KP Blown Fox tuning thread

Jun 8, 2016
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#1
I changed my oil last night and noticed a gas smell. I’m still working on the tune and iv been getting afr reading 10.1 at WOT around 10 psi could it be so fat that it’s washing the cylinders out or could it be a more serious issue?
 
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Jun 8, 2016
53
18
18
26
Maryland/Delaware
#3
Just a little back ground, my fule and ve tables should be good but the guy that did the tune has the mat correction table set up to add more fuel when IAT’s get above 210 which is anytime I’m in boost (I’m in the process of installing water meth to help with this) so I’m thinking that is the problem when I’m WOT. My target afr is set around 11.6 but I end up with 10.1 which is as low as my wideband will read so I’m think I’m could be even richer then that
 

a91what

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#5
What has occured here is that the guy that "tuned" your car is either a hack or does not understand the basic concepts of tuning a car. you never ever mess with the mat correction curve, it is based on the ideal gas law. unless he can redefine the laws of physics this is where he messed up. likely he did this to try and cover up some portion of the tune he did not understand or could not dial in.

EDIT- *maybe the above is a bit harsh but if you paid the guy to tune the car he should know better*

What tuning software? ECU? have a datalog and tune file?
 

a91what

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#6
Sorry to answer the first question about the fuel in oil.

The car is just running way too fat, anything below 11.5 is too much fuel unless you are trying to cool the cylinder off after a hard pull. (higher level tuning functions usually large boost applications 20psi++).
you will need to replace the plugs as they are likely carbon fouled.

here is a good read on how fuel affects a tune and power.

https://www.svtperformance.com/foru...arging-from-the-founder-of-kenne-bell.162486/
 
Jun 8, 2016
53
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Maryland/Delaware
#7
He tuned it that way as a safety feature due to very high intake temps. His heart was in the right place lol I’m running megasquirt I have tune files and data logs from a few passes at the track last year
 

a91what

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#8
He tuned it that way as a safety feature due to very high intake temps. His heart was in the right place lol I’m running megasquirt I have tune files and data logs from a few passes at the track last year
I understand completely, however he should have used the mat timing correction curve to pull timing under intense intake temps instead. This method will save the engine without loading the rings with fuel. You can actually cause alot of damage to the cylinder wall washing them down with fuel in a short amount of time.
I am going to move this to the Digital tuning forum for you, you can change the name of the thread if you like and i can help you get this sorted out.
 

a91what

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#10
no problem when you attatch the files be sure that the datalog matches the tune file that is posted with it.
@5.0Thunder thoughts on the subject?
 

stanglx2002

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#12
Just a little back ground, my fule and ve tables should be good but the guy that did the tune has the mat correction table set up to add more fuel when IAT’s get above 210 which is anytime I’m in boost (I’m in the process of installing water meth to help with this) so I’m thinking that is the problem when I’m WOT. My target afr is set around 11.6 but I end up with 10.1 which is as low as my wideband will read so I’m think I’m could be even richer then that
Thats the opposite of what is supposed to happen since the MAT Correction table is supposed to pull OUT fuel with increase of temperatures.
 

5.0Thunder

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Jan 31, 2018
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#13
@5.0Thunder thoughts on the subject?
You've covered every single thing I was going to mention.

-Way too much fuel at WOT, should be 11.5 or higher most times.
-Use MAT Timing curve to decrease timing when air temps increase rather than cooling with fuel (old alky tuning methods, never see it work well on gas).

Other things that can cause this are multiple short drives, especially where the engine doesn't get up to temp. Lots of cold start tuning and rich idle tuning can do this, though apparently this system has been ToOnEd so that shouldn't be an issue. The datalogs will tell all (which I'm unable to see at work).
 
Jun 8, 2016
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Maryland/Delaware
#14
cold start could use some fine tuning but its not bad idle is good and part throttle cruising all seem to be fine afr stays pretty stable around 14.8 the onluy place I have issues is WOT but now im concerned if the whole tune was done with correction in the mat table that is will throw everything else off
 

5.0Thunder

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Jan 31, 2018
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#15
It very well could be, again the datalog would probably show what's going on and how much it'd be affected.

as a side note, I usually see temp drops when going WOT with boost due to the heat soaked IAT sensor getting a nice rush of fresh air.
 
Jun 8, 2016
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Maryland/Delaware
#16
i have a GM style sensor located in the intake tube about 7 inches after the supercharger if that makes a difference. iv seen AIT in the 240 range on hot days
 

a91what

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#17
This is going to take a bit of work, let me do some serious math after i get home to see what can be done to correct the tune.

Basically i have to take the entire fuel algorithm and expose it then use your data and fill in the blanks replacing the current mat air density values with those from a proper air density curve.
It may take me a little bit to do this.
 
Jun 8, 2016
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Maryland/Delaware
#19
I appreciate your willingness to help. Go figure it’s going to be complicated that’s a going trend with everything I try to do lol
 

a91what

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#20
Damn, Steve. Pretty cool you're willing to take that on.
Its not as bad as my post made it out to be, really all i want to do is make sure that when i adjust the mat density correction back to where it should be his car does not go lean under boost. basically I want to verify his VE table values, once that is done i will know what i must do to correct the tune safely.