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optimum AFR for power
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Author:  nomad [ Mon Oct 15, 2012 9:04 am ]
Post subject:  Re: optimum AFR for power

It's minutae, don't worry about it. Lean the main jets to what Barry suggested.

Author:  74 firebird461 [ Mon Oct 15, 2012 9:18 am ]
Post subject:  Re: optimum AFR for power

nomad wrote:
It's minutae, don't worry about it. Lean the main jets to what Barry suggested.


So 91's all the way around? Why don't I see what u guys are seeing when looking at the graph ,lol.I thought u want it to be a little rich around peak torque which it is then taper it off thru the run which to me it is in the graph. Looking at the graph I have about 5 seconds that it's above 13.0 after the first shift. If it's at 12.8 towards the end now. Wouldn't 3 jet sizes make it way too lean? I just reread my post, and i posted the barometer wrong it shouldv'e been 29.78 , not 27.78! sorry!

Author:  Beretta [ Mon Oct 15, 2012 10:03 am ]
Post subject:  Re: optimum AFR for power

Trial and error like we all said before.........It will tell you want it wants and likes... To rich and it will make a big swing in et when the air gets a bit better. After you find what it likes then you can adjust the MAB to lean it a bit on the top end by going
ONE size at a time equal front and rear..

Author:  Beretta [ Mon Oct 15, 2012 10:38 am ]
Post subject:  Re: optimum AFR for power

What I would do is make a couple passes just like it is to get a base line number and then do the jet change..If it picks up go down 2 more #'s...Remember stay in the same lane,very important...

Author:  74 firebird461 [ Mon Oct 15, 2012 10:59 am ]
Post subject:  Re: optimum AFR for power

Beretta wrote:
What I would do is make a couple passes just like it is to get a base line number and then do the jet change..If it picks up go down 2 more #'s...Remember stay in the same lane,very important...



Yea I totally hear what your saying on the jetting, I was just confused cause u and bruce both said it looked fat , and to me i couldn't see that,lol. Honestly i still don't =; . The weather this saturday looks to be about what it was yesterday maybe a tad better, but not sure if i was going to go, being a fun race and traction may be a issue, thought i may just end the season on yesterday's wins, and start the jetting early next season. I also know not to use the AFR as gospel, But Being all i had yesterday was two of the smaller 21.5 bleeds i put those in the secondary to least richen that up, and it slowed it down,The Log shows this also as being richer when i did that, so if anything I think I may end up near 92's. Least yesterday when the weather started to get better in the late afternoon my car started picking up which the normal was it would stay the same from the morning to afternoon even if air got better, so I think the jetting is probably close now. I also like the way the car runs with it squared instead of using a power valve, the only other thing i may change is to put plugs in the PVCR's to keep them from drawing from one another like Ken said. So Does the graph show where my convertor flashes too about? I forgot to calibrate to graph for rpm's still shows volt's I can do that when i get home. To me it looks like its around 4200 by looking at the volts?

Author:  shrinker [ Mon Oct 15, 2012 7:06 pm ]
Post subject:  Re: optimum AFR for power

With all this talk about if its fat or not, ---- What do the plugs look like? Thats what tells you whats going on in each cylinder.
Its not reading lean before the shift its during and after the shift its reading lean. thats normal.

Author:  74 firebird461 [ Mon Oct 15, 2012 9:36 pm ]
Post subject:  Re: optimum AFR for power

shrinker wrote:
With all this talk about if its fat or not, ---- What do the plugs look like? Thats what tells you whats going on in each cylinder.
Its not reading lean before the shift its during and after the shift its reading lean. thats normal.


I didn't pull any plugs, I will tho next yr on a test day in the spring.

Author:  shrinker [ Mon Oct 15, 2012 11:10 pm ]
Post subject:  Re: optimum AFR for power

You need to work by pulling plugs not looking at WB's.

Author:  74 firebird461 [ Tue Oct 16, 2012 5:26 am ]
Post subject:  Re: optimum AFR for power

i know , do u have pics of good plugs running pump gas ? i have seen pics on race gas

Author:  Scott Smith [ Tue Oct 16, 2012 5:43 am ]
Post subject:  Re: optimum AFR for power

Quote:
So Does the graph show where my convertor flashes too about? I forgot to calibrate to graph for rpm's still shows volt's I can do that when i get home. To me it looks like its around 4200 by looking at the volts?


It looks like it flashes to 10 volts. =; =;

I see the overall curve going slightly down hill which would require one MAB bigger to correct.

Author:  shrinker [ Tue Oct 16, 2012 5:46 am ]
Post subject:  Re: optimum AFR for power

74 firebird461 wrote:
i know , do u have pics of good plugs running pump gas ? i have seen pics on race gas

Pump gas is no different to race gas.

Author:  74 firebird461 [ Tue Oct 16, 2012 6:23 am ]
Post subject:  Re: optimum AFR for power

Scott Smith wrote:
Quote:
So Does the graph show where my convertor flashes too about? I forgot to calibrate to graph for rpm's still shows volt's I can do that when i get home. To me it looks like its around 4200 by looking at the volts?


It looks like it flashes to 10 volts. =; =;

I see the overall curve going slightly down hill which would require one MAB bigger to correct.


Funny Scott! =;, I did change the graph to rpm's and its right around that 4200 range if I am reading it right where it looks like it stops and then it starts pulling off the line to the shift of 6000. I will post another tonight. I am running .024's now, so 25's would be about perfect then according to the graph anyway's. So U want it a tad rich in the beginning, then lean out just a bit on the top end huh? I have heard that pontiac's like fuel thru the beginning and the middle, any truth to that?

Author:  74 firebird461 [ Tue Oct 16, 2012 6:24 am ]
Post subject:  Re: optimum AFR for power

shrinker wrote:
74 firebird461 wrote:
i know , do u have pics of good plugs running pump gas ? i have seen pics on race gas

Pump gas is no different to race gas.



Okay,thanks

Author:  Scott Smith [ Tue Oct 16, 2012 7:25 am ]
Post subject:  Re: optimum AFR for power

99% of the time on these recopies .026 is the magic number.
I'm moving to a .025 this week because my curve has a smiley face in it.

Yours is a frown face if you exaggerate it. =P~

Author:  74 firebird461 [ Tue Oct 16, 2012 7:55 am ]
Post subject:  Re: optimum AFR for power

Scott Smith wrote:
99% of the time on these recopies .026 is the magic number.
I'm moving to a .025 this week because my curve has a smiley face in it.

Yours is a frown face if you exaggerate it. =P~


I do have some .026's i made last week too.

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