Mitleider

With variable quality gasoline offered and with even a 10% ethanol added attracting water I'm a believer that a good fuel additive can help prevent corrosion in the fuel system as well as minimize harmful deposits on valves and in fuel injectors

Question is which one is preferred and why? Your experienced opinion please....

USMC_DS1

I've used Swepco in the past. http://www.pelicanparts.com/cgi-bin/...20%2531%2532oz

I used to add one bottle to each gas refill over three sessions just prior to changing the engine oil. That way any fuel additives that leeches into the old engine oil would be removed during the oil change and would not adversely affect the new engine oil. Lately I've just stuck with Shell gas which already has it's own fuel additive. Curious as to what others use especially if there is an expert re this topic.

Bullseye7

Seafoam. Recommended by my mechanic. My car has always run great so I couldn't tell you if it's due to the additive or not...

CAVU

When researching these types of products, I like to start with their MSDS:

Seafoam - http://seafoamsales.com.previewc40.c...seafoam_EN.pdf

Swepco 503 http://www.chemcas.com/msds112/cas/1...-3_98-95-3.asp

Techron https://cglapps.chevron.com/msdspds/...&docFormat=PDF

At least it can give you a base line of what you are putting through your fuel system.

Mitleider

Don't the Techeditors @Excellence recommend Swepco 503 with each fill up?

alpine-al

Do you expect us to read through old isses of Excellence to answer your question?

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MJBird993

My BMW mechanic reccy'd Techron to help clean the injectors, but only one can every 30K miles or so. More often than that and you risk damaging things.

Stick with top-tier gas (such as Shell) and don't worry so much about things you can't change.

CORSASCHNELL

Techron

Macster

My info is while the gas pump may state alcohol can be 10% refiners have stayed at the 7% to 8% level for years. (This can be changing as the number of gallons of ethanol that is mandated to be used goes up refiners may have to nudge the percentage up to a true/full 10%.)

My 02 Boxster with just 270K miles is on its original fuel system hardware except the fuel pump which quit working at over 200K miles so these fuel systems can go a long time without any trouble.

There was no evidence of any water contact the pump nor any signs of water (and not much trash) in the tank. This is after running an estimate 8000 gallons of fuel through the tank.

As for corrosion gasoline already comes with a small amount (approx. 1%) of oil added as corrosion prevention.

Techron AFAIK offers no corrosion protection.

It is a fuel system cleaner. It is pretty good stuff but should not be used on a regular basis.

If you drive your car short distances the car might benefit from a Techron treatment say once a year. But use with care and don't over due it. It is powerful stuff. Also, try to arrange to use it then change the oil/filter.

The few times I've used Techron: After an AOS failure in my Boxster which dumped some oil into the engine; prior to my Boxster's first emission test here in CA; and with my Turbo after buying the car used with 10K miles I treated it to Techron to get the car's fuel system "clean".

To avoid variable quality gasoline, I just run a top tier gasoline (mostly Shell since there is a Shell station very convenient to me and its prices are very competitive) but Chevron or other top tier stations get used when I'm on the road. The engine shows no preference for any gasoline over another though I note when I get a chance to fill up with 93 octane vs.the 91 octane goat p*ss that is available here in CA the engine really loves 93 octane...

Also, be sure to buy from a busy station. This ensures you get the freshest gasoline. Premium gasoline can go stale.

slicky rick

Since we are here do these fuel system cleaners also have benefitial effects for the later dfi engines?

Macster

Techron really doesn't care if the engine it port or direct injected.

DFI engines can have a tougher time staying clean as the fuel injector doesn't spray gasoline against the backs of the intake valves which is where DFI engines can experience deposit build up.

The deposits get there from the slight reverse flow (on purpose) of exhaust gases which carries these exhaust gases into the intake valve area and the cooler valves tend to collect deposits from exposure to these gases.

slicky rick

exactly my point macster. techron and other fuel sytem cleaners can clean the valves as the chemicals are sprayed onto the valves cleaning the deposits. for our new dfi engines the chemicals are essentially sprayed into the combustion chamber and never really hit anything else. i guess cleaning sould be limited ot the tank, lines and the injector itself... less benefits?

CAVU

Macster, Are you referring to DFI engines in a general sense, or specifically Porsche? I am not a long term Porsche owner but I like to think that I left no "issue" stone unturned when looking for my first Porsche. Porsche is now 6 years (starting in 2008 with 2009 deliveries) worth of DFI engines in the market place and there doesn't appear to be an issue. What are your additional thoughts and experience on Porsche DFI.

Macster

Well, DFI engines in general since by definition fuel is injected directly into the combustion chamber. The older style port injected engines tended to keep the port exposed surfaces of the intake valves cleaner. These surfaces want to be clean to avoid causing extra and unwanted and bad turbulence of the air flowing into the chambers.

This is especially critical for DFI engines as they are lean burn engines under some operating conditions and depend upon the air flowing into the chamber and obtaining the proper form and flow for the best combustion.

At some time early in the Porsche DFI appearance I heard that there might be some kind of an engine/intake system cleaning process devised to feed the engine intake system with some cleaner (in I guess some fine mist or vapor form) to remove deposits but I have not heard that this is available. It could have been a rumor or perhaps the need just never materialized.

To reduce the possibility of deposits forming, to keep them at a minimum, run a quality gasoline. I know everyone thinks it is marketing but limit your car's gasoline to a top tier gasoline.

Buy fresh gasoline.

Run an approved oil that has suitable additive package. Keep the oil level up but do not over fill the engine with oil. Keep the oil reasonably fresh.

Why? Well, an oil that has an unbalanced additive package can result in an increase in deposits. Everything in the oil is potentially deposit forming.

Overfilling the engine results in more oil vapor being routed to the intake. This results in more combustion byproducts that can form deposits.

Also, if the oil is run too long it gets contaminated with unburned fuel and water and this lowers the oil's viscosity. Not only does this compromise the oil's ability to provide suitable lubrication the oil is more prone to foaming and forming more oil vapor. This vapor is routed to the intake and well, there are more combustion byproducts produced that can form deposits.

In short the idea is to avoid forming the deposits in the first place. Not to figure out how to remove them after they have formed.

Ideally the engine should be used for more than short trips.

I have not experienced this with DFI engines having never driven a car with one for any length of time but I can tell you the effect a "long" drive (50 miles or so) has upon my pre-DFI engine Porsches is rather remarkable.

As I have touched upon in other posts my cars get used quite a bit but even so a drive of around 50 miles or so at freeway speeds really has the engines purring like a kitten. This usage helps remove deposits.

(On a similar note I came upon a Boxster in for a broken valve spring. The head was off and the combustion chambers exposed. I took a good look and given the appearance I asked the tech if he had cleaned the chambers/valves. No he said that is the way they were. He said the driver (a woman) used the car to commute 15 or more miles each way per day. Gasoline is a detergent and can remove deposits if given the right conditions. Her usage was giving the gasoline the right conditions and deposits were minimal.)

neanicu

Very good advice here!