G5GT2007

im going to be needed my first tank of gas soon so i was wondering what kinda gas is better for the car.

blown06

i run 92-94 depending on what station i end up at

g5mike

Your 2.4 is 91or higher recommended, I think this is on page 54 of your owners manual

StinkBOMB

Mike has spoken.

Forseti

You can use a lesser octane, but the engine will not be able to produce peak power. "Recommended" octane is just that...not "mandatory"....

G5GT2007

really the dealer put in 84 i think. i cant remeber i was there when they filled it but i was on the phone. so then when i go to fill the tank put 91 in it. will i feel any power gain or lose from the motor?

g5mike

Is there such thing as 84? I thought it only went as low as 87,that sucks

g5mike

Your engine will retard too, also you will get engine knock

roccobladr

i run 87 all the time since i have gotten it. havent noticed any knocks or anything.

G5GT2007

oh yea no 84 i ment to say 87. the motor does have a little tick to it do i told my dad and he checked the owners manual and it said to use 91 so when i go to fill it up ill just put the 91 in it.

EtyrnuSS

Around here I have found I run best on Shell 93. We don't have 91 octane around here. Ran a couple of tanks of Exxon 93 and didn't get as good gas milage though.

Running on lower octane your car retards itself to prevent knock, also reducing your performance. It comes to about a $2-$3 difference in the price of a full tank. So if your car reccomends 91 or above, run it.

roccobladr

actualy...i do have a ticking sound in my car. sounds like its coming from the exhaust though. its kinda annoying cuz it still happens for a little after the car is off.

repoman

I have run a couple of gals of 100 through mine and seems to be more responsive. Also it gives that eye burning smell out the exhaust too.

JohnnySasakiMGS

I wish some of you guys would stop being cheap asses and just put 93 or 94 in. even if 94 is 20 cents more than 87. Whats that like 2.60 per tank? just put the good stuff in. Its better than having your car run like **** later on.

EtyrnuSS

They all do that. Its just the exhaust on these cars. Personally I am waiting for the police at the airport I work at to come ask me why my car is ticking.

But back to the subject, Just run premium. It isn't that much more total, and in the long run your car will be better off.

roccobladr

its actually alot more around here to use premium. ive seen 87 for 2.72$ but 93 for 3.12$

JohnnySasakiMGS

still on an absolutley empty tank its only $3.90 difference.

mike25

93 every time

OniMirage

make sure everyone on here is using top tier fuel in your ride

mike25

?....what do you mean dont buy the cheap ****...sheetz....or was that sarcasm?.....lol i cant tell

mstrpoz

i usually use 89 tried um all and the first time i put 91 it was amazing . i could feel the difference, and havnt went back

RJSS

Top Tier fuel is a standard developed by GM, Toyota, and a few other automotive companies. It is a recommended level of detergents/chemicals that are meant to keep engine valves and other parts clean as opposed to getting gummed up and sticking. There is a legal minimum level of detergents set by the government that must be met for all gas vendors, but Top Tier is a lot more stringent (use more/better detergents). Therefore, when you see the difference in price between two stations there is probably a reason. Just because two gasolines are the same octane does not mean they are of the same quality! I use Shell V-power 93 which is more expensive, but Shell is a Top Tier vendor. If you google "Top Tier" you can find a complete list of vendors who sell it.

OniMirage

straight from the top tier site

http://www.toptiergas.com/index.html

TOP TIER Gasoline Retailers:

QuikTrip
Chevron
Conoco
Phillips
76
Shell
Entec Stations
MFA Oil Company
Kwik Trip/Kwik Star
The Somerset Refinery, Inc.
Chevron-Canada
Aloha Petroleum
Tri-Par Oil Company
Shell-Canada

Why TOP TIER

The intention of the TOP TIER Detergent Gasoline standards is to create a winning situation for gasoline retailers, auto manufacturers and drivers. Currently, many gasoline retailers provide fuels with lower-quality additive packages that can build up deposits on fuel injectors and on intake valves. Others can build up deposits in combustion chambers and may lead to intake valve sticking. These lower levels of additives can have negative impacts on engine performance and vehicle responsiveness.


Deposit Control Standards

The standards developed by the four automobile manufacturers (BMW, General Motors, Honda, and Toyota) for TOP TIER Detergent Gasoline are described below. This technical document describes the deposit control performance of unleaded gasoline at the retail level that minimizes deposits on fuel injectors, intake valves, and combustion chambers. These standards comprise the requirements for TOP TIER Detergent Gasoline.

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.
Contain no less than 48 mg/kg sulfur. At least 60% of the sulfur shall be derived from FCC blend stock.
Produce a 90% evaporation distillation temperature no less than 290°F.
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.

RJSS

PS-When I bought my Cobalt I was so pissed when I found out they filled it up with 87. If your car was meant to be run on premium, you can get by with low grade, but once you switch back you'll know the difference. I sure did after my first fill-up. However, putting in an octane rating higher than what the car was meant to run on won't necessarily make you any faster. But then again, that's what HPTuners is for.

As another sidenote, before using Shell I ran Sunoco 94. I did not notice any power loss and made the switch because the Sunoco gave really shitty gas mileage. The difference was about 6mpg.

mike25

is bp top tier?