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Discussion Starter · #1 ·
The only engine mods I have is a new K&N filter & 3" Magnaflow cat back exhaust. I installed a Innovate wide-band gauge & I can now read real true A/F at WOT. I was surprised to see how lean it is at WOT now. I didn't get a reading before since my wide-band was my last mod. I have ran a wide-band on my last 2 cars & usually factory tunes are always pig rich at WOT. When I say lean I mean 13.8 to 14.2 at WOT. I advise anyone with this mod to enrich fuel in all ranges 2k to red line with your hand held tuner or better yet get a fresh custom tune with them using a wide-band/dyno combo. Simple enough to do yourself if you have a wide-band & a hand-held tuner in the modify tune area. It should run in the 12.7 to 13.1 max range. I know a lot of people now run 3" magnaflow cat backs so I can assume yours is doing what mine is & probable leaner if you have a custom tune. If a factory tune is that lean (usually factory is pig rich) a custom tune will be even leaner. Might just check it out with a wide-band. The only way to know for sure. My wide-band is new & had a fresh air calibration (best type).
 

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Good to know gonna have acustom tune put in soon will be sure and have them get it between 12.7 13.1. Thanks Ken.
 

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Discussion Starter · #3 ·
I guess no one else is using a wide-band A/F & don't know where they are at stock or with your canned tune. Canned tunes could have you lean if you have never checked this with a wide-band or does everyone just trust it's all ok? Lean conditions under WOT can cause a lot of damage.
 

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Thanx for the update on that. You have triggered my interest on the A/F Wide Band. So I caught this on another thread. Although its with a SC, the conversation is interesting about WOT. Do you agree with these A/F numbers?


A/F Question

You all know I got the Techco SC on my car. When Techco tuned it, they tuned it with a Diablo because that's what they use. Tillman converted everything to SCT X-Cal3 because that's what they use. When Techco tuned it was 11.5a/f at wot and about 13.5 to 14.5 cruising down the road. Now with the conversion that Tillman did my AF cruising down the road is between 14.5 and 15.5. When I run on the freeway and take my foot of the gas the car (I have the PLX Wideband) goes into lean, then goes into rich and back to lean, then it reads "air". If I keep coasting like that the car goes in safe mode (little engine blinking) and comes out of safe mode after I get on the gas for a few seconds. It only does this on the highway and after about 20 miles at cruising at about 80mph, not around town. Oh forgot to mention, to keep the CEL off, Techco raised the cat temp and left the O2 sensors on so I can pass inspection.

Sorry for the long post, anybody know what gives????????????????
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It's in the tune. You said that it did it after cruising for a bit so and not around town so im sure it wasn’t throwing the code while it was at the dyno. Best thing to do is Get it back to Tillman so he can take care of it.
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When I'm cruising at high speed and let off the gas my wide band shows extremely lean too , which is to be expected since the engine basically becomes an air pump at that point and you're not giving it any fuel. However I can coast like that and I don't get any light , so you may need an adjustment to the tune ...
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It's totally okay to be lean at a cruise or off the gas pedal, as there is no load on the engine. It's partial, and especially wide open, throttle (with a load on the engine) that needs to be rich enough to keep from hurting the motor with detonation. High 11's or very low 12's would be ideal wide open throttle numbers.
 

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Discussion Starter · #5 ·
N/A should fall in the 12.7 to 13.1 max & with a SC 11.5 to 12.0 Max probable 11.5 for boost over 6 lbs. Cruise 14.4 to 14.7 (14.7 perfect) anything over 14.7 will be lean except for just a blip. I am surprised that I see people spend $1000 plus on mods for performance but never consider a wide-band A/F gauge. The only way to get your tune perfect & also safe. Best insurance you can get. Even the tail pipe kind used by a dyno are at best close. If the dyno people don't take a reading before the cats it can't be trusted. Cats totally change reading when taken in the tail pipe. They will use your wide-band if you have one for a perfect reading. I would never mod or tune a car without having a wide-band A/F gauge. After doing mods for years it is one of my first priorities. Never trust a canned tune it could be anywhere since all cars are different at different altitudes & temps. The computer will compensate some but you got to understand it is figuring it's tune from factory non-wide-band o2's that are not even close to real world A/F they swing all over the place when you compare them to your wide-band. Go figure??? I paid $280 to my door & it took 2 hours to install. A new motor will be over 6k.
 

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Blindmelon said:
N/A should fall in the 12.7 to 13.1 max & with a SC 11.5 to 12.0 Max probable 11.5 for boost over 6 lbs. Cruise 14.4 to 14.7 (14.7 perfect) anything over 14.7 will be lean except for just a blip. I am surprised that I see people spend $1000 plus on mods for performance but never consider a wide-band A/F gauge. The only way to get your tune perfect & also safe. Best insurance you can get. Even the tail pipe kind used by a dyno are at best close. If the dyno people don't take a reading before the cats it can't be trusted. Cats totally change reading when taken in the tail pipe. They will use your wide-band if you have one for a perfect reading. I would never mod or tune a car without having a wide-band A/F gauge. After doing mods for years it is one of my first priorities. Never trust a canned tune it could be anywhere since all cars are different at different altitudes & temps. The computer will compensate some but you got to understand it is figuring it's tune from factory non-wide-band o2's that are not even close to real world A/F they swing all over the place when you compare them to your wide-band. Go figure??? I paid $280 to my door & it took 2 hours to install. A new motor will be over 6k.
Thanx. Are these numbers correct for all engines, or just 4.6L3V? Does the Innovate come with tuning information? Where do you learn this? (all I know is pulling the plugs and checking the color after pulling a grade... :lol: ) My altitude is primarily why I would like to learn how to custom tune.

Blindmelon said:
I am surprised that I see people spend $1000 plus on mods for performance but never consider a wide-band A/F gauge.
Right. Like the saying goes, "You can't expect what you don't inspect..."
 

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Discussion Starter · #7 ·
If you Google Tuning some links will come up. I found several on magazine sites. The A/F is standard for most modern motors. The 3v Mustang motor will take a little leaner 12.7 to 13.1 where most Chevy's are like a little less. Rule of thumb on a safe blower tune is 11.5 to 11.7 max 12.0 on 6 lbs or less maybe 11.0 to 11.5 above 6 lbs boost also higher boost will need more octane (above 92) to be safe or water/meth injection.
AS you advance timing you usually have to richen up fuel curves.
 

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You need to be careful with small wideband a/f meters

Even if they are calibrated you may want to put that car on the dyno with a tail pipe reading to see if your meter is reading high or low. I have a race car with a FAST with a wide band, and stand alone wide band meter, and dyno'd with a wide band. the value spread for the three was over .5 a/f with the stand alone meter being the outlier. It would be better to see where it reads on the dyno then trend with it there after. My bullitt with CMDP's and Steeda intake elbow started out at 11.1:1 a/f!
 

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Discussion Starter · #9 ·
This is my third Innovate wide-band & it was rated top A/F wide-band in a Mag test. Any A/F used before the cat is better then behind. Gauge may be small but they all use Bosch o2's. So does the FAST. I do a fresh air calibration on mine real often also.
 

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Blindmelon said:
The only engine mods I have is a new K&N filter & 3" Magnaflow cat back exhaust. I installed a Innovate wide-band gauge & I can now read real true A/F at WOT. I was surprised to see how lean it is at WOT now. I didn't get a reading before since my wide-band was my last mod. I have ran a wide-band on my last 2 cars & usually factory tunes are always pig rich at WOT. When I say lean I mean 13.8 to 14.2 at WOT. I advise anyone with this mod to enrich fuel in all ranges 2k to red line with your hand held tuner or better yet get a fresh custom tune with them using a wide-band/dyno combo. Simple enough to do yourself if you have a wide-band & a hand-held tuner in the modify tune area. It should run in the 12.7 to 13.1 max range. I know a lot of people now run 3" magnaflow cat backs so I can assume yours is doing what mine is & probable leaner if you have a custom tune. If a factory tune is that lean (usually factory is pig rich) a custom tune will be even leaner. Might just check it out with a wide-band. The only way to know for sure. My wide-band is new & had a fresh air calibration (best type).
Man I Hate when I miss important Threads that Good Info.

July mine will be taken care of ..........

Not long from now and since It sits in the garage for the most part I will wait.

Good Info.

tigerhonaker
 

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Rats, Ken now I have to spend more money.Seems like a good time to put this on would be when they are installing the headers, please correct me if I am wrong in that assumption.Don't you drill or burn a hole in the pipe and weld the bung there?This seems very involved how do you adjust the air/fuel ratio after the tune? is there a handheld thats you use? Can we use our sct devices?Sorry but this may well be beyond my meager realm of understanding.
 

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Discussion Starter · #12 ·
Rick you weld a bung in the 9 o'clock to 3 o'clock position (furnished). Most headers have a extra one already for a A/F o2 sensor. They need to be in front of the cat not behind for proper A/F readings. Diablo or SCT handhelds have a area to tweak you fuel trim curves & spark curves. You can built new fuel curves or spark curves for customs canned tunes or factory tune. It also will let you extend rev-limiter to higher rpm, idle speed, tire size & more. The canned tune will be close but needs a tweak. You just add fuel + to get richer or - to go leaner. It should have 3 areas in the rpm range like 1000 to 2000 rpm 2000 to 4000 rpm & 4000 rpm to 7000 rpm. Same on spark advance curve. Pretty straight forward. Add or take away a little at a time till it is perfect at WOT. The canned tune uses special software that can control almost every function like torque management also fan turn-on temps. You can also adjust changes when larger injectors are installed or a new size (larger intake). Go to Diablo or SCT forums for more info also print out the manual & read it. The A/F has about 3 grounds & 2 power wires so the rest is plug-n-play.
 

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Ken, Thanks for the info and the e-bay lead.
 

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Discussion Starter · #16 ·
R/T Chaser said:
So is it a decrease in exhaust backpressure thats throwing off A/F readings with the Magnaflow cat-backs?
No it just reads gases. Reading behind cats will show leaner, cats burn any extra fumes so you don't get a true reading & that even can vary depending on how good the cats are. In front of cats right off the headers is the exact A/F burn area.
 

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So in conclusion? The Magnaflow exhaust is flowing so much better than stock, it's causing a lean condition and needs a proper tune!???
 

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Discussion Starter · #18 ·
jymontoya said:
So in conclusion? The Magnaflow exhaust is flowing so much better than stock, it's causing a lean condition and needs a proper tune!???
That is correct. Combo of much better flowing cat backs & K/N filter = much better flow with leaner conditions. If you see the orig exhaust beside the new 3" Magnaflows you will see why. The orig. exhaust is really pinched down at the bends. The new 3" Magnaflow has to be a 100% improvement in flow. I can only imagine how it would flow without cats or with headers. Should be a easy correction with a handheld & a new fuel curve.
 

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Blindmelon said:
That is correct. Combo of much better flowing cat backs & K/N filter = much better flow with leaner conditions. If you see the orig exhaust beside the new 3" Magnaflows you will see why. The orig. exhaust is really pinched down at the bends. The new 3" Magnaflow has to be a 100% improvement in flow. I can only imagine how it would flow without cats or with headers. Should be a easy correction with a handheld & a new fuel curve.
So that would pose a problem with the electric cut-outs right?

http://www.quicktimeperformance.com/QTEC/index.php

And you can't go changing your tune every time you open up the by-pass.
Or can you adjust a tune so the A/F stays in an acceptable range for both closed and open by-pass?

 
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