What Gas Does The Max Take?

[punmax]

Hey guys, I've been putting 87 octane in my 6.0 litre 07, can I keep putting that in or do I need something higher?

 

And the gas gauge sucks! If I'm on a hill and its empty and I shut it off and turn it back on, it will say over half then go slowly back down to E lol.

[jrrod2004]

Hey guys, I've been putting 87 octane in my 6.0 litre 07, can I keep putting that in or do I need something higher?

 

And the gas gauge sucks! If I'm on a hill and its empty and I shut it off and turn it back on, it will say over half then go slowly back down to E lol.

 

 

91 octane for max performance, 87 should be fine unless it starts pinging/knocking bad

[C & A s Dad]

Search this subject and you will find many posts concerning this. The general concensus is that the late model 5.3s and 6.0s will make more power on 91 or 93 octane. The ECM system will adjust timing upward until the knock sensors detect ping at which time the ECM will retard timing. It will move timing up again until the ping is detected again. With 93 octane, the ping may come but it will come at a much higher degree of timing allowing for more power. Some do not agree with this but you will find many who do. I am one of the belivers and run 93 octane year round. I am fully convinced that my Yuk XL pulls my camper better with 93, especially when pulling a hill.

[punmax]

can i fill it with 91 octane with the 87 still in the tank? and will i get more mileage? also what is ping / knocking ;P

[327BlackBird]

Yes you can and ping and knocking is Premature detonation or premature ignition.

 

IMO

 

putting 91 octane and up in a stock 5.3 and up is just tossing money away and damaging your engine quicker then you normally would.

 

Higher octane ratings are for more performance oriented applications. Remeber, the higher the octane the longer the burn, the more wear on stock parts not meant to handle excessive burn time. This is where you get "Carboned up" engines around 50,000k when they shouldent be approaching the carbon level that the engine is in with the high octane use.

 

To Each their own but as a quick example.

 

stock 5.3 and the Maxx engine is not an 11:1 compression engine. It does not require higher octane fuel to operate, you will and can get cylinder wash after an extended period of use as the fuel is too rich for your application. Yes you can get better mileage to a SMALL degree, but the power difference is negligable for the added cost and excessive wear.

 

Where as my 80 Zedder requires no less then 94 Octane to run. Anything less will completely detonate the engine and the connecting rod may take a vacation though my oilpan. It is a 11:1 compression engine, with roller cam and roller rockers, forged internals etc etc, it WILL always make more power in respect to higher octane ratings because i built the engine in regards to that. Gas mileage? Forget about it, but it is not meant for fuel economy.

 

So basically if your engine was not designed for high Hp high Tq applications and your stock engine is NOT Huffed or juiced and has not been modified to bump up the compression ratio, higher octane fuel is a waste to your stock engine.

 

But your truck is not my truck and i am not bashing anyone who uses higher octane fuel, i am just stating a proven fact and widely known thoughout the automotive technician service. If you want to use 91 or higher knock yourself out, i will help you when you eventually wipe something out in the engine, after all i am a red seal master technician ;)

[ewiski]

red seal certified?

 

im a blue star certified bs detector. lol

[jnpaddison]

327BlackBird..

 

with regards to the cylinder wash - ( i am making my assumption on Fuel Injection rather than Carb'd )

wouln't the O2 sensor in the exhaust manifold sense a rich condition and adjust the injectors accordingly ??

 

( i realize there is a fine dance between detonation / octane / pinging and fuel mapping )

[07Graystone]

Anything less will completely detonate the engine and the connecting rod may take a vacation though my oilpan.

 

327BlackBird:

 

Thanks for the info. I always thought detonation causes a hole in the top of the piston, more so than a broken rod. I guess thats why I have no red, blue or any other color certification.

[redvett]

Look in your owners manual. Don't use any higher octane than needed.

[327BlackBird]

Yes red seal certified.

 

5 years of Automotive technician school, 10 years working in the field total and i still do time to time. Red seal is interprovincial, i can go anywhere in Canada and not have to retest for my Automotive service technician's license and i can go to the states without having to retest as well and i would make more money then an ASE certified technician. Red seal requires a exam score of %90 and above to aquire it, otherwise you just have your mechanic's license.

 

According to the Gm techs at work, too much octane will have the engine aquire a intermittant cylinder washdown after a period of time. It wont be %100 all the time but it can happen according to them. The AFM is still in it's baby steps and the ECM will let it happen at one point or another. Now in regards to the O2 sensors, once they get wet with unburnt fuel "overly rich condtiion in reguards to a richer fuel mixture" they will act up and let it happen more frequently as the ECM is now getting bum readouts and incorrect fuel mixture ratios and will eventually lean out the mixture resulting in a hotter running engine which as well know will cause excessive wear on the internals. Take it for what it's worth, i am not giving s**t out to people who do use higher octane, afterall it is there rig, not mine, i am just trying to shed light and hopefully prevent future repairs that can add up to big money.

[327BlackBird]

Anything less will completely detonate the engine and the connecting rod may take a vacation though my oilpan.

 

327BlackBird:

 

Thanks for the info. I always thought detonation causes a hole in the top of the piston, more so than a broken rod. I guess thats why I have no red, blue or any other color certification.

 

 

 

Yes it can blow a hole in the top of a piston, i was using my scenario as an example. If your spinning up the rpms to say 6 to 7 grand with detonation happening it can very well blow the bolts out of a rod or snap the rod and send it flying.you can also float your lifters and wipe out a cam or cam lobes, blow the piston apart, blow a hole though it, snap a wrist pin, crack a piston skirt, bend a valve, let the valve kiss a piston, all tons of fun, I have seen the aftermath of it happening.

[327BlackBird]

What is the Interprovincial Standards Red Seal Program?

 

The Red Seal Program was established to provide greater mobility across Canada for skilled workers. Through the program, apprentices who have completed their training and certified journeypersons, are able to obtain a Red Seal endorsement on their Certificates of Qualification and Apprenticeship by successfully completing an Interprovincial Standards Examination.

 

The program encourages standardization of provincial and territorial apprenticeship training and certification programs. The Red Seal allows qualified tradespersons to practice the trade in any province or territory in Canada where the trade is designated without having to write further examinations. To date, there are 49 trades included in the Red Seal Program on a national basis.

 

Legislation permits provinces and territories to designate trades and develop apprenticeship programs for their own requirements. Thus, in excess of 300 apprenticeship programs are available across Canada. The Ellis Chart, a comparative chart of apprentice training programs across Canada, is produced by HRSDC in collaboration and consultation with the provinces and territories and provides training and certification details for all of these apprenticeable programs.

[Raymond Lowe]

Carbon buildup and cylinder wash would be a bit of an assumption. There are dozens of variables with each engine design and setup. Injector pressure, tip design, timing, discharge rates/patterns, piston shape, combusion chamber, and the list goes on.

 

My ass-dyno can tell you this; a 5.7 Vortec in my 96 pulled the strongest at around 90 octane. Anything higher made no difference so I usually ran 89 or occasionally, 92. It had the factory 9.4:1 CR. After 11 1/2 years, this engine still runs strong with zero oil consumption at 265,000km. With that kind of time under my ass, rest assured, I could feel every ft lb that engine put out.

 

My issue with higher octane fuels is the cheap-ass way it's made. Every region has differences, so you might have to check what's being supplied in your locale. Gas refineries discovered that you can improve the octane rating simply by using more alcohol or ether-based additions (MTBE, ethenol, etc) which is a relatively cheap way to push the number up. They use terms like "oxygenated" fuels and talk about how good it is for the environment. But using these additives allow them to get a much higher yield per barrel by taking lower octane base stock and artificially raising the numbers. Meanwhile, your fuel economy starts to suffer because your OBDII engine will burn more of it to produce the same output and keep your cat temp within normal parameters.

 

What does this mean to you? You might be better off with a mid-grade fuel, 89 if it's available. In a modern computer controlled engine with CR's in the mid nines, I go with 89 octane. CR's in the 10's (like the Denali), then 92 octane.

[ewiski]

yea certifications=certified test taker.heheh

[hotwheels57]

I had the same concerns when I first got my 6.0l Silverado. The manual says 87 octane is fine. If you want to spend the money on premium, that's your choice. The computer can only adjust so much within it's set factory parameters. It's a waste of money IMO to use anything more...unless you've got some special "tune" and after market add ons to justify it.

My choice is to use only what the manufacturer recommends and occasionally use a bottle of TECHRON or LUCAS fuel injector cleaner to keep it clean.