Originally Posted By: y_p_w
Originally Posted By: HemiHawk
Sorry if this has been discussed before, I tried looking but didn't find much information...
Can the use of Top Tier gas all the time cause any kind of build-up of detergents? I use Costco gas as its on my way home from work, its cheaper than everywhere else, and its top-tier rated. They actually say they have something like 5x more detergents than Top-Tier requires. Is there any reason not to run this gas all the time? I found a couple people here and there online saying that you'd end up with deposits or detergent build up, and that you should alternate every so many tanks with something with less detergents. I have no idea the validity of this claim, so I'm checking with everyone here.
I remember seeing the AAA study showing that top-tier can actually clean injectors/valves/pistons. But that is assuming it needs cleaning, what about a brand new car? I'm not super concerned its going to blow my car up or anything, but thought the topic was interesting.
They don't say 5x what TT requires, but 5x what EPA minimum requires. It's probably about 2x what TT requires.
They don't really require a set amount. It's just that the specified "treat rate" must pass a test done on real engines. The more that's used typically means there's diminishing returns.
Some older detergents used to have problems. One type was supposed to be really good at removing varnish from clogged injectors, but then left deposits behind in the combustion chamber. The polyether amines used in many modern detergents is supposed to both clean injectors and remove combustion chamber deposits without leaving behind deposits. There are other types of detergents available.
Chevron used to say that they didn't recommend their Techron Concentrate fuel treatment be used than more than once every 3000 miles, and preferably before an oil change. Something about affecting the oil additives. I guess before an oil change meant that the oil additives would be restored soon after the fuel treatment.
I wouldn't expect anyone to know this, but the deposits build up that may be referred to online is valve sticking or combustion chamber deposits. In the Top Tier testing protocols there are 2 tests designed to prevent this kind of issue - one is the Ford Combustion Chamber Deposit no-harms test - which requires that the Top Tier dose of additive can create no more than 140% of the deposits compared to no additive at all (this is only in the combustion chamber, not on pistons, valves or injectors -which is what these additives are designed to clean). The 2nd test is a intake valve sticking test where 2x the Top tier rate is tested to make sure that over-additization will not cause a loss of compression pressure in each cylinder. There is also a BMW CCD test which is similar to the Ford test for CARB requirements if you live in California.
Use TT gas on every fill (or even higher treat rates from places like Costco that offer it) without any concerns of additives causing deposits.