[BUILDINGCTSAMG]

I was talking to the guys working on my car today and they told me that i should not but premium gas in the cts! Put 89 octane in it and the rumbles and such from the engine should go away......did other people know this?

 

[BeelzeBob]

That sounds very wierd...

 

[catbert]

I was talking to the guys working on my car today and they told me that i should not but premium gas in the cts! Put 89 octane in it and the rumbles and such from the engine should go away......did other people know this?

Mine's very happy with mid-grade 89 octane. (12,000 miles)

 

[elwesso]

It is stupid to put in a higher octance than what is required.... no power benefits..... If you care to know why, there is a thread about this somewhere.....

If the manual says 90, then 89 should be ok... the computer can compensate for that......

 

[shaggygrosser]

I've been switching back & forth between premium & mid-grade. I haven't had any problems over the 2000+ miles I've driven.

 

[Versatrak]

Some of the earlier CTS in the 2003 model year recommended Premium fuel. More recent ones, work fine on regular.

Check the owner's manual, or on the gas door, if it takes premium, there should be a little label there.

 

[caddieboy]

I was talking to the guys working on my car today and they told me that i should not but premium gas in the cts! Put 89 octane in it and the rumbles and such from the engine should go away......did other people know this?

I was under the impression that the 3.6 takes 87 and the 3.2 take a higher Octane.

 

[miscreant]

The 3.2L is recommended 91octane. The 3.6L is recommended 87 octane.

 

[caddieboy]

The 3.2L is recommended 91octane. The 3.6L is recommended 87 octane.

Wow, so not only will I be saving in terms of gas consumption but also in fuel grade? I can handle that.

 

[strindl]

Mine has run perfectly on nothing but 87 octane regular. Its the 3.6 though, so that is all my engine requires. Thats a nice benifit to the CTS over its competitors from Lexus, mercedes, BMW, Infiniti, etc..which almost all require premium.

 

[j-w]

Is it possible the higher octane would be causing engine noise/rattles/rumbles? That doesn't sound right. Usually it's just the opposite. Been using nothing but 93 octane in the 1600+ miles I've put on it so far.

 

[caddieboy]

Is it possible the higher octane would be causing engine noise/rattles/rumbles? That doesn't sound right. Usually it's just the opposite. Been using nothing but 93 octane in the 1600+ miles I've put on it so far.

My dad's old deville rattling was solved by using a lower octane.

 

[tzoid]

this is an old thread that has had lots of info provided on grades of gas for the '04 CTS with the 3.6L engine, many by the General's factory technocrats . Long story short...designed for 87 octane, will not provide ANY additional hp from higher grades, can potentially do more harm than good due to detonation points of higher grades and last, but not least, a waste of money. You should be thrilled that the 3.6L was designed this way...prestigue no longer exists because it burns high test!

 

[caddieboy]

this is an old thread that has had lots of info provided on grades of gas for the '04 CTS with the 3.6L engine, many by the General's factory technocrats . Long story short...designed for 87 octane, will not provide ANY additional hp from higher grades, can potentially do more harm than good due to detonation points of higher grades and last, but not least, a waste of money. You should be thrilled that the 3.6L was designed this way...prestigue no longer exists because it burns high test!

My appologies. I was going way back to look at posts and didn't realize I would bring this post to popular viewing. Now I get how things work. You post and it moves it forward to the front of the line.

Do I get a newbie warning and I'll be good from now on?

 

[silver bullet]

I agree that if a engine is designed for 87 octane there is no reason to put a higer octane in. But why does my 3.6 owners manual say for maximum performance use 91. It runs great on 87 but does feel stronger especally off the line with premium.

 

[Devil_concours]

I agree that if a engine is designed for 87 octane there is no reason to put a higer octane in. But why does my 3.6 owners manual say for maximum performance use 91. It runs great on 87 but does feel stronger especally off the line with premium.

where? page#?

 

[RobertCTS]

My 2 cents. It's my understanding that in the beginning all the gasolines are from same batch. Usually the lowest octane burns the hottest and the fastest. Cars with higher compression engines will knock and bang like crazy because the explosion is to fast. So the gas companies add retardants to slow the burn. Wouldn't make sense to burn the lowest you can for the biggest bang. That suggests for most of us that the premium grade is wasting money. I use 89 octane in my 3.6

 

[rollinincaddys]

I Have A Cts 3.2 All I Ever Put In That Car Was Octane 100. Its Expensive Like 3.25 A Gallon But Its Worth It. The Car Get More Torque .

 

[miscreant]

I agree that if a engine is designed for 87 octane there is no reason to put a higer octane in. But why does my 3.6 owners manual say for maximum performance use 91. It runs great on 87 but does feel stronger especally off the line with premium.

Because it's just a reprint/remnant from the 3.2L.

 

[miscreant]

I Have A Cts 3.2 All I Ever Put In That Car Was Octane 100. Its Expensive Like 3.25 A Gallon But Its Worth It. The Car Get More Torque .

$3.25 a gallon worth it???? I can think of a couple things I could buy for a 3.2L in a couple months from the money not spent on that gas that would give better performance than 100 octane. That's not worth it and most likely going to kill the 3.2 prematurely. The ECM will most certainly adjust for some serious retard you're running with 100 octane. That's like running race gas every day. I'd hate to see inside your engine.