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Discussion Starter #1
Yeah when i got my flowmaster muffler i wanted the " true " dual setup..with two mufflers, but i was told that with the new engines that you connot put two mufflers due to needed backpressure and all the computers involved....what are your comments on this??
 

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I was told you couldn't install true dual if you didn't already have the 2 cat setup. Stock, I had two pipes coming off my engine, and two cats with a two in, one out muffler. Texas law allowed me to set u p my car with two mufflers because of it.

I don't know why...so I guess I can't answer your question...but nothing is illegal if you do it yourself and tip off emmisions guys.


....just a thought

-zach-
 

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its not just the back pressure, but also the velocity of the exhaust. my 96 c3500 had dual cats behind the 454 and when i tried to run bored cats and open pipe beyond that it kept tripping the service engine light. dealer said the exhaust was too hot on one set of o2s, and too cool on the other. i put flows on it with tips at the back and the light didn't trigger after that. my truck had an o2 in front of and behind each cat. if you don't have four it may be different.
 

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YOu can install two mufflers typically (consult with local/state Johnny Law before attempting this tho) as long as you have a cat. converter for each pipe. Modern engines do need certain things, but the modification of dual exhaust will not (I've NEVER seen a vehicle not run right after doing this) cause any problems.

I know that in virginia if your vehicle came with two cat. converters you COULDN'T go to a single cat. setup, but if it had one cat you could go to two. Thing is, for emmissions purposes, you will need to place both cat. converters close to the engine so they get up to proper tempature. It took me three trys on my Z-28 to place the cat's just right (because there wasn't anywhere to tuck them in on my Z-28 and it sat so low I was really restricted on placement).

Got Mud?, you have four O2 sensors because your computer is an ODB2 setup. ODB2 is great because its the first "smart" computer system car makes have used, however its bad because you do have to have four O2 sensors and it can be a little tempramental at times (read: my Z-28) :):. The front sensor measures the fuel/air ratio before the cat. converter, and the second one (behind the cat) measures what the fuel/air ratio is after the cat. converter. The computer then compares the two and desides if any changes to your fuel injectors is needed (either more or less fuel to achieve the ideal air/fuel ratio). If you hollow out your cats, or modify your exhaust radically I would recommend getting "02 SIMMS". They are used primarily (and I believe designed by) the Camaro/Firebird guys. As ODB2 was (and may still be) a GM only computer setup. Any Camaro/Firebird website (www.camaroz28.com) that has a forum will have topics concerning how to purchase these items and how to install them, or you could probably do a search thru Yahoo, AJ, etc... for "O2 SIMMS". What they do is plug into your second set of O2 Sensor wireing (you can remove the second set of O2 sensors if you want to) and fool the computer into thinking the cat. converters are working JUST as they should be (i.e. perfectly) and keep the computer happy. Tho if you have to take the "sniffer" test I would keep your O2 sensors in place and rehook the second set up before taking the test.

If you need any help finding/installing those let me know, I had a set on my '96 Z-28.

-Chris
 

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there is a dummy sensor available from speed tweaks.com that will send a message to the computer that everything is fine. the down side of these sensors is that your computer cannot correct the fuel mixture as well. my buddy put a dummy sensor similar to this on his 96 camaro and it would not idle right. probably isnt a good idea to take your cat off and use one of these sensors if you have any emmisions tests.
 

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You need another cat. To make this work you need to scrap the current "Y" pipe off your manifolds or headers (this will be a custom exhaust job) install new (fabricated) "H" pipe with a cat on each outlet then a muffler off each cat. sounds simple ah! Also to make the dual cat work insatll another O2 sensor (Two sensors wired in parralell). I have never tried this experiment on my 94 or any other late modle dodge...eventually I'm going to do my truck but it has worked on others: early 91 thru 93 mustangs. It's a theory, look into it talk to some exhaust guys.
 

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Yah it will cost sum bucks if you take your truck in and have them do the complete job start to finish. The only thing you need the shop's for is making the H pipe and one tail pipe.

H pipe $100 to $150
tail pipe $50

If you have a small mig welder or even if you don't you can rent them from Home Depot. A couple friends and your set.
 

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Discussion Starter #17
then the second muffler too...wait two mufflers cause the one i have now it sinlge in dual out..damn gonna cost
 

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Wish we were rich! It suscks, when you want to do something and you want right so it lasts sometime it builds up in price. All the work I'm about to do on my dodge I' been saving coin since 2000, any one know a sugar daddy looking to adopt a son?
 
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