[Anchorman]

I've owned my car for almost two years and have done nothing in the area of fuel injectors other than to run some cleaner in the gas periodically. I have no reason to believe that the PO did anything, either. Currently the car runs well, and I've been averaging about 22.5 mpg for the two year period. I've heard about Marren cleaning, recalibrating, ???, injectors. Is this a step I should be considering? or is leaving well enough alone the better course of action?

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[Greimann]

You know, when it comes to something that is functioning perfectly and the act of removing them could possibly cause more problems that it fixes, I would say, if it aint broke, don't fix it. If you had some kind of lean surge or idle problems, then it might be a good thing to pull them and have them cleaned after trying the cleaner additive.



Regular doses of fuel injector cleaner can't hurt, but also know that premium gasoline also has a premium detergent additive package that keeps things pretty clean under normal driving.

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[Anchorman]

Thanks for the input. Recognizing the potential redundancy, I'll keep up the periodic additive use along with the 93 octane fuel.

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[flash]

there are guys who will swear that matching injectors and having them flowed and such makes for great power - probably does - probably won't really notice it on a normal street car though



i'm with dave - keep em clean and worry about it when something is wrong

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[ds968]

[quote name='Greimann' date='Mar 10 2005, 06:04 PM']if it aint broke, don't fix it. 

[right][post="1695"]<{POST_SNAPBACK}>[/post][/right][/quote]



Flash, foreign concept to you, right ? <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/tongue.gif" class="smilie" alt="" />





Back to the cleaning components in gasoline, I thought all the premium ones use the exact same additives, but many car nuts swear that Chevron is heads and shoulders above the rest; supposedly they either use a greater dosage in the mix, or just different / superior additives. Or so I'm told..

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[flash]

no, as i understand it, they actually use different additives brand to brand, or rather manufacturer to manufacturer

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[Anchorman]

There's no opportunity for me to use Chevron gas - I use Mobil premium - but the additive is Chevron.



Flash - how could you resist "no worries"?

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[flash]

roflmao - happens - i slip up sometimes - i have 4 conversations going on right now

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[earossi]

Okay, here is the true deal on gasoline additives. Since I work for ExxonMobil and head up an engineering group in a refinery, you can take this to the bank>



All gasoline is the same, except for additization. Gasoline is blended to an ASTM specification that is used by all refiners. In fact, as a function of shipping gasoline over pipelines we are required to pull samples of the shipment blend and test it to ASTM standards. The pipeline companies are also interested in this from a liability standpoint also. Since pipelines are highways to areas and are common to a number of refineries, no one wants a pipeline contaminated with off spec product if they are going to get into the same pipeline.



Oddly enough, ASTM standards do NOT measure octane rating........that is a marketing and product quality issue pertinent to the refiner. But, if you claim that your gasoline is 92 octane, the US DOT will test your products and determine if you have been misleading the public. State DOT agencies will also do similar certification testing.



Also, since gasolines are all the same, and since there are not always terminals in which to store product for each refiner, we do exchange deals: ie. if I have a terminal in Chicago and Chevron does not, I will provide gasoline to Chevron out of my Chicago terminal in "exchange" for either product from one of their terminals in an area that I market but do not have a method to get product to the area, or for money.



Since all gasoline is "the same", yet we want to differentiate "brands", product is additized as it goes into tank trucks. For this reason, if I am pulling out of a Chevron terminal (example above), I will load a tanker with Chevron produced gasoline, but will maintain an additization facility at their terminal, so that I can add additive to my tank truck as I am filling the truck.



Finally, there are several manufacturers of additives, and they are all similar. What the refiner can do is vary to type and dosage of additive to fit the company's internal specifications. So, you may "notice" a difference between brands. Some say they can notice a difference, and there is the camp that some of us are in that says that brand differentiation is a marketing gimmick. You'll have to decide which camp to be in.



To give you a feel for it........additization adds less than a nickel per gallon to the cost of product for the marketer.



For ExxonMobil product, it is true statement to say that we put a larger does of additive into our super product......that was decided by marketing when they came up with the "driving your engine clean" theme. But, if you can be objective, you have to ask the question of "how much additive is enough"? My personal belief is that I don't witness any differentiation in engine wear or "cleanliness" between the octanes that I run (super in my P-car and regular in my SUV).



I'm certain this posting will brew up a storm, but believe me when I say that "all gasoline is the same". There is one caveat.......independent marketers like the Mom and Pop gas stations or some of the secondary branders who do not manufacture their own product...........are not obligated to additize as long as they do not market their product as "additized".

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[Anchorman]

Earossi, thanks for this perspective. I've been in the oil refining business as well as the (petroleum) product business, and I can attest to the truth of the "exchange" and pipeline aspects of your post. I never thought about engine cleanliness or wear in the context of octane - considering octane to be a knock-related measure more than anything else. I guess what you're implying is that since (if?) the higher octane products also have more additives, one ought to see the difference - and you don't. The further implication seems to be that there's more than enough additive in the gasoline already (except, as you point out, with respect to "independents") so the step of running an additive periodically could very well be redundant. Interesting - further thoughts, anyone?

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[Greimann]

[quote name='Anchorman' date='Mar 11 2005, 05:21 AM']..... so the step of running an additive periodically could very well be redundant.  Interesting - further thoughts, anyone?

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In a normally functioning engine I thnk that is true. If you had a problem with excessive oil consumption where the deposits can build up on valves and piston tops, then detergent tank additives have been shown to remove these deposits.

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[flash]

where do the stations that sell 10% alcohol gasoline do thier mixing?

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[earossi]

[quote name='flash' date='Mar 11 2005, 10:53 AM']where do the stations that sell 10% alcohol gasoline do thier mixing?

[right][post="1718"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[earossi]

Most refineries make numerous blends of gasoline (our Illinois plant makes six different blends of gasoline). Gasolines that are marketed in US EPA ozone "non attainment" areas are required to run an oxygenate. There have been a number of oxygenates over the years, but the market, for a number of reasons (legal and performance related) have settled on ethanol as their choice.



Attainment areas are not required to add ethanol. I know that sounds complicated, so stay with me and I'll answer your original question.



Since ethanol adds to the octane rating of gasoline.........the blend that we market in areas where you will have to add ethanol leave the refinery at a lower octane rating than you will purchase. Ethanol is then added at the terminal before the product is trucked to the gas stations (this answers your original question).



Though research and experience has indicated that ethanol does not impair engine components (at least up the max of 10% stipulated by the EPA), there is one characteristic of ethanol that has been an issue. Ethanol is hydroscopic....meaning that it has an affinity for water. Ethanol will absorb water..........to a point. If the station you purchase gasoline from does not exercise due diligence in removing water that enters their underground tanks (ALL underground tanks will collect water......usually from condensation), there can be issues with ethanol.



For normal gasoline, that is not hydroscopic...........when water enters a tank, the gasoline will float on top of the water (due to density differences) and not mix. This is ok since the suction from these tanks is not taken directly off the bottom of the tank. So, as long as the service station keeps their tanks "reasonably" pumped dry, nothing but gasoline is pumped.



Ethanol additized gasoline, on the other hand, will absorb any water that exists in the underground tank.......which is ok until the ethanol reachs saturation.......meaning that it can only absorb just so much water. Once you go past the saturation point of ethanol, a phenomena that we call "phase separation" takes place..........and the ethanol along with the water will separate out from the gasoline. This is not a good thing, since you will either pump low octane fuel into your car...........or worse yet..........you will pick up a slug of the water saturated ethanol.........with little or no gasoline! Once water has entered the fuel system....the car's usually stall out and require that the entire fuel system from tank to injectors be flushed out to purge any remaining moisture.



When ethanol was first introduced to the market (mid 90's) we experienced a rash of phase separation issues that cost the majors a lot in repair costs and in brand loyalty. However, I am happy to say that with the creation of rigorous programs to assure that water is pumped from underground tanks......we are seeing less and less cases of phase separation related engine failure.



It just occurred to me while writing this that where ethanol is used, it is probably safer to purchase gasoline from a high volume station than from a Mom and Pop station where a load of gasoline may remain in his tanks for weeks or months.....thus allowing the stored produce to accumulate a lot of absorbed water.



Sorry for the long post, but there is a great deal of misunderstanding around oxygenated fuels.

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[968Z]

I would have to defer to an honest engineer/employee regarding the true nature of the petroleum fuel industry. From a strickly layman's point of view though, I highly recommend running a can (bottle) of Chevron Techron thru your fuel system every 5K or so. I try to do it at every oil change. I have done this with every vehicle I've owned in the last 15 years, and I would tell you that it does make a difference.



Rossi, if I am reading this right, are you saying that the octane level is determined by the additives mixed in at the tank, and not the gasoline from the refinery?

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[KensCab]

Is "Octane Boost" worth while, in your opinion?

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[Greimann]

[quote name='KensCab' date='Mar 13 2005, 10:21 AM']Is "Octane Boost" worth while, in your opinion?

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Off the shelf octane boosters work, but remember that when the bottle says "3 point increase" , that means 0.3, not 3 numbers.

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[rustech]

FYI, A couple cans of octane booster, mixed with only a couple gallons of gas, and I used to get ANY car to pass a smog check. It would bring the numbers way down. I'm sure 100 oct would do the same thing.

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[KensCab]

thanks, I usually split a can at fill ups... seems to help some. I also agree on the injector cleaner, IMHO it does help to keep the varnish and nasties out.

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[earossi]

968Z,



Sorry if I confused anyone about how octane is determined. Gasoline octane is determined in the gasoline blending stage of manufacture. Gasoline is actually a blend of 5 to 6 components which are the byproducts of crude oil. Each of these "components" has its own octane. Some octane numbers are relatively low, while some are much higher than you would every run in your engine. During the blending phase of gasoline manufacture, a refiner blends a number of the components mentioned above to meet an ASTM specification. Octane is also adjusted to meet the quality standards of the fuel....but this is not done to an ASTM standard......we actually have "knock engines" in a test lab that run on a manufactured blend. With these engines, we can determine the knock rating of the blend, and from that data, we adjust the blend to meet the requirements of the market.



What I mentioned, that is confusing, in the first post was that ethanol produces a boost in octane. So, for fuels that will not receive any oxygenate (ethanol), we blend to the pump octane (typically 87, 89, and 92 or 93 for regular, midgrade, and premium grades respectively). If the fuel is to receive ethanol, we will blend the gasoline to a lower octane and ship the suboctane fuel to a terminal. Then, when a tank truck is loaded, ethanol is added, by volume, to achieve the oxygenate level required, and coincidentally boosts the octane to the proper level.

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