so i just got the speedtuning chip and were out of premium(93) gas here in the high country (Boone NC). i know on the neuspeed chip i used to have a had to run 91 so im pretty sure i have to run at least that with the speedtuning. what i did for my last fill up was put mid grade (89) and put a bottle and a half of octane booster in the tank. my roomate was like just put the cheap stuff in itll be fine, but i didnt want to risk anything. i dont mind spending an extra 8$ just to be safe. so i guess my question is what are the possibilities that could happen if i ran low grade (87)? i dont plan on doing it, its more so i can explain to my friends/parents who always ask me why i run premium when "i wont even notice a difference" by running low and insist that it is ok even tho its recommended to run 91

 

just tell them that the price difference per fill up is around $ 3.00 (.20 more per gallon @ 15 gallons (to make calculations easy)) and if you drive 10k a year, and get (conservitavely) 333 miles per full tank (again to make calculations easy) thats AT MOST 30 fill ups a year @ $3 per fill up thats at most $90 ....

i cant think of a better way to spend $90 in one year (under 25 cents per day) to keep your car running much cleaner, more efficient, less stressed, get better gas mileage, less wear and tear on your engine/ fuel injectors.

it is definately worth it, especially for a turbo car, its a must!

dont cut yourself short, it doesnt seem like you do, but if you can get 91, dont bother putting in the octane booster IMO i think youll be fine

 

its only 87, 89, and 93 here, but were fresh out of 93 so i get the 89 and put a bottle of octane booster in. i ran premium in my saab turbo and i will continue running it in the audi, and i think of it like you do, its at most 3$ more a fill up. and with a car like this i dont think ill ever cut myself short. as always thanks for the reply

 

It wont hurt anything, thats what knock sensors are for. You just wouldn't get the full power of the chip though. If the knock sensor detects knock/ping due to the low octane your timing will get retarded (heh) to prevent damage to the engine.

 

^1+. Hasn't been proved to an extent that lower octane will DAMAGE the car, the injectors WILL run fine on 87. The octane rating is the amount of detonation its for, doesn't mean its any cleaner. For clean fuel go for Shell or BP. Your engine will not be running the correct fueling/timing that the ECU is mapped for, so why the hell even chip it. But if you MUST put in lower than premium, you won't exactly kill your engine. I just would never go lower than 93.

 

FWIW, California only offers a 91 octane premium. Most other parts of the country's premium gas is a 93 octane.

 

Yeah I know the west coast is hard to find 93, but octane also depends on where you get it from. Its all marketed different. In other parts 100 octane is really more of a 94. The only real way to find out what octane you're running on YOUR engine is to check your logs and see how your engine is running to various detonations.