Unleaded or Super Unleaded?
Discussion
The owners manual for a LS1 5.7ltr Camaro states that 91 octane or higher should be used. Given that octane is measured differently in the UK and that (I believe) 91 in the US is roughly equivalent to 95-96 in the UK, I guess I'd be fine to use standard unleaded at 95 RON. But do you guys find any real benefit from filling up on super unleaded instead....or is that just a waste of money?
). Might be best asking in the Corvette forum.
US gas is measured in PON while we measure in RON.
RON MON PON
90 83 86.6
92 85 88.5
95 87 91
96 88 92
98 90 94
100 91.5 95.8
105 95 100
110 99
so 91 is our 95.
The octane of a fuel is nothing to do with anything other than knock resistance. When the engine detects knock (or pinking), the computer retards the timing which cuts power. It follows that if you get knock using 95, the computer will always pull the timing. If you don't get knock then the computer won't and you will get the maximum 305hp (or whatever the real LS1 figure actually is
) and 99 will be a waste of money. However, if your car ever did knock, the 99 would stiop the knock and the computer wouldn't have to retard the timing.
So what this is about is whether your car will ever be used in conditions where it might pink and this is more likley to be in very hot or racing scenarios. Effectively, if the car is rated at 305hp and they advise 91 (95) then the chances are 99 is a waste. 99 won't ever endow the car with more power than it already has though.
I have a supercharger on my modified Mustang and detonation can be fatal so I use 99 because the application demands 93.
I used 95 in my LS1-engined Z28 for 4 years without any problem or need to use 99.
The only advantage in 99 is that it's supposed to give better mpg so it may even out slightly.
RON MON PON
90 83 86.6
92 85 88.5
95 87 91
96 88 92
98 90 94
100 91.5 95.8
105 95 100
110 99
so 91 is our 95.
The octane of a fuel is nothing to do with anything other than knock resistance. When the engine detects knock (or pinking), the computer retards the timing which cuts power. It follows that if you get knock using 95, the computer will always pull the timing. If you don't get knock then the computer won't and you will get the maximum 305hp (or whatever the real LS1 figure actually is
) and 99 will be a waste of money. However, if your car ever did knock, the 99 would stiop the knock and the computer wouldn't have to retard the timing.So what this is about is whether your car will ever be used in conditions where it might pink and this is more likley to be in very hot or racing scenarios. Effectively, if the car is rated at 305hp and they advise 91 (95) then the chances are 99 is a waste. 99 won't ever endow the car with more power than it already has though.
I have a supercharger on my modified Mustang and detonation can be fatal so I use 99 because the application demands 93.
I used 95 in my LS1-engined Z28 for 4 years without any problem or need to use 99.
The only advantage in 99 is that it's supposed to give better mpg so it may even out slightly.
Edited by LuS1fer on Friday 30th May 20:00
Thanks for the feedback guys. I'll stick with regular unleaded.
On a side note, I've just discovered that it's official mpg figures are exactly the same as my wife's BMW 525i (according to the US Govnt's fuel economy site). Now the 525 isn't exactly frugal with the juice, but it isn't horrific either. I've got a feeling that my 'soon to arrive' Z28 won't exactly be the gas guzzler that some of my friends think it will be....and it'll be a lot more fun than what they're driving :-)
On a side note, I've just discovered that it's official mpg figures are exactly the same as my wife's BMW 525i (according to the US Govnt's fuel economy site). Now the 525 isn't exactly frugal with the juice, but it isn't horrific either. I've got a feeling that my 'soon to arrive' Z28 won't exactly be the gas guzzler that some of my friends think it will be....and it'll be a lot more fun than what they're driving :-)
yabadaba said:
Thanks for the feedback guys. I'll stick with regular unleaded.
On a side note, I've just discovered that it's official mpg figures are exactly the same as my wife's BMW 525i (according to the US Govnt's fuel economy site). Now the 525 isn't exactly frugal with the juice, but it isn't horrific either. I've got a feeling that my 'soon to arrive' Z28 won't exactly be the gas guzzler that some of my friends think it will be....and it'll be a lot more fun than what they're driving :-)
Mine was an auto and would return about 20mpg in daily commuting and anything up to 30 on a run if I was careful. I wasn't very careful though. You might want to think about strengthening rails that weld on undeer the car and stop the car being so floppy, a Bilstein BTS suspension kit and some bigger wheels (18's look best).On a side note, I've just discovered that it's official mpg figures are exactly the same as my wife's BMW 525i (according to the US Govnt's fuel economy site). Now the 525 isn't exactly frugal with the juice, but it isn't horrific either. I've got a feeling that my 'soon to arrive' Z28 won't exactly be the gas guzzler that some of my friends think it will be....and it'll be a lot more fun than what they're driving :-)
http://www.cardomain.com/ride/471412
Edited by LuS1fer on Saturday 31st May 09:05
LuS1fer said:
Mine was an auto and would return about 20mpg in daily commuting and anything up to 30 on a run if I was careful. I wasn't very careful though. You might want to think about strengthening rails that weld on undeer the car and stop the car being so floppy, a Bilstein BTS suspension kit and some bigger wheels (18's look best).
Funny you should mention the wheels because they are the only thing I'm really not to keen on. The stock 16's just don't fill the rear arches enough, so was thinking of buying a set of 17's....hadn't considered 18"....but maybe I should. Some of the American Racing wheels look good, but I'll probably have to wait a while as new wheels will also mean new tyres and the whole lot will come to quite a pretty sum! yabadaba said:
LuS1fer said:
Mine was an auto and would return about 20mpg in daily commuting and anything up to 30 on a run if I was careful. I wasn't very careful though. You might want to think about strengthening rails that weld on undeer the car and stop the car being so floppy, a Bilstein BTS suspension kit and some bigger wheels (18's look best).
Funny you should mention the wheels because they are the only thing I'm really not to keen on. The stock 16's just don't fill the rear arches enough, so was thinking of buying a set of 17's....hadn't considered 18"....but maybe I should. Some of the American Racing wheels look good, but I'll probably have to wait a while as new wheels will also mean new tyres and the whole lot will come to quite a pretty sum! http://www.tbyrnemotorsports.com/ls1/wheelstires.h...
LuS1fer said:
True but some are surprisingly affordable. I used these guys in 2003 and the wheels arrived within the week. Using tyres like Kumhos keeps the initial cost down.
http://www.tbyrnemotorsports.com/ls1/wheelstires.h...
Hmm...interesting....nice link with some attractive prices. To be honest, I've never dabbled with after market wheels before, so if I was to look into a set of 18's, what should the other measurement be....9.5, 10.5? I take it that's the width and will determine what tyre choices are available....what did you have 18x10.5"?http://www.tbyrnemotorsports.com/ls1/wheelstires.h...
yabadaba said:
LuS1fer said:
True but some are surprisingly affordable. I used these guys in 2003 and the wheels arrived within the week. Using tyres like Kumhos keeps the initial cost down.
http://www.tbyrnemotorsports.com/ls1/wheelstires.h...
Hmm...interesting....nice link with some attractive prices. To be honest, I've never dabbled with after market wheels before, so if I was to look into a set of 18's, what should the other measurement be....9.5, 10.5? I take it that's the width and will determine what tyre choices are available....what did you have 18x10.5"?http://www.tbyrnemotorsports.com/ls1/wheelstires.h...
To some extent, you get what you pay for. The stock chrome wheels on the Z28 flake on the back of the rim and eventually lift and corrode to such a degree that the wheels are scrap. Can't get them re-chromed as it's not worth it. The choice for replacement is then more chrome which i would advise against as it's usually cheap Chinese chrome that flakes faster than an onion, polished - which can be hard work as they're not lacquered if you use it year round or painted which are the most practical if not the best looking.
If you want to sour ce some in the UK, North Hants Tyres will do you a wheel and tyre package for £800-£1000.
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