For those with forced induction installed....

[Speedy1975]

How are part throttle boost situations handled from an AFR perspective?

[ZZcamaro]

Originally Posted by Speedy1975

How are part throttle boost situations handled from an AFR perspective?

I believe that most people with a custom tune and automatics have the AFM turned off....I could be wrong, but that is what most people whom I have talkd to are doing. I am not sure exactly what the base tune file from Magna does with it.

[lawdogg149]

The cars are mass air tuned.

[old motorhead]

LS3 with TVS here. AFR's are still around 14.5 to 1 under mild boost. As boost grows, AFR's richen up to around 11.5 to 1. At cruise, they are around 15 to 1. Hope this is what you're asking. If not please clarify.

[Speedy1975]

Originally Posted by old motorhead

LS3 with TVS here. AFR's are still around 14.5 to 1 under mild boost. As boost grows, AFR's richen up to around 11.5 to 1. At cruise, they are around 15 to 1. Hope this is what you're asking. If not please clarify.

Yep, that's getting to what my question is about.

Under mild boost, 14.7:1 wouldn't be too safe in my eyes. I supercharged my 4Runner and was able to tune "closed loop" to richen up at boost comes on. So at mild boost my AFR drops gradually from 14.7:1 down to say 14:1 at 1psi and 13.8 at 2psi, 13.2 at 5psi etc. Then when I really get in to it and the ECM switches to open loop it goes to 11.5 - 11.8.

I was just wondering if the Camaro was able to have it's AFR (air fuel ratios) adjusted like that in closed loop and "mild boost" as you put it.

So say you just ease into the throttle to about 30-40% and boost climbs up to 5 or 6 psi as in easing away from a red light, but you're not flooring it....what does the AFR do?

[2Tightwads]

Originally Posted by Speedy1975

Yep, that's getting to what my question is about.

Under mild boost, 14.7:1 wouldn't be too safe in my eyes. I supercharged my 4Runner and was able to tune "closed loop" to richen up at boost comes on. So at mild boost my AFR drops gradually from 14.7:1 down to say 14:1 at 1psi and 13.8 at 2psi, 13.2 at 5psi etc. Then when I really get in to it and the ECM switches to open loop it goes to 11.5 - 11.8.

I was just wondering if the Camaro was able to have it's AFR (air fuel ratios) adjusted like that in closed loop and "mild boost" as you put it.

So say you just ease into the throttle to about 30-40% and boost climbs up to 5 or 6 psi as in easing away from a red light, but you're not flooring it....what does the AFR do?

You can change the % Throttle Position when PE (Power Enrichment) will kick in. For example: Basically go from a 14.7 to 12.5 sooner at say 30% throttle instead of factory 50+% throttle. There are also custom operating systems available for some GM models that you can add BE (Boost Enrichment) which is a seperate fueling table that allows you the option of leaving your naturally aspired PE table alone and using the BE table for when boosts starts...

[Speedy1975]

Originally Posted by 2Tightwads

You can change the % Throttle Position when PE (Power Enrichment) will kick in. For example: Basically go from a 14.7 to 12.5 sooner at say 30% throttle instead of factory 50+% throttle. There are also custom operating systems available for some GM models that you can add BE (Boost Enrichment) which is a seperate fueling table that allows you the option of leaving your naturally aspired PE table alone and using the BE table for when boosts starts...

Those both sound like good solutions. I'm just curious for all these folks getting blowers are the tunes going with them performing these changes?

[1meanss]

It's magic like information technology!

[Speedy1975]

Originally Posted by 1meanss

It's magic like information technology!

Haha, I work in IT, so I know better than that!

[old motorhead]

[QUOTE=Speedy1975;1112440]Yep, that's getting to what my question is about.

Under mild boost, 14.7:1 wouldn't be too safe in my eyes.

Damn, guess I'm living on borrowed time. My supercharged truck has been like that for probably 40,000 miles. HMMMM. TVS charged vette has been that way for 5K miles. Both get into boost with very little throttle pressure. By low boost, I'm meaning just going from vacuum to boost easily and gradually at low rpm. If I'm more aggressive and RPM's are higher, AFR gets to 11.5 in a hurry. The guy that does my tuning has tuned more than a few. He's literally tuned vehicles mail order all over the world. As well as in his shop on the dyno and on the street. I'm going to go out on a limb and say he knows what he's doing. I'm pretty confident that my tunes are safe.

[Speedy1975]

[QUOTE=old motorhead;1113567]

Originally Posted by Speedy1975

Yep, that's getting to what my question is about.

Under mild boost, 14.7:1 wouldn't be too safe in my eyes.

Damn, guess I'm living on borrowed time. My supercharged truck has been like that for probably 40,000 miles. HMMMM. TVS charged vette has been that way for 5K miles. Both get into boost with very little throttle pressure. By low boost, I'm meaning just going from vacuum to boost easily and gradually at low rpm. If I'm more aggressive and RPM's are higher, AFR gets to 11.5 in a hurry. The guy that does my tuning has tuned more than a few. He's literally tuned vehicles mail order all over the world. As well as in his shop on the dyno and on the street. I'm going to go out on a limb and say he knows what he's doing. I'm pretty confident that my tunes are safe.

So if you stay at 30% throttle at say 3-5psi does your AFR stay at 14.7:1? As in daily driving and say your driving up a mountain and you have to stay at that throttle position and subsequently in boost for an extended period of time?

That's what I'm referring to. I don't wanna get in to an argument about it, I'm just curious how the Camaro with a blower reacts to part throttle boost. You can decide what's safe for you, and I'll decide what's safe for me. 14.7:1 at 3psi won't be good enough for me. It should be in the low 13s or better by that point.

[old motorhead]

[QUOTE=Speedy1975;1113615]

Originally Posted by old motorhead

So if you stay at 30% throttle at say 3-5psi does your AFR stay at 14.7:1? As in daily driving and say your driving up a mountain and you have to stay at that throttle position and subsequently in boost for an extended period of time?

That's what I'm referring to. I don't wanna get in to an argument about it, I'm just curious how the Camaro with a blower reacts to part throttle boost. You can decide what's safe for you, and I'll decide what's safe for me. 14.7:1 at 3psi won't be good enough for me. It should be in the low 13s or better by that point.

Never said 14.7 at 3psi. I'm sorry if my post came across that way. I'm about 14.5 going from vacuum to just getting into boost at low rpm. That's my idea of "mild" boost. By 3psi, I'm way richer. Maybe 12.5 to 13. 3psi on my vette is hoofin' it pretty good.

[Speedy1975]

[QUOTE=old motorhead;1113724]

Originally Posted by Speedy1975

Never said 14.7 at 3psi. I'm sorry if my post came across that way. I'm about 14.5 going from vacuum to just getting into boost at low rpm. That's my idea of "mild" boost. By 3psi, I'm way richer. Maybe 12.5 to 13. 3psi on my vette is hoofin' it pretty good.

That's more like it. So I guess they are adjusting closed loop fueling somehow.

I was looking at supercharging my Challenger, but I'm learning there are limits to how much closed loop fueling can be adjusted to compensate for part throttle boost and it's a big issue. I was curious if the Camaro had an easier time of it.

[matt55]

a lil OT
in my car
Vac-0psi = 14.7 (open loop to closed loop)
as soon as boost comes = 13.5
26/27psi =11.0-11.3
I have a knock light and watch it all the time .