It appears that the owners manuel suggests regular unleaded but the dealer suggests using high octane. I am not thrilled with using high octane due ot the price, especially in Southern California but I will at the expense of performance and engine health. What is the general concensus? I am not a believer that high octane is always better.

You are correct the manual says regular..but the dealer says use a higher ocatane. I would mix super and plus which should yield around 90-92 octane....or do what i do...wait till super is cheaper on certain days. IN nj its 1.89 at the local bp..then again if you own a cadillac i hardly think .20 a gallon will break your wallet!

It appears that the owners manuel suggests regular unleaded but the dealer suggests using high octane. I am not thrilled with using high octane due ot the price, especially in Southern California but I will at the expense of performance and engine health. What is the general concensus? I am not a believer that high octane is always better.

I am no expert on this subject, but....

I've heard that this is one of the major pluses of the 3.6L on the CTS. It is designed to be run on regular octane fuel. Also, every car that I've ever owned that was supposed to use premium fuel made it very clear in the manual of this. Often times the wording is something like this. "the use of 93+ octane is recommended in this vehicle. using 87 octane will not damage the engine but there may be a slight reduction in engine performance"

Since the manual makes not comments about using premium, I think that you are fine with using regular and that you will not experience much, if any, benefit by using premium.

The skinny on octane..... A small science lesson, has to do with compression ratios and combustable volatility. A low compression engine only requires low octane gas, high octane gas provides no benefit nor detriment. A high compression engine however, requires high octane gas, and can be ruined by lower octane. Why, you ask.... As you increase the amount of pressure in the combustion chamber, you create heat. The higher the compression, the higher the heat. The octane rating allows a fuel to withstand a higher amount of heat before it ignites itself. Yes, there is such thing as spontaneous combustion! If you use low octane fuel in a high compression engine, the fuel will detonate prematurely, and wreak havoc upon your drivetrain. You dont want your fuel ignited before the piston has reached TDC! High octane fuel absolutly does not increase performance in standard compression engines. High compression increases engine performance. High performance engines require high octane fuel. As stated, low octane fuel presents the problem or premature detonation. As the 3.6 engine has Variable Valve Timing (VVT) it is able to electronically compensate for some pre-detonation. Newer computer actuated engines such as the VVT are better able to cope with different octanes of fuel, thus allowing you to manipulate the octane levels and possibly benefit with some miniscule performance increase. If you were to read the owners manual further, Cadillac recomends High octane fuel under "Towing Conditions", but normally suggests standard octane. With all this known, I use 93 octane on every 4th fillup, just for the hell of it. The difference in price per tank is roughly 3 dollars. Hope this helps.

I've been using strictly 87 octane regular in my 04 cts and it's run flawlessly with it. Using 93 octane premium is throwing your money away.

CTS Orlando thanks for the information, that was exactly what I was looking for. I am a techinal person and that was a great response. Much better then I just blah blah.

I've ran both 87 and 89 octane(many tank fulls of both). Both ran fine. I settled on the 89 octane for no good reason.

You are correct the manual says regular..but the dealer says use a higher ocatane. I would mix super and plus which should yield around 90-92 octane....or do what i do...wait till super is cheaper on certain days. IN nj its 1.89 at the local bp..then again if you own a cadillac i hardly think .20 a gallon will break your wallet!

$1.89 per gallon!!! WHERE IN NJ!!! Gas in midtown NYC is $2.20+

Details, DETAILS!!

Strindl is correct. Using anything over 87 octane is a complete waste of money. I always love it when I hear of people using the highest octane gas they can find to boost the performance of their car designed to run on 87 octane gasoline. To say that if you can afford a Cadillac you can afford a few extra dollars per tank is just plain stupid. If I am offending anyone, oh well.

$1.89 per gallon!!! WHERE IN NJ!!! Gas in midtown NYC is $2.20+

Details, DETAILS!!

Carlos, I sent you a forum email
Bob

Carlos, I sent you a forum email
Bob

Hey Robert thanks for trying however I do not have access rights to that.

Hey Robert thanks for trying however I do not have access rights to that.
Eyelids returned. Address label fell off. Need address again. martinptns@mindspring.com

See this thread:

http://www.cadillacforums.com/forums/showthread.php?t=1823&highlight=octane

I don't care what anyone says, I noticed better fuel economy and slightly more power from 91 octane over 87. I'd run it empty, fill up on 91, run it empty, fill up on 87, several times, and I noticed 2-3 points higher fuel ecomony and a little more grunt. Whether that offests the added price, that's up to you.

However, the 3.6L is recommended and rated at 87 octane, and the 3.2L is recommended and rated at 91+ octane.

See this thread:

http://www.cadillacforums.com/forums/showthread.php?t=1823&highlight=octane

I don't care what anyone says, I noticed better fuel economy and slightly more power from 91 octane over 87. I'd run it empty, fill up on 91, run it empty, fill up on 87, several times, and I noticed 2-3 points higher fuel ecomony and a little more grunt. Whether that offests the added price, that's up to you.

However, the 3.6L is recommended and rated at 87 octane, and the 3.2L is recommended and rated at 91+ octane.

Good to see you are still with us Miscreant. How is that Goat running?

Mileage is hard to argue. It's mathmatical calculations. Acceleration, unless you take it to the drag strip is harder to determine.

Has anybody the knowledge on fuel additives? Use to be that the distilleries added special bonuses for the high octane gasolines. The only example I can remember is the "anti-ice additive" I think they all have that now. John Arbuckle said, "You get what you pay for." Anybody know what we get extra?

You must not get out to NJ alot, drive out of the holland tunnel and hit the first bp you see. I paid today $1.89 for super which is normally $1.95
.

$1.89 per gallon!!! WHERE IN NJ!!! Gas in midtown NYC is $2.20+

Details, DETAILS!!

3.2 requires 91 oct

3.6 requires 87 oct

and i believe that if you put preimum in 3.6 it makes ticking noises.... so stay with 87 or 91...no preimum. ;)

my last 2 tanks were 87, my current tank is 93. Its not ticking, its not whining, its not crying or laughing, its not slower, its not faster, it hasnt offered thanks for using premium fuel, it hasnt even offererd to cook me breakfast. The 3.2 has a 10:1 compression ratio, and the 3.6 has a 10.2:1. Thats considered high compression in my book. Bottom line, the Computer controlled 3.6VVT compensates for any and all types of fuel. As far as I've seen, there are more questions than problems related to octane. Use what makes you happy.

I used to be in NJ all the time, I normally go across the GW Bridge to visit family.
But I will keep the info about BP in mind next time I use the Holland.

i feel bloated and sometimes constipated when i use 91+ octain in my 3.6

3.2 requires 91 oct

3.6 requires 87 oct

and i believe that if you put preimum in 3.6 it makes ticking noises.... so stay with 87 or 91...no preimum. ;)
Requires = recommended. The key term is recommended, not required. You will get alittle knock in the 3.2 with 87 octane, but it's minimal. But 91 octane works great in the 3.6L...

CTS Orlando thanks for the information, that was exactly what I was looking for. I am a techinal person and that was a great response. Much better then I just blah blah.


Just use high octane cause it's better...OK!?!?!?! :annoyed:





















kidding.

i feel bloated and sometimes constipated when i use 91+ octain in my 3.6

LMAO!!!!!! Too funny!

i feel bloated and sometimes constipated when i use 91+ octain in my 3.6

hmmm, is there a Taco Bell next door to your gas station?


changing topics- Is there any point to using higher octane gas after a couple of tanks of lower octane gas? and should I really care since I have 3.6?

changing topics- Is there any point to using higher octane gas after a couple of tanks of lower octane gas? and should I really care since I have 3.6?

It might be good to throw some higher grade gas in there once in a while to satisfy yourself that it doesn't add any additional performance or mpg. I doubt that you'd notice anything, but way stranger things have happened in this world. Especially because, as somebody noted earlier, of this engine's high compression ratio.
Let us know if you do notice improvements. Should be easy to notice, if you're normally using regual octane.

GFiLA and Coreyn,

When you say "dealer recommends", are you talking about your saleperson or a technician? In the latter case, I'd worry about having my car worked on at that dealership, if the techs are that un-informed/stupid.

salesperson and manager

You can't compare compression ratios from one engine to another and conclude that one needs more octane than the other. There's simply too many variables, including dynamic compression ratio, spark timing, valve timing, A/F ratios, combustion chamber design, etc.

The manual for my 2004 actually says to use premium, but I'm wondering if that's just a glitch on the Canadian manuals since every thing I've read elsewhere says to use 87.

Regardless, here's my take on octane. Modern engines will compensate down for whatever you fill it up with. I used to own an LS1-powered Z28 that recommended premium. However, at a $5 per tank additional cost, I never ran it except when I knew I'd be racing. And I didn't drive any differently-- if I wanted to floor it for 13 seconds from a stop, I didn't worry a bit. The ECM would simply pull timing and I'd lose a bit of power. Note, however, that the only time you'll notice this loss of power is at WOT. At any other time, all you have to do is press a bit harder on the loud pedal to compensate.

Now back to our engines. The 3.6 is designed to run on regular. This means the engine's optimal settings will accomodate regular gas no problem. There is not a "better" setting the engine can run at if you use premium. Cars cannot measure octane directly. The only way they know is when the engine knocks, so if it's not knocking with 87, there's nothing to tell it to dial in more power if you used premium.

Has anybody the knowledge on fuel additives? Use to be that the distilleries added special bonuses for the high octane gasolines. The only example I can remember is the "anti-ice additive" I think they all have that now. John Arbuckle said, "You get what you pay for." Anybody know what we get extra?

Shell advertises that their new V-Power fuel has 5X the additives the US Government recommends and "actively cleans" your fuel injectors & intake valves. The CTS owners manual suggests using such types of fuel. Check out these links for more info:

http://www.turbomustangs.com/techarticles/shellrelease.htm and http://www.shellus.com/news/relations/features/feature170.html

I'm not sure if it's just a marketing gimmick or not. I searched some other forums and it seems that there's a lot of skepticism regarding the V-Power fuel. Then again, other people swear by it. ...Who knows...

If it really made any difference one way or another what you used for fuel, you can bet your butt there would be a placard near the filler neck and a notice visible near the gas gauge like you see on cars where fuel grade actually is important. You can feel safe using whatever pleases you. This argument has been taking place as long as differences have existed in fuel, including preferences for oats expressed by Romans in the chariot races. Thousands of years from now there will be bar fights over the merits of the dilithium crystals found in the Trifect sector.

so what's the conclusion? stick with 87? yes? thanks

so what's the conclusion? stick with 87? yes? thanks

Chuck, you should just pour crude oil straight into your gas tank. That would solve your octane problem. RTFM

Better then that just pour grain alcohol
in your tank!

hmmm, is there a Taco Bell next door to your gas station?


changing topics- Is there any point to using higher octane gas after a couple of tanks of lower octane gas? and should I really care since I have 3.6?

First time I ever filled my tank I used the high octane, however ever since then I have been using regular. I just got my CTS in July so it is still relativily new, next time I fill the tank I will get high octane and check it out.

To answer a previous question I believe it was a salesman. I honestly think that he had no clue what he was doing. This was supported by the fact he was fired about 2 weeks after i got the car....this could explain why i never got a courtesy call to tell me my plates were in? HAs anyone experience this, i got my cts at Brogan in Totowa, NJ!

To answer a previous question I believe it was a salesman. I honestly think that he had no clue what he was doing. This was supported by the fact he was fired about 2 weeks after i got the car....this could explain why i never got a courtesy call to tell me my plates were in? HAs anyone experience this, i got my cts at Brogan in Totowa, NJ!

I can top that..I never even got a courtesy call to tell me when my new CTS came in. They had it on their lot for a month before I happened to see it sitting on their showroom floor with $9,000.00 worth of dealer added crap slapped on it. I was in every week checking on its status too..they just would tell me...nope, not in yet.