dyno chart and a/f questions.

derockgt

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first dyno with stock mid pipe, dirty air filter, stock plugs. 93 tune.
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today dyno off road x clean air filter tr6 @.032 new belt seeing boost around 13.4 most spike at 14.2 just hitting fourth. thinking the new belt added boost is leaning it. I thought it was odd it made the same numbers with the added boost? thought it would make alittle more and with no cats as well:shrug: also it was pinging around 5900-6000 on 91 az sh*t gas. tuner told me to mix 3 gallons of 100 in with the 91 till he can retune it. i was supposed to get it retuned today but he misplaced his laptop with all his tuning software:nonono:will it be ok with the 100 mix? and what is up with the sudden a/f drop at 4k? oh low torque was the tires spinning on the dyno
 

Cobra-21

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Were both the dyno sessions at the same shop? Similar weather/temp/humidity? Both sessions use a tailpipe sniffer, or o2 bung? All these variables can affect your numbers. If everything's the same except some simple mods then the tuner should be able to get your air fuel fixed up. The first graph was nearly perfect with 11.7's across the board. I'm surprised that the new tune was leaner and still made the same HP.

If you're tires are spinning on the dyno rollers, get someone to sit in the trunk during the run.
 

derockgt

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Were both the dyno sessions at the same shop? Similar weather/temp/humidity? Both sessions use a tailpipe sniffer, or o2 bung? All these variables can affect your numbers. If everything's the same except some simple mods then the tuner should be able to get your air fuel fixed up. The first graph was nearly perfect with 11.7's across the board. I'm surprised that the new tune was leaner and still made the same HP.

If you're tires are spinning on the dyno rollers, get someone to sit in the trunk during the run.

the second graph was not a revised tune just a baseline pull, tuner lost his computer with all his tuning software. same tune. just seeing more boost with the better belt wrap. not the same shop, 1150 elevation at new location, temps were about the same, humidity the same and tailpipe sniffer was used in both.
 

Bdubbs

u even lift bro?
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the second graph was not a revised tune just a baseline pull, tuner lost his computer with all his tuning software. same tune. just seeing more boost with the better belt wrap. not the same shop, 1150 elevation at new location, temps were about the same, humidity the same and tailpipe sniffer was used in both.

Different dynos, different numbers. Heck same dyno different day will net different results. And that elevation might make a difference.
 

derockgt

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the shop is closed Monday but supposed to hear from the tuner on tuesday, hoping to get it tuned then.
 

derockgt

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would to 91 gas cause the car to run leaner? im just trying to figure out why the a/f ratio went from 11.7 to 12.1-12.3?
 

Bdubbs

u even lift bro?
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Gas could make a difference. Heck when mine was tuned I seen a steady 11.7 a/f, then the following spring I always see 11.2 now. Wondering maybe the sensor for the wideband is doing something on mine?
 

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