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air/fuel ratio
Posted: Mon Jul 13, 2009 9:44 pm
by Lego
im about to buy an aem wideband setup. i have no EM and running 480cc injectors... i know im running rich but when i put the wideband on and it shows the numbers, what number should i be really worried about? and im going to run the jecs maf also to see if i can lean it out a little, what number should i also be worried about with that?
Posted: Mon Jul 13, 2009 11:55 pm
by BSOD2600
Various tuners or sites online all arrive at different 'ideal' ARF numbers while on boost. Revtronix has stated they targeted 11.5. While the ECU is learning, it's around 10-10.5 with 440cc. Without the chip, I was seeing AFR of 9-10 always during WOT with 440cc. I seem to recall that the stock injectors were around 12.2 during WOT. Others on the forum have stated no leaner than 12.5.
Idle ARFs are ideally 14.7. The revtronix chip has stated it runs idle a little leaner, to increase fuel economy -- I've seen it around 14-16. Around 17 or higher while trying to accelerate, is fuel starvation and the car will buck / have no power (this is a problem with the Stage 2 v1 revtronix chip while the O2 sensor warms up).
Posted: Tue Jul 14, 2009 1:05 am
by 93forestpearl
I shoot for 11.2-11.5:1 under high load. I taper down to that from a few psi to 23psi.
At light cruize, I tune for about 15.5:1 for economy, but I can advance my timing to make up for the slower flame front due to being leaner than stoich.
Posted: Tue Jul 14, 2009 3:34 am
by Lego
heres the results, let me here feedback
casual driving: 14.5-15.0
idle: 14.8-15.3
WOT: 11.4-11.8
9-10 psi up hill: 11.00 solid
now remember i have 480ccs and an intake bypass tube which makes it so that the maf doesnt see as much air as its really sucking in.
i want to put the jecs maf on next and take some logging, but are my numbers already good to where i dont need to lean it out?
Posted: Tue Jul 14, 2009 4:57 pm
by wtdash
When I tested the 440cc injectors w/the JECS MAF, blue MAF wire grounded, and stock ECU I saw over 14+ @ WOT....only did that once!
But I don't know what the 480's will do.
Be careful.
Posted: Tue Jul 14, 2009 5:04 pm
by douglas vincent
Lego, those numbers actually look pretty good for no tune!
Posted: Tue Jul 14, 2009 6:12 pm
by Lego
yeh i tried the jecs last night and on partial throttle it would exceed 16+... i immediately switched to hitachi.
i tried to tell you guys that 480s work... my quarter mile time should have also shown that.
Posted: Tue Jul 14, 2009 6:19 pm
by wtdash
Lego wrote:
i tried to tell you guys that 480s work... my quarter mile time should have also shown that.
I'm glad they work for you...but I wasn't so lucky.
My stock turbo ECU never learned to control the 480's-driveable, but not fun.
Td
Posted: Tue Jul 14, 2009 6:33 pm
by Lego
if u put them back on ill show u my maf bypass tube and that should work, also have to let the ecu relearn for quiet a bit.
oh and not saying this works but i also have that plate taken out of my hitachi maf... lots of speculation on that subject but i figured it wouldnt hurt to take it off
Posted: Tue Jul 14, 2009 9:01 pm
by 93Leg-c
Lego, can you post pics of your maf bypass tube and your hitachi maf?
Posted: Tue Jul 14, 2009 10:41 pm
by gijonas
This thread makes me really want to get some 480's to go with the 440cc tuned stage two chip i have,it also makes me glad that i did go forged with my pistons.Some numbers i see here are much more ideal than some that i have seen lol.
Posted: Tue Jul 14, 2009 11:59 pm
by Lego
yeh i guess i can post a few pics...
Posted: Wed Jul 15, 2009 2:24 am
by 93forestpearl
Interesting on the bypass tube, I'm curious too. That's a creative way to scale some injectors, lol.
Posted: Wed Jul 15, 2009 2:24 am
by Lego
