Those with longtubes chime in
12-25-2017, 05:08 PM
#1
Super Member
Thread Starter
Those with longtubes chime in
Ok i have a weird question ... I have just changed to MBH headers and love the sound and power they offer .... now i have just one weird thing going on.
So I have an AEM AFR gauge in the car and i installed it in the drivers side as I had it before and before the headers i would read 14.6 to 14.8 usually pretty steady at 14.6 cruising and since i changed so has my readings. Now it will fluctuate between 14.2 to 15.0 at idle lil more steady 14.4 to 14.8 and cruising it fluctuates between the 14.2 to 15.2 idle is rock steady, no codes, and when i come to a stop usually goes to 12.7 and then leans out to 14.6 not like it stays rich. I will also note that I eliminated all 4 cats at the same time but will be adding 200 cell race cats in a month or so. So just want to know if that fluctuating is normal car runs amazing and under wot the car is steady 12.6 down low and goes too a 11.8 and by redline is 11.6 ... very close to perfect. Dont know if theres something possibly wrong with my wide band or what I dont know if its cus now ea cylinder is feeding and scavaging causing weird readings
So I have an AEM AFR gauge in the car and i installed it in the drivers side as I had it before and before the headers i would read 14.6 to 14.8 usually pretty steady at 14.6 cruising and since i changed so has my readings. Now it will fluctuate between 14.2 to 15.0 at idle lil more steady 14.4 to 14.8 and cruising it fluctuates between the 14.2 to 15.2 idle is rock steady, no codes, and when i come to a stop usually goes to 12.7 and then leans out to 14.6 not like it stays rich. I will also note that I eliminated all 4 cats at the same time but will be adding 200 cell race cats in a month or so. So just want to know if that fluctuating is normal car runs amazing and under wot the car is steady 12.6 down low and goes too a 11.8 and by redline is 11.6 ... very close to perfect. Dont know if theres something possibly wrong with my wide band or what I dont know if its cus now ea cylinder is feeding and scavaging causing weird readings
12-25-2017, 09:22 PM
#3
Super Member
Thread Starter
i have torque pro an monitored the drive today i may have to check it out to see how it looked but i figure its ok or id have some kind of check engine code by now.
12-25-2017, 10:39 PM
#5
Super Member
Thread Starter
yeah the o2 is in another spot an cats are gone .... but its not hurtin anything an anthony will be coming to colorado soon i hear so ill drive up there an get street tuned 😁
12-27-2017, 11:18 AM
#7
Super Member
+1 on the new location of your O2 wideband sensors as the cause . Assuming your AEM sensor is in the forward bung and the stock sensor is in the rearward bung, the aem is sampling mostly off one cylinder so you will see that much variance as the pulses go over the aem sensor. You're AFR actually seam great to me assuming your IAT is in check as that's what I'm personally shooting for with my next tune with Tony.
On my headers, my wideband sensors for both banks sample heavily off one cylinder each and see about +/- 0.3 at idle and cruise where exhaust velocity is slow..I kept the stock O2s in the rearward bungs so they see the pulses from all 4 cylinders . At part or full throttle, I get very steady readings as the gases flow past the wideband more evenly.
On my headers, my wideband sensors for both banks sample heavily off one cylinder each and see about +/- 0.3 at idle and cruise where exhaust velocity is slow..I kept the stock O2s in the rearward bungs so they see the pulses from all 4 cylinders . At part or full throttle, I get very steady readings as the gases flow past the wideband more evenly.
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12-27-2017, 01:13 PM
#8
Super Member
Thread Starter
+1 on the new location of your O2 wideband sensors as the cause . Assuming your AEM sensor is in the forward bung and the stock sensor is in the rearward bung, the aem is sampling mostly off one cylinder so you will see that much variance as the pulses go over the aem sensor. You're AFR actually seam great to me assuming your IAT is in check as that's what I'm personally shooting for with my next tune with Tony.
On my headers, my wideband sensors for both banks sample heavily off one cylinder each and see about +/- 0.3 at idle and cruise where exhaust velocity is slow..I kept the stock O2s in the rearward bungs so they see the pulses from all 4 cylinders . At part or full throttle, I get very steady readings as the gases flow past the wideband more evenly.
On my headers, my wideband sensors for both banks sample heavily off one cylinder each and see about +/- 0.3 at idle and cruise where exhaust velocity is slow..I kept the stock O2s in the rearward bungs so they see the pulses from all 4 cylinders . At part or full throttle, I get very steady readings as the gases flow past the wideband more evenly.
