should i be using 87 or 91 octane gas in my car? it's a 2003 VW Jetta 1.8 turbo.

the gas cap says 87/91, and the opinions seemed to be pretty mixed on the VWvortex forums. some say use ONLY 91, others say it doesn't make a difference what you use. is it better for the engine/turbo to use 91? plz essplain... i didn't wanna ask on VWvortex 'cause i feel out of my element, lol.

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i don't know about turbos, but for almost all modern cars 87 is fine if not better. if you car doesn't knock then you don't need it.

http://www.ftc.gov/bcp/conline/pubs/autos/octane.shtm

quote:

Originally posted by igottaknow i don't know about turbos, but for almost all modern cars 87 is fine if not better. if you car doesn't knock then you don't need it.

+1

quote:

Originally posted by igottaknow i don't know about turbos, but for almost all modern cars 87 is fine if not better. if you car doesn't knock then you don't need it. http://www.ftc.gov/bcp/conline/pubs/autos/octane.shtm

informative article. thanks for that!

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My friend has that same car & has always used 87 since new. She has had no problems at all with the engine. Plus i cant even remember the last time I put anything higher that 87 octane in a car.

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with a turbo. 91

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Originally posted by Halcyon+On+On OOKA-OOKA ME NACHOS ME PRESS KEYS ON COMPUTER GOOD

chances are it's a stock turbo right?

87 is more then enough, you move up in octane when you burn leaner due to high AF ratios.

stock turbo doesn't come with a FMIC kit, it's probably sucking out of a stock air box.

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quote:

Originally posted by kid nyce chances are it's a stock turbo right? 87 is more then enough, you move up in octane when you burn leaner due to high AF ratios. stock turbo doesn't come with a FMIC kit, it's probably sucking out of a stock air box.

yeah, stock turbo.

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yea 87 is fine, just make sure your air filter is clean thats all

plugs, wires, engine/tranny oil, brakes, tires, and air/gas filters should be your maintence

engine depending on oil 3k - syn 5k
tranny 30K
plugs n wires 30K
gas filter 30k
rotate tires every 12k-15k
brakes as needed
air filter as needed

not a bad idea to flush your radiator before each winter

I usually go through a winterization in the fall. Lay a heavy coat of wax on the paint, change wipers, snow tires, rubber mats, emergency snow stuff in the trunk.

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If your car knocks, your knock sensor will pick it up and retard the timing, which will actually decrease your MPG and performance.

Aside from that, you're not gaining anything with the higher octane.

If the manual says 87 is fine, I'd go with that.

quote:

Originally posted by kid nyce yea 87 is fine, just make sure your air filter is clean thats all plugs, wires, engine/tranny oil, brakes, tires, and air/gas filters should be your maintence engine depending on oil 3k - syn 5k tranny 30K plugs n wires 30K gas filter 30k rotate tires every 12k-15k brakes as needed air filter as needed

normally id say 91, but since i have no clue on your driving style i cant say either is better. do you stomp on the gas? if so use 91. if you just put put around then 87 is fine since you wont be doing any heavy acceleration.

kid nyce: the octane rating has nothing to do with a/f ratios. its all for detonation aka knock.