46callaway
Registered
My car is currently set to 13.0 A/F ratio at WOT, would it be safe to make it a little but more lean like 12.6 at WOT? I'm only gonna adjust for WOT not part throttle.
help with tuning my car
- Thread starter 46callaway
- Start date
Old-Fart-Al
Registered
Isn't that going the wrong way if you want to lean the mixture Serge. If you dialed it in at say... 13.4 or 13.6, you'ld be leaning the mixture slightly, correct?
Air-fuel ratio (AFR) is the mass ratio of air to fuel present during combustion. When all the fuel is combined with all the free oxygen, typically within a vehicle's combustion chamber, the mixture is chemically balanced and this AFR is called the stoichiometric mixture (often abbreviated to stoich).
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.
Going from 13 to 12.6 will be making the mixture more rich.
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.
Going from 13 to 12.6 will be making the mixture more rich.
46callaway
Registered
Whoops, you guys are right, I meant 13.4. I get confused sometimes because I think about the number getting smaller (12.6) means less fuel but it's obviously not. So would a 13.4 at WOT be safe for NA?
What tuning software are you using?
To eliminate some of the confusion, have you thought about this in terms of "lambda" rather than AF ratio?
it's alot easier to 'cipher..if you use lamda rather than AF ratio
1.0 Lamba IS 14.6/1 AF
The base fuel tables for the Mark 8 are set up in Lambda rather than AF.
In my PCM at WOT at 5500 RPMs the stock calibration calls for .63 lambda
.63X14.6=9.1 AF ratio at WOT.. {can you say UBERFAT?}
Also, are you comparing what your commaded lamba is compared to your actual "delivered" lambda?
"commanded fuel" means nothing if you cant verify "delivered lamda".
Try to re-think this using the same terms you find in the software, because converting lambda back and forth to AF will drive you nuts.
once you get a good handle on lambda it's not so confusing.
Have you gone thru your base fuel calculations?
meaning setting all commaded fuel to 1, and turning "adaptive corrections" off? and then verifying the difference with WB02?
It really makes dialing in these cars a breeze.
If you turn off adaptive, set all base fuel to "1"..then datalog w/WBO2.
If you command "1" and your delivered lambda is .93 then your correction is .07 in that area of the MAF transfer function.
Rinse, Lather...repeat thru all areas of the MAF transfer..
Sounds confusing, but.. once you get a good grasp on it.. it's very simple actually.
VOODOO it is not.. so dont let anyone tell you otherwise.
46callaway
Registered
I am using Sniper Special Forces. The only thing I have control of is PT A/F for low, mid, and high rpm as well as Global A/F. I can makes changes in incremants of .2.
This is the best post I've seen in a while.
Maybe the mods can make it into a tech article.
Too Many Cars
Registered
I am very surprised that the stock calibration calls for .63 lambda! Is it similar in the Gen1 Mark's? If so I really need to find a way to correct that! Too bad that the Gen1 doesn't use flash memory for the mapping. What is the reason to go with that rich a mixture ? Are they trying to use the excess fuel as a coolant or something like they supposedly did with my two stroke Kawasaki triple motorcycle?!!
lol...expensive coolant...
It would be hard to imagine the cats NOT being fouled or passing a smog test if 1/3 of the fuel being pumped in to the engine is not being burned.
Thanks Mr. Logres.
If you haven't noticed I haven't been posting as much this year as I did last year.
Why?
Because I've been immersed in this tuning software, gathering and soaking up information like a sponge!
haha
The learning curve is literally vertical, but after working with it since nov-2006 it's all starting to make sense.
Not only does the stock PCM calibration call for "buttloads of extra fuel", the stock PCM calibration also has a NEGATIVE 20 degrees of "tip in retard"..which is insane IMHO..
meaning everytime you tip into the throttle, from a stop.. or from a roll.. the PCM is pulling TWENTY DEGREES of timing out of the motor.
Just addressing these TWO areas in the tune goes ALONG way in "waking up the beast from within".
Let me drill a hole in my day and I'll post a screen capture of the stock first gen base fuel table as a jpeg.
stand by.
If you haven't noticed I haven't been posting as much this year as I did last year.
Why?
Because I've been immersed in this tuning software, gathering and soaking up information like a sponge!
haha
The learning curve is literally vertical, but after working with it since nov-2006 it's all starting to make sense.
Not only does the stock PCM calibration call for "buttloads of extra fuel", the stock PCM calibration also has a NEGATIVE 20 degrees of "tip in retard"..which is insane IMHO..
meaning everytime you tip into the throttle, from a stop.. or from a roll.. the PCM is pulling TWENTY DEGREES of timing out of the motor.
Just addressing these TWO areas in the tune goes ALONG way in "waking up the beast from within".
Let me drill a hole in my day and I'll post a screen capture of the stock first gen base fuel table as a jpeg.
stand by.
That IS for the first gen Mark 8.
I compared 93 stock PCM calibration to my 95 stock PCM calibration and the base fuel tables are identical.
My solution to this was the SCT PRO RACER software, it's not cheap.. but it is a "very very robust tool" compared to the other tuning solutions out there.
For an EEC IV car the SCT stuff cost me 1097.00 {I got raped by a dealer)
But you can get the same package for AROUND 900.00ish dollars.
That IS alot of money, but the changes in my fuel economy should offset this expense in about a year {with my amount of driving} HAHA.
For about the cost of setting up a rear end with gears, or purchasing a set of headers.. you can have 100% control of your cars PCM.
to date.. I still dont regret spending the money, and knowing what I know now.. I'd spend that money again in a HEARBEAT!
With that said... the SCT proracer package was the "best bang for the buck mod I have done on my car in over 300,000 miles.
*ends SCT commercial*
HAHA
I've heard good things about Sniper, seems to be a good product.
I went with SCT because of "who was behind the scenes" which was Jerry W.
I put over 250,000 miles on a "jerry w" chip and I really trust what he has done.
from what I have heard about sniper stuff, it seems just a little bit "hobbled".
There ARE alot of things you can do with the software, but I have seen two different people run into scenario's like you have.. it just doesnt seem to have the "ability or resolution of control" that "I" personally would want.
not saying bad things about sniper, those that have it.. LOVE IT.. and I cant argue with that kind of success.
FOR MYSELF.. I "wanted it ALL".. in front of me.
Granted.. having it ALL, meant that I had ALOT of learning to do.
Sniper seems more user friendly for beginners, I have to give it props where props are due.
I opened up the software and the actual value is .687 not .63..but..
14.67X.687=10.078 AF at WOT at 5000!! still way way FAT
I changed the resolution of my base fuel table to reach higher than .899 load and higher than 5000 RPM's.
stock base fuel table only goes to .899 load and 5K rpms.
46callaway
Registered
Well Sniper has two setups, the Special Forces which is simple and gives you the ability to change the most important stuff, MSRP $499, and then there is the Delta Forces software which lets you have 100% control of the PCM like the SCT pro racer. The MSRP for it is $749 but you can get it for as little as $629 if you search around. I've been using an SCT chip for many years in my 95 LSC and my 98 LSC and it did the job. The most important changes to the PCM that make the most difference in my opinion are 1. Leaning out the A/F ratio at WOT, removing the timing retard in between shifts, firming up the shifts. I was playing around with my tunes, I made a performance tune with 13.0 A/F at WOT, 4 degrees global timing advance, +2 in the lower rpm at WOT, +1.5 in the mid rpm and + 1 in the upper rpm, setting the shift firmness to "firm" and it pulled really hard and shifted fast but still nosed over between shifts because of the timing retard. I sent Matt at Sniper Tech my file and asked him to remove the timing retard in between shifts, it was a huge DIFFERENCE on the same tune I made.
were you using the 6600 sct chip?
the "eliminator chip" with the 4 position switch?
I have been trying to source out another chip blank so I can have one to put my new tunes on.. while leaving the old ones intact on the old chip.
That way.. I have a 100% quick and easy "undo" function without needing to reburn the chip..if that makes sense.
If that is the chip you were using.. what would you want for your old one.. or old ones..??
jus curious.
Blank chips are 200.00, which is more than I want to spend for this...obviously..haha
..still amazed at the cost of a BLANK CHIP...whew.
all the time I "thought" the cost was so high due to the tuners time spent getting the tune right.
After seeing how much the BLANKS cost..
I dont know HOW anyone makes ANY money tuning cars for people..
ESPECIALLY since there is so much BS involved when people have problems with their car.. and try to blame the "tune" for their issues...
the "eliminator chip" with the 4 position switch?
I have been trying to source out another chip blank so I can have one to put my new tunes on.. while leaving the old ones intact on the old chip.
That way.. I have a 100% quick and easy "undo" function without needing to reburn the chip..if that makes sense.
If that is the chip you were using.. what would you want for your old one.. or old ones..??
jus curious.
Blank chips are 200.00, which is more than I want to spend for this...obviously..haha
..still amazed at the cost of a BLANK CHIP...whew.
all the time I "thought" the cost was so high due to the tuners time spent getting the tune right.
After seeing how much the BLANKS cost..
I dont know HOW anyone makes ANY money tuning cars for people..
ESPECIALLY since there is so much BS involved when people have problems with their car.. and try to blame the "tune" for their issues...
46callaway
Registered
Sorry I sold it already, used the money towards the Sniper Special Forces. I know Sniper can program you a 6 position chip starting at $199 bucks. PM me for info if you are interested.
Question about Sniper.
Does it have a "stock calibration" included that you edit?
Meaning, can you compare the stock tune to your custom tune?
If so.. can you do a screen capture of the base fuel table for your 96?
I'm curious as to how "fat" the stock table is in the 96 PCM compared to the 93's 4's and 95's
I've seen 93,94 and 95 PCM's base fuel table in SCT...
kinda curious as to how the 96's are set up from the factory.
I'm not asking to see a "custom" file, just the stock base file...if that makes sense.
Does it have a "stock calibration" included that you edit?
Meaning, can you compare the stock tune to your custom tune?
If so.. can you do a screen capture of the base fuel table for your 96?
I'm curious as to how "fat" the stock table is in the 96 PCM compared to the 93's 4's and 95's
I've seen 93,94 and 95 PCM's base fuel table in SCT...
kinda curious as to how the 96's are set up from the factory.
I'm not asking to see a "custom" file, just the stock base file...if that makes sense.