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89-91 tune

949 Views 7 Replies 5 Participants Last post by  Slvrpismochevy96
my nelson tune that's on the way is an 89-91 tune and i plan on running 89 most of the time, but just to ask the question...what would happen if i ran regular 87?
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Even non-audible knock is bad. If hes tuning it to run 89, hes giving it quite a bit mroe timing. Dont run 87, in the long run it wont be good. If the PCM senses long durations of knock it will fall back to the low octane timing table while pulling timing. I thought if the PCM sees a buttload of knock it threw an SES light and went into reduced power mode but I could be wrong. If my memory serves me corectly the max the PCM can pull is 8*.
 

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you can run 87 octane as long as you arent going to be racing it. hahahaha,. that usually doesnt happen. i have ran 87 on a trip but as soon as i went to pass a slow car she would knock. you need to run at least 89 since he has raised the timing in the lower tabels to accomidate the performance. but the pcm can correct for bad gas. oh yay the pcm can pull up to 20* timing.
 

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02denali said:
you can run 87 octane as long as you arent going to be racing it. hahahaha,. that usually doesnt happen. i have ran 87 on a trip but as soon as i went to pass a slow car she would knock. you need to run at least 89 since he has raised the timing in the lower tabels to accomidate the performance. but the pcm can correct for bad gas. oh yay the pcm can pull up to 20* timing.
Did your custom Westers come set up to automatically pull 20* when it got to a certain TPS%??? I just opened up Edit on my laptop and the spark retad limits are set at 10*.
 

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Discussion Starter · #8 ·
02denali said:
you can run 87 octane as long as you arent going to be racing it. hahahaha,. that usually doesnt happen. i have ran 87 on a trip but as soon as i went to pass a slow car she would knock. you need to run at least 89 since he has raised the timing in the lower tabels to accomidate the performance. but the pcm can correct for bad gas. oh yay the pcm can pull up to 20* timing.
Well I better just run 89 then becuase im used to having a Gen I vortec with a single chamber and the Gen1's just dont have the awsome smooth sounds when the peddle is down like my new Gen2. With this being said i cant go a tank of gas without gettin on it every once and awhile :head:
 
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