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Considering a QTP Cut-Out...will it effect AFR?

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Old Apr 18, 2007 | 11:42 PM
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soontobeLS1's Avatar
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Default Considering a QTP Cut-Out...will it effect AFR?

I have a LS1 Edit on my my minor bolt on car...if I get a QTP cut-out installed will it effect my AFR????

I just want a louder car...I am currently going thru a Magnaflow muffler...

Also, where does the cut out go??? in the Y-Pipe?????

Thx
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Old Apr 19, 2007 | 12:47 AM
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cutout will go on the I pipe and considering its after the o2's it wont affect your AFR
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Old Apr 19, 2007 | 02:40 AM
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Cutouts CAN be installed in the y-pipe before the cats, but it's expensive, difficult to install, and costs ground clearance. Up there it would affect AFR greatly.

Typically cutout is installed just under the pass sisde rear seat area, where there is a bit of room for the electric motor. All it does is bypass the muffler; a bit less backpressure, a lot louder, but AFR if affected at all will be corrected by O2 feedback under normal driving.

Please note: if you are tuned on the ragged edge, at WOT the car may change AFR enough with open cutout to require a little tuning tweak when the O2 feedback is not functional.

My car picks up 20 rwhp and 25 rwtq with the cutout open vs. closed... and that's with shorty headers, big ypipe, and hollow cat. So yes, it does make significantly more power, likely enough to result in different AFR. I had mine tuned both open and closed to be safe, with erring on the safe side when open.
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