Exhaust leaking badly, need some insight.

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Exhaust leaking badly, need some insight.

May 13, 2005, 10:34:03 PM

The exhaust leak is getting bad enough on the driver's side manifold that something needs to be done, exhaust is coming out from under my hood instead of the tail pipe. It's an 87 3.8 bird btw. I'd like to do the stock 'stang header thing but I fear the expense of it all. Is it going to cost more for the stock headers vs. the stock manifolds? Either way I'm going with junker parts (sandblast and high temp paint) so keep that in mind.

I'll probably need all new piping as well with the exception of tail pipe(s), I've got a couple of those in good shape. Can I safely junk the cats and still have it run fine? (no emissions testing here). What size pipe and lers should I run to keep a decent backpressure? I don't plan on any major upgrades. The only thing I've done is throw a 5.0 CFI on it.

I'd like to keep the expense as low as possible, so anything I can do myself is a big plus. I don't have a pipe bender or a lift, so everything I do has to be shadetree technology. Should I take it to a custom exhaust shop? Is it even legal for them to remove the cats without replacing them? I've got so many questions, sorry about the lengthy post. Any help is greatly appreciated.

Re: Exhaust leaking badly, need some insight.

Reply #1 – May 13, 2005, 10:44:38 PM

dude, for performance reasons.....get the headers... good size pipe would be 2.25 and yeah the car will run fine wo/catsjust make sure you hook the o2 censors back up.....

Re: Exhaust leaking badly, need some insight.

Reply #2 – May 15, 2005, 05:34:59 PM

If you get headers, you'll have to open up your existing Y pipe opening 1/2", as the header collector opening is too large.

I have stock manifolds off an '83; if you're interested I can give you the part number.

Re: Exhaust leaking badly, need some insight.

Reply #3 – May 15, 2005, 06:01:13 PM

you cant use headers on the stock y-pipe, the collectors are in totally different locations

pick up a set of stock 94-98 stang headers, you can use a stock h-pipe from a fox, you can also run an offroad h-pipe from a stang, which can be had very cheap, but if you do so, youll need to run something like a superturbo ler, because the h-pipes only come in 2.5", so you need to be sure to have some sort of restriction in the exhaust

Re: Exhaust leaking badly, need some insight.

Reply #4 – May 15, 2005, 06:44:44 PM

Exactly^

Re: Exhaust leaking badly, need some insight.

Reply #5 – May 16, 2005, 03:33:47 AM

My y pipe is pretty much shot as well, rusted beyond it's intended lifetime. I'm really looking to keep expenses down, cheap is good. Would a y pipe be cheaper than an h? I'm probably only going to do single exhaust if it will save me money. Same price? I'll go for duals.

And the big question, Can I accomplish this in my driveway with little or no headache? I'd hate to break off a stud and not be able to fix it, that's my main worry. I really don't want to drive to a shop with a busted bolt and throw money at them to fix it.

Re: Exhaust leaking badly, need some insight.

Reply #6 – May 16, 2005, 07:40:18 AM

Hardest part is gettin the old stuff off due to the fact it's usually rusted into place. Use some type of penetrating solvent. Most times it does the trick.

Quote

Would a y pipe be cheaper than an h?

Depends.....are you set on using a specific material(aluminized steel or stainless)? New or used? There is more demand in the aftermarket for an H as opposed to a Y (the exception being GM F bodies).

Re: Exhaust leaking badly, need some insight.

Reply #7 – May 16, 2005, 11:03:59 AM

i know for a fact your gonna end up dealing with a loss of power due to the free flow. I did and experiment last year on this topic,maybe the year before but anyway it was kind of wierd. I noticed lost of power loss off the line after gutting the one single large cat. My precats up on the y pipe were empty,,,***let me or us know if yours are also****,im curious. I could tell the engine really appreciated the gutting of the cat and i suggest you leave the housing but thats up to you. Id leave them only for a visual inspection purpose just in case.

I hammered a motor cycle baffel up in my tail pipe section to replace my backpresure. I had to open up the tail pipe a little with an exhaust pipe spreader but it all worked out ok. Ive since replaced my tailpipe and have not reinstalled the baffel. Its just one of the things i need to get around to.

Re: Exhaust leaking badly, need some insight.

Reply #8 – May 16, 2005, 12:27:01 PM

yes, youll lose low end torque, but you do make that up in the higher RPMS

the only reason i suggested an offroad h-pipe is due to cost, i seem em for 120 bucks, find some catbacks for less than 200 bucks, and headers for around 50 bucks, some modifying and whatnot might be needed, like dimpling a tube, or bending some hangers, but it should be able to be done for the most part

Re: Exhaust leaking badly, need some insight.

Reply #9 – May 16, 2005, 01:27:52 PM

higher rpm's arent going to matter that much on a stock v-6 is it? My 5.0 runs out of poop at about 4000. I wouldnt call that high rpms.

Re: Exhaust leaking badly, need some insight.

Reply #10 – May 16, 2005, 04:27:03 PM

well...a 3.8L peaks power at like, 2,800 rpms, but itll run to i think 4,800...then the valve float...

Re: Exhaust leaking badly, need some insight.

Reply #11 – June 02, 2005, 05:56:31 AM

Excuse my utter stupidity, but does the H pipe bolt up to the headers directly? Then the cats, then the lers? I like purty pictures, easier to learn when I'm looking at something.

Re: Exhaust leaking badly, need some insight.

Reply #12 – June 02, 2005, 08:39:23 AM

H-pipe will bolt to the headers. The cats are part of the H-pipe (unlees you pick up an off road H-pipe)

The Fox mustang H-pipe is designed for a car which is shorter than ours overall (total length AND wheelbase) so you might have to extend the tailpipes a bit.
-Fox Mustang Wheelbase: 100.5 inches Overall Length: 179.6 inches
-87 Cougar Wheelbase: 104 inches Overall Length: 197.6 inches