I have been given advice to use top tier fuel in my Z3. Greatly appreciate this tip. I never noticed a problem with 87 octane until I was backing up a steep incline (heard pink; engine seemed to labor). Today I filled with 93 octane and feel the difference - or is it mind-over-matter? Also, I checked my mpg and seemed to be improving 1-2 miles per gallon. To some degree, this could off-set the extra fuel costs. Mobil gas was not listed on the toptiergas.com. I wish I had known there was recommended list out there. Oh well - I'll use one next time. Is Mobil a good fuel??? Thanks to all for communicating.
I always use Shell. Since I started using their fuel, I felt the engine didn't have more power, but did have a little bit more get up and go, or it felt like it. I know for a fact that my engine has been running a bit cleaner as I've been getting maybe 1mpg more than other fuels. But anyway, I think the difference you feel is because of the switch to 93 octane. It was my understanding that all of the models from 95 on used 91+ octane? Isn't this true?
Octane number and 'Top Tier' designation are two different things. Your car is set up to use a certain Octane fuel. Check your Z3 Owner's Manual. If you feel a difference, I would bet it can exploit the benefit of 93 octane, but check the manual. Likewise, modern cars can handle lower octane without knocking/pinging. In contrast, my car (a 1987 E30) can only use the fuel it is set up for since the engine management system just isn't sophisticated enough to adjust timimg that much. (Currently I can only use 91 octane because I have a Dinan chip. Stock chip is for 87 octane.) (I felt a big change.). Conversely, there is no power benefit using a fuel with better detonation characteristics than your car can exploit. .My car would run happily on 93 octane, but would only deliver 91 octane performance. 'Top Teir' refers to deposit cleaning performance of the fuel. Chevron was the first oil company to achieve the Top Teir specification set out (I believe) by car manufacturers. BMW was heavily involved with the spec. I was lucky to tour Chevron's fuel test lab at their Richmond Refinery shortly after they achieved Top Teir with Techron etc. It was cool to see BMW engines spinning away testing fuel. Top Teir gas reduces deposits on the tops of valves etc. Car manufacturers want this. I believe Top Tier fuel also does a good job of removing deposits caused by non-Top Teir fuels.
Thanks for comments (some great detail) about fuel. Brian, I still have a question floating out there regarding "old gas" at the pumps. Unfortunately I've learned my lesson about older/non-top fuel within the car's tank, but I was wondering about the breakdown of fuel properties before it's pumped. We have stations that I'm sure do not see a lot of demand for premium fuel; yet it's offered. FYI for those interested, the fuel I used before winter storage was purchased at Costco. I'm embarrassed to say this, however, I will not do this again; nor would I want others to take this risk. (Since putting the car back on the road this spring, I have still not completely corrected the backfires and stalling. Although it's much improved since the new fuel, Techron, and freeway driving.) Ted
I don't know much about it - somebody correct me if I am wrong - but I can't believe evaporation is significant, even after extended periods of storage. Modern cars (even mine!) have tightly sealed fuel systems as do Gas Stations. It not like the bad ole days of 1959 when gas would evaporate to tar in no time. I can't imagine even low volune sellers having their 93 octane go bad. ... But, maybe I am clueless. I HAVE had a bad tank or three. I've always thought this was from water or crud stirred up in a circa 1959 subterrainian tank.
Brian, I too remain clueless. When I pulled the car out after 4-5 months of storage, the engine acted as though it were starving for fuel (abruptly, but not consistently). The first thing that the BMW shop asked was "Did you put in Stabil to keep the gas fresh?) Auto stores had similar q's. Both sources suggested Techron to help clean fuel system components . Since the "experts" were bringing up problems centered around gasoline, I assumed that fuel that just sat in the tank was causing my problem. This is also why I had a question re "old fuel" at the pumps. I live in Big Three country country, and most of the vehicles operate fine on 87 oct. The car is running much smoother now; but spits and stalls on start-ups. I am changing the fuel filter tomorrow since it should be done as part of maintenance. If this and Techron doesn't correct my problems, I'll cave to diagnosis --though I enjoy research and tinkering. By the way, the sending unit for the fuel gage acted up shortly after second fill-up a couple of days ago. Was it you who suggested fuel could also impact the sending unit? I hope I haven't repeated myself too much. It's easy to do when you have more than one question in the system. Thanks again.
USA Today Article - Gasoline Here's a link to a USA Today article on gasoline written before it went above $4/gallon: http://www.usatoday.com/money/indus...tm?imw=Y&loc=interstitialskip&POE=click-refer
Thanks to all. ExGMan, Thanks for article. Just what I was seeking. Hope others find it as valuable as I did. All this business on gas, oil, brake fluids, plugs, filters, etc. have sooo many points of view on what to use, when to change, etc. I'm for moderation more than hype - but, I did store my car a non-top tier fuel and I'm having some probs. Ted Note: I believe my 1.9 calls for 89 octane. That's what is says on the gas cap. Anyone ever seen gas on the rubber gasket on the inside of gas cap? (This question is not connected with plugged drain or recent fill-up)
Top Tier is a measurable specification What I find interesting about "Top Tier" is that it seems to be a standard set by the car companies for the oil companies to achieve. If this is true, then its measurable scientifically rather than just a marketing campaign. Here is a summary of the spec as outlined in the link AZ provided: http://www.toptiergas.com/deposit_control.html I think the USA Today article is a little sloppy and inflammatory for the sake of "balance" such as counterpointing Shell's statements by quoting an autoshop teacher who doesn't "...see the benefits". I wonder if BMW has made any public statements about "Top Tier" gas and whether they feel it is better. The underlying presumption is that engine deposits affect engine performance. The shop teacher doesn't think so; BMW might.
Shell seems to be fuel of choice Greetings: Partial thread hi-jack here.... I emailed Mike Miller of Tech Talk recently regarding the use of ethanol in fuels and top tier fuels. Seems like I read that 46 states have ethanol in their fuels nowadays. I have always tried to use Chevron and/or Shell in our vehicles. It seems in our area every blend now has this pesky stuff in it. Personally the only alcohol I like is in a tall glass with a little ice and comes from Lynchburg Mike's response seems to be that Shell seems to be the fuel of choice these days.... Here is his response back to me.... Ethanol is horrible on so many levels, yet unlikely to go away due to the nature of American politics. BMWs have been historically very sensitive to fuel quality, so it's no surprise that ethanol is causing some driveability problem. BMW says it's okay to use fuel up to 10 percent ethanol as long as it has the correct octane rating, which on all modern BMWs means premium fuel. BMW does recommend Top Tier gasoline (www.toptiergas.com). What is surprising is the amount of fuel tested at BMW dealerships that turns out to have more than 10 percent ethanol, even though the pump was marked 10 percent. Not much we can do about this unless you want to test fuel before filling up. I have also noticed engines pinging (or knock sensors cutting in) on what purports to be high octane fuel. This is not a problem with Shell V-Power 93, but it seems to be with many other name brands. In the northeast, it's not possible to buy gasoline without ethanol. Where it is possible, I recommend doing so. I also recommend Shell V-Power 93 gasoline, one of the few Top Tier fuels, whether blended with ethanol or not. I've found that BMWs run better on this fuel, and I can only guess it is due to superior detergent additives as well as honest octane. As for the effect of the ethanol blend, you should expect a bit less power and a slight reduction in fuel economy, as ethanol does not contain as energy as gasoline. Best regards, Mike Miller BMW CCA Roundel Magazine Technical Editor techtalk@roundel.org...
I'll add to the "Shell is the best for BMW's" comments. My daily commute is 80 miles RT in my 318ti and my best mileage is with Shell 93 @ 34.8MPG. I can also tell a slight performance increase in the little four-banger. Prior to Shell adding the 10% ethanol, I was getting 35.1 (!) I also tried a local gas which recently was added to the Top Tier list: Turkey Hill Minit Markets. After two tankfuls of their 92 octane, my mileage had dropped down to 31.6 MPG. (knocked my esteem for the Top Tiers list down a few pegs after that) Other fuels like Hess and Sunoco averaged around 33.1 MPG per the OBC. Shell is about 10cents a gallon more in my area and only a few stations, but worth the $ and time.
I hate to wear this out, but I read a post where a guy used 93 v-power Shell in his old bimmer (didn't require 93) and got 2-3 mpg more than other octanes, and other top tier fuels. Sounds like a commercial for Shell, but he said he drives 80 mile each day and ran several checks. I thought ya all said use correct octane. Technically and scientifically a I get most of what has been said in these replies; but then I read testimonials that clearly contradict.
Yes, use the correct octane. Just because his Bimmer was older doesn't mean it won't accept 91+ octane fuel (premium). Mine accepts 87 or 91 straight from the factory, as mentioned in the owner's manual, and mine is 21 years old.
What is the born on date on your E30? On my E28 (that I got back from the shop this morning ) the born on is July 86, thus making her 22 years old .
