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Do you see huge benefits in premium/hi-test/whatever you wanna call it.

Interesting...Guys now we have to know why this is the case?

Heads are slightly different?
GenV blower
Returnless fuel system
Drive by wire throttle
Something in the transmission is different. PCM setting have to be changed versus the other years.

None of these things should matter, should they?
 


I would think heat would be the main thing. Higher compression means higher heat, more likely pre-detonation is to occur. Since the compression hasnt changed (that Im aware of) that would lead me to believe that heat has been dealt with in some way. We know the blower is more efficient and I believe the L32 heads have larger exhaust valves. Perhaps its all enough to lower the fuel requirements?
 
I would run 100 most of the time if they sold it near me. ;)

If I understand right, the Low Octane spark table is used only after you get KR, and if KR is not present for a while it goes back into the High Octane table. So, by running 87 you run the risk of constant KR and you can't be sure you'll get the lower timing all the time, which risks initially high KR until the switch is made. This would probably only be an issue for WOT, but I wouldn't do it without a custom tune and lots of scan feedback.
 
Just spoke to TooMch and his 04 book says 93 octane. His is a Comp G, you wouldn't think it matters but apparently it does.
 


Well, not quite.... that's what I thought because that's what I had been told. Here's what the 2004 Manual says:

Gasoline Octane
If your vehicle has the 3800 V6 engine (VIN Code 2),
use regular unleaded gasoline with a posted octane
of 87 or higher. If the octane is less than 87, you may
get a heavy knocking noise when you drive. If it is
bad enough, it can damage your engine. A little pinging
noise when you accelerate or drive uphill is considered
normal. This does not indicate a problem exists or
that a higher-octane fuel is necessary.
If your vehicle has the 3800 Supercharged V6 engine
(VIN Code 4), use premium unleaded gasoline with a
posted octane of 91 or higher for best performance. You
may also use middle grade or regular unleaded gasoline
rated at 87 octane or higher, but your vehicle’s
acceleration may be slightly reduced. If the octane is less
than 87, you may get a heavy knocking noise when you
drive. If it is bad enough, it can damage your engine.

I just went out and looked and there is no sticker on my fuel door or gas cap.

I always run 93 but I've been told you should run the least octane you can without getting knock. That is the most cost effective for your engine.
 
Well thanks for the research on the 04+'s everyone. I put in 93 octane this morning as I was a little under a 1/4 tank before it started snowing and I have to say I did notice a difference. So I have run 87, 89, and 93 in my car and wont run anything but 93 from now on.
 
Thanks for the discussion folks! I was more curious to see what was the reality vs the blah blah in the manuals.

I planned to burn premium anyway. I know I'm taking a trip soon to some more remote sites we service, so JIC there was only 87...I bought some octane boosters anyway.
 
TooMch said:
Well, not quite.... that's what I thought because that's what I had been told. Here's what the 2004 Manual says:

Gasoline Octane
If your vehicle has the 3800 V6 engine (VIN Code 2),
use regular unleaded gasoline with a posted octane
of 87 or higher. If the octane is less than 87, you may
get a heavy knocking noise when you drive. If it is
bad enough, it can damage your engine. A little pinging
noise when you accelerate or drive uphill is considered
normal. This does not indicate a problem exists or
that a higher-octane fuel is necessary.
If your vehicle has the 3800 Supercharged V6 engine
(VIN Code 4), use premium unleaded gasoline with a
posted octane of 91 or higher for best performance. You
may also use middle grade or regular unleaded gasoline
rated at 87 octane or higher, but your vehicle’s
acceleration may be slightly reduced. If the octane is less
than 87, you may get a heavy knocking noise when you
drive. If it is bad enough, it can damage your engine.

I just went out and looked and there is no sticker on my fuel door or gas cap.

I always run 93 but I've been told you should run the least octane you can without getting knock. That is the most cost effective for your engine.
Click to expand...

Thanks for popping in Rick. I thought when you typed in 93 you meant 91 on IM. A lot of people can't get 93..mine says 91 or premium. On the Impalas there is a sticker on the gas door and under the speedo it will say Premium Unleaded Only IIRC. Mine says Limited Edition instead.
 
I have a 99GTP and when I bought it from the dealership they had 87 in it and the salesman said it doesnt matter. I was mad when I got home and I read my owners manual. It clearly states running high octane and warns use 87 only in an emergency as it may result in dammaging the engine. I have ran 93 or better ever since. For 3 bucks a tank why risk. My logic if i risk doing thousands of dollars worth of dammage why chance it to save 3 bucks a tank?
 


I agree completely. There's what $0.20 difference between 87 and premium? So in a 17-18 gallon tank you save what a whole $3.50 or so? Lets say you get away with doing so for a whole year and you fill up once a week. And on the 53rd week the engine goes boom. So you save a whole $180 or so vs. the cost of an engine. The math just isnt there.
 
SyntheticShield said:
I agree completely. There's what $0.20 difference between 87 and premium? So in a 17-18 gallon tank you save what a whole $3.50 or so? Lets say you get away with doing so for a whole year and you fill up once a week. And on the 53rd week the engine goes boom. So you save a whole $180 or so vs. the cost of an engine. The math just isnt there.
Click to expand...

Exactly !
 
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