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So I'm a bit stumped, and worried at the same time.

I just had an Armytrix Exhaust w/ Racing Midpipe installed on an otherwise stock 2015 GTR, and I'm feeling a noticeable loss of power, locally and on the highway. There's clear lack of passing power on the highway, and getting any "pull" out of the car is near impossible.

I've been testing this for a few days, to make sure I wasn't going crazy and the closest thing I can compare it to is having the car in "Save" mode. Am I missing something here?
 

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What PSI are you reaching on the MFD?
 

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Bbq Anyone?
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I had the same problem happen to me with an armytrix in another car. Replaced the exhaust and problem solved.
 

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Wow that's crazy if the exhaust could cause that much of a change!! Almost like it's blocked or something
 

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15 PSI is about right, normally with bad fuel etc the limp mode is about 10 PSI. Difficult to say what's happening with respect to the perceived loss of power though, I'm stumped.
 

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There's no doubt it's the one of the best on the market; it sounds and looks amazing. I'm starting to think this is a one-off problem, so I'm not trying to set off too many alarms, but it still boggles me.

I did a little digging and people on other cars (BMW, and Mustangs) attributed loss of back pressure to decrease torque, but mentioned it was made up for on the high end of the power band. Wasn't buying it.

I contacted ARMYTRIX and they said they've never heard of a power loss, and they're looking to get back to me. One thing I have noticed, and taking the car back for today, is a pretty serious rattle, that can be felt banging against the drive train after about 20 mins of driving; an audible fast-repetition knocking that can be felt through the shifter and e-brake. Could that possibly be interfering with a sensor?

p.s. No tune, stock downpipe.
 

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Does it feel sluggish even with the valves open? Is there a noticable difference in loudness/tone when the valves are open? You'll really hear a difference between opened and closed on a cold start when the engine is idling at 1500-2000 RPM's for the first few seconds.

Disconnect the Tee splitter and plug the original vacuum line back in to the engine so that the Armytrix vacuum system isn't connected at all. Unplug the dongle from the OBD port to ensure there is no computer interference. At this point the valves will be wide open and the car's vacuum system will be back to stock, so you can rule that out as causing any problems. If it still feels sluggish, it's definitely something with your exhaust.
 

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Wow, thanks a lot! Definitely sluggish off the line, identical to SAVE mode. There's certainly a different tone in the exhaust between opened and closed, most notably on a cold start.

That's a great idea, though. Yea, I'm no gearhead, but I can't help but think it has something to do with air/fuel. Maybe it's me but it also seems like the gas milage went down a bit with heavy driving.

Thanks again, it'll be up in the air within the hour.
 

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Remove the catback and run it that way. See if the power comes back. If it doesn't come back, remove the mid pipe and run it straight out of the downpipes.
 
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