Fuel additives and Octane

[drumrpunk]

OK, I know there has to be alot of opinions on this topic so please feel free to chime in.

Fuel additives: I have 150k on the spedo and use my Tahoe as my cruiser. So it's typically out on the weekend only. So therefore with the high mileage I figured that a fuel additive may help keep my fuel system clean and possibly extend the life....plus I can afford a bottle or two a month. Do you use them? Does it really help? If so, what are good brands?

Octane: What is recommended by Chevy (5.7)? Since I am still quite new to Chevy's, I don't know what is recommended. I use 89 just in case. I figured with my miles that I probably have a bit of carbon build up and 89 would be a safe bet. And since it's a relatively low compression that 91 would be a waste of money. What do you use? What should I be using? :confused2:

 

[sasquatch094]

I was always told not to use octane boosters and fuel additives. Something with injectors, but i cant really tell you why tho...

As too octane rating. i Just use Premium or 94 in Ohio. Sh*t- gas prices are down, i mind as well make my hoe run a tad bit better. i havnt noticed anything in mpgs, BUT i do start my truck every morning for about 10 to 20 min and have been still getting the same miles on the tank as to when i never started my truck in the summer time use 87 octane...

 

[95TwinTT]

One of the greatest Myths of the modern world is the belief that higher octane fuel has more power. Horse Pucky. They all have the exact same BTU’s of power.

Because high performance engines NEED high octane, to prevent detonation, it is assumed that the fuel is the source of that power. Horse Pucky. The HP engine have higher compression ratios along with better breathing throughout providing the power.

The higher the compression, the higher the power of each power stroke.

The octane rating relates to the flash point. High octane, will not begin to burn from the heat caused by compression, it will wait for the spark. Lower octane will ignite from high compression before the spark, causing detonation or “pingingâ€. High performance engines run as high as 12 to 1 compression.

So in short, if you are running the stock equipment that GM designed to run on 87 octane, then higher octane will not hurt it, but is not needed. In other words it is a waste of money.

All of the gasoline additives probably have some positive attributes. Almost all gasoline these days have additives designed to keep injectors clean.

However, the small bottles of “octane boost†are mostly a rip off. If you look at the fine print, the claim of two to four points of boost, are “tenths†of a point. So if the bottle say’s it will boost 4 points it is .4 of One point, in reality.

Not trying to start an argument here, just thought I would chime in as the voice of reason…………… I’m not selling anything. :Yawn:

 

[drumrpunk]

Thanks for the replys. And no worries about arguments since I would like to know what anyone thinks (good or bad). So is 87 Octane GM's recommendation for most V8's? And like I mentioned above, with high mileage and therefor more carbon build up (which may increase compression ratio)....would 89 be a better choice? I still can't find any recommendations in the manual or on the truck anywhere. I use to race VW's (water cooled) and from the factory it was "recommended" 91 octane. It even said it on the gas door. When you did performance upgrades you started to get worried about pining (since Cali's limit is 91). I remember reading the "Octane Booster" bottle for the first time when I was getting into racing and found that most of the time you only get about 0.5 higher Octane. Octane booster is definitely a rip. But it's the only option for some people like us Californians who can only get up 91 at the pump. Anyways, when it comes down to it, I don't want to waste money on higher Octane if it's not needed. If 87's fine...then thats what ill stick with.

As for additives, I am looking not for raised octane but for fuel conditioning (to help prolong life). There are alot of brands out there that claim to help....but do they really? Most say there safe for ALL cars. Yet, when I ready the manual for my Nissan it says to NEVER put additives of any kind in the tank. So contradictory!

 

[95TwinTT]

I don’t know anything about the additives for fuel. I do suspect that they could have an affect on O2 sensors. You remember the problem with lead and O2’s?

Maybe that is why the Nissan manual was against the additives.

Deposits in the combustion chamber can for sure cause pre ignition. Most of the time you would not know, because the knock sensor hears it before we do and offsets the timing.

If you can feel a definite increase in performance with premium gas, then it is the result of the knock sensor NOT pulling timing back. It would be letting the engine fire when it is supposed to rather than having it’s timing retarted by the knock sensor.

I don’t know of any way to clean deposits out of the engine without pulling the heads. Maybe someone on here knows of some miracle additive that will remove deposits.

There is not much truth in advertising these days, so it is hard to sort through all of the products on the market.

For sure all of these vehicles left the factory expecting to just run regular fuel. California vehicles used to have extra pollution equipment, but I don’t know if there is any difference now.

One of the things I have done to increase octane is to blend some E85 with regular gas. I would put in 12 gallons of regular and 8 of E 85. That put me near 100 octane for race day. It is kind of a PITA for a daily driver though, unless you only live one mile from work like I do.

 

[sasquatch094]

But ive noticed a gain from higher octane. Its maybe not the power, but theres not as much hesitation from when i punch it and when it goes.... But my truck does run alot better using 93 octane. ticking sometimes occurs in my cars when using 87 all its life, so then i jump to 93 for some time and it goes away. I have always been told too, to atleast run your motor on 93 once or twice a year... idk.. im just saying and telling everything i believe. it may not be true, but idc..

 

[SSport]

I swear by Marvel Mystery Oil. I had a 1992 Saturn which burned about 4 quarts of oil a week (frozen piston rings.) Anyway I started putting in Marvel Mystery Oil every oil change and eventually got it down to about half a quart every 2 weeks after about 1 year of owning it.

You can also put it into the fuel system as well to keep the injectors clean and what not.

 

[GPChief]

I don’t know of any way to clean deposits out of the engine without pulling the heads. Maybe someone on here knows of some miracle additive that will remove deposits.

One of the things I have done to increase octane is to blend some E85 with regular gas. I would put in 12 gallons of regular and 8 of E 85. That put me near 100 octane for race day. It is kind of a PITA for a daily driver though, unless you only live one mile from work like I do.

I am sure the flames will start with this answer but it works for me and has for years.........I put ATF in my fuel. The cleaning agents clean the fuel system and lubricate it. I put one QT in every other tank, I do it in my truck, both cars and the wifes minivan :cool2: I swear by doing it.

Another way to clean the top end is with some Top End Cleaner.
http://www.sytyarchives.com/howto/viewarticle.php?article_name=top_end_cleaner.php&dir=engine

http://www.gm-trucks.com/forums/lofiversion/index.php?t12856.html

http://www.ls1tech.com/forums/gener...foam-top-end-cleaning-but-not-alot-smoke.html

This product (when used correctly) will clean the top end and you will notice a difference.

HTH