LT Tune Question

[El_Joker]

Have a question for anyone running LT's and A/F numbers you're seeing. I have a 2013 GT with a TVS (82mm) and 1 7/8" Kooks with a catted H. In traffic between shifts I am seeing A/F's dropping down to 11.5 or so from the dash gauge; sometimes even lower. This being normal acceleration mind you. I've had a few times at stops where it would just cause my engine to die.

I've talked with my tuner and they said everything was fine but it doesn't seem that way to me. When I was running just the 575 kit I had no problems of it dying or seeing go so rich, so would the addition of LT's change things that much or should I be looking for a new tuner? I've found raising my idle rpm's by 500 rpm helped it from dying. but it still surges like crazy when the A/F goes so rich under normal driving.

 

[Voltwings]

what size intake, sounds like the MAF may be losing resolution when you come off the throttle, do the rpms bounce when you clutch in and coast (assuming its an m6)? Are the LT's the only thing you've changed?

 

[El_Joker]

I started with the stock Roush 575 kit and the only changes since were from the 85mm to 82mm pulley, and most recently the LT's and catted H and a BAP. No other changes so whatever the stock size for TB and MAF...not sure of the numbers.

When I clutch in is when the RPM's dip, usually down to 500-600 and then it normally comes back to 700 or so and smooths out.

 

[mebcop]

I started with the stock Roush 575 kit and the only changes since were from the 85mm to 82mm pulley, and most recently the LT's and catted H and a BAP. No other changes so whatever the stock size for TB and MAF...not sure of the numbers.

When I clutch in is when the RPM's dip, usually down to 500-600 and then it normally comes back to 700 or so and smooths out.

What intake?

 

[El_Joker]

Stock Roush intake.

 

[Voltwings]

granted, its a different platform, ususally when we see this its the MAF losing resolution. Basically when you let off the air starts to swirl around the MAF and it gives it all kinds of funky readings, usually resulting in dipping idle and whacky AFRs. I would check installation, even an intake bouncing can cause airflow readings to be skewed, and since the intake had to come out to do the longtubes it is a possibility. I am not saying the issue is NOT the long tubes, i'm jsut stating what it sounds like in my experience.

 

['14 Shelby]

I can relate and have lived with this same problem for over a year. I don't DD mine tho. It does not stall everytime and its more frequent when the engine temp reads below 200*. I was advised by my installer that it was the tuner, the tuner said the installer (vacuum leak). So they finger pointed at each other and I'm left holding the bag of $h!T.
I had everything checked by a different shop for vacuum and pretty much ruled that out. I have the Rousch kit with JLT intake into a twin (65?) throttle body.
All of my engine mods were installed at the same time.

op:

 

[soldier0829]

Pretty sure I see mine dip in to the 11s when I let off the gas and come to a stop. I have a (VMP) TVS, 79mm, ARH LT's and catted x pipe.