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2000 Chevy Z71 performance problems

This is a discussion on 2000 Chevy Z71 performance problems within the Performance forums, part of the General Discussion category; I have a 2000 Chevy Z71, I want to put a true dual exhuast system on it with two seperate ...

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    2000 Chevy Z71 performance problems


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    I have a 2000 Chevy Z71, I want to put a true dual exhuast system on it with two seperate single in-single out flowmaster 40 series. Will this damage the engine or cause any performance problems since there will be no catalytic converter?

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    Re: 2000 Chevy Z71 performance problems

    You need to keep the cats on also need to keep the X pipe as well.Chevy has them engines designed to run on a certain amount of back pressure. and Yes it will hurt your horsepower of the engine If you run just the true duals. You should have two cats under the truck already with the X pipe. Just go from the X pipe back with the true duals.



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    Re: 2000 Chevy Z71 performance problems

    Without the cat, you'll lose some low-end torque because of loss of backpressure. You can get O2 simulators to plug in and tell the computer all is well without the sensors or cats in place, but a better solution is a custom tune from Black Bear.

    In the end, I would recommend just putting in a high flow cat and keeing your O2 sensors. Especially if you live in a state that has vehicle inspections or sniffer tests.
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    Re: 2000 Chevy Z71 performance problems

    No no no no no, no. Back pressure has nothing to do with it. Its called velocity. Without good velocity you have poor scavenging. That being said true duals on a 5.3 is going to give you terrible velocity until you get it wound out tighter then an 8 day clock.


    There is not one single good reason why the stock cats should be removed unless they are bad. The only thing they will do is make it quieter, they flow quite well actually. As for will it hurt the engine? Of course not. Your foot constantly being on the floor will though.
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    Re: 2000 Chevy Z71 performance problems

    Quote Originally Posted by oldred95
    There is not one single good reason why the stock cats should be removed unless they are bad. The only thing they will do is make it quieter, they flow quite well actually. As for will it hurt the engine? Of course not. Your foot constantly being on the floor will though.

    my friend "bluecat" tuned his 04' 5.3 trailblazer, dynoed it, then cut the converter's off, and re-dynoed: lost 10ft-lbs of torque down low, and gained nothing up top.

    he noticed the truck (suv, whatever...) would accept 4* more timing all across the board, after the converter removal (even on 87octane) resulting in a gain of 20ft lbs (+10 over baseline after tune) and gained 20ft-lbs on up in the RPM, with a similar amount of hp (not sure on the HP to be exact)

    cutting the cats off, with out a tune is a bad idea, you'll lose torque, and gain a horrible rasp in the exhaust. with a tune? I can live with the rasp it produces for the power increase, as well as the satisfaction of knowing I no longer have emission's control equipment on my vehicle
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    Re: 2000 Chevy Z71 performance problems

    What would have happened if he added the extra 4 of timing with the cats in place?

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    Re: 2000 Chevy Z71 performance problems

    I wouldn't go out of my way to get rid of cats. Good for the environment and fine for your truck.

    I think the most cost effective way for true duals would be to cut the stock Y and fab up from there on out.
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    Re: 2000 Chevy Z71 performance problems

    ^ thats what i did.

    But dont recomend true duals unless you have an x pipe.

    Just go with a dual in dual out muffler...

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    Re: 2000 Chevy Z71 performance problems

    Quote Originally Posted by oldred95
    No no no no no, no. Back pressure has nothing to do with it. Its called velocity. Without good velocity you have poor scavenging. That being said true duals on a 5.3 is going to give you terrible velocity until you get it wound out tighter then an 8 day clock.


    There is not one single good reason why the stock cats should be removed unless they are bad. The only thing they will do is make it quieter, they flow quite well actually. As for will it hurt the engine? Of course not. Your foot constantly being on the floor will though.

    Agreed. Backpressure is a common myth often confused with velocity.

 

 

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