injector help
08-18-2012, 11:36 AM
#1
2nd Gear Member
Thread Starter
Join Date: Aug 2010
Location: Texas
Posts: 293
injector help
im running a dss promod shortblock, high compression (10.75-1) PI heads, comp cam stage 2's, full exhaust, ect ect. Im looking to get bigger injectors but idk much about what would be good enough to where there not to big. Can someone help me out please? Thanks ahead.
08-18-2012, 02:17 PM
#2
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
The stock 19 lb/h (orange) injectors were too small before you made your mods, that's why Ford used 21 lb/h (pink) injectors from late 2002 through 2004.
24 lb/h would be dead on for you, supporting 345 fwHP (295 rwHP) at 40 psi and 90% duty cycle. Unfortunately the FRPP M-9593-AA302 24 lb/h injectors have been out of production for three or more years and vendor's inventories have dried up as well. They were EV6 bodies with Jetronic/Minitimer connectors making them plug right in on our cars.
Venom has a set for $220 that would be a good deal. You will of course have to retune the low and high injector slopes, breakpoint and minimum injector pulse...
24 lb/h would be dead on for you, supporting 345 fwHP (295 rwHP) at 40 psi and 90% duty cycle. Unfortunately the FRPP M-9593-AA302 24 lb/h injectors have been out of production for three or more years and vendor's inventories have dried up as well. They were EV6 bodies with Jetronic/Minitimer connectors making them plug right in on our cars.
Venom has a set for $220 that would be a good deal. You will of course have to retune the low and high injector slopes, breakpoint and minimum injector pulse...
08-18-2012, 07:09 PM
#5
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08-18-2012, 09:42 PM
#7
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Join Date: Dec 2006
Location: Saint Augustine, FL
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You won't need adapters with the Venom injectors--they use the Jetronic/Minitimer plug same as the stock GT units.
There is a lot of misinformation about this out there, EV1 and EV6 are injector body styles unrelated to the electrical connector style:
The OEM plugs in our cars are EV1 with the Jetronic connector, the FRPP 24 lb/h injectors I referred to above are EV6 style with the Jetronic connector. The EV6 style has a lighter weight components for better response at short pulse widths.
You can see this in the specs for the EV1 and EV6 FRPP 24 lb/h injectors.
The older M-9593-A302 EV1 injector has these specs:
low slope: 26.2 lb/h
high slope: 24.9 lb/h
breakpoint: 22.1 μlb
min pulse: 1.052 ms
The M-9593-AA302 EV6 injector has these specs:
low slope: 31.5 lb/h
high slope: 24.3 lb/h
breakpoint: 9.24 μlb
min pulse: 0.521 ms
You can see that the EV6 style can accomodate a much shorter minimum pulse width (because it reacts faster), and that because of that the breakpoint (the fuel delivery point in micro-pounds)--the point at which the PCM switches to use the low slope capacity rating--is much lower at 9.24 μlb rather than 22.1 μlb.
This is why the low slope value is higher, at the shorter pulse widths the opening and closing times become proportionally greater as compared to the commanded pulse width; and also why the high slope is closer to the rated delivery mass.
This does not mean a whole lot from a performance perspective, however it will provide improved idle and low-rpm cruising and overall fuel economy.
There is a lot of misinformation about this out there, EV1 and EV6 are injector body styles unrelated to the electrical connector style:
The OEM plugs in our cars are EV1 with the Jetronic connector, the FRPP 24 lb/h injectors I referred to above are EV6 style with the Jetronic connector. The EV6 style has a lighter weight components for better response at short pulse widths.
You can see this in the specs for the EV1 and EV6 FRPP 24 lb/h injectors.
The older M-9593-A302 EV1 injector has these specs:
low slope: 26.2 lb/h
high slope: 24.9 lb/h
breakpoint: 22.1 μlb
min pulse: 1.052 ms
The M-9593-AA302 EV6 injector has these specs:
low slope: 31.5 lb/h
high slope: 24.3 lb/h
breakpoint: 9.24 μlb
min pulse: 0.521 ms
You can see that the EV6 style can accomodate a much shorter minimum pulse width (because it reacts faster), and that because of that the breakpoint (the fuel delivery point in micro-pounds)--the point at which the PCM switches to use the low slope capacity rating--is much lower at 9.24 μlb rather than 22.1 μlb.
This is why the low slope value is higher, at the shorter pulse widths the opening and closing times become proportionally greater as compared to the commanded pulse width; and also why the high slope is closer to the rated delivery mass.
This does not mean a whole lot from a performance perspective, however it will provide improved idle and low-rpm cruising and overall fuel economy.
08-19-2012, 12:08 AM
#8
5th Gear Member
Join Date: Jul 2005
Location: Georgia
Posts: 2,387
I've been looking at the 24lb recently after I realized that even my stock #21 are about max. Does most tuning software account for the difference between EV1 and EV6, or is it a function of an experienced tuner? I have looked at the venom, but have not decided. How much fuel economy are we talking? What type of connector are you running, Cliff?
08-19-2012, 12:41 AM
#9
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
I've been looking at the 24lb recently after I realized that even my stock #21 are about max. Does most tuning software account for the difference between EV1 and EV6, or is it a function of an experienced tuner? I have looked at the venom, but have not decided. How much fuel economy are we talking? What type of connector are you running, Cliff?
Re: fuel economy, like most things in life "it depends". If you do mostly in-town short trip driving it makes no difference as you are not driving in a fuel efficient environment to begin with. If OTH you do a lot of long distance highway driving in closed loop it can add maybe 0.5 to 1.0 mpg.
I got a set of the EV6 FRPP 24 lb/h injectors before they went away (got 'em for $100 from a forum member), they have the Jetronic/Minitimer connectors, same as the stock harness. The adapters just match the harness to the injector connector--no magic or rocket science. Before such things were available we'd find a Jeep (or whatever) in a junkyard that have the right connectors and "graft" them to the harness...
