i want my afc in the -

[larryriverside]

i am sick of having my afc set in the -. for some reason i think i am rich, but i know that im not. i have data logged my car, and tuned it for 0-3 counts of knock. also my egts are below 1550 at high sustained rpms.(5th gear) i have 660 injectors, 255 lp walbro, 2g mas, 60 trim turbo@20 lbs of boost on 97 octane gas. my high settings are at +8 to +12 on the high setting. if i go lower i get knock. does this sound right? and what size injectors would you suggest to get me in the - on my afc. i think my computer is sensing a major load at +12, and backing my timing off. not sure. my timing goes to 16 at 4500, then to 21 at 6500. all with no knock. any opinions?

 

[larryriverside]

opps

 

[kpt4321]

What are your low throttle corrections, and what are your fuel trims?

 

[larryriverside]

i will check my med and high trims tonite. my low trim says 139 my low corrections are -20 to -25. oh i forgot to mention my fuel pressure is set at 55psi! i am wondering if they sent me 550 injectors instead of 660's. i got them from slowboy. ball style i think.

 

[Bohrn]

from your knock count, your trims and your timing, I'd say

DONT TOUCH ANYTHING!!

Its lookin like a dream datalog.

Have the injectors flowed tho, because with 660's and 44psi, you should have to pull some fuel out.

What MAF are you running?

 

[larryriverside]

my mid fuel trim is at 110, and high is 81. i made a 3rd gear pull, and my timing seems odd. the car pulls nice, but i think there's more. ok here it the timing. 4000rpm-29 deg, 4500rpm-17 deg, 5000rpm-19 deg, 5500rpm-22 deg, 5687rpm-32 deg, 5700rpm-45 deg! that was as high as i took it. not ready to take it higher yet. i have to build up some trust in the set up. why is my timing jumping like that. i have 0 counts of knock the whole time.

 

[larryriverside]

me again, as you cvan see my timing has totally went south. the car still pulls strong though. the other day i tried to lean it down and was getting 15 to 18 counts of knock so i just put it back. could my computer be storing data from yesterday? would that affect my high rpm timing today? hmmm i just don't know enough about tuning yet.

 

[larryriverside]

nevermind about the timing. after a closer look at my datalogger it looks like i started easing off the gas at 5650 rpms. :laugh: i live in a small town, and i have no idea where to have my injectors flow tested. is it something i can do?

 

[Bohrn]

here ya go, read up, understand it, and go tune man


http://www.labattz.com/phpBB2/viewtopic.php?t=2418

go down to the John Hartman post, the tuning ones are in there

Merry Christmas and stay safe with your new found speed.

 

[larryriverside]

i don't want to sound rude, but i know some about tuning. those sites seem a little basic. but thanks for replying. more than most people would do. for how fast my car is pulling now it has to be in tune. i just want to get all i can out of it. it's just those damm injectors that are bothering me. cause i know if i can get in the negative on the high setting i will gain major torque. i want my timing to be at 17 - 19 at 7000 rpm. not 23

 

[kpt4321]

Well no offense, but you still have stuff to learn about tuning.

First of all, your fuel trims are off. Fix them.

Second of all, why do you want 17-19 degrees of advance instead of 23? 23 will give you more power. With 97 octane fuel, you probably want more like 25+ degrees of advance.

However, something is seriously wrong with your fuel flow or air metering. What kind of MAF are you using, and is it hacked? Have you checked for boost leaks?

Turn your fuel pressure down, 55 psi base pressure is too much.

You need to take a few steps back, and make sure everything is set up right (because something isn't). Then you can work on tuning.

 

[larryriverside]

2g maf unhacked. i am going to check for boost leaks tommarow. i #ucked up and haven't done that yet. what do you think could be the problem?

 

[larryriverside]

2g maf unhacked. i am going to check for boost leaks tommarow. i #ucked up and haven't done that yet. what do you think could be the problem? what is the injector p/w should be at full? i am not sure if i am gonna get cut in hard for not knowing something in this forum, but my p/w is at 20.77. and i don't know if that is bad or good.

 

[Bohrn]

thats fairly high p/w.

Also the 2g maf flows more air, so you will be adding more fuel than with a 1g maf.

not to be mean, but these are the sorts of things you can gather by reading the links that I put up for you. And as Kyle said, you can still learn.

 

[kpt4321]

Since the 2g MAF reads lower than the 1g MAF, you will not have to correct as much for large injectors as you normally would. The correction for a 2g MAF is *approximately* 25%, but it will vary.

Set up the fuel trims properly and see what the corrections are for that. The WOT / high throttle stuff should be similar to the 3k+ low throttle settings.

However, before you do any of that, you need to make sure you have ZERO boost/vac leaks.

 

[larryriverside]

would a boost leak make it nessisary to add more fuel? that dosen't seem right. wouldn't that make it richer? (asking this for conformation of my thoughts, and not to be a smartass)

 

[HighPSI TSi Guy]

Originally posted by larryriverside
would a boost leak make it nessisary to add more fuel? that dosen't seem right. wouldn't that make it richer? (asking this for conformation of my thoughts, and not to be a smartass)

you are correct.

what are your O2s? also what is your TPS? is it reading properly? have you tried resetting the computer or trying a different knock sensor? it could also be possible the MAF is going bad and missing counts

 

[larryriverside]

i did some more low setting tuning. i was way to lean on the low and mid. i finally got it tuned close to perfect i think. but to run good my hi trims are high. here they are. low 97 to 105 mid 100 high 81. my high is high, but the car runs great, and the o2 cycles when it should. my o2 is .90 at full. the best i can get it on the high setting is -2@3000 rpms. then i have to go all the way to +9@6000. i don't think i can get anymore out of it on pump. now i am running 93 pump at 20 lbs of boost. 0 knock. i am satisfied. i just need bigger injectors. thanks for all the help. justin

 

[Bohrn]

big boost, low knock, sounds good to me

I would tune the lo settings for leaner(higher numbers) like 120 or so, you will get crisper throttle response, quicker part throttle spool, and way better mileage. At least on my car and a few other cars I have helped tune.

 

[kpt4321]

I disagre Bohrn.

If you are in the range of the fuel trims (which you are at 120), then there is no reason ANYTHING will change since you will have the same overall A/F ratio.

 

[Bohrn]

yea, most people will

I know that you know alot more about this than me, but if I tune for close to 100% on my low/med trims, its a total dog, poor throttle response, slow spool, and horrid mileage.

With my maf(hugely ported) I am at 140 low trims, 132 med and about 115 high. Works best.

Gettin a 2g Maf in there soon, and I can begin all over again.