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Discussion Starter · #1 ·
Hey guys , so i have an s550 2017 gt . I'm currently running vmp blower and tune , car is making 687hp with an 88 pulley which is smallest for pump gas and what I daily with very reliably for the past year .

So I want to pulley down 2 sizes to the 82mm pulley . This runs 9.5 psi. I would need an octane booster for this and is only for a couple dyno pulls then back to the daily 88mm pulley.

What do you guys think. Is it safe to do this for a couple pulls? Also what boostane would you guys run? The premium or professional version ?
 

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Just as a matter of interest, what’s the point? Are you just wanting a Dyno-sheet to showcase?
 
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Discussion Starter · #3 ·
Well to have a dyno sheet , but more so to see the capabilities of what higher octane and that pulley are capable of . Just an experiment really
 

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Well to have a dyno sheet , but more so to see the capabilities of what higher octane and that pulley are capable of . Just an experiment really
As far as octane goes, there will be little to no difference....this is an age old question the Engine masters as an fyi did a show on testing NA and turbo's engines.... they used 87, 91, 110, 116 and E85 fuel (California) and found really no difference except with the E85
 

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Discussion Starter · #5 ·
So has anyone tries this or thinks it's alright to go 2 pulley sizes down with boostane and a tune for a few runs ?
 

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I doubt anyone can give you a definitive answer on this; I think you are just going to have to take your chances, if you want to try this experiment.

Hopefully you are working with a tuner who knows what they are doing. I am not sure exactly how this works, but make sure you do NOT defeat the knock sensors, so the ECU will pull timing if it senses knocking / detonation, hopefully before it goes boom. I don't know any way to predict how much octane you would need to prevent the detonation; the only way I know is to try it, and then back off the timing and/or stop the pull if it starts knocking.

As far as octane goes, there will be little to no difference....this is an age old question the Engine masters as an fyi did a show on testing NA and turbo's engines.... they used 87, 91, 110, 116 and E85 fuel (California) and found really no difference except with the E85
Did they adjust the tune to take advantage of the higher octane between runs? I'm guessing probably not, and that would explain it.
 

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Discussion Starter · #7 ·
I doubt anyone can give you a definitive answer on this; I think you are just going to have to take your chances, if you want to try this experiment.

Hopefully you are working with a tuner who knows what they are doing. I am not sure exactly how this works, but make sure you do NOT defeat the knock sensors, so the ECU will pull timing if it senses knocking / detonation, hopefully before it goes boom. I don't know any way to predict how much octane you would need to prevent the detonation; the only way I know is to try it, and then back off the timing and/or stop the pull if it starts knocking.



Did they adjust the tune to take advantage of the higher octane between runs? I'm guessing probably not, and that would explain it.
Thanks for the reply man
 
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