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#1
09-26-2020, 07:05 PM
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Air Fuel reading?
Ok, so I went to the 1/4 mi. track last Thursday, Car ran ok, about what i expected with the weather. ( hot and sticky) I cleaned my O2 sensors earlier in the week so I could log the reading and see whats happening as I pull down the track. It stays lean through the staging but immediately shoots to rich. Stays in the low 9s on the meter through low, goes up to flashing between high 9s to low 10s until high where it stay low 11s on the FAST air fuel meter. What are you all seeing for "good" numbers. I think I should be shooting for 13.5 to 13 reading. FYI its a N/A combo if that makes any difference.
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#2
09-26-2020, 07:14 PM
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As a point of reference, my engine does best around 12.8 at the track, and on the chassis dyno, best power was around 12.8 to 13, but there could be a little difference in my o2 sendor vs the tailpipe sensor.
Sent from my SM-G965U using Tapatalk
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68 Firebird-- Street/Strip - 400/461 Eagle Forged Bottom End & Ross Flat top pistons. KRE 325 CFM D port, Ultradyne 263/271 @.050, .4267 lift. Crower Solid roller lifters and 1.65 stainless rockers. Quickfuel 1000 on Torker2 intake and 2" open spacer. Hedman 1.75" headers. TH400 w/brake. Ford 9" w/3.80 gears & 28x9 Hoosier pro bracket drag radial. Best ET: 1.35 60ft, 6.29 @ 107.20 mph, 9.99 @132.33 mph. 3,300 race weight |
| The Following User Says Thank You to leeklm For This Useful Post: | ||
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#3
09-26-2020, 08:05 PM
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Good to know. I wish i would have brought my jet kit to the track but I made the decision to go at thw last minute and didnt bring any thing with me.
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#4
09-27-2020, 07:40 AM
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I concur with the 12.8 number that leeklm says works best for his combo. Probably anything in the 12.5 to 12.8 is going to be close. We played around with jetting on Curtis' car and found that richer than 12.5 didn't help and over 13.0 car started to slow down.
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69 Bird w/1970 400 block(409 cubes), #64 heads, hyd. roller, Q-jet by Jeff E., original interior, ps, pdb, th350, and 3.73 gears. Pump gas, street driven muscle. 3800 lbs. race weight. Best, 11.39 @118, my son's car. 79 T/A w/463, Scat crank, Eagle rods, Icon pistons, Lunati solid roller, 262/270, KRE 325 heads, Northwind intake, QF950 carb, full interior, ps, pdb, th350, and 3.73 gears. Pump gas, 3650 lbs. race weight. 10.68 @ 126 so far... no tuning yet. |
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#5
09-27-2020, 07:59 AM
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Scott,
You cleaned your sensor? I usually buy a new one... After a run did you pop some plugs out to see if it confirms what wideband showed?
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Carburetor building & modification services Servicing the Pontiac community over 20 years |
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#6
09-27-2020, 02:59 PM
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I did not pull a plug. I clean the sensors a few times with some carb cleaner before replacing them. I will bring a plug wrench next time when i go to do some jetting.
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#7
09-28-2020, 05:42 AM
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Do your sensors require a free air calibration?.
If so I would do so, and re test
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Working on going faster (and now staying dry at the same time !!) |
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