Ok so I rolled out to the Indy dyno day today to strap down on the rollers for the first time. The dyno was a Dynojet. My mods are:

GM Stage 2 - 42# Injectors, 3.0 Pulley, GM Reflash
Airbox Mod - Spectre Filter
Bad-Mab header
3" ZZP Catted Downpipe
Stock catback to a Megan Racing muffler

Looking at the dyno sheet starting at 3k rpms in 3rd i'm sitting at 15 afr drops to around 13 from about 3700 up to about 5k then down to solid 12 from 5k to 6k then suddenly it spikes to 18 by 6.2k and then the chart stopped reading it from 6.2k to 7k. Shouldn't I be rich considering I have the GM stage 2 and gm reflash? I'm purchasing the 3 pod pillar from zzp as we speak and as soon as i can get my hands on the money a wideband gauge so i can start getting this taken care of, but why would i be leaning out so bad??

on the other hand I made 246.61Whp and 220.49Wtq.

 

were these numbers read by a tail sniffer? If so, buy yourself a wideband and begin to lol.

Tail sniffers are the lulz

What I'm trying to say is; to have afr read correctly it needs to be @ the collector or right before the cat.
The sniffers are always way off... its amazing people let dyno shops tune them w/ those.
Realistically your afr is between 10.3-11.0 depending on your location and gas.

 

yea it was in the muffler. At the same time 1 other cobalt ran and it's afr stayed right around 12-13 the entire pull.

 

like I said... very inaccurate..

 

for it to lean off the charts shouldn't i still be pretty concerned though?

 

get a wideband and be done

 

x2

 

just ordered the zzp triple pod. soon as i can scrape the pennies up for a wideband i'll get one asap!

 

wanna know if your running lean?

pull your plugs...

 

what should they look like if i'm running lean? i'll pull them right now.

 

ok i pulled the plugs

 

white for lean

very black/clogged looking for rich

 

the prong is a hazy like grey. the ring around the top is black. the thing in the middle is whitish with a hint of tan/brown.

 

post pics here in a sec

 

 

bump

 

Your lean. My plugs looked like that when I pulled them and my brother (a mechanic) said the middle white part should be cappuccino in color. black is rich, white is lean

 

toss some new plugs in there...

autolite copper 3923 (1 step colder) $6-8

or

autolite copper 3922 (2 step colder) $6-8

 

i'll order some new plugs when i get the afr gauge. very short on cash right now.

 

dont waste $$ on shipping

call up your local nappa, autozone or pep boys

 

ok. these ones are the NGK 1 step colder from zzp right now. had them in there for i wanna say about 8k miles maybe.

 

that isn't much

they're just a little pricey

 

Autolite Copper/Spark Plug (3923) | AutoZone.com

 

Makes me wanna check my plugs to see how mine look!

 

I'm just wondering why i would be running so lean especially being on the gm reflash cause it's supposably supposed to be rich from what i've heard. could it be some other issue? i'm building boost right up to about 15-16 like i should be.