Twice Pipes

[mikewags]

What should I know about 3 to 2 header/twice pipes installation? Would I be better off taking this setup to my muffler guy, or doing this myself. I don't want to take on something that has been known to be a b*tch, and get stuck or caught up in a long drawn out exhaust overhaul.

Thanks guys!

Edited September 21, 2008 by mikewags

[sblake01]

'Better off' is a relative term. For me, now keep in mind that this is not my car or my situation but if it were, 'better off' would mean putting everything back in the box and sending it back for a refund. I just wouldn't got through all of the hassle and expense involved to put dual pipes on a single bank engine. I could do it; I have welders, both gas and mig and tubing benders, expanders, etc. but just wouldn't have the desire. That being said, if you are set on doing this, having read what others have gone through to accomplish this installation, I'd take it to a good muffler shop.

[mikewags]

I haven't bought anything yet, i'm actually still deciding whether or not it's worth getting into.

Headers + Twice Pipes + Exhaust work = 400 - 500$.

Stephen, I appreciate your opinion on the subject. I'm aware that you think the dual exhaust setup is a complete waste of time and money; especially for the straight 6; but I'm curious why I have had several people telling me that the performance/sound gain would be worth doing this.

Are these people full of it, or just don't know what they are talking about?

Ideally, someone here that has a dual/twice pipe setup can give me some feedback on any performance gains/general review of doing this. I'm not about doing the dual exhaust, if it's just going to make a "sweeter sound" - To me that doesn't justify removing stock components/spending the money to get this done.

Thanks!

[Seppi72]

My title is a variant on the line that Ronald Reagan used about the Soviet Union; i.e., "Trust, but verify." It is probably the only thing on which RWR and I have ever agreed, but right is right, and he was right on that.

IMO, anyone who is selling some bolt-on performance part should be asked to "show me the numbers." (I guess I'm into paraphrasing today.) What I mean is that for about $200 they could get dyno runs of the car before and after the bolt-on installation and have them verified, witnessed, notarized and available for inspection. If a business isn't willing to invest that much money in a commercial product on which they expect to make many, many times that much in profits, you can pretty much write the mod off as crap.:sick:

[~KnuckleDuster~]

I installed the twice pipes set-up in my driveway. It's soposed to be easier to install in the 240's though. I did notice a bump in performance which I tested on my butt dyno. As for the sound its amazing. The sound alone is worth it in my opinion. Heres a vid: Please excuse the crap sound quality

<embed src="http://videos.streetfire.net/vidiac.swf" FlashVars="video=9d9c723a-f9e7-47b5-8b2c-9ae60179c8ab" quality="high" allowFullScreen="true" bgcolor="#ffffff" width="428" height="352" name="ePlayer" align="middle" allowScriptAccess="sameDomain" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer"></embed><br /><a href="http://videos.streetfire.net/video/Twice-Pipes-on-the-Z_174052.htm">Installed MSA Twice Pipes onto the 71 240z</a>

[Cutlass372]

Anyone else have any info on this system or even one for sale? I am also interested in this and looking for more opinions.

[Arne]

I can't see any reason that twice pipes would be better for performance than a single exhaust of adequate size tubing. Remember that twice pipes were used back in the '70s as "THE" performance choice. Why dual pipes? Because the large diameter pipes that we all use routinely these days were very hard to find. Two inch pipes were the largest your local muffler shop had available. These days we have larger 2.5" pipes available, which are much easier to work with, and have vastly better tuning ability.

[ozconnection]

Arne, I have reseached this topic myself for quite a while now.

What I have found is it's not just the diameter of the exhaust pipe that's important.

Exhaust system tuning can reap substancial power and torque dividends if done correctly. There are a number of textbooks that promote the idea of dividing the exhaust system into two separate banks for a six cylinder engine with a firing order of 1,5,3,6,2,4. Just like the intake side of things where there are dual plane, single plane, tunnel ram, individual runner etc type configurations, there should be insight given to these possibilities where the exhaust is concerned. There's lots of 'theory' on the topic. May I suggest you grab a book like "Scientific design of Exhaust and Intake Systems" by Smith and Morrison and have a litte read.

I haven't done this yet on my car, but I've already made the promise in another thread that as soon as my system needs replacement, this is the path I'll be taking.

Edited October 11, 2008 by ozconnection
changed some stuff

[Nigel1943]

The Datsun works rally team in the 70's MUST have used dual pipes for a reason and it can't have been because they could'nt get hold of 2 1/2" tube:)

[Arne]

OK, I should have said, "I can't see any reason that twice pipes would be better for performance on a mostly stock street driven car than a single exhaust of adequate size tubing."

I'll concede that there are flow characteristics that may be advantageous if properly developed. I also strongly suspect that most exhaust shops do not have the knowledge to take advantage of this.

[darkstarrocker]

There was a post with pictures of an instal over in the tech section at zcar.com a couple of days ago.

http://www.zcar.com/forums/read/1/1975877/1975877#msg-1975877

Edited October 11, 2008 by darkstarrocker
Didnt want to sound like an ass on my first post

[ozconnection]

I'll concede that there are flow characteristics that may be advantageous if properly developed. I also strongly suspect that most exhaust shops do not have the knowledge to take advantage of this.

I guess that's the value of forums like this. With our collective and shared knowledge we could probably go to the exhaust shop and tell them what we wanted on our cars.

Knowledge is power:geek: