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What is the difference between the 87 Octane tune and the Performance tune on an 05 Avalanche with the 5.3L with Predator U7193??

The Performance tune has timing added, the 87 tune does not.

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Is there any difference in how the vehicle performs with each tune or is it just timing to handle the octane in the performance tune?

Yes, obviously the 93 tune when used with 93 octane fuel will make more power than the 87 tune.

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Sorry to but into your thread, but how does the 93 octane tune make more power? There is no more energy in 93 octane than there is in 87, right? It's just that the 93 will flash at a higher temperature/pressure than the 87. Does the timing really allow the engine to make more power?

yes, more timing will make more power - up to a point. but between the 2 tunes, yes - the 93 tune runs more timing than the 87, so it does make more power.

higher octane burns slower - therfore more of the fuel actually gets burned/ignited, resulting in more power. using 93 octane allows you to run more timing without getting KR.

Why, then, does my Ford manual tell me to run 87 octane in my engine? Wouldn't Ford want my car to make more power?

it depends on the engine. my wife's 3.4L v6 in her Equinox certainly isn't a performance engine and doesn't need 93 octane - but my 5.3L V8 performance engine in my Monte SS does. It tells me right in MY manual that I CAN use 87/89 octane, but performance will be reduced and it will cause knocking/pinging. 93 octane is highly recommended.

But MY manual tells me to run 87, period. There is no mention of pinging, knocking, or anything else. And my engine is a performance engine. I've run 93 octane in my car to see if there is a difference, and there is none. 93 octane is required for engines with higher compression, so they don't pre-detonate. So apparently my engine is designed and "tuned" to be optimized for 87 octane.

it would appear so then...

prpilot wrote:But MY manual tells me to run 87, period. There is no mention of pinging, knocking, or anything else. And my engine is a performance engine. I've run 93 octane in my car to see if there is a difference, and there is none. 93 octane is required for engines with higher compression, so they don't pre-detonate. So apparently my engine is designed and "tuned" to be optimized for 87 octane.

Correct, it is now tuned for 87, thats why we are able to find 15-20 rwhp through tuning for higher octane levels.

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Ok, so if I get a tune for 93 octane, I'll see approximately 15-20 rwhp improvement. So,( sorry about stealing this thread!) what else changes? I must admit I'm leery of changing things on my car. I want more power, and better throttle response, but at what cost? I can't help feeling that by gaining in these two areas I'll lose somewhere else. Obviously I'll have to fork out the extra cash for 93 at the pump. But are there other drawbacks? Will my engine idle differently? Will it run hotter?

thanks in advance for your reply.

Have your cake and eat it too!
Not only will it add 15-20 rwhp and better throttle response, you can see gains of 1-2 mpg on the highway!
There are NO negative side effects of tuning a late model gas vehicle, they should all come from the factory with a Predator...

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