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Discussion Starter #1
So I gots me a new toy to tune my carb in better but I don't know what to do next. Engine is a ZZ383 w/MSD Ign & 670 Avenger Carb.

I installed an AEM wideband and took out for a trial run and noticed the following:

On avg. running in the low 14:1 range.

In 4th gear (TKO 600) at steady cruise I can start seeing low 15:1 and for rare instances goes up to 16:3. I'm guessing that maybe this is saying my primary jets may need to be larger. (I live at 5,500ft. above sea lvl. and reduced all jets by 2 sizes from stock).

When I mash the pedal it drops to around 12.5 - 13.5:1 range and stays there fairly steady while the pedal is on the floor and going through the gears.

I suppose I would like some feedback based on others experience about:

1. What is the ideal air/fuel ratio for good power?
2. What is considered too lean?
3. What is considered too rich?
4. What other type of info. should I be looking for
5. What have you adusted (primaries, secondaries, etc) to address your tuning needs to achieve an ideal air/fuel ratio accross the spectrum?

Any tips, ideas, links on how to tune this way would be greatly appreciated. :thumbsup:
 

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You are darn near dead on the money. Full throttle might be the slightest lean
you want about 12, and med cruise 14+ , at od 15 is great. I wouldn't change a thing.
 

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Discussion Starter #5
What wide band O2 do you have?
Im asking because thinking of putting one in myself.

It's an AEM and was recently on special at Jegs for $225. Can't think of model # but came with all I needed for the install & also had various options to change the bezel and color of the gauge face.
 

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Discussion Starter #6
You are darn near dead on the money. Full throttle might be the slightest lean
you want about 12, and med cruise 14+ , at od 15 is great. I wouldn't change a thing.

Shoot - don't tell me that - you mean I'm done, no more changing jets, etc? Seriously - good to know I'm well within the ballpark and thanks for taking the time to respond.
 

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Your basic #'s are, as John said, very very nice.

As far as "what's good" tho, that's a tough one. "too lean at cruise" is where you start to surge, or ping when some load comes on.

Just right @ WOT is where you get your best MPH, assuming you can leave consistently, the d/a is decent, etc etc.

In between is where a lot of the more involved playing comes in.
Try this...
At cruise, say 2.5k in 4rth, slowly lean into the throttle and watch your vacuum gauge and wideband, you should be able to see the powervalve open. Is it where it needs to be?
 

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So I gots me a new toy to tune my carb in better but I don't know what to do next. Engine is a ZZ383 w/MSD Ign & 670 Avenger Carb.

I installed an AEM wideband and took out for a trial run and noticed the following:

On avg. running in the low 14:1 range.

In 4th gear (TKO 600) at steady cruise I can start seeing low 15:1 and for rare instances goes up to 16:3. I'm guessing that maybe this is saying my primary jets may need to be larger. (I live at 5,500ft. above sea lvl. and reduced all jets by 2 sizes from stock).

When I mash the pedal it drops to around 12.5 - 13.5:1 range and stays there fairly steady while the pedal is on the floor and going through the gears.

I suppose I would like some feedback based on others experience about:

1. What is the ideal air/fuel ratio for good power?
2. What is considered too lean?
3. What is considered too rich?
4. What other type of info. should I be looking for
5. What have you adusted (primaries, secondaries, etc) to address your tuning needs to achieve an ideal air/fuel ratio accross the spectrum?

Any tips, ideas, links on how to tune this way would be greatly appreciated. :thumbsup:
Hey Bill,
Where did you tap in for your 02 sensor and the 16.3 is lean or a lean spike. Just make sure you have good fuel pressure and its not running out of fuel. My system will spike at 16.0 also from time to time but its only when im letting the clutch out and not giving it enough throttle.
 

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Hey George do you have a video of your set up.

Thanks Skip
Sorry Skip..I am pc and camera challenged.:eek:.I rely on my go to guy buddy DavidF.(Note to self..time to get off the pot).
My installation is simple..the heated 02 is in the left bank inches behind the collector reducer and the AEM gauge is slightly left of the cig lighter mounted just below the dash pad for easy viewing.let me correct that..there is no easy viewing at anything near wot with a blown bigblock.:D
 

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Sorry Skip..I am pc and camera challenged.:eek:.I rely on my go to guy buddy DavidF.(Note to self..time to get off the pot).
My installation is simple..the heated 02 is in the left bank inches behind the collector reducer and the AEM gauge is slightly left of the cig lighter mounted just below the dash pad for easy viewing.let me correct that..there is no easy viewing at anything near wot with a blown bigblock.:D
No problem George,
What numbers are you seeing and how is your buddy's 496. I may have ask you about that 496 but it keeps ringing a bell, i think we have the same cam or something.
 

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No problem George,
What numbers are you seeing and how is your buddy's 496. I may have ask you about that 496 but it keeps ringing a bell, i think we have the same cam or something.
Actually Skip..my a/f #,s will be of no use to you.I am typically 1 point richer everywhere with the 8-71 supercharger aside from high vac cruise/no load.At 50 mph in od..I am still on the transition slots..no mains engaged with dual 850 dp.s at 1800 rpm.
Good memory for an old fart(Happy Birthday).not a 496..a .030" over stroker @ 489 cid in a 32 F$3d.Same cam though.My bud is very patient..most likely will be spring before she lights off.Myself..I would have slapped this baby on the backside months ago to clear the lungs.:D
 

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Actually Skip..my a/f #,s will be of no use to you.I am typically 1 point richer everywhere with the 8-71 supercharger aside from high vac cruise/no load.At 50 mph in od..I am still on the transition slots..no mains engaged with dual 850 dp.s at 1800 rpm.
Good memory for an old fart(Happy Birthday).not a 496..a .030" over stroker @ 489 cid in a 32 F$3d.Same cam though.My bud is very patient..most likely will be spring before she lights off.Myself..I would have slapped this baby on the backside months ago to clear the lungs.:D
That cam will act bigger in that 489 vrs my 498 :thumbsup:... Cant wait to hear it fire off.
 

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Discussion Starter #17
Hey Bill,
Where did you tap in for your 02 sensor and the 16.3 is lean or a lean spike. Just make sure you have good fuel pressure and its not running out of fuel. My system will spike at 16.0 also from time to time but its only when im letting the clutch out and not giving it enough throttle.
I tapped in on the drivers side header collector about 4 inches before it dumps into the 2.5" exhaust sytem.
 
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