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<B>dasgalloway</B>
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This graph has proven to be quite useful today.
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Comparing an aftermarket ypipe to the OEm ypipe (relevant to your question on loss of low end power)
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You can see that an aftermarket header... WHEN USED WITH AN AFTERMARKET YPIPE... does lose a LOT of low-rpm power... in some places more than 10hp and tq below 4000 rpms compared to an afmarket header with the OEM Y pipe. (This has been tested and proven)
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Now... what happens when you're tuned whit a raceECU?
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(the following is my theory and hasn't been proven)
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Check the AF graph at the bottom of this image. You can see the OEM Y causes the car to run a little leaner... call it .5 points leaner from 3k-3.5k rpm.
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Given that the raceECU is not tunable (it's got a fixed air fuel correction map in it... so it "retunes" the car a fixed amount no matter what your mods are) you can't tweak it any from that fixed map.
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Therefore, the fixed map should affect both setups the same fixed amount. The point I'm getting at is that both setups won't end up at a perfect 14:1 line... I'd say the OEM Y would end up around .5 points leaner than the aftermarket Y. Given that, I'd assume that both power bands should increase appx the same amount, and as such the OEM Y will maintain it's distinct advantage over the aftermarket Y in the low RPMs.
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My Theory: When coupled with an aftermarket header... you'll make less down low power, even with an SRT race ECU, than you will by keeping the OEM Y pipe.
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