2g with side&lower honeycombs gone... 720cc injectors... tuning gone!!!

[myblack98gst]

okay a little history

98 GST 6-bolt motor w/ 2g pistons
walbro 255 fuel pump, denso 720cc's, higher flow fuel filter
Digital tuning datalogger, AFC 2
big 16g ported

okay since I got these injectors my car has ran RICH.. to the point it smokes like a diesel, when at full throttle. even with the AFC @ -50%

I was searching through some site and saw that hacking the maf could re-solve this problem. so I removed the side and lower honeycombs and backed the screw all the way out. now messing with getting it tuned the fuel trims at 1,000 rpms finally get to the 0-3% area when the lo trim is set at +50% at idle then +10% the rest of the way on low.

the high is set to -30% it still smokes pretty good but it running slightly leaner.


does anyone have a set-up similiar to this that is tuned right?? if so let me know where your settings are at

 

[Blk_99gst]

Geez, that sounds all messed up to me. First, I wouldn't recommend hacking your 2g maf. If you can't compenstate for 720 injectors with a safc (ie you're hitting -50% on the safc), then I would recommend getting a newer ecu chip that has some compensation for larger injectors in it, or probably better yet, upgrading to different fuel tuning with the gm maf. With that, you get a bigger maf and you can use the translator to compensate for some pretty large injector size.

But for you current situation, the car is getting a lot of un-metered air, so it's going to have a hard time running because that amount of unmetered air is not constant, it will be different at idle, different at normal driving, different at wot. So you will have CRAZY safc settings, like your current +50% low and -30% high. That's just nasty. You know that there are times the safc uses interpolates and uses values from both the low and the high tables. You'll get some crazy intermediate values when your low and high tables are so much different from each other.

 

[cfisher]

that sucks man. i've got a 2g with 680cc and i'm around -35 on the highs. i'm at .96 on my o2's which is still a little rich but i'm happy with the results. i would not take out the honeycombs. it will screw up your readings and they will never be consistant. what turbo are you running. i guarentee you go with a 20g you'll be just fine. they pull more than enough air to compensate for the fuel. also, do you have a fpr. i was running into somewhat of the same problem and once i installed the fpr i was at 52psi at idle and turned it down to 43psi and it made a world of difference.