Exhausted Exhaust

[Jack Meoff]

The exhaust on my Fifth is becoming exhausted so I figure I might as well just redo the whole setup so the old gal can breathe....I'll have to get one of those lovely new hollow cats that NoCar posted.

The question is.....what is the biggest diameter pipe I can run off the stock exhaust manifold?....not sure what the outlet is..
2 1/4"??? or 2 1/2"???

 

[NoCar340]

There's absolutely no reason to go to 2.5" off the engine with a stock 318, particularly with iron manifolds. I think you could get away with 2.25" but I think you'll find the manifold outlets are 2". I would probably go with either diameter but jump to 2.5" at the Y junction, unless you're going full duals, which I think are also overkill on the stock engine. Get a free-flowing muffler and call it good. On a single exhaust, it probably wouldn't kill you to go 3" with smoothly-tapered transition cones (such as Flowmaster R3025, sold as a pair) to system size, in and out. It would be a little louder, but for good flow while staying quiet you might consider a parts-store single-tailpipe conversion muffler for a mid-'90s Chevy K1500 350 truck application in 3". Make sure you specify 3", though--there are oddball 2.75" ones out there. There's a bastard of a pipe size. As far as I'm aware, only GM used it.

 

[Jack Meoff]

Thank you Sir.
I will tape this information to the forehead of my buddy who will be doing it for me... :tard:

Do you happen to have that link for those cats?

 

[NoCar340]

Click here and scroll down. I'll be going with the stainless myself... can't beat it for the slight price increase.

 

[Jack Meoff]

Thanks!!
Same here....only the finest for my cars...

 

[holmes]

Hey Capin', you ever consider one of these? https://www.rockauto.com/catalog/x,carcode,1090730,parttype,10038
Woodvark just put one on his Gran Fury and helped his performance noticeably.
Oops, forgot you are Canadian to start with so you most likely don't have the 2 mini-cats on your y-pipe anyway.

 

[Jack Meoff]

Hey Capin', you ever consider one of these? https://www.rockauto.com/catalog/x,carcode,1090730,parttype,10038
Woodvark just put one on his Gran Fury and helped his performance noticeably.
Oops, forgot you are Canadian to start with so you most likely don't have the 2 mini-cats on your y-pipe anyway.

Nope.....no pre cats on any of my cars
But I know lots of you US folks have installed those.
Might save me some money anyway to get that setup instead of paying a guy to fab it all from the manifolds back.

Thanks for the link!!

 

[8v-of-fury]

Hmm, my Canadian spec 88 5th has precats, even though I have read those pre-cat-less y-pipe's are for Canuck market.. My car is so Canadian market it has french on it ok! lol

 

[NoCar340]

Eight individual zoomie pipes straight through the hood. Problem solved. No garage? Raincaps, like a bulldozer. :eusa_dance:

 

[Jack Meoff]

eight individual zoomie pipes straight through the hood. Problem solved. No garage? Raincaps, like a bulldozer. :eusa_dance:

lmao!!!!!

 

[Jack Meoff]

Hmm, my Canadian spec 88 5th has precats, even though I have read those pre-cat-less y-pipe's are for Canuck market.. My car is so Canadian market it has french on it ok! lol

I'm not sure but I think my 87 was the last year for no pre cats.
At that point though I suspect it was hit and miss at Chrysler
I've seen Canuck 88's with the smog pump and without.

 

[Sublime440]

Shift your tank over and run duals...

Mine are 2.5"...I think you've heard them in one of my videos.

 

[Jack Meoff]

Shift your tank over and run duals...

Mine are 2.5"...I think you've heard them in one of my videos.

I have indeed......sounds wicked too.
But the Fifth is the daily mule so I'm not sure if I want to be deviating too much from stock appearing in case I raise an eyebrow with the envirogestapo....

 

[Mr.Lopar]

you can still make it look stock. just get the jegs a-body kit
member ark on the other board has that kit on his 5th ave and they turn down behind the rear bumper, hardly noticeable, and when they are they appear to be a factory install

 

[Jack Meoff]

you can still make it look stock. just get the jegs a-body kit
member ark on the other board has that kit on his 5th ave and they turn down behind the rear bumper, hardly noticeable, and when they are they appear to be a factory install

I'll have to check his out.
Everyone around here is saying to keep it as stock looking as possible.
Even a 2 1/4" pipe will be a big diff from the 1 7/8" pea shooter on there now.
When I eventually do the lean burn conversion everything including computer will stay.....it just won't do anything.... :icon_mrgreen:

 

[Mr.Lopar]

gut out the computer and put the orange box in there, youll have to run a extra ground for it though
and if you wanna get real tricky, use one of the factory plugs on the computer, but rewire it to work with the ecu

 

[Jack Meoff]

gut out the computer and put the orange box in there, youll have to run a extra ground for it though
and if you wanna get real tricky, use one of the factory plugs on the computer, but rewire it to work with the ecu

Wow!!
That's a smokin' idea!!

 

[Mr.Lopar]

I even went and dug up a couple pics of Ark's car.
the exhaust is more noticeable then I thought, but still has a factory look to it

 

[Jack Meoff]

Yeah. I think I'm staying with the single....
I don't want to raise any smog suspicions....

 

[NoCar340]

There's not a lot to gain with duals on your application. The Fifth Ave I built for the ex ripped with a single factory system and 3.21 gears. No rocket, of course, but enough that the guy that bought it from me lost his license within six weeks. :icon_biggrin: