flynhi

Are these two additives roughly equal or is one superior to the other for fuel system, injector and valve cleaning?

bikgc

I've been wondering the same thing.
BUMP

I've been using Chevron in my car just because it's been highly recommended on here.

00Corvette

Just run whichever is cheaper...GM states that they are both "Top Tier" fuel

flynhi

What is the criteria for Top Tier?

00Corvette

I really don't recall, Lucky posted a link awhile back to the TSB.

Do a search using Luckys username and "top tier fuel" and you'll probably find it.

lucky131969

I wonder if you could google "top tier fuel"?

Florida99

No, too much typing. It'd be a whole lot easier if you just provide all the answers.

lucky131969

Apparently. Even with information at one's fingertips.....some just want to be spoon fed.......

jrose7004

You can Google anything and get answers.

Rob04C5LM

From www.toptiergas.com:
Standards

1.1 Retail Gasoline Performance Standards. The deposit control performance of unleaded gasoline conforming to section 1 of this document shall be met at the retail level in all grades of gasoline sold by a fuel company in all marketing areas of a selected nation. In addition, conformance to the standards shall mean gasoline sold in the selected nation shall not contain metallic additives, including methylcyclopentadienyl manganese tricarbonyl (MMT).

1.2 Deposit Control Additive Requirements. The deposit control additive used to meet the performance Standards described in 1.3 shall meet the substantially similar definition under Section 211(f) of the Clean Air Act. Also, the additive shall be certified to have met the minimum deposit control requirements established by the U.S. Environmental Protection Agency (EPA) in 40 CFR Part 80. Lastly, the additive shall be registered with the EPA in accordance with 40 CFR Part 79.

1.3 Deposit Control Initial Performance Standards. Initial deposit control performance shall be demonstrated using the tests shown below.

1.3.1 Intake Valve Keep Clean Initial Performance Standard.

1.3.1.1 Test Method. Intake valve deposit (IVD) keep clean performance shall be demonstrated using ASTM D 6201, Standard Test Method for Dynamometer Evaluation of Unleaded Spark-lgnition Engine Fuel for Intake Valve Deposit Formation. Tests demonstrating base fuel minimum deposit level (1.3.1.2) and additive performance (1.3.1.3) shall be conducted using the same engine block and cylinder head. All results shall be derived from operationally valid tests in accordance with the test validation criteria of ASTM D 6201. IVD results shall be reported for individual valves and as an average of all valves.

1.3.1.2 Base Fuel. The base fuel shall conform to ASTM D 4814 and shall contain commercial fuel grade ethanol conforming to ASTM D 4806. All gasoline blend stocks used to formulate the base fuel shall be representative of normal U.S. refinery operations and shall be derived from conversion units downstream of distillation. Butanes and pentanes are allowed for vapor pressure adjustment. The use of chemical streams is prohibited. The base fuel shall have the following specific properties after the addition of ethanol:

Contain enough denatured ethanol such that the actual ethanol content is no less than 8.0 and no more than 10.0 volume percent.
Contain no less than 8 volume percent olefins. At least 75% of the olefins shall be derived from FCC gasoline as defined by CARB (advisory letter, April 19, 2001).
Contain no less than 28 volume percent aromatics as measured by ASTM D 1319 or D 5580.
Contain no less than 24 mg/kg sulfur as measured by ASTM D 2622 or D 5453. At least 60% of the sulfur shall be derived from FCC blend stock.
Produce a 90% evaporation distillation temperature no less than 290F. as measured by ASTM D 86.
Produce IVD no less than 500 mg averaged over all intake valves.
1.3.1.3 Demonstration of Performance. The base fuel from 1.3.1.2 shall contain enough deposit control additive such the IVD is no more than 50 mg averaged over all intake valves. Results for individual valves and an average shall be reported. The unwashed gum level of the fuel containing deposit control additive shall be determined according to ASTM D 381 and reported.

1.3.2 Combustion Chamber Deposit Initial Performance Standard.

1.3.2.1 Test Method. Combustion chamber deposits (CCD) shall be collected and weighed along with IVD using ASTM D 6201, Standard Test Method for Dynamometer Evaluation of Unleaded Spark-Ignition Engine Fuel for Intake Valve Deposit Formation. ASTM D 6201 does not contain a procedure for collecting and measuring CCD. Adapting a scrape and weigh procedure developed by CARB is recommended (see referenced test method dated March 12, 1999). Results for individual cylinders and an average shall be reported.

1.3.2.2 Base Fuel. Combustion chamber deposits shall be measured for the base fuel from 1.3.1.2.

1.3.2.3 Demonstration of Performance. The base fuel from 1.3.1.2 treated with additive at the concentration meeting the standard found in 1.3.1.3 shall not result in more than 140% of the average CCD weight for the base fuel without additive.

1.3.3 Fuel Injector Fouling Initial Performance Standard.

1.3.3.1 Test Method. Fuel injector fouling shall be measured using the TOP TIER fuel injector fouling vehicle test available from GM. GM will run the test on a first-come-first-served basis and shall make the method available to those who wish to run the test on their own.

1.3.3.2 Base Fuel. Two options for base fuel are available:

1.3.3.2.1 Option 1. A full boiling range hydrocarbon gasoline or gasoline blending component, without oxygenates and without deposit control additives, that results in at least five inoperative injectors when tested by the method in 1.3.3.1.

1.3.3.2.2 Option 2. Federal emissions test gasoline specified in DFR 86.113-04, into which 4-methylbenzenethiol (WARNING: Flammable solid; irritant) has been blended at a concentration of 56 mg/L. The blended fuel must result in at least four inoperative injectors when tested by the method in 1.3.3.1. the Federal emissions gasoline, without deposit control additives, available from Haltermann Products (1201 South Sheldon Road, Channelview, TX 77530; tel.: 800-969-2542) has been found to be satisfactory.

1.3.3.3 Demonstration of Performance. A demonstration of injector fouling shall be done first. At least five out of six injectors (with Option 1) or at least four out of six injectors (with Option 2) shall be inoperative for the test to be valid. A demonstration of additive performance shall be done after the fouling tendency demonstration; no other test shall be conducted on the vehicle in the interim. A demonstration of additive performance shall be conducted using the same vehicle (including the fuel drain and flush procedures and installing new injectors) with the same batch of base fuel, but now containing the same amount of deposit control additive as in 1.3.1.3. A pass is defined as no more than one inoperative injector.

1.3.4 Determination of Deposit Control Additive Performance Concentration.

1.3.4.1 Methodology. The concentration of deposit control additive needed to meet the standards in 1.3.1.3 and 1.3.3.3 should be equivalent. However, if the concentration of deposit control additive in 1.3.3.3 is grater than in 1.3.1.3m the higher value shall be regarded as meeting both standards. Also, if the difference between the two concentrations is grater than 15%, 1.3.2.3 shall be repeated using the higher concentration.

1.3.5 Intake Valve Sticking Initial Performance Standard.

1.3.5.1 Test Method. Intake valve sticking tendency shall be determined using either the 1.9 L Volkswagen engine (Wasserboxer according to CEC F-16-T-96) or the 5.0 L 1990-95 General Motors V-8 engine (SWRI IVS test). Two options are available for demonstrating intake valve sticking tendency.

1.3.5.2 Option 1. The valve-sticking tendency of the test fuel by itself will not have to be demonstrated prior to testing the candidate additive. The following shall be required of all tests:

Test fuel shall be either the same as in 1.3.1.2 or CEC valve sticking reference fuel.
Concentration of deposit control additive in the test fuel shall be at least twice the amount determined in 1.3.4.1.
Test temperature shall be -20°C.
Three 16-hr cold soak cycles, each followed by a compression pressure check, shall constitute a complete test.
1.3.5.2.1 Demonstration of Performance. A pass shall result in no stuck valves during any of the three cold starts. A stuck valve is defined as one in which the cylinder pressure is less than 80% of the normal average cylinder compression pressure.

1.3.5.3 Option 2. The valve-sticking tendency of the test fuel together with an additive known to cause valve sticking shall be demonstrated prior to testing the candidate additive. The following shall be required of all tests:

Test fuel shall be either the same as in 1.3.1.2 or CEC valve sticking test reference fuel.
An additive known to cause valve sticking shall be selected, and, when blended into test fuel, shall demonstrate valve sticking tendency as follows: (a) for the Volkswagen engine, at least two valves shall be stuck; (b) for the GM engine, at least three valves shall be stuck.
Test demonstrating performance of the candidate additive shall be conducted at a concentration that is at least three times the amount determined in 1.3.4.1.
Test temperature shall be -20°C.
One 16-hr cold soak cycle followed by a compression pressure check shall constitute a complete test.
1.3.5.3.1 Demonstration of Performance. A pass shall result in no stuck valves during the cold start. A stuck valve is defined as one in which cylinder compression is less than 80% of the normal average cylinder compression pressure.

hardcore4sure

Oh boy really?

my02cents

I use Shell because there is a close, nice station right up the street... Also my next door neighbor was a Chevron VP and it pisses him off. Win/Win

dbbspider

Just don't use Sams Club gas. I did and it f'd up my gauge. Took me 3 tanks of chevron with and 12 oz of techron in each tank full to get it back to normal

dgrant3830

I'm not a chemist or a combustion expert but I have my doubts about them using nitrogen in the fuel to do anything other than save money for them. Nitrogen is totally inert which means it can't do anything to help the combustion process or anything to help clean the system. At this moment, too me, it seems that Shell is already adding ethanol which is hurting our gas mileage as any ethanol fuels do, then adding nitrogen to it...charge us more money for less. Sam's Club gas is a hair cheaper but again, its just the cheaper ethanol fuel. I only wish I had a Chevron station out here where I could get some real gas. There is one station only that sells gas with "No Ethanol" and they charge a premium price for it. Yesterday, $4.03/gallon, way out here where we are normally about 20 cents/gallon cheaper than most of the US. The closest Exxon station is about 25 miles east of us.

rtvols

I use Texaco with Techron. I will not use anything less.

Rob04C5LM

I've had this discussion a number of times with a gearhead friend of mine who also happens to be a Ph.D. in chemistry and works at Valero's refinery in Benicia, CA. I don't get all of the details of the chemcial reaction, but in lay terms: nitrogen (coupled with the other proprietary detergents in Shell's gas mix) reacts when exposed to the carbon deposits in your valvetrain and loosens the chemical bonds in the deposits.

What he's told me is that you shouldn't worry about "how" they do it because all of the major refiners use their own top secret proprietary process and they all involve greater or lesser amounts of the various detergents. What we should care about is the result, essentially, does it meet the "top tier" standard or not. In fact, your motor may benefit in different ways from different mixes, so you may be benefitted from switching around from Shell to Chevron to 76 to Mobil, etc.

I always laugh at him at this point in the conversation because his Valero gas that he can get for FREE, doesn't meet this standard so he doesn't use it in anything other than his daily driver honda.

dgrant3830

Sure nitrogen at the elemental level can be combined with other elements to create molecules that will actually do something for us, so I'll give them that credit, if that is what they are doing. But they advertise they are using nitrogen (N2) by itself which can only serve to take up space, therefore less gas for more money...but its a gas at these temperatures so it would simply vaporize away. N2 at liquid is -320 degrees and its obvious they aren't doing that. So sure, I have no clue what they are doing or how they can claim it helps us. Shell openly posts on the pumps they are using ethanol so how it meets the top-tier fuel requirememts is beyond my understanding.

BenC5

Up here in NewEngland, we have no Chevron's so I've been using Shell for both my truck and C5 for years, 2 years for the C5 and I've had no problems with the Vette.

Got the Vette with 32,505 and now have almost 67,000. Not a single issue related to fuel/Shell.

For about 30,000 miles in my truck, I was putting the cheapest gas I could find and one day I paid close attention and could hear my engine knocking under a load. I switched to Shell 87 and never heard any knocking since. Every now and then I put a tank of 93-in for the extra cleaning as the truck has 106,000 miles no it now.

dgrant3830

Actually, the higher the octane, the slower it burns therefore less knocking. I don't think higher octane promotes cleaning over the lower octane fuels that burn hotter.

worldtraveler

I read somewhere that it is recommended to alternate the fuels every once in a while as the additives act differently on the engine. thus by changing fuels, you attack different issues. I use both Shell and Chevron in mine, mostly Chevron.