capacity of 20.37 while a 24 lb/hr injector will have a flow capacit of 25.73. We also had a set of Red '01 injectors tested (at 43.5psi)...21# injectors.
(You can ask Matt Bonnette on that - he's got the data sheet from the flow-test). RC Engineering tested a few weeks back and the reds are 19# when tested at 3 bar pressure. I think the confusion comes in
with the factory 49-50 psi in the trucks which then puts their output at close to 21#. The 5.9 would certainly be more for forgiving of the 24s than a 5.2 of comparable setup.

24# seems to be a tad big for the 5.2L... Your only flowing about 65-76% of max. with the 19# in a 5.2L from what I recall. ON a 5.9, the 19# flow at nearly
85-95%... Adding 24# to a 5.2L without major rework of the engine calibration might cause for some REAL poor fuel economy, plus major loading up of fuel.
You might want to wait until you go for NOS then get the 24#s...

Dodge uses a Seimens injector on the Magnum engine ( I checked the 1998 5.9L Magnum). The Dodge P/N for the 98 injector is 53030778 and that is the same Seimens P/N. The injector saturates at 232 cc's (approx. 82% cycle duty) and it is the high impedance type. The flow rating translates into approx. 22 lbs/Hr. Little know fact, Chrysler owns Seimens.

Currently Seimens, Bosch, Lucas, Rochester, and Bendix make high impedance injectors with this flow rating (232 cc's). The next step up from all of the
above manufactures is a flow rating of approx. 245 cc's and the step above that is approx. 270 cc's. The 270cc flow rating translates in approx. 25 Lbs/Hr.

All of the above manufactures (with the exception of Lucas) manufacture the pintle style injector with production tolerances ranging from 5% to 10%. The exception on tolerances comes from Lucas which advertises flow ratings within 1% additionally the plate injectors (identified by multiple holes in the nozzle) saturate at approx. 87% cycle duty. I just purchased a set of the 270 cc injectors to try with
the big bore TB.
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The fun continues.........

Calculations show that these injectors should be good for about 330 horsepower. The only question surrounding these injectors will be whether or
not the O2 sensor can reduce the pulse width enough to not be rich at an idle. If it is rich at an idle, then the only option will be to drop down to the 245 cc injectors. Again all of the above manufactures have these flow ratings as off the shelf items, it
is just a matter of knowing where to get them. I ended up purchasing a set of Lucas injectors this time and I watched them being flowed, high was 271.1 cc's and the low was 269.6 cc's. We did flow the above Dodge injector.

Injector colors are as follows (Bosch):
> 19#--orange
> 24#--light blue
> 30#--red
> 36#--medium blue

"Seimens, the military weapons systems manufacturer, has an automotive division that makes injectors for all automotive manufacturers. They make injectors for GM, Ford, and Chrysler. Well..., you see, late-model Rustangs use an injector that supplies the engine with a few more pounds of fuel delivery beyond the OEM 360 units- and they're a drop-in for the Magnum.
They're available from the Blue Oval store under part
number M 9593 A302." (that was a Ford motor sport part # page 17 of the Motor Sport catalog).

According to the formulas from RC Engineering, unless you're pushing 280+HP (Flywheel) from a V8, the 19# should work just fine. You can use the 19# FMS "High Flow" Injectors if you need to "push" them a little bit.

I have also read on plenty of sites that the Mopar PCM can handle 24# injectors...sometimes 30#...but not 36#. I tlaked with a guy who installed the FMS 24# injectors in his Dakota. He said what a
difference it made! His mods: PCM, QuickD intake and TB, 1.7 rockers, headers and 3" exhaust, his engine must have been starving for more fuel. He said he can't believe how much harder the truck is pulling now. "The small amount of low end torque that was lost from the 3" exhaust and high flow cat is back, and then some. Less pedal gives more acceleration,
no doubt about it. It felt strong at first, but as the computer relearned it got better. The pull is strong and steady, all the way through the powerband. No flat spots or problems I can feel."

I also talked with guy who swapped out the #24s for his stock #19s:
"I've now had my stock 19lb injectors in for a week now, after swapping from the 24lb and the results are in:
1. Decreased throttle response, a little dead spot (okay, a big dead spot) when I nail the gas at a low rpms in a low (2nd) gear. The 24's felt a little better, but idled very rich. I would still have them in if I did not have a bad injector.
2. No decrease in overall power detected.
3. Fuel economy up to 15 mpg from 12 mpg.
NOTE: I did have the stock 318 computer with the 24lb injectors, when I later swapped the Mopar 93 5.9 HP-SBEC, the 24lb injectors seemed to run way too rich. I later found that the O2 sensor was unplugged, which may have influence the results."

Just some info. Not saying it is all 100% correct or you should read the above posts and taken them as "gospel", but it is just some good tech info on injectors for our 318/360 motors.

I would first invest in the Fastman TB and then run the truck for a long time, and then see if you need different injectors.
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