Mongo

I know there have been numerous fuel injector threads, but I cannot find anything clear about minute flow variances. I was looking at specs for some 19lb and 24lb injectors last night for Design I, II and III styles.

The following are specs to injectors I have looked at:

24lb Injectors:
0280150947 (used OE for S3 cars and Porken's S300 LH chip for the S4+ cars)
DESIGN II
260cc @ 3 bar

0280155715 (Ford Lincoln/Taurus and I am considering for use with the LH chip)
DESIGN III
256cc @ 3 bar

19lb Injectors:

0280150556 (OE for S4+ cars)
DESIGN I
210cc @ 3 bar

0280155710 (Ford Explorer and Mustang 5.0 Fox Bodies)
210 cc @ 3 bar
DESIGN III

0280155746 (OE for Volvo 850s I think)
208cc @ 3 bar
DESIGN III

*Flow rates sourced from Witch Hunter.

The variance between the 24lb injectors above is 4 cc or ~2%. As such, there is also a variance with one of the 19lb injectors but only 2cc, less than ~1% from the OE injectors.

Based on the criteria mentioned above, I assume a 1%-2% variance is negligible when it comes to the LH compensating for the difference? Would this throw the oxygen sensor out of loop when measuring when load is applied? At WOT, O2 goes open and is ignored. I would assume using a 24lb injector 2% leaner wouldn't kill the motor whereas a 1% leaner 19lb injector wouldn't do either.

Imo000

What did you base these assumptions on?

jcorenman

Andy, the 87+ LH ECU has a fuel adaptation range of +/- 20%. This is the stored correction, and is active all the time. So a 2% difference from one set of injectors is of no concern.

However there can be significant differences in latency (dead time, opening time, whatever you want to call it) which do matter-- the problem being that info is hard to find. Sticking with stock injectors (cleaned and flowed if needed) is probably the best option for a stock engine.

Fitting 24# injectors instead of 19# is another matter, and either requires Sharktuning or chips that are tuned for 24# injectors. For stock engines I don't think there is any advantage.

Mongo

Yes the latencies are very hard to obtain. I can't find anything on 0280155715.

My initial thoughts were to actually see if I can dyno my car baseline now, then with an X-pipe, then add 4-hole Design III 19# injectors with the S300 EZK, and finally switch to 24# and add the S300 LH.