280z Dual Exhaust?

[mikewags]

I was talking to a buddy at work that restores classic cars about a few ANSA exhaust tips I bought recently, and he brought up the idea of me installing dual headers for the Z.

Basically the header will lead to an exhaust pipe for each 3 chambers, then each pipe will split in direction and lead off to the back of the car. He mentioned I might get 10-15% performance increase.

Has anyone done this or suggest this? It seems like a pretty simple bolt in process installing the headers, but what about all the hoses and stuff ontop of the exhaust manifold?

Any and all suggestions would be great. Thanks!

[Arne]

Search the forums for 'twice pipes'. MSA sells 'em. Clifford used to make 'em too. To do it all the way, you need a 6-into-2 header, or custom work on the dual downpipe.

[m4xwellmurd3r]

you're thinking of twice pipes. MSA makes a 3-2 header and a twice pipe kit, however, you need to modify some parts to make TRUE twice pipes (the MSA kits come with a 2-1 pipe on both ends, so it goes 2-1-2)

I really don't think you'll see a 10-15% increase in performance, BUT they sound REALLY REALLY NICE! I don't know what you mean by "all the hoses and stuff" on top of the exhaust. there's one pipe for the EGR, and msa does make an egr compliant header. other than that it's bolt in.

[mikewags]

http://www.thezstore.com/page/TZS/CTGY/PEC02

So #1 on this list...

3 into 2 header...(Arne: I don't see any 6 into 2 - but I think you mean 3 into 2 right?)

I have an exhaust guy that can do the rest of the work once the headers installed (installing the pipes/muffler to the back - along with the tips I bought)

You say MSA sells a kit that includes the rest of the exhaust system? I wonder if that would be the best route to go.

[Arne]

Yes, MSA sells the rest of the system, but there have been complaints on how it fits. As I said, search the site for 'twice pipes' to get first hand experiences.

http://www.thezstore.com/page/TZS/PROD/PEC09/15-6030

As for the header terminology, MSA is wrong. That's a pet peeve of mine, that dates from my early motorcycling days. There are 6 primaries, exiting into 2 collectors. That's a 6-into-2 header, and it also comes with a Y-pipe to mate to a single exhaust. You could also call it a pair of 3-into-1 headers, but since they share a single head flange that's not really accurate either.

[mikewags]

The twice pipe kit isn't absolutely necessary though right, any muffler shop should be able to fabricate the rest of the exhaust system right?

If there was one pipe that ran to the back of the car from each of the 3-2 header outlets; this is basically the same as it being "twice piped" 1 pipe going into 2 (back of the car) then to the tip.

Basically, what I had in mind was to split the exhaust from the header to the left and right side of the car, then run it back.

I don't see much need for twice-piping it to the back, unless this will provide a huge difference in exhaust flow. The way I see it, splitting it from STOCK (single straight back) to 2 pipes (1 pipe per 3 chambers) with that new header/exhaust will make the biggest difference.

Edited September 7, 2008 by mikewags

[d240zx2]

I installed a 6 into 2 header, then ran two pipes all the way back, through glasspacks into a stack on the driver's side. Before I replaced the glasspacks about a month ago, the old (35 years) glasspacks provided a sound that I can only describe as delicious. The new ones toned it down considerably, but still give the same general sound. After my next track excursion, the new g-packs should be blown out a bit and sound more like what I really want to hear....

And a muffler shop did everything from the headers back...about $200.

[sblake01]

Basically, what I had in mind was to split the exhaust from the header to the left and right side of the car, then run it back.

The main problem you'd have there is the lack of space between the gas tank and the right side of the car. I haven't looked under a 75-76 lately but on a 77-78, you'd have no room on the right side for a tailpipe.

[mikewags]

Good point Stephen, i'll take a look underneath the car in the morning.

I'm not sure how much different the 75 is, to the 77/78.

[Arne]

I missed that part. There's no room for exhaust on the right side of a 240Z, either. So I'm going to assume that to be true for ALL S30s.

[geezer]

Without going to a fuel cell and losing the spare tire well, you are limited to what you can do with the available space. Ground clearance and interference are the major issues. This is why the original twice pipe systems exited on the left side only. This would be true of all years I believe. If you route the intermediate section like this original one coming from the header into a 6 into 2 configuration, I can suggest a few mufflers to duplicate this part of the system. I am using this original as a template. What you can do after this section is up to your personal preference. I have some example pics somewhere I can look for if you want.

[mikewags]

That looks pretty good geezer.

I wonder what it would look like with both twin ANSA tips on it like that.