I want to build the ultimate exhaust for my 3.5L Intrepid. I want the best of both worlds, that is an exhaust that will give me increased horsepower and looks good but at the same time remain fairly quiet. I guess what I want is a 'factory' type performance exhaust. What I was thinking of doing is building a dual system, that is straight through....with 2 Magnaflow dual tip mufflers, 2 vibrant resonators and 2 magnaflow cataylic convertors. I would totally eliminated the stock cats. What I want to know from people who have already played with the exhaust system, is that if this system would remain fairly quiet? Give me your opinions on my idea.
Ultimate exhaust for 3.5L
roshg
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I want to build the ultimate exhaust for my 3.5L Intrepid. I want the best of both worlds, that is an exhaust that will give me increased horsepower and looks good but at the same time remain fairly quiet. I guess what I want is a 'factory' type performance exhaust. What I was thinking of doing is building a dual system, that is straight through....with 2 Magnaflow dual tip mufflers, 2 vibrant resonators and 2 magnaflow cataylic convertors. I would totally eliminated the stock cats. What I want to know from people who have already played with the exhaust system, is that if this system would remain fairly quiet? Give me your opinions on my idea.
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I am fairly sure I'm doing a true dual exhaust come spring time.
I think as long as you still ahve cats and mufflers you will be fine as far as backpressure is concerned. I think 50 series will meet your needs well; I think I'm going for the louder 40 series.
Your proposed setup will definitely be louder than stock, but it would be that loud.
Just so you know, most people on the site doubt that going to a true dual over a performance cat-back exhaust won't give you much or any gain.
Oh, and one more word on dual exhausts: Making each engine bank go to its own exhaust is not a great idea. It'll make it sound as if you have a couple 3 cylinder engines. Yuck. You'll want to look into a pipe connecting the two sides somewhere in your exhaust (after the cats?) called an H-pipe or an X-pipe. There's been plenty of talk on this before: just search through the old threads and you'll find some good info.
My advice is to go to a good trusted exhaust shop and have a good talk with someone who knows what he's doing.
I think as long as you still ahve cats and mufflers you will be fine as far as backpressure is concerned. I think 50 series will meet your needs well; I think I'm going for the louder 40 series.
Your proposed setup will definitely be louder than stock, but it would be that loud.
Just so you know, most people on the site doubt that going to a true dual over a performance cat-back exhaust won't give you much or any gain.
Oh, and one more word on dual exhausts: Making each engine bank go to its own exhaust is not a great idea. It'll make it sound as if you have a couple 3 cylinder engines. Yuck. You'll want to look into a pipe connecting the two sides somewhere in your exhaust (after the cats?) called an H-pipe or an X-pipe. There's been plenty of talk on this before: just search through the old threads and you'll find some good info.
My advice is to go to a good trusted exhaust shop and have a good talk with someone who knows what he's doing.
Re: Re: Ultimate exhaust for 3.5L
Would that make cat-back exhaust, throttle body spacers etc. illegal?? 'Cause that's what I was planning on doing
(I'm in London, Ontario so this would effect me just as much as you
Anti-mod law??! :crazy:Black94ES said:
Would that make cat-back exhaust, throttle body spacers etc. illegal?? 'Cause that's what I was planning on doing
(I'm in London, Ontario so this would effect me just as much as you
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I wouldn't say better, just more... cost-effective.
I say go for it. If you have the money and all, why not? I want to and prolly will have true duals eventually.
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If your going to go true duals try to go with a small diameter tubing like 1 and 1/8 or 2inch. Or else your going to loose alot of torque. If your going to take the time and money to go true duals use an X pipe instead of an H pipe as it will help Power, and sound.
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Definately use an x-pipe, but for Christ's sake...1.78 or 2 inch pipes!?!?!? Thats way to small even if there were too. If I were you, I would run 2.25 inch pipes right off of the headers, have them collect at the x-pipe AFTER the engine, and run two 2.25 inch pipes straight back to the two mufflers and tips.FunkRider said:
If you plan on removing the catalitic converters...then you will have a check engine light come on because the downstream O2 sensors (after the cats.) are reading the same and the upstream O2 sensors (before the cats.) To fix this, I know of a place that makes MIL eliminators for the Intrepids. I believe they are charging $125 for a pair. All they do is mimic the signal that a proper emmisions controlled O2 sensor would give. They just plug in between the sensor and the stock harness, its a direct fit. If you want more info on them, drop me a PM and I will look up there phone number.
no downstream sensors for keith.. as he has a pre '96 (OBD I).
but I am looking at true dual with X/H pipe here right now. I am planning on taking the current setup... and having the exhaust shop work in a way so I can swap in my 3rd cat come emissions testing time.... put those 3 bolt flanges on the front and make a Y pipe after the cat. this setup would favor 2.5" pipe from the mid pipe (whatever you call the thing with the downstream O2 sensors on)... I will need to bump up from that 1 7/8 or whatever it is.. but that shouldn't be a problem. I am not really worried about low end torque..... I don't think I will even notice it much.. as my tires suck right now and I will still be able to spin them up into the torque range.
but I am looking at true dual with X/H pipe here right now. I am planning on taking the current setup... and having the exhaust shop work in a way so I can swap in my 3rd cat come emissions testing time.... put those 3 bolt flanges on the front and make a Y pipe after the cat. this setup would favor 2.5" pipe from the mid pipe (whatever you call the thing with the downstream O2 sensors on)... I will need to bump up from that 1 7/8 or whatever it is.. but that shouldn't be a problem. I am not really worried about low end torque..... I don't think I will even notice it much.. as my tires suck right now and I will still be able to spin them up into the torque range.
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tell ya sound like a lot of cash to do this. Save your money and just go with a y pipe system or a one in two out muffler. As for this Anti-mod crap in BC??? been driving here for 12 years and never heard it. the only rules here are nothing over 600hp, must be under a certian noise level, and be able to pass the body year emmisions, not engine year. eg 90 S10 orginal engine was a 4.3L, now with a 5.7L, must pass as if it was a 4.3L. There are other little rules but nothing to stop mods on vechiles.
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Dammit Mike, get it straight!
My trep is a '96 just like yours!And as for these MIL eliminators, their price is a bit steep. They should be cheaper than the sensors, not WAY more. Anyway, you can make a setup that includes O2 sensors can't you? I plan to have some cats in my setup. Will they be enough for the sensors to read okay levels?
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No problem. As long as you leave the factory exhast manifolds and precats intact, you'll be OK.Knightmare_3.5 said:
Good news, I took a peek under the car last night for 96trep4u and noticed the downstream O2 sensors for ODBII cars are attached on the engine side of the main cat's disconnects. In other words, you could disconnect the main cat, replace it with a dual in/dual out cat and the PCM wouldn't even know it. Also, a dual in/dual out cat would kinda act as your crossover pipe at the same time. No need for an X or H pipe with this setup.
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That's all well and good, but I was thinking of cutting the whole stock system out and running performance cats. Still doable?
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If you mean remove the headers and precats too, then you'll have problems getting the O2 sensors placed and working properly.Knightmare_3.5 said:
If you mean cutting out only the main cat on back, then it shouldn't be a problem and is very doable. I'm sure the feds don't condone this though.
Anywho, you'll see that there's pipe clamps you'll need to loosen on the dual inlets to the main cat. They’ll prolly be a ***** to loosen, i.e. corroded.
I think there's only 2 or 3 hangers/brackets after that you'll have to pop off or loosen. Then, basically the whole exhaust system (from the main cat on back) will drop right out.
Let us know what you plan....
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