best 928 injector with Porken chipset and 87 fpr?
#16
Intermediate
Thread Starter
Yep, great video! I am sold, definately going to the newer style injector. Maybe after talking to Ken I can contact Roger for availability. I like the offer from Blue Oval that was mentioned earlier. I like that someone used them and they worked well.
#18
Inventor
Rennlist Member
Rennlist Member
It's batch fire. Digital L-Jet.
Half of the fuel load for each cylinder is fired onto a closed intake valve.
Weather conditions will change WOT AFR more than anything else.
Idle and part throttle AFR is controlled by the O2 loop, which cycles between 13-ish and 15-ish.
Adjusting the MAF CO screw to the the CO spec, or a 14.7-ish AFR at idle with the O2 sensor unplugged, should account for minor injector differences.
The code for CO adjustment has also been reprogrammed to add to WOT fueling as well.
Half of the fuel load for each cylinder is fired onto a closed intake valve.
Weather conditions will change WOT AFR more than anything else.
Idle and part throttle AFR is controlled by the O2 loop, which cycles between 13-ish and 15-ish.
Adjusting the MAF CO screw to the the CO spec, or a 14.7-ish AFR at idle with the O2 sensor unplugged, should account for minor injector differences.
The code for CO adjustment has also been reprogrammed to add to WOT fueling as well.
#19
Rennlist Member
Adjusting the MAF CO screw to the the CO spec, or a 14.7-ish AFR at idle with the O2 sensor unplugged, should account for minor injector differences.
I don't know much, but I do know that the A302 and AA302 Ford 24# injectors are OOP and hard to find. The LU24A are widely available at around $200 for a set. I also know that my existing injectors, whatever their opening time was or is, are around 27 years old.
When expressed in percentages, the differences between injector opening times seem substantial. When expressed as segments of the amount of time it takes a honeybee's wing to flap once in flight, the differences do not seem as great. Unless the differences between injectors are so great that the engine management system cannot properly adjust the mixture in closed loop, is it safe to conclude that the newer Ford injectors can be used?
BTW, does anybody know what the opening times etc. are for the stock injectors? I couldn't even find this spec for the Ford injectors.
#20
Captain Obvious
Super User
Super User
That only shows tge difference in spray pattarn and I was aware of that. What I was after is proof they make more HP or increase mileage or do something other than have a nicer mist. Something that is statistically significant.
#21
Rennlist Member
That only shows tge difference in spray pattarn and I was aware of that. What I was after is proof they make more HP or increase mileage or do something other than have a nicer mist. Something that is statistically significant.
If you want to pay to have my original injectors cleaned and flow checked to ensure they are comparable to new injectors, I would be willing to compare them to new ford injectors (if these are deemed to be acceptable by Ken or the assembled Rennlist multitudes) through dyno testing. I suspect, as I believe you do too, that the differences between the two might be so small as to defy detection.
If I am going to buy an 87 MY FPR and do some or all of the other checks and upgrades needed to ensure getting the known bang for the buck out of putting in PorKen's chip, can you just let me have my fun and believe that new Ford injectors will work better than my 27 year old Bosch injectors? What am I going to do, save the $200 and leave it to the kids?
#22
Rennlist Member
Opening times are 0.93 ms for the stock (S3) 24# injectors, and 0.94 ms for the stock S4 19# injectors. I haven't found spec's but that's what Sharktuner uses, and I've got some data that indicates the 19# number at least is correct. Ken may be able to confirm the 24# (S3) number.
#23
Rennlist Member
Thanks for the info. This would mean that the new Ford 24# injector takes .32 milliseconds longer to do its thing.
I am not trying to be argumentative, I just want to learn. How does that .32 ms affect things? In closed loop, isn't the ECM going to be adjusting the pulse width based on the o2 sensor outputs?
Certainly, if an injector is taking a really long time to open, the system could not compensate. Otherwise it would appear to me that the programming must have some "headroom" for lazy injectors and an ability to make adjustments. If there were no feedback loop from the O2 sensor, then the slower opening time would shorten the actual versus the commanded pulse width and there would be less fuel provided. However, the system does not just look up a pulse width for a certain flow of air, it also strives to maintain an optimum mix based on what the O2 sensor tells it.
I am also not sure I understand why a slower opening injector than stock is "worse" than one that opens faster than stock. Wouldn't either deviation from stock be wrong? Is slower opening "bad" because it impinges the pulse width to the extent that the ECM cannot make the system attain the proper A/F ratio at WOT or somewhere else?
I am not trying to be argumentative, I just want to learn. How does that .32 ms affect things? In closed loop, isn't the ECM going to be adjusting the pulse width based on the o2 sensor outputs?
Certainly, if an injector is taking a really long time to open, the system could not compensate. Otherwise it would appear to me that the programming must have some "headroom" for lazy injectors and an ability to make adjustments. If there were no feedback loop from the O2 sensor, then the slower opening time would shorten the actual versus the commanded pulse width and there would be less fuel provided. However, the system does not just look up a pulse width for a certain flow of air, it also strives to maintain an optimum mix based on what the O2 sensor tells it.
I am also not sure I understand why a slower opening injector than stock is "worse" than one that opens faster than stock. Wouldn't either deviation from stock be wrong? Is slower opening "bad" because it impinges the pulse width to the extent that the ECM cannot make the system attain the proper A/F ratio at WOT or somewhere else?
#25
Inventor
Rennlist Member
Rennlist Member
There is a large range in the MAF CO adjustment.
WOT fueling is adjustable with a 'WOTpot'. Programming for this is already in all S300s chipsets (V3-up).
I have tested the chipset with cleaned stock pintle type and metal body 'Ford' 4-disc injectors that were available >5 years ago.
Since I have not tested them, for other newer types, you may need to verify with a WBO2 and/or adjust the WOT fueling with the WOTpot accessory (variable 0-900 ohm resistance for the WOT input) for a sub-13:1 average AFR.
I have changed the (many years old) recommendation to the following text.
WOT fueling is adjustable with a 'WOTpot'. Programming for this is already in all S300s chipsets (V3-up).
I have tested the chipset with cleaned stock pintle type and metal body 'Ford' 4-disc injectors that were available >5 years ago.
Since I have not tested them, for other newer types, you may need to verify with a WBO2 and/or adjust the WOT fueling with the WOTpot accessory (variable 0-900 ohm resistance for the WOT input) for a sub-13:1 average AFR.
I have changed the (many years old) recommendation to the following text.
Professionally cleaned stock injectors (24#, other types EG. plastic body, may require WOTpot)
#26
Intermediate
Thread Starter
I installed the new injectors this past weekend along with a silicone coupler and hose clamp set(it looks truly amazing). I went with the red Bosch injectors p/n: 0280156013. It starts quite well but have not had a chance to take it on a 20 min drive to get hot enough to heat soak. They are rated at 24lbs/hr, 255cc/min at 43.5 psi. the top and bottom o rings measured exact to originals and were plug and play. They also had the slot for the clip already there. they have a resistance at 14 ohms. The engine idles a lot smoother although it would not idle after restarting it next day after the install. had to feather accelerator on startup. has been sitting 24 hours since then. will try again when I get home from work. If all goes well I will put some miles on it, make sure its hot, drive to the house, and do the stop wait 15 mins then restart to see if it starts right away or vapor locks. Will report back...
#27
Race Car
sounds like you may have a dripper. Great of you to come back and post course of action and results -- too often the threads tail off without a conclusion.
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#28
Intermediate
Thread Starter
I forgot to post an ending to this one. I had the maf connector slightly loose. clipped it on and have been tearing up Colorado all summer. DO THESE INJECTORS