2G MAF in 1G Target O2 Trims??????

[GSXlaunch]

I just installed some 650cc injectors and a 2G Mass via the hard wire method. I started the car and everything was great. The car idled like a champ, my A/F gauge cycled normally. I just have a question regarding the O2 trims I should be adjusting for via my old style (5-Knob) SAFC. Before, I was always told to shoot for a range of 100-110 for the O2 trim and that for my car a max low of 60 was full rich and high of 120 (max high) was full lean. I got it to hover between 100-110 at idle with a setting of -8 for my 800rpm setting. Well when I revved the car and held it at about 2k rpm my O2 trims varied from 135-150 range, which is the highest I have ever seen it. I realize this is because of the 2G mass but I am wondering what the "new" perameters are. Did the full rich and full lean values change and if so to what? Should I still try to get it to stay in the 100-110 range???? Sorry for all the questions...these are pretty much the last mod(s) I am doing before I shoot for my 12 sec goal. Thanks.

TT

 

[awdrst]

you should still look for 100 as far as your fuel trims go.

 

[GSXlaunch]

So your saying that when I see 130-150 values for the O2 trim I am going max lean??

 

[peregrine]

its real hard tp set fuel trims with the old afc as there is no part throtle adjustments. great for full throttle but shitty for driveability.

 

[GSXlaunch]

I am quickly finding that out...ehhh it was cheap tho.

 

[psychlow]

Stick that sucker on eBay and get yourself a SAFC-I/II.

Otherwise, you're going to have to find a compromise setting that will satisfy both O2 trims, and also work at WOT. Usually, this means you're going to have to run ridiculously rich at low-mid throttle, which will suck down gas like no tomorrow, and idle like crap.

 

[GSXlaunch]

Well since the Cowboys are getting spanked I took the car out tonight for a few quick logs. Boost was set at 15.5...at first the car was pulling very nicely...at 50-75% throttle and rpms up to 6k. The next log I figured I'd go wot in first and second. As soon as it got above 6500 in both gears, it bucked and hesitated badly in first and second gears...it was not boost cut just a horrible hesitation/spuddering. There was a total of 5 logs with one at wot and the rest at about 60-75% throttle. I did see 2 counts of knock at 3513rpm during one of the partial throttle runs. Timing never dipped below 20. I noticed my O2 trims were all over the place until I got on the throttle where it sould stay at 100% until I let off. Mid and high fuel trims never changed and remain set at 100%. The low trim would range from 110 to 118...lean??? I also noticed when decelerating there was alot of backfiring which I thought meant a rich situation. I am not too concerned about the trims since there is no knock...I do need some ideas on what that hesitation could be. Since it was dark I couldnt say if the car was throwing out black smoke.

Here is what the log shows at the point the hesitation started first Gear:

RPM Knock Timing
6468-0-23
6687-0-23
6812-0-22

O2 Trim was at 100 though out. Low Trim was 110 through out.

Perhaps I was hitting the rev limit...my high rpm in second was only 6350???
Thanks again for the help.

 

[psychlow]

Run the same 'hesitation' log again, and this time log O2-V. I want to see what your oxygen sensor is reading directly at those RPMs.

 

[GSXlaunch]

If it stops raining I will get it out again tonight. Things I noticed after the above logs were that my Power Transister connector was loose, just a little. My two and three injector connectors were loose, just a little. For some reason, with the 650's in I dont have enough room to get the clips on the injector connectors. I used a dab of rtv on the sides of the connectors to get them to stay put. I have no explanation for the hesitation. My logs dont show it at all but it was pretty bad...right at the high end of 1st and 2nd gears...I didnt get into third. What is the easiest indication of running either lean or rich (not looking at the logger)?

 

[peregrine]

learn to read your plugs. BUT you need a fresh set before you try to read them. do a third gear pull, pull over immediately and check them.

 

[GSXlaunch]

...took the car out last night and got a few more WOT logs. Just wondering if anyone wants to chime in with thoughts. First off, changes I made since the last logs on Monday night were, tightened up power transister connector (was a bit loose), tightened up injector connectors on no. two and three cylinders (were also a bit loose), and turned the MBC up about a full turn. I did not touch the settings on my AFC. So here are the logs...

Log 1: thru 2nd and 3rd gear at 20psi w/spikes up to 21psi, pump gas…

RPM-Knock-Timing-O2 Volt-Inj DC-Thottle Position ---2nd Gear
4093-0-24-.84-37%-25%
4343-0-28-.84-29%-38%
4750-0-29-.82-27%-37%
4937-0-30-.82-27%-39%
5062-0-30-.80-33%-43%
5437-1-28-.82-51%-47%
5531-1-25-.82-59%-52%
5718-1-24-.82-72%-60%
5875-0-23-.80-82%-84%
6250-0-21-.78-89%-100%
6375-0-19-.78-88%-100%
6687-0-20-.80-90%-100%
6750-0-18-.80-86%-64%

RPM-Knock-Timing-O2 Volt-Inj DC-Thottle Position ---3rd Gear
4812-1-17-.82-66%-70%
5031-1-17-.80-69%-85%
5250-1-20-.80-75%-100%
5562-1-20-.80-78%-100%
5750-0-22-.80-79%-100%
6031-0-22-.80-83%-100%
6250-0-21-.80-86%-100%
6218-0-21-.80-86%-100%
6312-1-34-.57-8%-9%

Log 2: thru 2nd and 3rd gear at 20psi w/spikes up to 21psi, pump gas…
---2nd Gear
3718-1-30-.80-17%-36%
3906-6-29-.80-20%-40%
4062-5-26-.78-33%-47%
4406-5-21-.82-46%-50%
4750-4-18-.82-60%-62%
5343-4-17-.80-75%-79%
5718-3-21-.80-81%-100%
6000-3-21-.78-84%-100%
6343-3-18-.80-89%-100%
6531-2-19-.80-89%-58%
---3rd Gear
4531-1-25-.82-46%-97%
4843-1-17-.80-70%-100%
5000-0-19-.80-70%-100%
5281-0-20-.80-74%-100%
5593-0-21-.80-77%-100%
5812-0-22-.78-80%-100%
6031-0-23-.78-82%-100%
6125-0-23-.80-83%-100%
6281-0-21-.80-85%-100%
6406-0-29-.61-6%-9%

Note: The car simply hauled ass lastnight. It has never felt that strong before. It pulled hard and the boost came on quick. No hesitation at any point and more importantly no boost cut I realize there are some issues with knock but I believe there is still a lot more tuning to go. Timing seems to be advancing decently. I wish I had time to look at the egt gauge during all this but I was too concerned with the RPM. With the light weight flywheel it revs extremely quick and I hate bouncing of the limtter. I was surprised to see the duty cycle of the 650's reach 90%. Correct me if I am wrong but it seems I may be leaning out a little. May not have done any good but I pulled my plugs this morning and the ground electrode is grayish in color, the center electrode is dark as well as the insulator for the center electrode. Thoughts and/or recommendations...

Thanks and sorry for the long post.

 

[GSXlaunch]

Took the car out tonight. I had already turned up the boost about a 1/4 turn according to the mbc. Went out and got some logs. Funny thing is the car did not make any more boost then last week. It is still right at 20 with occasional spikes to 21. I thought ok I need to turn the mbc up some more. So I screwed the knob in (Joe P boost controller) almost a full turn and tried again. You guessed it, she is still right at 20psi with quick spikes to 21. What the hell? I also noticed during an 80-90% throttle run in 4th my egt's were still climbing to 900c!!!!! My ported evoIII turbo should be able to make quite a bit more boost. I did a compression check when I got home with the engine still quite warm. Results were:

1. 170
2. 165
3. 165
4. 165

So compression is great. The car does not smoke one bit and basically drives great. It is weird that it only took about a full turn on the mbc to go from 15-16psi to 20-21 and now after another full turn it wont go any higher. Does this sound like a boost leak??? It does seem to hold 20lbs...? Shit! Here we go again. Any help is appreciated. I am so freaking close and now this!