Upgrade flexfuel 5.3?

06sierra5.3 · August 3, 2006

Will any or all of the basic upgrades for performance still be ok for the flex fuel 5.3? Intake, chip, supercharger and such.

Ape0r · August 4, 2006

Will any or all of the basic upgrades for performance still be ok for the flex fuel 5.3? Intake, chip, supercharger and such.

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I can't imagine an intake would do any harm. If you chip it, be sure to get a custom one from a reputable company such as Westers that will (hopefully) be able to make provisions for ethanol. The flex-fuel model comes with larger capacity injectors, so that will only help with the supercharger. I would expect that the injectors would be more of a power limiter with a supercharged E85 than with a supercharged gasser, because the computer sprays more E85 into the cylinders to begin with. So, if you want to make 400 HP on ethanol, be ready to upgrade those injectors .

But then, are you running E85 in it? If not, it won't make a bit of difference.

06sierra5.3 · August 4, 2006

Im not currently running e85 because its really hare to find here. But I dont want to do any upgrades that will cause any problems when e85 is more available to me. I am looking to start with an intake and exhaust and then maybe look into a custom chip or supercharder depending on the pros and cons of both with e85.

BlueTahoe · August 4, 2006

In my 03 tahoe flex-fuel I had an outlaw intake, Gibson Catback, and Westers 93-91 hot tune. None of these mods were a problem at all. I was sure to tell westers that I still wanted to use E-85 with the tune and they assured me that wouldn't be a problem. I did run E-85 for a couple thousand miles after these upgrades with no problems at all.

The supercharger may be a different animal. I did read that in a flexfuel truck you don't have to upgrade the injectors because they will produce sufficient flow for the chargers so the kit was actually cheaper. What they didn't tell you is if they would flow enough and run ok on E85 after the supercharger was installed. Due to the high octane of E85 it may be a good combination with the supercharger if the injectors can handle it.