bignatedogg

2nd gen people! pull together on this, we were the only gen blessed with the beautiful and very sexy dual exhaust. keep it that way please!

banzaitoyota

FAKE DUALS WERE A MARKETING PLOY/GIMMICK in my opinion. Exhaust TIPS the size of COFFE CANS are the epitomy of RICE! But to each his own!!!

West TX RX-7

It really only matters what you think not what everyone else thinks. I run an Apexi N1 single sided because it is the most practical, less weight better flow. I do not run a cat and it sounds just fine, hear it at idle it sounds beter when your gassin it but not too loud. I like the looks just fine but wish i could find a rear bumper with a single side cutout.

RotoHusker

Yes

RexSe7en

I am not going to say that the singles look like ****, but I prefer the dual

marlaman

I just got the Mazdatrix true dual setup with 2 pipes ALL te way back. it's my treasure and it purrs.

but oh damn they forgot one gasket. sons of bitches..........

NZConvertible

Um, they're not fake...

banzaitoyota

They are not "true dual" from the Exhaust back, They are 2 functioning mufflers , split at a Y pie, designed for looks only.

banzaitoyota

Congrats Marleman, did you dyno b4 and after to see if real world gains are realized with this setup?

RotoHusker

marlaman

I just did the same thing, and was also one gasket short !! I thought I'd misplaced it in all the clutter in the garage. ~$3.00 at advanced auto.

Has anyone ever considered putting a crossover pipe in one of these setups just just aft of the presilencers? Documented improvement on some V8s. I don't have a clue what the impact would be on a rotary.

banzaitoyota

Rotoo, good question. I haven't found an answer either.

Barwick

on a TurboII there's NO reason to go with a dual exhaust. Everything is already collected into one pipe after going through the turbo, so why split it up again?

banzaitoyota

Thank you BARWICK!!! My point exactly

NZConvertible

I'm sick of explainging the engineering reasons behind it, I've done it plenty of times. Believe whatever you want.

ReZ311

iTrader: (4)

That is pretty moronic what you said there.

NZConvertible don't waste your freakin time. Obviously they didn't read the whole thread and get educated by your posts on this thread.

zyounker

A straight single will flow more then one with a y in it.

The 2 mufflers are for looks, because people like the look of 2 mufflers which make them think dual exhaust.

Now, true duals are also not the best either. They should be joined for the best scavaging effect. But you also need to join them at the correct time (length) which i believe is longer then the Rx-7's body


That is why racing beat joins the exhaust on the 1st gen RX-7 in their long primary system.

it runs dual ALL the way to the rear axle, and then joins to a muffler with dual tips. The reason they joined the 2 pipes was because it helps the engine scavange exhaust gasses in the combustion chamber.


-Zach

nima_taba

Well, I started this post a few month ago to get some feedback from you guys. I decided to go with the CS single. It was just installed last week, is one loud **** and looks sweet.

I'm glad I went single cause I'm not broke now, just to get an extra muffler (and some more flow, according to our expert on such matters, NZConvertible).

Thanks all for the good debate!

Single rules (if you're poor!)

Nima

mikeric

iTrader: (20)

You're right, single rules if you are poor. I got mine not only for the price, but also for the weight savings. All of my mods were done with weight savings in mind. How do you like 14lb MOMO seats and 16lb 17'' rims?
I do wish I didn't have the coffee can look at tip, but what can I do?
To each his own.

NZConvertible

Making blanket statements like that prove you don't really know what you're talking about. Like I said, I've explained this before... Ha! Old school V8 drivers might think that way, but the RX-7 was designed in Japan, where the the looks of some 70's muscle car are completely irrelevant.

zyounker

Whatever..

You can nit pick at my statements and call them blanket statments even though you know i am talking about the RX-7.


There is a reason for the "Duals besides just looks but it will not make the car preform better then a single.. it will make it quiter and allow using less restrictive mufflers to quite it down.
but, Any time you add turbulance to an exhaust, you slow down the velocity of the exhaust gasses.

A single muffler will flow BETTER on a 86-91 Mazda RX-7, and care should be taken to make as few bends as possible.

Is that specific enough for you?

NZConvertible

There are many different sizes of pipes that will fit under an RX-7, so to say that any single sytem will outflow any dual system is nonsense. This is true, but you need to look at the rest of the system too. For example, the pressure drop (a measure of restriction) through two 2.5" pipes will be considerably less than for the same flow though a single 3" pipe. So the restriction through the rear half of the system is lower. There is some restriction introduced with a Y, but a well built one flows a lot better than most people here seem to think. Again, you're making statements that are not necessarily true. Pick your pipe sizes correctly, and a dual can flow as much or more than a single.

ka8legend

Man you're confusing the hell out of us. I really think you meant, as volume decreases, density increases, just like how the universe has evolved. Recall what you said at the bottom of page 3.

zyounker

I don't think you are disagreeing with anything i said. you are just taking the fact that i didn't specify every single variable, and saying i don't know what i am talking about. I understand everything you have said.

So to be perfectly specific:

A 1986-1991 Mazda RX-7 with a 13B intercooled turbo charged engine, with a 3" exhaust all the way back with as few bends as posible with a 3" muffler without baffles, will flow better then a 3" exhaust all the way back with as few bends as posible with a Y pipe splitting it to two identical 3" muffler without baffles.

The "Dual" muffler exhaust will be quiter, but will not flow as well.



Is that Good enough for you? Damn, talk about picky....


-Zach

KiyoKix

I personally love the dual exhaust because it just "fits" the car, but it's really up to you and you're taste. Sinlge isn't bad, but i don't like very large tips (unless they actually do something besides look shiny and tell everyone you think your car is fast/cool).