Nija

Ok, so this is all about the Postal jeep

We've got the boy running, and it sounds good. It's not really smoking (well anymore ) and I want to get it to be a daily driver. I figure I need to have it pass smog. To pass smog I was told that I would basically need an entirely new exhaust system. (the reason being there is some sort of spigot right before the muffle that I guess is a bypass for the exhaust, total custom jobby for the Government ) Anyways, I figure instead of going back and adding more later, I can do what I want, upfront.

I want to add some headers to my engine. From these, I want to take them back to a dual flowmaster exhuast system (I'm partial to dual exhaust). I wanted to go with the low-end flowmasters, for their sound (the american thunders are too loud )

Would this be a fairly simple (i.e. weekend, with a couple of friends) job, or would it be a complex one, that should be left to someone who isn't learning?

Thanks

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attgig

i have no clue...but post some pictures!!! i'd love to see this thing.

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look_ma

For something like this you can either A. have a buddy hook you up, B. (Only heard about this, never been in a smogging county/state so I do not know exactly how it works)Go around to dealerships/auto repair and "Borrow" their used catalitic converters and frankenstien multiple ones together, add a muffler and be sure it can still run just enough to get it to inspection. When you are finished you can rip you smog set up off.

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johnnymk

I thought this Jeep topped out at 55 MPH?

Well, anyway, a decent muffler shop could do this. However, if you don't utilize a "Y" pipe but have a "true" dual exhaust, you will need an additional catalytic converter.

Don't expect any performance gains, though.

I would spend the money on a different rear, if you can find one that fits.

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Nija

yeah, it's that jeep

I'm still not sure about replacing the rear-end (i haven't put much thought into that aspect yet =\)

A decent muffler shop, eh? So it's too advanced for a few guys to do in a backyard, and still keep it legal?

Maybe I am misunderstanding the exhaust system. I assumed the headers come out and down, straight to the mufflers, then out the exhaust pipe, and what I'm getting from you is that they come off the engine, into 1 muffler (this is the Y pipe, you speak of?) and then out?

or am I missing something?

sizemic1

doesn't that jeep just have a 4 or straight 6 cylinder?

If that's the case, then you would need a Header (singular). It would also be fairly pointless to have a dual exhaust other than maybe looks.

What year is it again? If may be old enough that it's exempt from smog checks.

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johnnymk

If it's a V8 or a V6, yes, the crossover pipe goes to one muffler.
After thinkimg about it, like sizemic stated, it may have a 4 cylinder.

Nija

it's an '81, not exempt

yeah, it's a 4.

So what would be a better solution to my exhaust system problem?

(the rear is next johnny )

InfiniteNothing

The easiest way is to go all bolt on.
Race 4:2:1 long headers, cat, resonator, muffler.
You can totally do this without a mufflershop. I like the frankenstiening idea but you'd need to do a bit of welding.

But before you did anything get it smogged....it just might pass.

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mechmike0034

The only exhaust system that you are likely to find off the shelf would be a stock replacement system. Somehow I don't think that performance manufacturers are lined up to offer pre-bent and configured hi-po exhaust systems for Postal Jeeps. I could be wrong.

Since a performance exhaust system would then have to be fabricated, then you probably could not do so in the driveway unless you had your own pipe bender, bulk pipe and welder.

Find a good custom exhaust shop, tell them/show them what you want, and let them do it if your heart is set on performance exhaust.

I don't know if anyone makes a header for that motor or not. It's a GM 2.5 "Iron Duke" four-cylinder, if memory serves correctly, so perhaps a header for a Chevy S-10 with that motor would fit. I don't know for sure, but it would be where I would start.

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civicdidex

just being nit-picky...inline-4s have a header [no 's']

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johnnymk

It all depends what your definition of a header is. To us old folk, it generally means a set of custom tubular "exhausts", each one exiting directly from each cylinder to a common point around 18" from the engine instead of a cast iron piece which restricts flow.

civicdidex

yeah same definition but since an inline 4 exhaust ports all on one side all u need is on set of tubular cylinders. V6,8,etc need 2 sets and therefore are plural.