I've been bad
#1
I've been bad
Against the suggestions of many people I went ahead and ran 89 grade gas (midgrade) in my car since it'* about $11 cents cheaper a gallon than premium. What I have found, is that my car doesn't run like it used to. In fact, it runs better! It seems to have a bit more power and my gas mileage has actually gone up, instead of down. I usually can drive around 50 miles before I leave full, this time I'm at 75 miles and I'm still on full. The only mods I have that might allow this is a gutted air box, K&N filter, removed MAF screen, and exhaust upgrades. Has anybody else ran midgrade without problems on their L67 like I have been? The engine runs fine and has more power it feels like so I dont' really think I'm having any problems with engine knock. comments?
#2
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Its not something I would continually do there Custom, however, that toulene mix that Bill posted is the best way to get low to mid grade gas to work for you.
Over the long term...the lower grade will have adverse effects.
Over the long term...the lower grade will have adverse effects.
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As long as your not getting KR you can run as low a grade as you want. In fact you will get more power from less octane. However if you ARE getting KR then running any octane that is giving you KR is bad for the engine.
Lower octane gas burns easier hence the more power, however higher octane can in some cases give your more advanced timing if the computer sees the right conditions and commands it.
Lower octane gas burns easier hence the more power, however higher octane can in some cases give your more advanced timing if the computer sees the right conditions and commands it.
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Originally Posted by Sigma
Im sorry its off topic, but what is the MAF screen?
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Originally Posted by Sigma
Im sorry its off topic, but what is the MAF screen?
The screen sits in front of the MAF sensor and aids laminar flow which the sensor uses to determine how much air your car is getting.
The screen can impead air flow and some of us have removed it.
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Just noticed the MAF thing. If you have no way to scan your car I would put the screen back in. Sometimes the MAF reading can be affected screwing up your A/F ratio.
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what is KR? Id love to put 87 or 89 in mine too, it costed me 55 bucks to fill it on Saturday with 91...
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Originally Posted by SSEimatt93
what is KR? Id love to put 87 or 89 in mine too, it costed me 55 bucks to fill it on Saturday with 91...
The advantage of high octane is that the computer can always advance timing when conditions are right, so your car can only perform better. Using low octane fuel with no knock is ok until something happens to offset the balance (you develop a hotspot, either through booststacking, or heatsoak) and the only thing the computer can do is pull timing to try to cool it down, this significatnly reduces your hp and can damage the engine. I for one will always use 94 or better. I could possibly get away with 91 but with my mods if something were to happen and the computer couldnt compensate then by-by engine.
This is why running lean in a supercharged car is so dangerous. More air and less fuel means its easier to combust so a hotspot can set it off a lot more easily. A custom PCM can add fuel to help make the fuel charge more resistant to predetonation but this also reduces hp. Getting the air/fuel mix just right so your not getting knock but not making the charge too fuel heavy is a fine line and a great place to try and tune the car.
Leaner = more horsepower but also closer to the edge where if something goes wrong it could be catastrophic for the engine.