Thread: cant seem to run the 'correct' afr

im using a ngk afx wideband and tuning via powertuner but also with small tweaks to the afc 2.2 and happy knob. with the 3.1" pulley running 18* of timing and no adjustments to the afc and NO meth injection my afr is ~11.3-11.5 but i get as much as 3-7* of knock at WOT. my IPWs is approxiately 16-17ms and my nb is prolly 945s to 935 FWIW. am i doing something wrong? i noticed that if i add fuel via afc a bit i can shoot for high ~10s on the wb and run knock-free. am i using too small a pulley? im trying to tune w/o the alky/meth first then work from there. if i run kr-free w/o the meth and shoot for a afr of ~10.8 then if i lean it out and use the meth and add timing my afr shoots to the 9s
any suggestions? if anyone wants to look at my bin and give me some pointers please by al means

sounds like the pulley is too small.

i guess so, but i dont understand how others are running smaller pulleys and be able to run a 11.5 and leaner afr where i have to run a 9.x afr with a 3.1" to run knock-free? o_0

Because you're running 18* of timing, perhaps?

Originally Posted by Sabrewings

Because you're running 18* of timing, perhaps?

true, so would that mean i'd aim for a richer afr at like 11.1 or even a 10.9?

edit- a tad offtopic, but does anyone know in the dhp to correct shift knock? i seem to get shift knock mainly in the 2nd to 3rd gear upshift. i tried lowering the rpms shfit point as well as lower the timing at the top of 2nd gear but i still get anywhere from 4-7* of knock at and after the shift.

If it's knocking that much at the shift, you either have something hitting something else or the knock sensors are picking up the sounds of the clutch packs in the transmission. Only way to fix the second part is dynamat between the transmission case and the rear knock sensor.

I'm running mostly DHP file transmission settings and barely get a 0.5* blip at a shift.

im running TEP tranny, i cant recall if it had dynomat on the casing already or not as the core i sent to him had it. my tranny settings are close to stock minus the shift time is shortened

sounds to me that if you want to run that pully with 18* you will need some way to cool that air charge down. either tune with stock timming and no meth or start using the meth. im running a 3.3 (comparitivly the same setup) and i need meth to run with no knock. 11.5-11.7 should be your goal for AFR. forget about your O2s as well if you have wide band. Narrow band is a terrible way to tune if you are running a wideband. all the methanol will do is cool the air charge down, just like a top mount intercooler. only thing i would do if you really want to tune without meth is attempt stock timming and see if it knocks.

^true, but stock timing ewww lol...i just swapped back to the 3.3" just now and i'll tune w/o the meth(actual 100% meth for once lol, was been the -20*F washer fluid) and see what the car runs with xx timing at a 11.5-11.7afr then go from there. i just redid my maf table a bit after looking over it on a graph and my previous maf was skewed pretty rich above 9950+. now's a nice linear line above what an LS6 maff table i was using as a reference point is.

well, just for ****s i swapped to the 3.3" pulley and did a few test runs. i can run a 11.2afr with ~17-18* of timing w/o the meth. if i add more timing i'd need to add more fuel. did a few more runs and turned on the meth and im at the point where i can run kr-free(just blips of knock and aside from the shifts) with 25.6* of timing with a 9.7-9.8afr lol. im gonna tone it down to 23-24* for street tune and see if i can lower the meth max psi setting a bit.

wow dude, your car is crazy. with my 3.2 and stock timing with straight meth with a DO5 nozzle my AFR dips into the mid 10s. can you lean it out when you start spraying the meth on top of it?

i dont think i can if im running anything over 19* of timing. heres the scan i did from a slow roll with the 25* of timing
scan