Medium Grade Fuel - Deal or No Deal? - The Unofficial BMW M5 Messageboard (m5board.com)

Izzyzx · 6th September 2006, 07:39

Since the price of US gasoline has gone crazy (by American standards) I’ve been trying 89 Octane. There I said it... I feel so ashamed.

I have notice a slight hesitation under hard acceleration but no real lost in performance under normal to moderate driving demands. In fact I checked my MPG and was getting 27 MPG (according to the Onboard Computer) cruising at 65-70 MPH on Interstate 80 (an American Motor Way). I rarely exceed 80 MPH, I don’t race the car (officially). My fuel economy and no moderate acceleration problem - such as pining tell me things are cool.

I guess someone would say I'm not "race ready" should some clown want to pass me in his/her Audi or Benz. It's like going on a big date without a box of protection -Very Embarrassing.

What's your opinion: Deal or No Deal?

What am I hurting? I could be saving $100 per year (Oops! I just answered my own question). I spend more than $500 a year at Starbucks...

de Witt · 6th September 2006, 07:46

I drop in the highest grade I can get. If it puts a $50-60 dent in the pocket, then thats the way it is. I would do the same...89 is not what these engines need. 9.8:1 is still high.

GSM5er · 6th September 2006, 16:17

I only buy the sweetest juice I can find. I figure the risk/reward of using the lower octane is not attractive.

Izzyzx · 8th September 2006, 03:01

After seeing Premuim Gasoline ("Sweetest Juice")Prices in this chart http://www.eia.doe.gov/emeu/international/gas1.html . I have a new appreciation for US gas prices... It would cost me $120/wk (an addition $3000+/yr) to drive M5 in the UK.

doolie · 8th September 2006, 12:57

just come back from an overland drive from UK to China (not in an M5!). Cheapest fuel was Turkmenistan at 1 cent per litre (yep, we filled up six cars with 88 octane for less than $5 US ). Some of the fuel out there is very low octane (72) and it'll make the engine rattle like you wouldn't believe. Anyway, my experience with fuel is always put in the manufacturers recommended Octane when you can as long term damage can occur by running lower grade, even if you can't hear the 'knocking'.