My dyno sheet says 14.62 and I beleive wide open throttle is 12.07. Is 12.07 that rich ? and how much power can I gain back by leaning it out ? I have an auto with a 3400 stall,228/236,578/588,114 and stock ported/polished heads,all bolts ons.
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My dyno sheet says 14.62 and I beleive wide open throttle is 12.07. Is 12.07 that rich ? and how much power can I gain back by leaning it out ? I have an auto with a 3400 stall,228/236,578/588,114 and stock ported/polished heads,all bolts ons.
who did you have tune it? I'm not sure on actual power gains but you're leaving some on the table that rich. Do you know Bill from COFBA? Have him take a look at it for you.
Just a example what happened with my car... after my LT headers I dyno'd 319 rwhp sae. Put the car on a wideband and seen my A/F was in the 10's, brought it up to 12.9's and instant 22 hp increase.
the 14.62 is the stoichiometry AFR thst is used for part throttle closed lop operation---most Gm V8's come even richer from the factory--commanding an AFR in the middle 11's--your slightly leaner 12.07 is from the increased airflow of the cam and mods without tuning correction---as mentioned 12.9 is a good AFR to shoot for to achieve max HP--A slightly richer 12.7 is used when trying to get more torque instead of dyno HP-- preferred by many tuners to get a more "streetable" power /TQ curve
thanks for the replies.I learned something new.
I think a wideband is a great investment for our cars. Since they are so cheap now in the $300 area, I think it is worth it to get one and makes a great tuning tool. If using pc tuning software or handheld tuner. The price of going to the dyno once to bring your A/F into range almost pays for a wideband you can own. I'm going to buy one soon... Little changes can throw your A/F off and may not be a bunch of lost hp and tq, but every bit counts. Innovative LC1 is a great wideband. I have friends than own them and they never had any issues.
I agree about the wide-band. Every FI car we do gets a wide-and, usually the LC-1 with a XD-16 gauge.
With that said, your AFR may not be to far off. Ideal AFR is very dependant on timing. Going from 12.0 to 12.7 - 12.9 without changing timing, will most likely net you 5-10 rwhp.
I got my tune we bumped it up 3 degrees its now 28 with no knock and at wot I got the af around 12.5-12.7 and my shsift points were at 6500 or 6600rpm.I am running strong now.Iam sure I picked up a few hp/tq.
How can you say that? A/F ratio has NOTHING to do with timing. timing in NO WAY affects the amount of fuel injected to mix with the air. It MAY affect the emissions, but it in NO WAY affects the mixture.Quote:
Originally Posted by edgz06
Timing may affect the burn, therefore the emissions, the final product spewed from the tailpipe, but that cannot be misconstrued as affecting the A/F ratio. Thats just false info.
Those sound like pretty sound specs. 28 degrees, and 12.7:1 A/F is right about where you want it. No knock retard under WOT, and you're good to go.Quote:
Originally Posted by 01WS6475hp
It's not false info. I didn't say A/F has anything to do with timing, I said " ideal AFR is dependent on timing."Quote:
Originally Posted by edcmat-l1
What that means is, when tuning your torque/hp curve, you don't necessarily want a totally flat AFR, across the board. Lower in the rpms, you can get away with running more timing with a richer AFR, and after you have reached your peak torque point you can then lean out the AFR some to continue building power.
So you may have an AFR of 13.1 drop to 12.3 and then gradually rise to 12.9-13.1 and you will make more torque and average power than just dialing in an AFR of say 12.9 across the board.
This is not hearsay, this info is from my tuning many Gen3 cars on the dyno.
So ideal AFR is dependent on timing. :)
:iagree: I agree with you totally---and understand exactly what you mean--don't feel left out--this dude claims to be an expert about everythhing--when in reality doesn't know anything about computer controlled engines or their tuning--I as you are am a profesional tuner with EFILIVE and have tuned and data logged over 250 cars and trks--Very much so a richer AFR will allow you to add more timing and vice versa--too lean a mixture will produce KR with too much timing---and as you say moving the AFR around as the RPM increases from rich to lean will make more power--The timing curve works best with more fuel in the mid-ranges and more timing--then as the RPM's increase--the AFR is leaned out and timing is subtracted--Just look at any GM engineers STOCK timing and fuel curves--they are programed the exact same way-can't say those 100's of engineers are all wrong !!!Quote:
Originally Posted by edgz06
So you are right--Ideal AFR IS achieved dependant on timing---
Oh this guy likes to argue with everyone--very low on the comprehension scale---and obviously not current---A dyno or a data logger doesn't lie--
Gotcha.. Sounded to me like you were saying timing had an effect on A/F ratio.Quote:
Originally Posted by edgz06
You're a joke dude. Dont get me started. Go back and post in the thread where I proved you wrong.....Quote:
Originally Posted by tblu92
you're the one that dont know sqwat. OBD2 drive cycles, readiness tests and what not.
I been a CERTIFIED driveability specialist for better than 15 years. How bout you? you wont even put your name in your profile.
I OWN a shop. how bout you?
I OWN a dyno. how bout you?
And I stand by my statement. A/F has NOTHING to do with timing.
I did misunderstand the statement made.
And if you're a "PRO TUNER" why dont you sponsor at least ONE of the boards?
Remember, you started this junk by attacking ME, when in fact you were dead WRONG.
http://forums.corvetteforum.com/show....php?t=1749705
Here, just to refresh your memory. And to show everyone else what kind of idiot you are. You cant even go post and suck it up and admit you were wrong.
See Posts #8, #9, #10
http://forums.corvetteforum.com/show....php?t=1739310
Heres another one. Look at post # 7 everyone.
tblu92, please tell everyone how 'adding fuel' in the low rpms is going to help ping.
Talk about not comprehending how computerized FI works.
Adding fuel in the lower RPMs will do NOTHING as long as its in closed loop. Except for make it have to correct less.
Please, tblu92, direct everyone to somewhere I've posted some BS like you. I told you once, I'll tell you again, I make my living being right. Not just "tuning"......
I'M A JOKE ? you argue with everyone--everywhere--I can only imagine how it must be to live around you--Look buddy--you are def. stalking me--I am going to turn you into the P.D.-
Don't go away mad-just go away! people are afraid to confront you--I'm not--Ive chatted privately with several people accross the forums--they all just wish you would find another hobbie and get a life !!! you take this forum stuff way too serious--
YOU need counseling and psycotheraphy !!! take your medication--and stop stalking me--this is my last attemp at being civil--stop stalking me-
Whos stalking who?Quote:
Originally Posted by tblu92
I only argue with people like you, who think they know, but dont reallyQuote:
Originally Posted by tblu92
Peaceful, til you attack me like you did on CFQuote:
Originally Posted by tblu92
Do what ya gotta do.....Quote:
Originally Posted by tblu92
Thats funny. I get positive feedback all the time. not to mention business is booming.Quote:
Originally Posted by tblu92
Thats not what my shrink said...Quote:
Originally Posted by tblu92
You havent been civil from the start. You started this mess, and decided to continue it here.Quote:
Originally Posted by tblu92
You also decided to stoop to cursing and name calling.
I proved you wrong and you werent man enough to admit it. Several people on the CF think you're a joke. You wont even share your name. Everyone knows who I am. Whether they like me or not. I have nothing to hide. Seems you do.
ok guys, lets keep it on topic and take the personal stuff to PM's please.
yea i was trying to se if i could learn something so i could do some expertmentation with my diablo about added fuel but all this is a pissing contest
The first question I would have is if you have a wideband? When tuning AFR a wideband is almost mandatory. I know people use the O2 voltages but in order to be at all accurate a wideband is needed. It's also really handy to have something that datalogs because you want to be able to go back over your log and see what your AFR is doing at a given RPM/load.Quote:
Originally Posted by kyemt
well to the topic..
since u guys seem to know a/f and timing
do you know what the stock timing for an ls1 in a trans am is...
just wondering just to have a little added information
any info would help
also to the original post..would the diablo change timing or mainly shift points and little things..
Show some "LOVE" guys!!!! Come on!
here's a stock T\A timing table see the pdf.Quote:
Originally Posted by ls1speedster
i,m running 26* wot at 6000rpm. most hand helds alter the timing thats the main differencein the high and low octane tunes in a hypertech where 91 octane is an option.