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Author Topic:   Carb Jetting Question
Dirt Maniac

Total posts: 120
posted May 31, 2005 10:53 PM  
We are dropping in octane from mixed (pump & turbo blue) to straight 93 pump gas. Do we need to change jets when we do this? And if so which way.

Dirt Freak

Total posts: 402
posted June 01, 2005 02:51 PM  
Yes, The turbo blue weighes less than straight gas. I'm sure some of octane boost, wether it's ethanol, or what ever will affect the specific gravity. Since carbs work on the principle of mass not volume, Your floats will change height, your idle settings will change RPM, etc....

Gasoline is lighter in mass than water at about .76lbs of water, In other words it's 3/4 the mass. Mix in some race gas at .73 for turbo blue and track tech and your asummed 50/50 mixture is now averaged to 74.5. You'll need to increase jet size up to maintian steroich mixture quantities's.

A simpler answer would be up the jet one no. and double check your floats levels.

Dirt Freak

Total posts: 238
posted June 01, 2005 03:28 PM  
Probably you will have to back off the timing some with the lower octane to keep from detonating.

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