Fox T-Bird/Cougar Forums

I am looking for an H-pipe that will directly fit my 88 Thunderbird Sport Coupe (5.0). I have seen the BBK off road pipe used on Mustangs but I don't know if they are long enough for my car. These will be going to a pair of Flowmaster 42443 lers. I was also considering upgrading to a pair of Hedman 88380 headers as well.

If there are no "direct fit" H pipes, my other option is hollowing out the cat and adding a better Y pipe, like a Cherry Bomb ?



Thanks for any info... :D

The big one is you have to use shorty mustang headers and then you can use a 87-93 Mustang Hpipe (with cats or w/o).  They will not bolt up to stock cast iron Tbird manifolds.  This will also route your oxygen sensors downstream further so you will need either longer oxygen sensors or add length to old ones wires.

I have a Pacesetter offroad Hpipe on my 88 Cougar XR-7 and it fit decent.  Had to hack off the ears for the crossmember brace and dimple by the shifter cable bracketry on the transmission.

With the Standard Output 5.0 in your bird, I would not go any bigger than stock 87-93 5.0HO Mustang or Lincoln Mark VI (LSC) tubular headers and a 2 1/4" hpipe.  coolcats.net has good info on the 1983-1988 fox Thunderbird and Cougar and stages of modification.

Thanks for the info...Im thinkin I should just stick with my Ypipe setup, but I just purchased a pair of Flowmaster 44 series lers and I noticed my stock lers appear to be two different sizes (driver's side is longer). The flowmasters are identical in size. If I mount the flowmasters up, is the Y pipe not going to be long enough on one side ? I would like to keep the lers mounted where they are so I can add the tail pipes later. I had to purchase a replacement Y pipe from Walker because my stock one was all rusted and had to be cut off.

Thanks

Agree with eveything beast50 stated.  I used a BBK 2 1/4 catted H-pipe with oem shorty headers.  The pipes from the rear  of the H-pipe to the lers must be made longer than mustang pieces to account for the additional wheelbase.  The oem lers are indeed slightly different sizes (case length, not pipe size) to combat exhaust drone these engines produce at certain rpm's.  Now, what is annoying exhaust noise to some is music to others, its all subjective when it comes to this. But that factory "Y" with its single cat I believe is the biggest restriction in the factory system.

Get some factory Mustang shorty headers (they can be found super cheap), install them. Install the H-Pipe of your choice for a Mustang (Fox body) have the ler shop go from there. Anybody with aftermarket lers will have two of the same kind and size under their car, and there's plenty of room for them. Easy stuff, and worth the time for a good exhaust.

Y-pipes are for sissies.  The Mustang H-pipe IS the direct fit H.  If you're squeamish get a Mark VII pipe.  It's smaller, but either way you slice it you need  the HO stock headers (at minimum).  There is no such thing as a better Y-pipe, pull it off, sell it to the catalytic converter recyclers and forget you ever had it. The Mark VII exhaust is all 2", but the lengths are right, the mounts are right, and it's the bare minimum you should consider.  You will have to go from the ports to the bumper no matter what you do, so man up and get moving.  If they sniff in NY, don't sweat it, the Mark VII stuff will pass AT LEAST as clean as the single exhaust.  If you get NEW parts it may even be cleaner.

That's a real sharp ride, make sure you hook it up right, if you don't you'll look and feel like a half-ass and that's not really who you are.  Is it?

So if my 5.0 EFI engine is all stock, what kind of headers are on there right now ? I need to get everything in the correct lengths and sizes to make sure it all bolts up correctly, and reaches the lers okay

I forgot to mention my cat IS now hollowed out and still intact with the Y pipe...is the H pipe still going to make much difference ?

The manifolds you have now are cast iron and they suck,  throw them away. Once you do, get 1 5/8 shorty headers for a Mustang, check steering shaft clearance, relief the header tubes as necessary to avoid conflict.  Once you have headers, your y-pipe will no longer fit the s, owing to the wider bolt pattern on all available headers (even the stock headers from the HO).  This is ok, because you don't want the y-pipe anymore anyway. Throw it away, cats or no cats a y-pipe is garbage.  Get a H-pipe for a 79-93 5.0 Mustang, it will fit perfectly as the difference in the car's length is AFTER this point.  Here's where it gets sticky.  You get the cat-back for a 86-93 5.0 Mustang (GT or LX is simply a matter of aesthetics. GT tails ride higher and turn down at the end, LX tails hang slightly lower and dump straight) The lers are the same, the inlet pipes need to be lengthened several inches but it's not brain surgery, the tails will also have to be extended, but the extension will be needed in the straight section, so that's not rocket science either (if you use LX tails, you can just install long chrome tips) then you need to hang the piped using the T-bird hangers. done.

If you are in the market for a set of stock mustang headers, I have a set... PM me if interested

Stock headers from a Fox Stang will be just fine, BUT, if you go with aftermarket headers, don't get equal length headers. It'll just be a huge pain for you. Also, your engine lift tabs will have to go. they are different from Mustang style pieces.

I think replacing the headers equals "headache"....im gonna just go with a nice pair of Flowmaster 44 knockoffs ($27 each..cant beat that) and end the pipes at the lers, with maybe some turndown tips. Should sound good with the 5.0 and no cat. Im not looking to race anyone...just change the sound of the engine / exhaust. It's too restricted right now.

I had turn downs on my lers....had to have tail pipes. The drone killed me. Sure, it's cool for a while, but a short while.

Adding the new exhaust is very straight forward. It's sounds more complicated than it is....bottom line...

1. Unbolt and remove old exhaust.
2. Install headers and H-Pipe
3. have ler shop install lers and pipes out the back. new system. Better power, even from a stock engine, and done.

I honestly don't mine the interior noise...im actually looking for that "growl" or rumble that im not getting right now, except when I ran open headers....but that was just too much and cop attracting...lol.

But are you looking for that growl that drills a hole in your head?  because that's what you'll get with flowmasters echoing off the ground.  Besides, you'll never get turn-downs through inspection.  Headers are easy, they'll drop right in, I promise,  The H-pipe will slip in place fairly easily as well, combine that with some o2 sensor extensions and you can't go wrong.

I am exempt from emissions in CT being that's a 25 year old car. Same in NY state. If the noise is too much I would just add tail pipes, but I think that will choke the sound being that they go up and over the rear axle...maybe not ?

Good tails are how you're going to tune the sound you want.  Dumps, aside from being a cop-out, are really just uncontrolled and sound obnoxious, I promise that you WILL tire of them quickly.  Beside that, flowmasters, being a chambered ler, require a minimum length tail for the chambers to work correctly.  But if you're going to keep the y-pipe, you might as well just do a single flowmaster, because when you y-pipe out to two, you lose so much velocity that you'll have great torque until about 1800rpm, and then she's going to fall flat on her face wheezing for breath.  Making an exhaust bigger after it's run smaller (y-pipe) ends up a big loud mess. 2 y-pipes equal a more expensive single exhaust, because face it, you can't flow any more that the narrowest part of the system (single section between the y's).

Tbird tail pipes go up and over the rear axle....and then out the rear of the car. That is a lot of length to kill the sound of the exhaust

http://www.youtube.com/watch?v=UJS_X3r0eWU

That was my old Sport with b303 cam, stock Mustang headers, stock t-bird y-pipe with gutted cats, ler deleted, and turndowns on the rear y-pipe... SO it was headers and then 2 into 1 into 2. all factory sized except the piece were the ler was deleted and it was the same size as the ler inlet/outlet. It sounded better in person, didn't really change much going to a 2.5" h-pipe and glasspacks

The tails are going to MAKE the sound of the exhaust.  lers don't determine the sound, they reduce the volume and determine the velocity drop, the tails will determine the shape and tone of the exhaust note.  How much sound volume do you think you're going to lose?  What are you intending to do; break people's windows or something? 
Also, if I'm not much mistaken, being emission exempt doesn't make you exempt from your safety inspection, and pretty much everywhere I'm aware of, they require the exhaust to exit at the perimeter of the vehicle to prevent gas pooling and entrance of exhaust into the cabin.  Doubly important if you have hollowed your cats out.

re: Dougy Fresh:
How did you get the headers to fit the Y pipe on the cat ? Usually the collector size on mustang or racing headers is over 2", and the stock y pipe is 2" diameter, at least I believe mine is

You're emotionally attached to this y-pipe for some reason I am unable to understand.

No...I. just want to get an H pipe and find out it doesn't reach the lers.....money and time wasted

Of course it's not going to reach the lers, it's not supposed to.  You need the ler inlet pipes for mustang, and you'll need to extend them about 5 inches, but the
h-pipe need not be altered in any way, the only alterations you need to make are to the inlet pipes and the the tail pipes. Both need to be extended with straight bits of pipe.

i'm not sure, it was done when I bought the car, BUT, I know they slotted the holes in the y-pipe so that the studs would work and other than that I saw no modifications