Predator tuning for headers
03-11-2004, 11:43 AM
#1
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Join Date: Feb 2002
Location: Albuquerque, NM
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Predator tuning for headers Hello all,
I recently installed headers and a very free flowing catback. I went out to tune the AFR and what I found was incredable.
Predator PE settings before headers:
+5%
Predator O2 readings before headers:
890 millivolts
Ok, after the header/catback install I went out to get some readings on the O2 sensors. Here's what they read:
990 millivolts
I expected to be rich, but that reading suprised me.
So far, I've made several corrections to the PE setting. Here's what it is currently and also the O2 sensor readings.
PE: -.50
O2: 935 millivolts (still rich!!
)
I'm going to continue to lean out the PE setting, but do headers really make this much of a difference???
For a list of mods follow this link and go to my car page. It has everything save the headers and exhaust.
I recently installed headers and a very free flowing catback. I went out to tune the AFR and what I found was incredable.
Predator PE settings before headers:
+5%
Predator O2 readings before headers:
890 millivolts
Ok, after the header/catback install I went out to get some readings on the O2 sensors. Here's what they read:
990 millivolts
I expected to be rich, but that reading suprised me.
So far, I've made several corrections to the PE setting. Here's what it is currently and also the O2 sensor readings.
PE: -.50
O2: 935 millivolts (still rich!!
)I'm going to continue to lean out the PE setting, but do headers really make this much of a difference???
For a list of mods follow this link and go to my car page. It has everything save the headers and exhaust.
03-11-2004, 10:42 PM
#3
Sorry I use LS1edit only so I'm not familiar with Predator tuning. But I'll tell you this much: you shouldn't be messing with your WOT mixture (PE) unless you have a wideband O2 meter. Those millivolt readings you're getting from the factory O2s are inaccurate at best and missleading at worst.
Another thing is, the headers you installed are unlikely to have made the engine run rich at full throttle. Any richness would be at idle and very low rpm. This is because headers increase the volumetric efficiency at high rpm, and decrease VE at low rpm. So if anything, the headers made it leaner at high rpm. See why you shouldn't be changing your PE? The truth is the engine is probably running very close to the same AFR at WOT now as it was before the headers.
Another thing is, the headers you installed are unlikely to have made the engine run rich at full throttle. Any richness would be at idle and very low rpm. This is because headers increase the volumetric efficiency at high rpm, and decrease VE at low rpm. So if anything, the headers made it leaner at high rpm. See why you shouldn't be changing your PE? The truth is the engine is probably running very close to the same AFR at WOT now as it was before the headers.
