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TXLIGHTNING
09-13-2010, 06:38 PM
I was wondering, what is a safe AFR for a built stage 2 longblock? My meter is reading in the high 11's.
Mark #2
09-13-2010, 08:01 PM
I was wondering, what is a safe AFR for a built stage 2 longblock? My meter is reading in the high 11's.
Depends on the gas and boost level, I would say mid 11s on 93 at 18psi, but lean is mean, I have run high 12s on a stock block at 18 psi with race gas, but probably not safe.
dboat
09-13-2010, 08:35 PM
Depends on the gas and boost level, I would say mid 11s on 93 at 18psi, but lean is mean, I have run high 12s on a stock block at 18 psi with race gas, but probably not safe.

at what air temps?

Dana
Mark #2
09-13-2010, 08:41 PM
at what air temps?

Dana
It doesn't matter AFR is AFR, just have to monitor as it gets cooler.
dboat
09-13-2010, 08:59 PM
It doesn't matter AFR is AFR, just have to monitor as it gets cooler.

you are correct..thanks

Dana
L8 APEX
09-14-2010, 06:28 AM
Remember the gauge is averaging at least 4 cylinders depending where it is located. There is usually a lean one or two in the motor that are higher than the average. Kind of like running 8 pyros to monitor each cylinder. Extended WOT running requires a richer tune with less timing. Stan martin who ran the 160 class in the Silver State Classic had a stage 2 engine de-tuned to 440hp so it would survive.
svtroky
09-14-2010, 07:21 AM
So do you all Guys think it will be better to run a dual ARF Gage for safety.
TXLIGHTNING
09-14-2010, 08:04 AM
Remember the gauge is averaging at least 4 cylinders depending where it is located. There is usually a lean one or two in the motor that are higher than the average. Kind of like running 8 pyros to monitor each cylinder. Extended WOT running requires a richer tune with less timing. Stan martin who ran the 160 class in the Silver State Classic had a stage 2 engine de-tuned to 440hp so it would survive. That's the answer I was looking for. I will add some fuel to the tune, say low 11's AFR. Thanks Terry :beer:
tiffo60
09-14-2010, 01:43 PM
That's the answer I was looking for. I will add some fuel to the tune, say low 11's AFR. Thanks Terry :beer:

Its not just about AFR, its timing too. and too rich can be just as bad as too lean.....

Everything in moderation:D
TXLIGHTNING
09-14-2010, 01:52 PM
Its not just about AFR, its timing too. and too rich can be just as bad as too lean.....

Everything in moderation:D 17# of boost, A/F now in the low 11's, and timing @ 14* for street tune :tu: