headers as my first mod

Re: headers as my first mod

Postby murphinator » Wed May 02, 2012 10:45 pm

bud659 wrote:would the range of a WB be of help with my limited mods? i dont have a cam or IC or anything. just a pulley, headers, cai thats it.

and i always thought 11.6 commanded AFR a WOT is what works best. WB or not. just that the WB is more accurate at commanding that 11.6 than a NB02.

I try to shoot for .920-.940mv on the NB02

if your chasing KR using a wideband will make it much easier . you will chase your tail going by nb mv people without widebands will say no but ask anyone who has used one how much easier it was to get things in line.

a norrowband or a wideband does not command an air fuel ratio like 11.6 all 02 sensors do is verify readings within their range of operation or report full rich or full lean once beyond their range of operation. this is why cars with narrowbands from the factory come out of closed loop ( looking at 02 sensor feedback and adjusting accordingly) and go into open loop where the 02 sensors get ignored and pe (power enrichment) is employed to add fuel based on extensive factory testing with stock components in place to maintain safe afr's - the factory determines these safe settings for wide open throttle during testing with-you guessed it wideband 02 sensors.

Once you add mods - especially increasing cylinder pressure through smaller pulleys these oem wot settings are no longer an accurate default , if you had a cam it would hold valves open longer allowing airflow through your engine dropping cylinder pressures , if you had an ic it would be cooling the intake charge , either of those would give you more safety margin than you have now on the same pulley , of course when people cam or ic they usually do it so they can drop pulleys further so again wideband monitoring can be beneficial.

A good example is a buddys ss camaro ls1 auto convertible with intake , catback , raised shift points when I put my wideband on it and tuner connected it was showing 950 mv while running at 14 to 1 afr , I did some maf tuning on it changing percentage of reported airflow based on the 10% lean condition it was seeing and it came right into line at 12.5 to 12.7 afr which is about what you want NA , the car immediately pulled much cleaner - it had a slight surge before from being so lean but came up through the rpm's nice with the added fuel. Then we increased timing significantly now that we had enough fuel in place to keep detonation (KR) at bay.

The car went from squawking 2nd on a shift to kicking sideways all in about an hour , without the wideband you can fart around for days , weeks ,months but never truly know if your afr is correct.

We all think we are doing fine without a wideband until we get one on our car and see how much easier it is to defeat the enemy now that he is in broad daylight lol , I also read the posts and shot for 920-940 back in the day , ask any tuner worth his salt if they would feel safe with that on a forced induction car with mods.

The best $17 you can spend to understand how tuning works and why you need things like wideband o2 sensors pick up Greg Banish Advanced Engine Management & Tuning , I have read it through about 10 times and refer to it all the time when I need to refresh my memory on something.

Greg writes tunes for OEM's and teaches tuning on the side via classes , books ,tuning dvd's , for short money his books can teach you a lot.
2000 Z28 M6, 11.95 @111 street tires through the exhaust, QTP long tubes 3" duals , slp lid & intake, spano/koni/hotchkis susp. etc..

99 z28 long tubes , catback ,lid

1998 Z28 built A4 3600 stall , slp lid & lower , ls6 intake ,80mm tb, Kooks long tubes , 3" ss catback , 3.73's 12.1 @112 oct/2013 11's coming up spring 14

2002GS 1/4 mi 13.165 108.09 trap ,1/8 mi 8.562 , 84.87 trap on spray , 13.5 @104 without

GTP ON SPRAY 12.209 @117.75 1/8 MI 7.73 @94

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Re: headers as my first mod

Postby hitman92499 » Thu May 03, 2012 1:14 am

I think I can get that book through work for $15 if your interested.
1997 Grand Prix GT - The IncREDi-hoopdy - Top Swap - 3.8" Pulley - 180* T-stat - AL104's - GMPP F&R Sway Bars - 12" Front Brake Upgrade - 219000 miles and counting - GETRAG 284 5 Speed build in progress
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Re: headers as my first mod

Postby bud659 » Thu May 03, 2012 6:47 am

thanks for all the good information. getting that right tune is so important and looks like using a WB is in my future. if i can get one borrowed or if have to purchase, that would be awesome for the car cause it def need it. im going to post some scans soon and all feedback would be great for this work in progress. thanks again
2004 CompG headers, pulley, plugs, cai, RTA's, custom pcm
1998 Pontiac GrandPrix GTP rockers, headers, pulley, plugs, custom pcm, GMPP handling Kit
1988 Chevrolet Monte Carlo SS 350 GM Crate Motor, Alum Intake, Jet-Hot Hooker Headers, Hypertech chip, MSD 8.5 Ign Wires, Accel Ign Module,Cap+Rotor, Dynomax cat-back 2.5" exhaust, 3:73 Gears, 200-r4 tranny street/strip build
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