# Race Gas Program on 93 oct?



## AntParmenter (May 8, 2010)

With a progressive controller that only starts spraying at a set boost, how is it safe to run a race gas program with 93 octane? When the water/meth isn't spraying wouldn't that jack up the engine or what-not?


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## BoostedDubVR6T420 (Dec 4, 2009)

Not if the motor is already tuned for the 93 oct. It only needs to rich up the mixture when there is added air pressure.


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## TheBossQ (Aug 15, 2009)

To be more specific, the reason it is safe is because when you're not in boost, the operation of the engine is pretty much like a naturally aspirated engine.

All 1.8t engines are under 10:1 compression in stock form, which is average for a naturally aspirated engine. Most naturally aspirated engines run 87 oct. It's only under hard acceleration that forced induction cars utilize the higher octane.

With W/M injection, you could run 87 oct gas with 100 oct software, provided the W/M began spraying just before the point in which 87 oct no longer provides resistance to engine knock. You just need to tune for it correctly.


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