lt1 dyno but lean as hell....what ya think
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From: Chicago/Crown point
lt1 dyno but lean as hell....what ya think car has full bolt ons and has never been touched internally at all...stock stall and gear.....it has a mail order tune which i believe is why it went lean....but put it this way the numbers were 292hp 322tq with a 13.8afr thats so fn bad i cant believe it dont blow up running.....so what ya guys think of the numbers and correcting this issue how much power can be added to this lt1 if it has a better afr...
I would put money on the mail order tune. This is the same problem I faced with my mail tune. I actually kept my original pcm and swapped it in during the dyno and the lean spike was gone. This is another reason why I don't rely on mail tunes because some of them suck *****. My lean spike was almost in the 13's like yours.
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From: Decatur, TN (N-W of Athens)
Here's what Tony Shepherd said to me in some PMs about tuning as what I should try to aim for: "Also at WOT try to target your O2 millivolts at 910 which is about 13.2 A/F."
That is apparently the sweet spot for performance, so your 13.8 is actually damn nice!
Then again, I could've totally misunder stood him as I'm not a tuning Guru, hence me asking him for help lol
That is apparently the sweet spot for performance, so your 13.8 is actually damn nice!
Then again, I could've totally misunder stood him as I'm not a tuning Guru, hence me asking him for help lol
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From: Chicago/Crown point
for myself,
yea definately the tune thats lean so if he richens it up i can get it to be better and make more power but like i said i wonder i much power can be picked up
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Some WikiPedia lovin'
So you're running rich, not lean. 11.2 is WAY too rich. But again, that's assuming I'm understanding things correctly 
Originally Posted by WikiPedia Air-Fuel Ratio
For gasoline fuel, the stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel. Any mixture less than 14.7 to 1 is considered to be a rich mixture, any more than 14.7 to 1 is a lean mixture
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Verdad Gallardo All I can donate too the thread is, at WOT my air fuel was right at 13.2 and ran like crap. This was with my mail order tune. Sent it back to have it looked at and had the same issue once again after I got it back...car ran lean. Swapped my original back in and it ran perfect with no lean spike.
That A/F isn't bad for a NA engine, just remember this, "lean is mean", & "too rich can be a bitch", the old wives tail was shoot for 12.8-13.2 for best power, but this is not always the case, so your A/F is about superb.
Who tuned it? I had my mail order done by Ion, & i couldn't be happier, mail order tunes do work IF done right!! So fatten it up & see what it does, sure you may gain 5 hp, but it may also get lazy in the lower RPMs too, not good for a DD, plus your plugs/eyes won't like you lol. I ran my BEST ets with stone white plugs, & a narrow round tan ring at the base of the porcelin, cars in sig. (Duster)
Who tuned it? I had my mail order done by Ion, & i couldn't be happier, mail order tunes do work IF done right!! So fatten it up & see what it does, sure you may gain 5 hp, but it may also get lazy in the lower RPMs too, not good for a DD, plus your plugs/eyes won't like you lol. I ran my BEST ets with stone white plugs, & a narrow round tan ring at the base of the porcelin, cars in sig. (Duster)
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From: Decatur, TN (N-W of Athens)
Another source :\
EDIT: While I generally tend to stay away from magazine info, here's quite a bit of AFR talk, even if it's indirectly.
http://www.gmhightechperformance.com...onclusion.html
AFR: air:fuel ratio, how much air is combusted per unit of fuel; the ideal AFR for balancing power production/MPG with reduced emissions is 14.7:1. More power is generally made with richer AFRs (less than 14.7:1), down to 12.6:1 or so, depending on the individual engine.
http://www.gmhightechperformance.com...onclusion.html
11.2 is good for N2o, but not NA, thats way too rich, what you need to do (before knocking that 13.8) is, play around with the A/F ratio, you also need to test the car at the track & get some real #s, you might be quite surprised at what you find, i still say 13.8 is not bad at WOT "NA", don't assume that 13.8 is way lean, thats a misconception. Do you realize how lean your family car is from the factory, but it still runs fine, try 16.8-17.2, some are even leaner, but its how they optimize that A/F ratio, thats where computers come in handy, timing controllers, MAF sensors, knock sensors ect., all that fancy stuff, so no matter where that A/F ratio ends up at, you want to have the best MPH, thats what you shoot for, but that can't be done on a dyno, but it can get you close, so unless you can download the software from a laptop too your PCM, along with tweaking with the A/F ratio (at the track), you just can't say 13.8 is too lean, hope this makes sence.
"with a 13.8afr thats so fn bad i cant believe it dont blow up running....."
LOL 13.8 is not LEAN!!!!
Stoic is 14.7 as was mentioned before but what you have to understand is stoic is the point of least emissions not most power.
A custom tuner will normally go 10-15% richer than stoic (lower number here) because that is where the most power is made. Every car and application (N/A, Boosted, N02) is different but that's a general rule of thumb.
Do some reading up here http://innovatemotorsports.com/resources.php and familiarize yourself a little more with what's going on with the A/F mixture before criticizing your tuner...
Your AFR was about 7% richer than stock which is pretty damn good. Won't be pig rich and hurting your fuel mileage but will make more power than stoic.
LOL 13.8 is not LEAN!!!!
Stoic is 14.7 as was mentioned before but what you have to understand is stoic is the point of least emissions not most power.
A custom tuner will normally go 10-15% richer than stoic (lower number here) because that is where the most power is made. Every car and application (N/A, Boosted, N02) is different but that's a general rule of thumb.
Do some reading up here http://innovatemotorsports.com/resources.php and familiarize yourself a little more with what's going on with the A/F mixture before criticizing your tuner...
Your AFR was about 7% richer than stock which is pretty damn good. Won't be pig rich and hurting your fuel mileage but will make more power than stoic.
Good lord fellas.
14.7 is stoich for CRUISING
13.8 is LEAN for WOT
12.5-13.2 is the target range for na WOT usage depending on your combo and at what part of the curve you are near, peak tq or peak hp.
LEANER than 13.2 at wot generates high piston crown and ring temps and becomes much easier to detonate and hurt the motor.
12.0 and below for WOT NA is bad for your motor too it washes the cylinder walls down with gas and causes quite alot of wear to the rings and cylinders.
This is not the case for boosted/nitrous engines the extra fuel does not remain liquid in those applications and is used to cool things down so they survive.
13.8 nor 11 is good for wot.
WOT fueling does not affect part throttle fueling in the lt1 pcm. Running poorly at whatever air fuel ratio at WOT can have to do with a whole list of things in the tune.
I hope this helps to demystify some of this.
14.7 is stoich for CRUISING
13.8 is LEAN for WOT
12.5-13.2 is the target range for na WOT usage depending on your combo and at what part of the curve you are near, peak tq or peak hp.
LEANER than 13.2 at wot generates high piston crown and ring temps and becomes much easier to detonate and hurt the motor.
12.0 and below for WOT NA is bad for your motor too it washes the cylinder walls down with gas and causes quite alot of wear to the rings and cylinders.
This is not the case for boosted/nitrous engines the extra fuel does not remain liquid in those applications and is used to cool things down so they survive.
13.8 nor 11 is good for wot.
WOT fueling does not affect part throttle fueling in the lt1 pcm. Running poorly at whatever air fuel ratio at WOT can have to do with a whole list of things in the tune.
I hope this helps to demystify some of this.