What is too lean?
Drifting
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From: Shawano WI
Re: What is too lean? (Matt Gruber)
The EGT on that cylinder peaked at 1452°. The A/F had a maximum of 14.27.
A piece of gasket material had gotten into the main circuit that feeds the the boosters, causing the right primary booster to go lean. The piston was in the #4 cylinder.
When I tried O² sensors they were mounted in blocks that sandwiched between the headers and the cylinder head. The main problem is that they did not read accurately. For example if you had a sensor in the #1 cylinder that read a lean condition and a sensor in #2 cylinder that read a rich conditon and then swap those to sensors around they would then show that #2 was lean and #1 was rich. So the end results were that they were not reliable enough to give any usable data.
Again I stress that this is on race motors were accuracy and repeatability is extemely important. On street motors I am sure they work fine.
Pete
A piece of gasket material had gotten into the main circuit that feeds the the boosters, causing the right primary booster to go lean. The piston was in the #4 cylinder.
When I tried O² sensors they were mounted in blocks that sandwiched between the headers and the cylinder head. The main problem is that they did not read accurately. For example if you had a sensor in the #1 cylinder that read a lean condition and a sensor in #2 cylinder that read a rich conditon and then swap those to sensors around they would then show that #2 was lean and #1 was rich. So the end results were that they were not reliable enough to give any usable data.
Again I stress that this is on race motors were accuracy and repeatability is extemely important. On street motors I am sure they work fine.
Pete
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From: central FL, near the beach.
Re: What is too lean? (Pete79L82)
I'm afraid you hit the nail on the head! I was looking thu my notes and i see the opposite side of my 61 is lean compared to my 72! Both have dual planes, the 72 is a weiand 8004, and the 61 a 2101. i don't see how they could be OPPOSITE! it has to be the 2 sensors! Now i will have to calibrate both of them. I would say it's like if you have 2 torque wrenches and they are off, you don't say torque wrenches are no good, you calibrate them(might pick up some used sensors and pick out the best ones). But, i didn't know they could be calibrated until 2 days ago when i read it in Vizards book! Learn something new every day! :cheers:
on that motor with the holed piston, was that A/F ratio an average of all 8 cyl?
[Modified by Matt Gruber, 7:16 AM 6/12/2003]
on that motor with the holed piston, was that A/F ratio an average of all 8 cyl?
[Modified by Matt Gruber, 7:16 AM 6/12/2003]
Thread Starter
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Joined: Oct 2000
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From: central FL, near the beach.
Re: What is too lean? (Matt Gruber)
i couldn't take the suspense any longer so i switched my 2 o2 sensors. It would have been nice if they were it, but readings at WOT are the SAME :cry Either i wrote my figures down reversed(unlikely) or the 8004 flows quite different than a 2101.(there is a huge plenum difference) I did spend 2 hours equalizing the runner size on the 8004, the 2101 was not even checked(done years before).
There is a difference in my mount, 1 is about 6" from the head, the other 2".
Still need to try to calibrate. i hope there is a visable flame 2" out of the head at 1500-2500 rpm in neutral. if not i will need a colortune. :skep:
There is a difference in my mount, 1 is about 6" from the head, the other 2".
Still need to try to calibrate. i hope there is a visable flame 2" out of the head at 1500-2500 rpm in neutral. if not i will need a colortune. :skep:
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From: central FL, near the beach.
Re: What is too lean?
Pete
i get instant o2 reading;
as i adjust the throttle i can see mixture changes as they occur. i can see when it gets a poor pump shot as it goes lean and it stumbles.
i can see it instantly transition off the idle circuit to the main jet when i crack the throttle.
the only time there is a delay is when the sensor cools off, it takes afew seconds to warm it up on a cold start, by the time i back out of the garage it is warmed.
When i started tuning it was very rich, 12.5 or less:, and it is cool due to excessive fuel. That is the only time i can think of that would cause a delay. This might be what happened on your dyno? Or, you got BAD sensors?. i had a problem with bad grounds once(now i run seperate ground wires)! what kind of gauge did you use? Could there have been an exhaust leak? Very wierd, your experience :confused:
are you using race gas with lead?
[Modified by Matt Gruber, 11:51 AM 6/12/2003]
i get instant o2 reading;
as i adjust the throttle i can see mixture changes as they occur. i can see when it gets a poor pump shot as it goes lean and it stumbles.
i can see it instantly transition off the idle circuit to the main jet when i crack the throttle.
the only time there is a delay is when the sensor cools off, it takes afew seconds to warm it up on a cold start, by the time i back out of the garage it is warmed.
When i started tuning it was very rich, 12.5 or less:, and it is cool due to excessive fuel. That is the only time i can think of that would cause a delay. This might be what happened on your dyno? Or, you got BAD sensors?. i had a problem with bad grounds once(now i run seperate ground wires)! what kind of gauge did you use? Could there have been an exhaust leak? Very wierd, your experience :confused:
are you using race gas with lead?
[Modified by Matt Gruber, 11:51 AM 6/12/2003]
Thread Starter
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From: central FL, near the beach.
Re: What is too lean? (Matt Gruber)
and now the calibration attempt WITHOUT a colortune:
i took out the #5 o2 sensor and started it. you know how a small exhaust leak sounds like a lifter tap, well this sounded like a ROD KNOCK :eek:
got a weak blue flame, the only way i could get yellow was to crack the throttle open far and fast, then upon closing it it backfired and flashed yellow.
any steady speed from idle up showed blue.
i had expected to find a white spot, but the white elephant was nowhere in the jungle.
if i was in the tuning busines i would get a colortune. But, since my sensors are equal, i suspect they are pretty close, based on the plug color and gauge readings thus far.
However, if somebody lends me a colortune, i will certainly try it out.
i took out the #5 o2 sensor and started it. you know how a small exhaust leak sounds like a lifter tap, well this sounded like a ROD KNOCK :eek:
got a weak blue flame, the only way i could get yellow was to crack the throttle open far and fast, then upon closing it it backfired and flashed yellow.
any steady speed from idle up showed blue.
i had expected to find a white spot, but the white elephant was nowhere in the jungle.
if i was in the tuning busines i would get a colortune. But, since my sensors are equal, i suspect they are pretty close, based on the plug color and gauge readings thus far.
However, if somebody lends me a colortune, i will certainly try it out.
Thread Starter
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Joined: Oct 2000
Posts: 14,994
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From: central FL, near the beach.
Re: What is too lean? (Lasse)
Lasse
i've added your DYI gauge kit link to my A/F article.(in my profile link)
it has the A/F ratio for each voltage, many others don't :cool:
thanks!
.
Pete
according to 427V8 your gauge probably has a capacitor which slows the gauge. Like a gas gauge does not show every slosh, but takes a slow average. Remove the capacitor for instant response like i have with the Racer Wholesale AUT-9901 gauge :cool:
[Modified by Matt Gruber, 8:36 AM 6/13/2003]
i've added your DYI gauge kit link to my A/F article.(in my profile link)
it has the A/F ratio for each voltage, many others don't :cool:
thanks!
.
Pete
according to 427V8 your gauge probably has a capacitor which slows the gauge. Like a gas gauge does not show every slosh, but takes a slow average. Remove the capacitor for instant response like i have with the Racer Wholesale AUT-9901 gauge :cool:
[Modified by Matt Gruber, 8:36 AM 6/13/2003]
