castorino220

it definitely has a tune i just dont know what it is. i want to get a programmer they are just a little costly. the car has quite a few mods, feels fast, i have not had her to the track so i dont know how fast yet. with the 4.10 gear she gets up pretty quick. when i get a programmer i was leaning toward 1 of the Bama tuners, is this comparable to what you listed?

CalBoy101

Well, now that I troubled you guys for the info on the 24's, it looks like 21 lb injectors are in my future.

I had bid on some on ebay, $80. including shipping, about 2 weeks ago but they never showed up and I thought the guy was backing out, he wouldn't respond to my requests to let me know if he had shipped them, so I thought the deal was dead.

But I just got a notice from ebay that he shipped them on Friday, I think ebay must have leaned on him, they had sent me a notice saying they were looking into the situation.

I think the 21's are enough for my mods for now and I realized that there is probably an advantage with them. I'm in Kalifornia so I'll have to get a smog check in a year or 2, the plan is to reload the stock tune back in for the smog check.

I'm assuming the stock tune will be able to compensate for the small change up to the 21's, is that a reasonable assumption? I've heard that they didn't even change the ECM calibration when they went to the 21's, is that true?

I'm figuring that passing smog with the 24's and the stock tune would be a stretch.

I'm having a blast with this car, and it made me realize an important secret of life- make sure you have at least one thing in your life that is just pure fun.

cliffyk

It is true that Ford did not change the injector settings in the tune when the change to the 21 lb/h injectors was made--at least I have seen no indication they did, in at least 75 or 80 pre- and post-change tunes I have reviewed. The high and low injector slopes are 19.15 and 23.76 respectively in both the "19 lb" and "21 lb" tunes.

However with the 21 lb/h units your engine will run quite rich in open loop mode, with AFR dropping into the mid 11s, even high 10s on some engines. This costs you power (10 to 12 HP in the upper mid-range and above); and money as more fuel than needed is being consumed. This is one of the first things done in any new-edge GT tune is to lean out the target AFRs in the Stabilized Open Loop Fuel table.

My experience has been that when running the 21 lb/h injectors changing the injector slopes to 20.50 and 24.10¹ will get the AFR at WOT back to 12.5 to 13.0:1 range and get back that missing 10-12 HP. This should not impact the emissions testing in any way and it will get the short term fuel trims in closed loop operation to be closer to what they should be; ± 5%...

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¹ - Changing the low injector slope is not required for performance tuning, but while "you're there" why not alter it just for sake of completeness.