# Losing Power, think its the 02s and the cat



## anthony jackson (Jul 16, 2002)

hey guys, i just got back from the drag strip the other night, in which i ran a 17.1 flat in my stock 93 Sentra SE-R, a very very bad time. now i did have my girlfriend with me in the car and almost a full tank of gas and also i had a bunch of stuff in the trunk (not to mention i weigh 265 (10%body fat)). now dispite all of those set backs i shouldn't have ran a 17.1. i should have been down in the low 16s. i was just wandering if it could have been my 02 sensor and my cat and muffler that was holding me back. i havent changed any of it sinse i bought the car. it hasn't ever been changed in fact. my buddie at auto zone tells me that i could lose up to half of my horse power because of that. Any knowledge would be apprieciated!! thankx guys


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## GA16DESentraXE (Dec 17, 2002)

full tank of gas - about 90 pounds
you - 265 pound
girl - 120 pounds (more or less, you didn't say)
trunk crap - 50ish pounds
total - 525 pounds

When you're doing weight reduction for racing,*ROUGHLY* every 100 pounds lost is like gaining 10 hp.

So in theory, let's reverse this, since you're adding weight.
You're car is now 50 hp shy of what it should be. You're essentially putting down the same power as a stock GA powered Sentra (actually, less).

A stock GA powered sentra will run low 17's, high 16's in the 1/4 mile. So, you running a 17.1 isn't too off.

Then again, I'm usually full of shit.


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## mpg9999 (Nov 22, 2002)

The o2 sensor isnt it. ECU ignores it at WOT. If your having power problems you should do a tuneup, and pull the cat off to see if its clogged. Also, what was your trap speed and 60' time?


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## ForsakenRX7 (Mar 14, 2003)

im not too sure of what my trap time was but my 60, was like in the 2.2's. if that counts for anythng


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## Guest (Apr 9, 2003)

Lose the weight of the girlfriend and most of the gas... and have your cat checked for blockage... remeber that the O2 sensor does nothing in "open loop" mode. This would be the mode that you would be in during heavy acceleration of WOT.


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## anthony jackson (Jul 16, 2002)

i went to the muffler shop last week and got my cat chopped off and replaced with a peice of straight pipe. Only $50 fixed all my problems. i know that im probably losing a little power form the original factory hp gains, but with my intake and a little octane booster it fixed it right up. im now in the mid 15s.


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## GA16DESentraXE (Dec 17, 2002)

Good way to kill the environment, buddy.


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## landlord (Jun 11, 2002)

anthony jackson said:


> *i went to the muffler shop last week and got my cat chopped off and replaced with a peice of straight pipe. Only $50 fixed all my problems. i know that im probably losing a little power form the original factory hp gains, but with my intake and a little octane booster it fixed it right up. im now in the mid 15s. *


welcome to the "no cat" club.


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## barnoun (May 7, 2002)

Might as well have gotten a high flow cat. Same power gains without ruining your home.


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## LIUSPEED (May 29, 2002)

barnoun said:


> *Might as well have gotten a high flow cat. Same power gains without ruining your home. *


roger that


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