Wouldn't turn COT off if it still has cats. The extra fuel keeps them from burning up while towing.

 

Truth.

 

OK, I spent about 20mins on the phone with my tuner. We were talking about LS swaps and my C5 and supercharging vs turbocharging the Tahoe and yeah; you know how it goes

I am running 29 degrees near redline, and 24-25 through most of the peak torque range. He estimated peak torque was about 3200rpm. 91 octane, 5.3, full exhaust, no cats. We didn't spend any time talking about idle or EOIT. Although, my truck has 0 idle issues and the only reason for EOIT changes (imo) is to lessen the smell of the exhaust. The last datalog he has for me was when we were messing with stuff to pull the racecar to LS Fest 2018 and it puts me at 12.5 at the end of a pull, no cats, wideband installed ~6" behind the merge in the Y-pipe

I did tell him about this thread and he brought up a good point, that the 4.8 in question may not be able to evacuate gases very efficiently and therefore can't get a lot of timing into it

 

Exhaust gas is inert to the combustion...so it requires more spark, not less.

 

if fresh air can't fill the chamber, what is more spark gonna combust? If the charge is preheated, due to an inadequately evacuated chamber, wouldn't more spark risk detonation?

How do OEMs program EGR strategies? I guess my answer is there lol. Do they advance or retard based on EGR open/closed?

 

More exhaust dilution equals a slower burn which equals more timing. Regardless if it is cam overlap or EGR the timing needs to be advanced for more exhaust in the mix.

 

Yea i see that tune does need quite a bit of work.
Wondering about the torque limit settings and the WOT shift RPMs and quite a few other things.

 

It's a good I'm not a tuner, clearly

 

Might wanna forward that tip on to your tooner as well

 

Its entirely possible I misunderstood what he was trying to say. I have no reservations or doubts about my tuner or his abilities. What I love most about him is I bring him a project and the first thing he asks me is "peak power or safe" and for most things I pick safe

He has several records in the Honda and 2JZ community and everything he has done for me has worked in all conditions, never left me stranded, never blown up and drives smooth as butter. I'll keep going to him, even if I don't always understand what he's trying to explain

https://sqctuning.com/