Gasoline Additives

[Salvatore I.]

Been reading in the latest issue of Corvette Fever that there are benefits of adding certain chemical additives to today's gasolines due to the reduction in detergents mixed into the fuel at the refinery. Did some research and found that some of today's fuels utilize as much as 66% less detergent than the gasolines of just a few years ago (2001)...Other discussion here also addressed the lowered octane in today's fuels and the greater proportion of alcohol in the fuel creating all types of detonation, evaporation and other issues in our old-style carbureted engines.

Polyether Amine (PEA)is suggested to be added to gasoline at each oil change to cleanse the engine of harmful deposits that form as a result of the reduced detergent in the gasoline.

My question is: what are the member's thoughts on the use of these additives, such as a product sold by Chevron (Techtron)---real benefit or a waste of hard-earned money? Also, are they harmful to the internal components of the motor, fuel system, or carburetor?

The article also went into another Chevron product (Purescape) to add to each tankful to enhance the "combustibility" of today's fuel and increase engine responsiveness and performance....again, a real benefit or a waste of money?

Lastly, would this last product help with detonation in place of an octane booster?

I am not an engineer or a scientist.........Thanks.

[Dick W.]

Re: Gasoline Additives

Even with my daily drivers I have found that a good major brand (BP, Shell, etc) fuel will clean my injectors. I can run discount gas for two or three tanks and the vehicles will start running rough, put a tank of good gas, still regular, and they will start running like a clock again. The only time that I run additives is at the start of the winter season, I will run something to prevent fuel line freezing. I am paranoid about this as it took me over 1/2 day to thaw a car out one time (45 years ago) and I have used a fuel line antifreeze since.

[Andrew Nehra]

Re: Gasoline Additives

I was wondering the same. I am from Detroit and just moved out to Los Angles where I can only buy 91 octane when in Michigan I can buy 93 octane. Any thought?

Thanks

[Duke W.]

Re: Gasoline Additives

I haven't read the article, but I tend to keep up with what's going on in the fuels industry by reading various technical publications, many of which are available on the Web if you do some googling.

Today's gasolines are the more tightly controlled in terms of physical and chemical properties than anytime in the past. I am not aware of any detergent reduction, and modern fuels have to pass ASTM detergent effectiveness tests. In general, modern gasolines operate satisfactorily in both modern and vintage cars, but vintage Rochester FI engines tend to suffer percolation problems - possibly due to more mid range volatiles, such as ethanol, that boil between 150 and 200 degrees F.

That said it comes down to individual situations.

1. Does your engine detonate?

2. Does is suffer vapor lock or have other driveability problems?

3. Are the fuel and ignition system components OE or modifed? Are they in good operating condition?

4. Have you analyzed your operational and maintenance practices?

Techron (patented by Chevron) has a good reputation and has been recommended by some OEMs as a way to cure rough idle and other glitches due to deposit buildup on modern emission controlled engines that idle lean (stoichiometric) compared to pre-emission engines.

Low annual mileage accumulation can cause problems on both modern and vintage cars. Loss of the light end fuel components due to vaporization (which occurs much more rapidly on vintage vented fuel systems than modern systems with vapor recovery) reduces octane and can cause hard starting. Infrequently driven carbureted cars can suffer carburetor deposit buildup due to residuals left behind as the fuel in the float bowls evaporates between infrequent drives.

Leaving fuel tanks less than full can allow water to condense, and with modern ethanol-laced fuel it will blend rather than dropping to the tank bottom. This can increase corrosion rates throughout the fuel system. Ethanol acts as a cosolvent that allows much more water to mix with the fuel than pure hydrocarbon blends.

A car should be driven enough to consume at least one tank of fuel per year and the tank should be full during winter storage.

Many articles in enthusiast publications are written by well meaning enthusisats, but they often lack education and professional experience in the fields that they write about, which can give rise to myths and misinformation.

Also, many enthusiasts are quick to blame "bad gas" on any number of maladies that can effect both vintage and modern cars, when often the cause is some mechanical, maintenance, or operational issue. And most 40 year old cars have no documented history of maintenance, repair, or modification, which certainly doesn't help when trying to troubleshoot a problem. You are essentially flying blind.

The bottom line, if it works, don't "fix it" by adding magic elixirs based on the marketers advertising. Use you own knowledge and experience to troubleshoot problems, and lacking that, ask this Board. And using additives as "insurance" is just plain foolish and a waste of money.

Duke

[Duke W.]

Re: Gasoline Additives

The old "fuel system antifreezes" were just an alcohol blend. As I mentioned in my other post, alcohols are a cosolvent that allow much more water to blend with the bulk fuel rather than dropping to the bottom, freezing, and blocking the fuel system.

Since virtually all fuel now sold in the US has up to ten percent by volume ethanol, it has plenty of "antifreeze", and there is no need for any "antifreeze" additive prior to winter as your experience from 45 years ago is unlikely to be repeated with current ethanol-laced fuels.

The good news is that these modern fuels virtually eliminate the possiblity of fuel line freezing due to separated water. The bad news is that I have some concerns over long term corrosion due to the possiblity of more water mixed with the fuel.

Duke

[Duke W.]

Re: Gasoline Additives

Do your engines detonate on 91 PON. If not, there's nothing to worry about. If they do, there are usually easy solutions for each case.

Duke

[Salvatore I.]

Re: Gasoline Additives

Duke

I drive the car regularly and use about a tank of gas every 3 weeks. Gasoline rarely sits longer than a month in the car, even in the winter. I have no issues, no detonation, an occasional rough idle, but then again, if the deposits are forming as a result of changes in the gasolines, is it worth the $9-$10 every oil change to cleanse the deposits that are forming?

I use Sunoco Ultra (93 octane) gasoline and have had some rough idling at times which honestly after just some increases in use tends to improve on its own. The motor is recently tuned..so, to follow your advice, "it ain't broken"......On the otherhand, I have seen other engines with thick deposits on the valves and tops of the pistons that I attributed, perhaps falsely, to gasoline deposits that forced engine rebuilding....

Was just thinking if the product works well and clears up deposits after 1-2 tankfuls, is it worth the prevention of an engine rebuild before its time....

[Joe L.]

Re: Gasoline Additives

Sal-----

It's really hard to get a tank of "bad gas", anymore (unless a "local problem" such as a station with fuel contamination is encountered). The EPA (and certain state air resources boards like, especially, California) have LOTS of specifications that the fuel has to meet. One of these specifications is for detergency. Even "bargain basement" fuel has to meet minimum detergency standards. These standards have been set to ensure that fuel injectors, used in all modern cars for the last 20 years, or so, are kept clean. The "basis" for the requirement is emissions control, but it works favorably in other areas of engine performance, too. I've not heard of any reduction in detergency requirements. In fact, I would expect the opposite.

The fact that any fuel meets governmental requirements for detergency required for fuel injected engines almost automatically results in the fuel having PLENTY of detergency for carbureted, older applications.

[Salvatore I.]

Re: Gasoline Additives

Joe

As I understand the point being made in this article, the issue is the level of detergent may not be at a sufficiently high enough concentration to prevent the build up of deposits in a normal engine and the use of the product would eliminate the build-up and then be used as a preventative measure thereafter...seemed like marketing hype to me at first, but then I got to thinking about it...

Given the current price of a gallon of Sunoco Ultra, I am not looking to spend more money per tankful! Just wanted to get the member's reaction to this idea...if the additive supposedly doesn't harm the motor, is there a longer term benefit? Certainly an issue for some debate!

[Duke W.]

Re: Gasoline Additives

You're probably experiencing some fuel percolation problems. Since most of us don't drive our vintage cars in very cold weather, one fix is to minimize heat in the heat riser passage, and the first thing to do is wire open the heat riser valve.

Also, on 300 HP configurations that have the "heat slot" under the front of the carb, it's a good idea to seal it off with welsh plugs or threaded pipe plugs.

Also be sure that you are running the correct "stack" of components between the manifold and carb, which can include a gasket, thick insulator, and thin metal heat shield on cast iron manifolds. Most SHP aluminum manifolds just have a gasket.

Details for each specific engine configuration are, of course, In the applicable AIM and/or service manual.

Before you use additives I would recommend the above changes to minimize percolation.

Valve and piston deposits are not a big deal IMO. On modern lean idling emission controlled engines they can cause some drivability problems. I have a pet theory that valve deposits may actually improve flow. They form in what is essentially "dead air" space at the top of the valve, which actually may improve the streamlines of the inlet flow.

My Cosorth Vega had substantial valve deposite prior to me refreshing the head when oil consumption got below 200 miles per quart. Other than high oil consumption through the worn valve guides, which is what built up the deposits, it ran very strong.

I don't worry much about valve and chamber deposits, and, of course, an occasional Italian tuneup blows some of them out.

I do have some concerns about fuel system deposits since all my cars are pretty old, and I drive them less as time passes.

Duke

[Christopher R.]

Re: Gasoline Additives

"Corvette Fever" also recently published an article where the author claimed a huge increase in gas mileage by the addition of one of those jobbies that goes in the intake and provides turbulence in the incoming air stream. It was bad enough that the editor let it into the magazine. But when questioned on it, he defended it. He stated that he stood by the author's conclusions on the device because the author was reporting actual experience. I wrote him, and somebody on this Board wrote him. The thing was called the "Toranado" or "Tornado" or something. Worked great on a Corvette and his brother-in-law's regular vehicle. I was grateful because I get too many magazines coming to the house. Now I can cut one. I won't be renewing that subscription.

[Verle R.]

Re: Gasoline Additives

Sal,

There are numerous injector cleaners on the market; "add X number of ounces to the gas tank per fillup". They MAY have some benefit on an fuel injected vehicle with lots of miles where there may be build up on the injector nozzles. If the problem is internal to the injector the additives probably will not help. Note they say to not add more than recommended.

Local garages have more aggressive injector cleaner that may do a better job.

Notice I said may in both cases.

Most often, if the car is running well, don't do anything. If the car is running bad you might try some of these fixes but don't bet the farm on it. If it has lots of miles and is running bad any one of several things may be wrong.

There is no "magic elixir".

The main benefit of these products is to the bottom line of the sellers.

Verle

[Salvatore I.]

Re: Gasoline Additives

Understood....sometimes it is better to leave things as they are....

Thanks for all of the member input on this...I agree, just because it is in a magazine it doesn't mean it is accurate or complete information...That is why I brought it here....

Thanks all......

Sal