Need Injector Help

[bratcop]

Well, I have been bitten by the stroker bug. I am building a stroker from my 2001 Grand Cherokee Laredo 4.0

First I would like to thank everyone here and all the others who take the time to post info on the web regarding this. I would be lost without the info...

anyway, my setup is this...258 crank and rods, 677cp pistons, ported and polished stock head,stock cam, standard water and oil pump, and the hi perf head gasket. I am hoping to make near 250 hp and 300 lb/ft. Anyway, standard injectors flow at 22.5 lb/hr and doing the calculations, I need 26.04 lb/hr to sustain those hp/tq numbers. I know about the ford motorsport 24lb/hr injectors, but those are rated at 39 psi, whereas my jeep pushes 49psi with non adjustable FPR. Using those injectors would equate to 26.9lb/hr actual rating...is that too much?

Finally the questions, I read that the '01 4.0 will not accept the 24lb ford motorsport injectors, something about them having a different connector?. Does anyone have any first hand knowledge of this? I saw where some accel 24.4 lb/hr injectors would fit the bill nicely, if they will drop in (equate to 25.719lb/hr at 49 psi)

Lastly, I am going to make the MAP adjuster so I can fine tune the fuel/air mixture...which should give me some leeway on the injector size...

I think this is last bit of the puzzle I am dealing with. Any info would be greatly appreciated.

I did use the search function, but most are not building strokers on this new of a Jeep 4.0, so specific info is limited...thanks.

Joel

[seanyb505]

Not sure about injectors fitting or not fitting your application, but I think and MAP adjuster only lets you adjust across the board. It wont do much for rich or lean spots. If you have some time I would take an injector from you engine to the junkyard and see if it fits the connectors of some older years. Or snag a connector from the junkyard and bring it to your house. I know its a different electrical system, but I think my fuel pressure is also rated at 49psi (97 Cherokee). Right now Im using injectors from a Lincoln Mark VIII with the 4.6 and they run just fine. Theyre rated at 24# and are high impedance, good for Jeep strokers.

[dwg86]

I got a st of Ford 24lb EV6 injectors from my stroker that is going into a 2003 TJ. That is what FIVE O reccommended. I am still gathering parts for my engine, so I don't know how they are going to run. I am at work right now, but when I get home I will post the part numbers.

[gradon]

Someone is using 25# Cobra injectors that plug into the newer(99/00+) style injector harnesses.

[SilverXJ]

I got a st of Ford 24lb EV6 injectors from my stroker that is going into a 2003 TJ. That is what FIVE O reccommended. I am still gathering parts for my engine, so I don't know how they are going to run. I am at work right now, but when I get home I will post the part numbers.

Are they the Bosch 24 LB injectors for the Cobra, 0280155865? http://www.fiveomotorsport.com/Injector_SetsMODS.asp If so they will flow at more like 26 or 25.5 lbs with the late model 49PSI fuel rail. They are a bit much, even though all the web calcs say 26. It will run rich unless you use a piggy back. AFAIK they are the only drop injectors for the stroker that 5-O offers.

[dwg86]

Those are the ones. I got a set of 8 off ebay for $60.00.

[Cheromaniac]

Well, I have been bitten by the stroker bug. I am building a stroker from my 2001 Grand Cherokee Laredo 4.0

First I would like to thank everyone here and all the others who take the time to post info on the web regarding this. I would be lost without the info...

anyway, my setup is this...258 crank and rods, 677cp pistons, ported and polished stock head,stock cam, standard water and oil pump, and the hi perf head gasket. I am hoping to make near 250 hp and 300 lb/ft. Anyway, standard injectors flow at 22.5 lb/hr and doing the calculations, I need 26.04 lb/hr to sustain those hp/tq numbers. I know about the ford motorsport 24lb/hr injectors, but those are rated at 39 psi, whereas my jeep pushes 49psi with non adjustable FPR. Using those injectors would equate to 26.9lb/hr actual rating...is that too much?

Finally the questions, I read that the '01 4.0 will not accept the 24lb ford motorsport injectors, something about them having a different connector?. Does anyone have any first hand knowledge of this? I saw where some accel 24.4 lb/hr injectors would fit the bill nicely, if they will drop in (equate to 25.719lb/hr at 49 psi)

Lastly, I am going to make the MAP adjuster so I can fine tune the fuel/air mixture...which should give me some leeway on the injector size...

I think this is last bit of the puzzle I am dealing with. Any info would be greatly appreciated.

I did use the search function, but most are not building strokers on this new of a Jeep 4.0, so specific info is limited...thanks.

Joel

Sounds like you're going for a stroker very similar to mine. You'll need injectors that'll flow roughly 24.5-25.0lb/hr at 49psi so they'll need to be rated to about 24lb/hr at 43.5psi. The ones that fit the bill are indeed the Accel 24lb'ers.
A MAP adjuster will not work well with the '01 computer. The reason is that the '00+ computers are locked into a program that provides a stoichiometric 14.7:1 A/F ratio at WOT up to 2300rpm and thereafter goes richer. The only way to dial in an even 13.0:1 A/F ratio across the rpm range at WOT is to install a piggyback computer such as the Unichip and have it mapped on the dyno. An alternative would be the Apexi SAFC 2 but that'll only allow you to alter the fuel curves, whereas the Unichip also allows you to program new timing curves.

[Mgardiner1]

Why wouldn't a MAP adjuster work? An air flow controller is just a fancy version of a MAP adjuster. They both modify the the MAP value going into the ECU. An AFC has an advantage of monitoring other things such as throttle % and RPM and adjusting to different %'s of fuel dependant on its input values

[SilverXJ]

Why wouldn't a MAP adjuster work? An air flow controller is just a fancy version of a MAP adjuster. They both modify the the MAP value going into the ECU. An AFC has an advantage of monitoring other things such as throttle % and RPM and adjusting to different %'s of fuel dependant on its input values

I think he was saying a simple home brew MAP adjuster wouldn't work that just has one point to program for the whole RPM range. A piggy back would get past that problem. Since the PCM in OBD II will maintain 1.47 AFR up until open loop you can't do anyhitng about it so no need to worry about that.

[Mgardiner1]

If you say so. I thought in closed loop, all ECU's tried to achieve the same 14.7....

[SilverXJ]

If you say so. I thought in closed loop, all ECU's tried to achieve the same 14.7....

I don't have much knowledge about OBD I systems so I don't know much about them. In my case I wouldn't use a home made map adjuster. With the stock injectors it was running leaner at 3000-3500 than at 3500+. So, if I set the home made map adjust to richen up the 3000-3500 it would make the 3500+ too rich. I don't recall my exact RPM numbers, but you get the idea. With teh home meade map adjuster you can only adjust the afr over the whole RPM range, not specific points.

[Mgardiner1]

HAHA yeah i didn't agree that the home made adjustable map was any good or extremely adjustable

I am still trying to decide which system i'd like to go with. I had a car with an Apexi SFC in it once. Felt kinda cheesy though. I like the idea of the PSC1 with the laptop connectivity....

[SilverXJ]

HAHA yeah i didn't agree that the home made adjustable map was any good or extremely adjustable

I am still trying to decide which system i'd like to go with. I had a car with an Apexi SFC in it once. Felt kinda cheesy though. I like the idea of the PSC1 with the laptop connectivity....

Yeah.. its a bit on the cheesy side, but it supper easy to use and gives you some extra info on its screen and it has adjust on the fly. But the PSC 1 hides away and have much more adjustment than the Apexi.

[bratcop]

thanks guys, keep the discussion coming...I was looking at the PSC-1 as well, now that I have decided against the radioshack special....The Uni looks good, but needs a tuner/dyno to dial it in, and I don't think that is available in my area...I wish you could do the Uni by yourself, save on dyno and tech time $....

Joel

[Mgardiner1]

thanks guys, keep the discussion coming...I was looking at the PSC-1 as well, now that I have decided against the radioshack special....The Uni looks good, but needs a tuner/dyno to dial it in, and I don't think that is available in my area...I wish you could do the Uni by yourself, save on dyno and tech time $....

Joel

Thats exactly why i'm leaning more towards the PSC-1. I've got 2 holes in my exhaust for o2 sensors. One will be for the computer, and the other will be for my wideband sensor that i'll use for tuning