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AF ratio/plug question
Thread Starter
Instructor
Joined: Jun 2008
Posts: 209
Likes: 1
From: NY
AF ratio/plug question
Guys,
Here is a 'log' of my TT ZO6 at 12psi, with meth injection. The plugs come out looking IDENTICAL to brand new plugs right out of the box with no signs of detonation, etc and the engine compression is solid at 155psi across the board. The 'lean' spot from 4500-4900 initally scared me, but the builder assured me it was fine. Just curious what you all think and if you guys' plugs look similar to mine. This is on a forged shortblock with dart heads BTW.
Thanks
Travis
4000rpm-11.9
4100-11.7
4200 11.2
4300 11.2
4400 11.8
4500 12.5
4600 12.4
4700 12.5
4800 12.4
4900 12.4
5000 12.1
5100 12.2
5200 12.1
5300 12.1
5400 12.2
5500 12.0
5600 11.9
5700 11.8
5800 11.8
5900 11.8
6000 11.8
6100 12.0
6200 11.6
6300 11.7
6400 11.5
6500 11.2
6600 11.2
Here is a 'log' of my TT ZO6 at 12psi, with meth injection. The plugs come out looking IDENTICAL to brand new plugs right out of the box with no signs of detonation, etc and the engine compression is solid at 155psi across the board. The 'lean' spot from 4500-4900 initally scared me, but the builder assured me it was fine. Just curious what you all think and if you guys' plugs look similar to mine. This is on a forged shortblock with dart heads BTW.
Thanks
Travis
4000rpm-11.9
4100-11.7
4200 11.2
4300 11.2
4400 11.8
4500 12.5
4600 12.4
4700 12.5
4800 12.4
4900 12.4
5000 12.1
5100 12.2
5200 12.1
5300 12.1
5400 12.2
5500 12.0
5600 11.9
5700 11.8
5800 11.8
5900 11.8
6000 11.8
6100 12.0
6200 11.6
6300 11.7
6400 11.5
6500 11.2
6600 11.2
Melting Slicks
Joined: Sep 2005
Posts: 3,082
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From: eagle mountain utah
Melting Slicks
Joined: Mar 2003
Posts: 3,116
Likes: 10
From: Macomb MI
What gear what this pull done in and what conditions? What is the data derived from, built in wideband or?What is the average airfuel at cruising? That would give me some back ground as to what that info really means. Passing judgement on this info without the requisite background information is futile.
Thread Starter
Instructor
Joined: Jun 2008
Posts: 209
Likes: 1
From: NY
What gear what this pull done in and what conditions? What is the data derived from, built in wideband or?What is the average airfuel at cruising? That would give me some back ground as to what that info really means. Passing judgement on this info without the requisite background information is futile.
This was in 3rd gear @WOT using FJO datalogging software. Last night I turned up the boost to 13psi and it got slightly richer but it's still in the low 12's in spots.
Melting Slicks
Joined: Mar 2003
Posts: 3,116
Likes: 10
From: Macomb MI
I would pull it from 3500 through that area in question in 4th gear. I think you will find its fine. Also look at idle/steady state cruise airfuel. Often there is an offset in readings one way or another that needs to be taken into account.
Former Vendor
Joined: Feb 2004
Posts: 10,876
Likes: 8
From: Las Vegas NV
St. Jude Donor '06 & '12
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Thread Starter
Instructor
Joined: Jun 2008
Posts: 209
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From: NY
The car cruises at 14.7. I'm going to play it extra safe and get the car retuned to low 11's just so I have a wide safety margin for climate/altitude changes, etc.
Thread Starter
Instructor
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From: NY
Travis
Thread Starter
Instructor
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From: NY
Former Vendor
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Burning Brakes
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From: MARRIOTTSVILLE MD
Race Director
Joined: Dec 1999
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From: Alexandria, Virginia, USA VA
Help Me Obe Wan, you are my only hope
the type of wideband and location as well as other factors can throw off the readings. the most accurate is up front generally
Phil does a great job tuning!