Help me build a new exhaust system :)

[Si|v3r72]

I want to replace the entire exhaust sytem on my stock engine 72 240. The current setup is aftermarket and doesn't even fit the car. The things I am looking to achieve with a new exhaust system are more horespower and a better sound - not too quiet, not too loud, but sounds like it's got some muscle. As far as price goes, I don't want to go crazy, but I don't want to go cheap either. So given that and given that I'm car illiterate, my questions to you are:

1) Should I use headers?

2) What is the desired configuration behind the headers/manifold?

3) What type of muffler should I use? Should I add glass packs?

4) Should I go stainless steel?

5) Where can I go for parts?

6) Anything else I need to think about?

I really appreciate any help. I'll be sure to post results when the time comes.

BTW it's for this car:

[Marty Rogan]

I believe this car is pretty stock right? Unless you have real sleeper here with a monster motor under the hood, forget about the headers and exotic pipes. It won't do much with a stock engine. A header will only net you 1-3HP, and will be prone to exhaust leaks, rust and make the car louder. 2 1/2 inch pipes tend to be loud and create a nasty booming sound under the car @ 2500RPM. I suggest you go to a good muffler shop and have them custom bend you one with 2 1/4 inch pipes, teminated with a nice turbo muffler at the back. Thats what I did. It has a real nice growl, without being obnoxiously loud. It only cost me $126.00 complete.

Good luck!

Marty

[Si|v3r72]

yup, it's a stock L24 w/ dual roundtop SU's.

I was under the impression that headers would get me more power, but I like the sound of an inexpensive solution with similar results. Thanks.

[Marty Rogan]

To get any significant additional HP, you would need to stick an L28 block in there, with triple carbs and a high lift cam. Take me advice, you will love the sound.

[kmack]

Marty,

I know the factory system came w/ a "pre-muffler" in it. At some point, a PO had installed what looked like a glasspack in the middle of my otherwise stock system. I need a total rebuild of mine, and will go to the 2-1/4" system. What do you recommend for this middle muffler or one at all? As for the Turbo muffler, what brand(s) do you recommend?

I want something that is rather subdued, but will growl when driven hard. Looking for suggestions also.....

[Si|v3r72]

kmack - I'm basically wondering the same as you. The pre-muffler is a resonator but I'm not sure if it's even necessary. Anyone care to share some knowledge about this?

Also, I've read conflicting reports about what headers will do for horsepower on an L24 engine. What's the scoop? I don't want to throw money at something that's not going to perform.

[Mike]

I was very happy with my 2.5" exhaust system. I purchased a 6-to-1 header and a complete exhaust kit from MSA.

While the header was worth it, the exhaust kit was a POS. Don't buy a exhaust kit. Bring your Z down to the local shop and ask someone to 'bend' you a new system and install it while you wait.

I spent nearly the same price on my kit after I had to ask one of the local guys make it 'fit' right. It hung too low, the clamps hung down, and it just didn't seem to fit at all. When he was welding new pieces, he 'discovered' (by accident), that the kit metal was very thin. He ended up replacing 1/2 of the system.

When you have a custom system installed, they will do it all right.

IMHO, stainless isn't worth the price unless you're gonna show off the car.

As far as the header, make sure the flange thickness (the metal flat part that holds the header to the head) is the same as your intake manifold. I had troubles because these thicknesses were different.

I bought a standard 'turbo' muffler. It worked great and sounded AWESOME. But, I know there are better mufflers on the market. I also eliminated the pre-muffler. Not sure of the exact function of that muffler (besides making it quieter). But, that location is now used for the catalytic converter (sp?). Basically, a piece of metal gets hot and burns off the fumes if they get through .

[jcdozier]

You can surf around the various Z sites and find lots of opinions on headers and big exhaust systems, but I haven't seen any posts that indicate a significant power increase. IMHO they don't give much "bang for the buck" when it comes to increasing horsepower.

I have to agree with Marty Rogan - headers tend to warp and leak. I have Hookers and after about 60,000 miles they had leaks at 5 of the 6 exhaust ports. They were so badly warped they had to be "weld-filled" before they could be machined. I also have a 2 1/2 inch exhaust with no pre-muffler, and it's pretty loud.

If I was doing it all over again, I would forget about the headers and find a local muffler shop that can do mandrel bends to install a 2 1/4 exhaust system. I would go with a flow-through muffler, and if the system was too noisy, add a bullet-type glass-pack pre-muffler.

[Marty Rogan]

The "pre-muffler" is a resonator. Its function it to quiet the car down further. I did not use one and don't miss it. There is a brand of muffler that is very popular, I think it is called a Dynomax. Stay away from that one, as I heard it is really loud. Talk to the guy at the muffler shop and explain what you want. They usually will have a couple of choices. I wish I could remember the brand I bought, but that was over 3 years ago.

Good luck!

Marty

[Si|v3r72]

In reference to not installing headers, I was wondering what happens at the manifold if you upsize your pipes to 2 1/4"? Doesn't the stock manifold create a restriction thereby defeating the purpose of upsizing the pipe?

[Marty Rogan]

The pipes from the manifold all come together at one point. On mine, the sort of cut off part of that collector, flattened out the tube and welded it on there.

Marty

[73240z]

Headers don’t “make” horsepower – they simply relieve the engine from the task of shoving exhaust gases out through stock manifolds. Installing properly designed exhaust systems frees up any energy wasted pushing out exhaust, and allows it to be used in propelling the vehicle. This increase in efficiency can be thought of as “free horsepower.” Engines (especially those with emission controls) are designed to operate most efficiently with a designed amount of back pressure.

I have had numerous mechanics tell me that headers won't do anything for you until you hit at least 5000 RPM, but I have never seen it in writing.