: Injector Cleaner Kills MPG?



carguy16
03-16-05, 07:56 PM
I think this theory is valid, Im running premium fuel, and put in a bottle of Super Concentrated injector cleaner, I've gone 60 miles and im on less then a quarter tank, go figure.

I have gone 60 miles on the highway without one bar disapearing. Either way, its drinking alot of gas! I cant wait till I drain this tank of gas, im putting 87 back in, and will see how gas mileage is, since I ran premium for the past 2 fill ups, and put injector cleaner in on the last fill up.

caddycruiser
03-16-05, 08:21 PM
I filled mine up with 89 last week while I was home on Spring Break and it did not seem to like it. Drove the same as I always do, but it dogged in the power department and I could watch the notches disappear. Weird, because the few days beforehand, it ran like a top and sipped gas.

I've been tempted to put injector cleaner in it, but have now sworn off that too. From now on I'm sticking with plain old 87, and nothing else, because this car doesn't like anything more. :rolleyes:

carguy16
03-16-05, 09:50 PM
Yeh, Im going back to 87 too! I wanted to try 91 and see how it would like it, maybe clean something up with detergents and such, but, I dont think it worked too good. Im going with 87, much cheaper anyways, and recomended.

The only thing I can think off, if the injector cleaner actually cleaned the injectors, and now its spraying more fuel.:annoyed:

I filled mine up with 89 last week while I was home on Spring Break and it did not seem to like it. Drove the same as I always do, but it dogged in the power department and I could watch the notches disappear. Weird, because the few days beforehand, it ran like a top and sipped gas.

I've been tempted to put injector cleaner in it, but have now sworn off that too. From now on I'm sticking with plain old 87, and nothing else, because this car doesn't like anything more. :rolleyes:

scurling
03-16-05, 09:50 PM
Carguy16,

Why are you using premium fuel in your LT1 when it is designed to operate using Regular gas octane levels? Higher octane levels can actually decrease fuel mileage.

What makes you think the fuel additives decrease your gas mileage? If anything, they help to increase it by increasing the fuel efficiency of the engine. I really doubt it affects gas mileage to any noticeable degree.

I don't know what gas you are using, but if you are using a quality gas product (I know, quality is a relative term, but I mean from a major manufacturer), they already include cleaner additives, and there is talk within the induster of adding more or at least more gasoline producers standardizing on a minimum level of additive. I've been searching for this news article which I saw recently read, but haven't found it.

I did find this other article from USA Today, in 2003:
http://www.usatoday.com/money/autos/2003-07-30-premiumgas_x.htm

I don't believe it is "gospel", but it does add some good insight.

89fatb
03-16-05, 10:01 PM
i also have an lt1 in my 96 z28 and the owners manual says u have to run premium fuel. so i would assume all the lt1's are the same

scurling
03-16-05, 10:15 PM
I'm no expert on the LT1 builds, but I know different car applications, had different setups. The factory owners manual recommends Regular gas for the Fleetwoods.

caddycruiser
03-16-05, 10:21 PM
Same here. I know the car was designed to run on 87 only, but I just like to put something "better" in once and a while to see if it makes any difference. Clearly it doesn't, and I won't waste the extra couple of dollars again.

MrSmith
03-16-05, 10:28 PM
Whats go'in on here!!! I thought we were suppose to run Gold/93 My book says 93. Im not getting whatyall R talkin' bout'

juiceE
03-17-05, 11:09 AM
i usually put in 89 ... once in a while ill put in 87 seems to run up faster, and on occasion ill put in 93, which seems to last the longest, other then that, i never noticed anything different in the way they drive... u guys gettin me confused

scurling
03-17-05, 09:03 PM
Hey guys, maybe we can get a CHemical Engineer to join in and give us a really technical explanation of the how and whys of octane.

Basically, Octane is only an additive which increases the maximum compression at which gasoline will explode, e.g; pre-ignition. That's why higher compression engines (which usually means higher HP/CID) require higher octane levels in gas to prevent pinging.

thepitboss
03-26-05, 12:41 PM
My experience has always been that the tank after you put in a fuel additive is when you should get your best results.

N0DIH
03-26-05, 07:51 PM
Octane is nothing more than "Resistance to detonation". Nothing more, nothing less.
Not BTUs (British Thermal Units, aka, the amount of thermal energy in a specific amount of fuel), not specific gravity, and not vaporization point (RVP).

Sources:
http://www.handymanusa.com/articles/octane.html,
http://www.geocities.com/TimesSquare/Alley/7026/octane1.html
http://www.chevron.com/prodserv/fuels/gas_qanda/api_octane.shtml
http://www.petro-canada.ca/eng/prodserv/fuels/6823.htm
http://www.cyber-north.com/autotipnet/octane.html

It takes a little bit more oil at the refinery to make 93 octane over 87, and the specific gravity is more. 93 burns a little bit slower than 87, and it takes a little bit (LITTLE, like no mods on a good HEI or Optispark) more electricity to ignite.

On a 91-94 4.9L the factory timing specs are 10 degrees for 92 octane. The book (FSM) states that you can re-adj timing to 6 degrees to run 87 octane. I have done so for many years with no ill effects. 8 degrees works well with no pinging on my 91. You will need to experiement, and weather (temp and humidity) have a big effect on pining. Mileage is the same, and drivablity is nearly the same. sometimes I would get some off idle hesitation. which didn't happen with 93 octane and 13 degrees timing.

With more and more reports on injector clogging with ethanol "enriched" (yes, that is an oxymoran) fuels, I am wiling to pay more to run pure gas instead of that mixed crap. That also has some effect. Ethanol will have more cooling effect, adiabatic (sp?) cooling, but with the short run from the injector to the chamber, it is very small. Ethanol fuels burn a significant rate slower than non-eth fuels. Which is one reason why increased compression often helps reduce the side effects of ethanol based fuels. But ethanol fuels will allow a little bit more ignition lead than non-eth fuels. But there is an average 10% reduction in fuel economy with ethanol fuels. And the emissions does get worse, as our ECM/PCM's are designed to maintain a strict 14.7:1 A/F mix, and 10% Ethanol fuels require a 14.1:1 A/F mixture. So they run lean, creating higher HC levels and higher NOx emissions levels than non-eth fuels. Cars that are deisgned to be multifuel, like e85 and e95 do not have this emissions issue. So when your politician or favorite tree hugger pushes you to use ethanol fuels, punch them in the nose, they are the #1 cause of acid rain.

On octane, often used in cars, is aviation fuel. It is much lower specific gravity of fuel as compared to auto gasoline. This fuel is designed for high altitude engines, which often can also tweak and adjust timing and fuel mixture in flight. It often makes less HP in cars than lower octane auto gas. Race gas is often higher specific gravity than std auto gas. It is designed for power.

Gasoline for cars has around 125,000 BTU's per gallon. Diesel has more like around 140,000.
Sources:
http://www.nooutage.com/fuels.htm
http://www.exxon.com/USA-English/GFM/Products_Services/Fuels/Diesel_Fuels_FAQ.asp
http://www.hawaii.gov/dbedt/ert/fueltax-act143.html

I am far from a chemical engineer, but I have read some excellent articles in Hot Rod/Car Craft back in the 80's on fuels. If I can find them and get permission to scan and post them, I will. They were well documented articles from discussions with fuel engineers at popular oil companies.