Stupid factory exhaust systems and how to fix them!

[Tim_K]

I just don't understand what car engineers are thinking. We all know that a free flowing exhaust makes power and helps mileage, so why doesn't EVERY car come from the factory with a nice large exhaust system? The metal to make the larger pipe can't cost THAT much more, and the engine computers can easily be modified to support the exhaust system.

Case in point: I just bought an 89 Dodge Spirit with a 2.5 Turbo 1 automatic in it. It's a Mitsubishi turbo, but otherwise nice. the exhaust system has 2-1/2" pipe coming off the turbo so it should be a nice exhaust system, right? NO!!!

It's bad enough that the car has / had a catalytic converter (more on that later in this post), but behind the converter is 20 inches of 2-1/2" pipe with kinks pressed into it around the pipe in 5 or 6 places along its length.

I can see what that's supposed to be - a kind of in-line muffler. I've seen mufflers like that in the Summit Racing catalog. But as I found out, the pipe going through the middle of this pseudo-muffler is ONLY 1-5/8 INCHES IN DIAMETER!!! What the HELL kind of car engine (153 cubic inches, no less) can breathe efficiently through a 1-5/8" exhaust ?!?!?! And this thing has a turbo on it as well!!!

Now, the car ran good even with this stupid exhaust system in place. It would spin the tires off a stoplight if you hit it right. But I just HAD to do something.

So now on my second day of owning the car (actually I've only had it about 22 hours so far!), I drove the car up on ramps, measured the pipe diameters and the length of the offending section of the pipe, and went out in search of replacement pipe.

The auto parts store has 18 inch sections of the 2-1/2" pipe, but at a cost of $4.68 each. With clamps and a connector sleeve, we'd be near $20 to patch in a piece of pipe!

So I just got the connector sleeve and 2 clamps. I started going around to about 5 garages in the area who could make exhaust pipe, and every one wanted $20-$22 for a 43 inch piece of 2-1/2" pipe with one end flared out a little! I finally found one place who would do it for $15, so it got done. I'm pretty cheap, huh?

So I drove over to my dad's house (he has the garage with all kinds of tools), and put the car back up on ramps and got out the Sawzall. I chopped out the entire catalytic converter and the muffler-pipe. That's when I saw that the inside tube was an unbelievably small 1-5/8 inches. The catalytic converter wasn't all clogged up, but it was there, and that's too much for me. I slipped in the 2-1/2" pipe, which fit perfectly thanks to my careful measurements, and started the engine.

Now it sounds better! A mild rev of the motor will make the turbo whine, whereas before you had to hit it pretty good to get the same sound.

As for driving, it accelerates better and pulls harder than it did before. But I have to wait for April to take it to the dragstrip. :frown:

The muffler still sounds quiet, but you can tell it's different. It has a little more bark to it if youy stand near the tailpipe and listen. And no more of that stupid catalytic converter smell from the exhaust.

Performance modification #1 is done! Now to free up that muffler a little bit, install my boost gauge, go get that Ford Probe intercooler at the junkyard...

[2Lebarons]

why un-cork the exhaust system, only to cork up the intake with a probe intercooler??? its just too small for the job...

as for the catalytic converter smell, id rather smell that any day, than to smell that filthy stinking crap that comes out the pipe without one....talk about a stench...im putting a cat. back on my 87 just so i dont have to smell that crap...

[Mopar_Nutz]

Quote:

Originally posted by 2Lebarons as for the catalytic converter smell, id rather smell that any day, than to smell that filthy stinking crap that comes out the pipe without one....talk about a stench...im putting a cat. back on my 87 just so i dont have to smell that crap...

I've never noticed any bad smell comin outta my tailpipe and I have no cat or muffler.

[TBird232ci]

Quote:

as for the catalytic converter smell, id rather smell that any day, than to smell that filthy stinking crap that comes out the pipe without one....talk about a stench...im putting a cat. back on my 87 just so i dont have to smell that crap...

you must have other issues with your car to cause a stink, youll be able to smell exhaust, but it shouldnt change very much with a cat or not on it

[92lebaronGTC]

this is why i plan on redoing the exhaust eventually

[turbovanman]

Quote:

Originally posted by TBird232ci you must have other issues with your car to cause a stink, youll be able to smell exhaust, but it shouldnt change very much with a cat or not on it

Cars do stink without cats! Cars without EGR valves, like ours, stink to high heaven as the cat reduces NOX emissions and NOX is very smelly. On white cars, it will turn your bumper orange.
As for no cat, I don't want to hear you guys whine in 20 yrs when you can't go outside without respirators cause the ozone layer is gone. Cats work, put a large one on, and be done with it. If you hate them that much, have it so you can take if off when racing. Thats my rant for the day. "thumbs up

[89daytonaTII]

screw that, they rob hp and will never be on my car again. And I don't know where you guys get that a cat-less exhaust stinks. mine smells normal

[turbovanman]

Quote:

Originally posted by 89daytonaTII screw that, they rob hp and will never be on my car again. And I don't know where you guys get that a cat-less exhaust stinks. mine smells normal

Like I said, when you can't breath, you only have yourself to blame Dumbass

[Akromix]

those kinks are actually mufflers...here's a picture of what we found after cutting the cat out:

[89daytonaTII]

Quote:

Originally posted by turbovanman Like I said, when you can't breath, you only have yourself to blame Dumbass

ruining the enviroment for you and everyone else :big grin: your welcome

[Tim_K]

Akromix - yes, that's how mine is/was. I cut out that entire 20 inch section of kinks and put in a 2-1/2" straight pipe.

turbovanman - what's the matter with you? Cats stink. Period. An open exhaust smells fine. I've had many 1970's Mopars with NO emission controls (no EGR, fuel vapor can, or anything except the PCV valve) and none of them ever smelled bad unless the fuel mixture was VERY rich. Then you smell the gas.

Cats are required by politicians who don't know anything about cars. So I took mine off.

Cats are a restriction. And I don't care how free flowing an aftermarket 3" one may be, my cars will NOT have cats!

Cats produce sulfuric acid and sulfur trioxide, which contributes to acid rain. So my car has no cat.

With no other mods except straight piping the cat and kinked muffler-pipe, my 89 Spirit 2.5 Turbo automatic will peel tire off stoplights all day long. That's the only reason I need.

[turbovanman]

Quote:

Originally posted by Tim_K Akromix - yes, that's how mine is/was. I cut out that entire 20 inch section of kinks and put in a 2-1/2" straight pipe. turbovanman - what's the matter with you? Cats stink. Period. An open exhaust smells fine. I've had many 1970's Mopars with NO emission controls (no EGR, fuel vapor can, or anything except the PCV valve) and none of them ever smelled bad unless the fuel mixture was VERY rich. Then you smell the gas. Cats are required by politicians who don't know anything about cars. So I took mine off. Cats are a restriction. And I don't care how free flowing an aftermarket 3" one may be, my cars will NOT have cats! Cats produce sulfuric acid and sulfur trioxide, which contributes to acid rain. So my car has no cat. With no other mods except straight piping the cat and kinked muffler-pipe, my 89 Spirit 2.5 Turbo automatic will peel tire off stoplights all day long. That's the only reason I need.

What is wrong with me. I for one would like to be able to breath in a few years, I am a smog shop and fix cars for a living. I know what cats can and can't do and they do a great job of cleaning the air. Sulphuric acid, I don't think so but they do produce alot of CO2. As for NOX, yeah, I love that yellow haze hanging around my mountains, smells so good!!!!!! Just ask LA how much theres is gone since they introduced smog checks. We got smog checks starting about 10 yrs ago and our yellow haze has almost gone. I don't want to hear that crap that they don't work, they do.
I agree they don't flow as well as straight pipe but its a small price to pay to be able to breath. As for exhaust stinks, it reaks with no cat! I have an idea, route your pipe into the car and go for a drive, no put a cat on and do the same. After your in tears without the cat, email me back
Its people like you that will cause our air to dissapear. We can debate this till were blue in our faces but fact is they work, plain and simple and no, I don't work for the government. This is actually something they did right!

you can't beat the smell of unburned hydrocarbons in the morning!

Quote:

Originally posted by turbovanman I have an idea, route your pipe into the car and go for a drive, no put a cat on and do the same. After your in tears without the cat, email me back Its people like you that will cause our air to dissapear. We can debate this till were blue in our faces but fact is they work, plain and simple and no, I don't work for the government. This is actually something they did right!

you die with or without the cat, both ways emmit CO, which is what kills you. exhaust has very little smell with a cat, but it smells absolutely great without a cat, especiall when running alcohol or leaded fuel. cats cut down emissions NOx and HC to almost nothing but it still has CO2 which is a greenhouse gas which is still unsafe for your air and your planet. the only way that is safe for the planet and the air is no cars and that is no fun.

[turbovanman]

Quote:

Originally posted by turbo600 you die with or without the cat, both ways emmit CO, which is what kills you. exhaust has very little smell with a cat, but it smells absolutely great without a cat, especiall when running alcohol or leaded fuel. cats cut down emissions NOx and HC to almost nothing but it still has CO2 which is a greenhouse gas which is still unsafe for your air and your planet. the only way that is safe for the planet and the air is no cars and that is no fun.

I agree about CO2, but its the lesser of 3 evils, NOX stinks and causes the haze but the funny part is, CO2 is spewed by Volcanoes so who knows."thumbs up