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  #1  
Old 09-11-2010, 08:59 PM
thebrain thebrain is offline
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Default LS1 WOT AFR is 11.5 will MAFT resolve rich condition

I have a 99 Pontica trans am mild street stripe cam, Fast intake & long tubes. mainly a daily driver however I do like to get on it when I can.

car was tuned w/ HP tuners by a novis after the cam swap. has not be retuned after the Fast intake.

had car scanned w/ HP tuners man told me it was rich at WOT (wide open throttle) AFR 11.5 I have recently verifed this ratio w/ a wide band.

will a MAFT w/ it's maxium of 14% lean at WOT be able to adjust this rich condition closer to the desired AFR?

Also the rest of the tune seams fine AFR at idel is steadie at inbetween 14. -15 same w/ part throttle driving it's at the higher 4K and up RPMs it richens up.

I am concidering a used MAFT off a 98 camaro so I'm assumming it's one of the orginal MAFT.

Thanks for any helpful advice
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  #2  
Old 09-11-2010, 09:36 PM
TurboBob TurboBob is offline
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what's your desired AFR? 14% puts you at approximately 13.1

Bob
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  #3  
Old 09-12-2010, 05:10 AM
thebrain thebrain is offline
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Default unsure of desired AFR

Bob I have been reading a little about the perfect AFR being 14.7

acording to my AEM wide band my car actuelly idels and part throttle is allmost dead on w/ the 14.7.

I'm unsure of desired AFR at WOT thinking it's usalley a tad richer than the 14.7 for saftey?

I have been told that this 11.5 rich condition adds way to much fuel (and is just as bad as a lean condition) in that this extra fuel washs out the cylinder walls and there's not enought spark to burn the extra fuel.
? is this extra fuel creating the little detenation (I cured a good part of w/ my double chamber catch can) however there is still a slite pinging at WOT.

the 13.1 seams much better than the current 11.5 however I'm no expert.

please advice.

Thanks Bob
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  #4  
Old 09-12-2010, 12:21 PM
TurboBob TurboBob is offline
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I think you need to read more.

11.5 is not extremely rich, but it is kinda rich. Its not causing detonation.

For a non-turbo car, you could probably lean it out to 12.5 and gain a little power. But your detonation may increase. On an LS1, when you lean out the fueling with the translator, the spark advance increases.

How much spark advance is the car running? How much octane are you running.

Bob
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  #5  
Old 09-13-2010, 05:30 AM
thebrain thebrain is offline
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Default 28 degrees of timing at WOT, 93.5 octane fuel

Quote:
Originally Posted by TurboBob
I think you need to read more.

11.5 is not extremely rich, but it is kinda rich. Its not causing detonation.

For a non-turbo car, you could probably lean it out to 12.5 and gain a little power. But your detonation may increase. On an LS1, when you lean out the fueling with the translator, the spark advance increases.

How much spark advance is the car running? How much octane are you running.

Bob
28 degrees of timing at WOT, 93.5 octane fuel

I believe idel timing in gear is 17 & part throttle is 22.

? if I was able to lean it out w/ the MAFT to 12.5 how much timing would be added?

11.5 is not extremely rich, but it is kinda rich ? is this 11.5 AFR at WOT damageing the engine?

Thanks Bob

Last edited by thebrain : 09-13-2010 at 05:36 AM.
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  #6  
Old 09-13-2010, 10:34 AM
TurboBob TurboBob is offline
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I do not believe 11.5:1 will cause any damage.

If you lean out to 12.5, you will probably pick up 2 degrees or so.

Bob
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  #7  
Old 09-18-2010, 10:25 AM
thebrain thebrain is offline
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Default leaning out

Bob with the leaner condition just at WOT about how much power if any will I gain?

also 30 degrees of WOT sounds kindof aggressive I will then create more detonation.

I understand you guy's make a timing retarder (mainly for Nitrous cars) would this be an alternative to lowering the WOT.

I still have a slite ping at WOT the double chambered catch can seriously reduced this ping.

I'm trying to avoid the high cost of a HP tuners tune.

Thanks Bob
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  #8  
Old 09-18-2010, 12:21 PM
TurboBob TurboBob is offline
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How many miles on the engine?

I would lean it out slowly and see if it runs better. If you get more detonation then you may not be picking up any power.

The Timing Tuner can be used to adjust spark, even without N2O

Bob
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  #9  
Old 09-18-2010, 02:58 PM
thebrain thebrain is offline
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Default 112k

112K miles on engine.
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  #10  
Old 09-28-2010, 02:23 AM
thebrain thebrain is offline
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Default leaning out w/ larger TB

Bob I have a stock 75MM ported throttle body.

? If I ream out my FAST 78MM intake manifold an use a 85mm throttle body & 85MM mass air meter would this extra air lean out this rich 11.5 WOT AFR?

Thanks Bob
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