Twice Pipe Exhaust System

[geezer]

I'm at a loss trying to figure the best option available to complete my exhaust system. I am using the header that came as a Sports Option (14004-E4620) and the second section that I don't have a number for. I believe it was originaly from the same car as the header. It's pictured here. I have never seen the last section for sale anywhere and will have to fabricate one. Here's the question. Has anyone seen or know where to find a 2 in & 2 out muffler such as the original or close to it? Each pipe is 50mm OD or a little less than 2" OD.

[Nigel1943]

I'm guessing here but that system looks as though it's designed for two separate mufflers and for each pipe to come out from each side of the car. The early Datsun works rally cars had a similar system. Aside from its' vunerability it should theoretically be far more efficient than a single pipe system.

[Carl Beck]

Hi Ron:

You would seem to have a couple options - related to where you want to bring the tail pipes out from under the car.

The NISMO Factory Sports Option set up brings straight pipes out the center of the car, and I believe that BRE did the same with their C-Production Z's. I'd guess that on the cars set up for road racing, the stock fuel tank was replaced with a safety fuel cell - otherwise the tail pipes would seem to be very close to the gas tank... and somewhat low to the ground.

Bob Sharp seems to have run a set up sold by Datsun Competition that brought the tail pipes out to the left side - in the stock location. The Datsun Competition setup had the option of running straight pipes or two mufflers.

If you are thinking of putting a single oval muffler, with two inlets/outlets - in the stock location (instead of two individual glass packs)... Then you'll most likely have to go with something like the Magnaflow

http://www.magnaflow.com/02product/shopexd.asp?zone=main&id=475

I could be wrong, but as I recall, you need a muffler on the left that is about 14" long - so the example above might not be the exact one... You'll have to get exact measurements... Most muffler shops have catalogs of universal fit mufflers and they could easily come up with something to fit your needs.

FWIW,

Carl B.

[HS30-H]

I am using the header that came as a Sports Option (14004-E4620) and the second section that I don't have a number for. I believe it was originaly from the same car as the header. It's pictured here. I have never seen the last section for sale anywhere and will have to fabricate one.

Ron,

The centre section that you pictured is part of the Optional system for the L-series engined cars in the Japanese market, which was standard equipment on the S20-engined cars. It wasn't a 'Sports Option' part - it was in the standard sales brochures. It did however mate with the L-series Sports Option exhaust manifolds.

Original part number for the centre section in your picture was:

20010-E4201 arse'Y-TUBE, exhaust with muffler

....which was paired with:

20050-E4200 arse'Y-TUBE, exhaust with booster

....which was superseded by:

20050-E8710 arse'Y-TUBE, exhaust with booster

....in 1973, and I believe the difference was simply detail in the mounting points.

That 'booster' is simply a fat round box which the two pipes run through. The two pipes that run through it are perforated with multiple holes, but become solid again where they exit the box - so in effect it is a two-pipe system all the way through. The last six inches or so of the pipes are chrome plated and slash cut. These systems sound rather nice on the car.

I have a complete NOS system hanging in the roof of one of my garages. I can take some measurements and detail photos of it if you want to try and replicate it - but the shape of the pipes is rather complicated.........

[geezer]

Thanks for the responses guys. I really appreciate the help. I’m trying to loosely recreate the outward appearance of the original dual pipe system and only hope it produces a sound that could be described favorably. A nostalgic touch of the homemarket, I guess.

Carl – The Magnaflow example you found is the closest to the original muffler I’ve seen so far. I will find out if they can be had with 2” inlets and outlets. The original has a length of 12” and the Magnaflow has an 11” or a 14” length.

Alan – I’ve seen your photos many times while doing searches. There are not many other examples to be seen. I think I even dreamt about your stainless system once or twice. I can replicate the pipes for the intermediate and rear sections from the original intermediate I have and from photos of the rear section. I do need a little help with the “booster” dimensions. I don’t know if it is possible to see the perforations in the through pipes to get an idea of, how many holes there are, the size of them and the arrangement. Also I’m left wondering if there is a single expansion chamber for both through pipes or is it divided in half? Please don’t put yourself out, taking it out of storage and measuring. In this case close is good enough.

[WingZr0]

Fujitsubo also makes a nice Twin pipe system you might like.

We talked about it in another thread.

They look like the Z432R set up.

They also make a set with single exhaust too.

Don't know much about 'em other than they look nice.

other thread here...

http://classiczcars.com/forums/showthread.php?t=27632&highlight=fujitsubo

~Z~

[geezer]

"Fujitsubo also makes a nice Twin pipe system you might like.

We talked about it in another thread."

You're right...I like, but that much bling would take away from the modest/simple, clean, bare bones, functional early '70s look I'm after. I am borrowing components from other S30 markets/models and using a select few aftermarket pieces you would have seen in the early 70's. Any deviation from this plan just ruins the vision I have, if that makes any sense to you. I'm even concerned with the prospect of the paint looking too good.

[Arne]

Ron, given the parts and pictures that you have, a good exhaust shop should be able to build a rear section for you. Probably less cost than what you'd pay for an original rear section, assuming you could even find one.

[HS30-H]

I do need a little help with the “booster” dimensions.

I happened to be at the garages this afternoon, so I took some measurements from the NOS 'Booster':

Overall length of the 'box' itself ( measured to the outer edges ) is 350mm, and it has a diameter of 165mm ( it is perfectly round ).

The pipes going in and coming out are actually 50mm diameter. The slash-cut and chrome plated exit pipes measure 220mm ( top one ) and 180mm ( lower one ) at their longest points. I forgot to get an idea of that slash-cut angle. sorry.

I looked down the exit pipes to see what I could see and it was DARK in there. I didn't have a torch with me either, so you'll have to wait a couple of days until I go over there again armed with a torch. Sorry I can't be of more help with regard to what's going on inside there, but it certainly doesn't seem to be hollow ( must have some sound-deadening material in there I'd think ) and I can't see any evidence in the way of spotwelds on the outer casing that would show the presence of a 'divider' inside...........

Alan T.

[WingZr0]

"Fujitsubo also makes a nice Twin pipe system you might like.

We talked about it in another thread."

You're right...I like, but that much bling would take away from the modest/simple, clean, bare bones, functional early '70s look I'm after. I am borrowing components from other S30 markets/models and using a select few aftermarket pieces you would have seen in the early 70's. Any deviation from this plan just ruins the vision I have, if that makes any sense to you. I'm even concerned with the prospect of the paint looking too good.

I get you, the Rat Rod look.

Or in todays terms, Street Racer

[geezer]

Arne - There is a good muffler shop not even a 5 minute walk from here. I have strolled down there many times toting a length of pipe. Once I showed up with a box of those hard foam swimming pool noodles wound with coat hangers, to keep the shape, when I was building a set of headers. That's where I get my bending and expanding done. Hopefully, the rest of the fabrication I can do in my own shop.

Alan - Thankyou for taking the time getting these measurements. As far as taking a look inside, that is not terribly important. I do have some past experience building similar devices. I'm assuming it is glass packed.

[madkaw]

Pvc pipe makes for a good template>