Air to fuel ratio question

[BLKBULLITT]

I figured.

I'm gonna have the car on a hoist Friday so ill check the o2 sensor as well. Gauge must be off because the car runs solid under boost

 

[TurboX]

14 at no boost or 1-2 psi is probably fine, but NOT at 10

My old Lund Tune use to go above 14:1 under part throttle with way more than single digit boost numbers. I would be curious to hear from the experts but even my new tune is in the 13/14 range under part throttle and boost.

 

[BLKBULLITT]

Ill probably get a baseline dyno done to see what it's running just to be safe. I don't drive the car hard so should be ok (knock on wood)

 

[stkjock]

My old Lund Tune use to go above 14:1 under part throttle with way more than single digit boost numbers. I would be curious to hear from the experts but even my new tune is in the 13/14 range under part throttle and boost.

I'm not versed enough to say at what point it would become unsafe, other than WOT, however, part throttle is not going to give you much boost.

 

[ZmanM3]

Hmm, I just sent my Cobolt A/F guage back to autometer because the LED's in the display were going out. Never had any issues with it not reading correctly though. With my Brenspeed tune It hangs out between 14.7 - 15.3 and then when I get into boost it goes into the 11.2 - 11.5 range.

 

[stkjock]

Hmm, I just sent my Cobolt A/F guage back to autometer because the LED's in the display were going out. Never had any issues with it not reading correctly though. With my Brenspeed tune It hangs out between 14.7 - 15.3 and then when I get into boost it goes into the 11.2 - 11.5 range.

that sounds spot on. It could be a bit leaner by .1-.2 for a tad more power, but sounds like a solid and conservative target to me.

 

[ZmanM3]

Eh, I'm happy with the wiggle room and told Bren that when he was about to tune it. I know I probably left some on the table but I'm happy with the power and it seems that the older I get the more I like turning so 523 at the wheels works fine for me.

 

[lito]

My old Lund Tune use to go above 14:1 under part throttle with way more than single digit boost numbers. I would be curious to hear from the experts but even my new tune is in the 13/14 range under part throttle and boost.

I'm not versed enough to say at what point it would become unsafe, other than WOT, however, part throttle is not going to give you much boost.

The problem is that since early 2000s, GT calibrations commanded fuel is throttle position referenced, it was load based before and that was better for these kind of combos, the thing is that (with the turbos mostly) in certain high gear/load conditions they can pressurize the manifold even with very little throttle openings, so yes, your engine has the pressure you see, meanwhile timing is still load (and commanded fuel) based so this load (and fuel) will see not too much timing, but still get somehow hot due to big fills, this is usually corrected with sooner (throttle wise) switching to OL and some hacks to make it run a little richer during CL.

 

[muztangman93]

lmao I have no clue what lito said but that's the guy you wanna have take a look at your stuff.