I know its not a good idea to run 87 in these babies but does pontiac require only high octane be used just wondering ? Probably a stupid question considering these are high performance machines. thanks.....
They recommend Premium. I use nuthin but Premium and I think most others do also. These cars need it for optimum performance. However they will run on a lower octane, maybe not as well as the should though.
With my understanding of how the LS2 functions, yes!!!!
The car follows two fuel programs, one is low octane which the engine defines based on knock and it comes into play with octane of 90 or less, and high octane which is 91 plus. While it could be possible that your car wouldn't trigger the low octane tables on 89, it more than likely would. On low octane your car retards the timing and richens the fuel mixture. This results in less power and lower fuel economy. The real question is, how much power loss and how much fuel economy loss. Some say you can't feel the difference and others say you can. Some say fuel economy isn't much if any changed and others say it's a large difference. There is also the question of what the richer mixture, needed to compensate for the lower octane, does to things like oil life and catalytic converter life.
What I say is, for $3 per tank of gas I'm not giving away the extra performance or chancing engine damage. Plus if there is fuel economy loss with lower octane your real world savings would be less than $3 per tank.
I use Sunoco Ultra 94 if it's available where I'm at (it is where I'm located in PA). Otherwise it will be a well-known brand of 93, usually Shell V-Power 93.
When I went to Watkins Glen last summer, I couldn't find Ultra 94 in NY state - they had "Ultra 93" as their highest grade. $3.69 per gallon as the gouging was in full effect (Labor Day weekend). Yikes.
Filled up with Sunoco 94 on Sunday for $2.69 per gallon.
The engine needs the octane for peak acceleration. If you are not racing, the cheap stuff will not hurt the engine at all. You will just not see all your ponies show up on the race line. I work for a petrochemical company and here's a secret. Fuel carriers will routinely dump Super into the midgrade storage tanks when making a delivery (load does not fit in allocated storage tank etc.). Also, if the fuel rack (pipeline end storage facility) is having supply issues versus allocation, they will just deliver Premium and bill the manifest as midgrade. The fed requires minimum octane for each grade sold, it does not specify maximum octane. I would estimate the average inground octane on midgrade at 90-92 octane give or take. You get much better performance than the cheap stuff, but save yourself .05-.10 per gallon depending on the pricing and competition in you market.
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