TIIFC3S

Personally, the only thing that sounds better than a NA PP 3 rotor is a NA PP 4 rotor.

Look and listen to that engine:

http://www.youtube.com/watch?v=HWTUL...eature=related


http://www.youtube.com/watch?v=T7J48...eature=related

Jimmy2222

iTrader: (3)

Yeah with a 2 rotor it's gonna be hard to get the sound you're looking for most of those badass "unique" sounds come from crazy builds like this
http://www.youtube.com/watch?v=JaAKO...eature=related
You're gonna have to get some more rotors if you want that sound.

Bamato

iTrader: (6)

Are you referring to volume? Because my exhaust in not loud by any means.

89FC Alpino White

duals are not purely for looks. dual exhaust with give a small amount of higher end hp, while single exhaust will give you a small amount of low end torque.

hardly noticeable, but proven.

GT car sound, maybe from a 3 or 4 rotor. save some money bro!!

jjwalker

Getting GT car exhaust sound needs 2 things...

1)High RPM
2)many exhaust pulses

V12 Piston engines can achieve this easily because of the high amount of exhaust pulses, per crank rotation. V12 engines typically also have smaller piston bore diameters and shorter stroke, so they can rotate at very high speed.

The 13b has the exhaust pulse pattern of a 4 cylinder engine. The reason the 13b has a distinct exhaust note is because of the absence of a poppet valve and much larger exhaust port area.

20b has the pulse pattern of a v6, a 26b has the pulse pattern of a v8. The reason they can achieve "GT car" exhaust sound is because they rev so high.

jimmydanny

Rallycar exhaust is just pure love imo.

http://www.youtube.com/watch?v=4TshFWSsrn8

Around 1min and out a bit, straight before the rev limiter, and when he drives in. Just sick sound.

fc3s91

iTrader: (23)

Here is my fc at Mazfest. It sorta sounds like a f1. Top speed that day was 171mph...
http://www.youtube.com/watch?v=3hhunwtiGLk

Syritis

iTrader: (2)

http://en.wikipedia.org/wiki/Formula...and_Technology

R.O.D

iTrader: (3)

sorry not important, and not meaning to thread jack,

but, i had always thought a 13b had the pulse of a six cyl., because of the total of six faces, alternating. eg: face1 ex. then face4 ex. then face2, face5, face3, and finally face six.

then the 20b having a nine cyl. pulse and the 26b having a 12cyl. pulse

am i totally wrong? wheres my goof up

jjwalker

but our eccentric shaft rotates 3 times for every rotor rotation, so one combustion event per rotor, per rotation.

A cranshaft rotates twice for every complete movement of a piston. 4 pistons, 2 combustion events per rotation, as 2 pistons are exhausting and the other 2 are in compression/combustion.

AF_H1VLTG3

ATM I have a stock ish motor and small non-factory turbo and manifold while I refine my tuning ability. I have a PP engine with N/A tranny with miata gears on standbye for when I feel I'm ready. Its a different strategy for both but practice makes perfect right? Also it would be a shame to slag a whole bunch of work while I learn to tune stand alones.

AF_H1VLTG3

Not PP, Street Port. Derp. Can you tell I have been looking at PPs?

R.O.D

iTrader: (3)

ya so rotor 1 has event one, then two, then three (full rotation)
and rotor 2 has event one, then two, then three (full rotation)
.................................................. ................+___________
.................................................. ...................6 pulses??

we're talking actual puleses, not rotaion equivalence, right?

like if ur testing for compression, your looking for SIX pulses, so the exhaust would be the same...

Aaron Cake

iTrader: (1)

If you really want your car to sound F1, then you'll need to start with one of these...



...but you can't have mine!

tuscanidream

iTrader: (6)

Nice shaft dude. No homo.

jjwalker

you have one combustion event, one intake event, and one exhaust event per revolution of a rotor, time two rotors.

3 faces, 3 rotations of the eccentric shaft.

6/3=2

We have 2 exhaust pulses per revolution.

4 cylinder engine. Has a complete up/down movement of piston in one rotation. It takes 2 rotations of a piston engine to complete a cycle. Intake, compression/combustion, exhaust. takes 4 revolutions of the crankshaft to do this. You have 4 pistons, only 2 will be exhausting in the same rotation because the other 2 pistons are going through compression/combustion.

We have 4 faces, 2 rotations of the crank shaft. Faces being pistons.

4/2=2

Make sense now? You have to visualize the engine working then do the math based on how both work.

This link may help. It actually talks about displacement but the same information applies.

http://www.rx7.com/techarticles_displacement.html

R.O.D

iTrader: (3)

http://auto.howstuffworks.com/rotary-engine4.htm

in the image u can see three ex. pulses for one rotor, over one rotation, with another rotor, thats six pulses

from what ur describing, one rotor only fires once per rotation.
it fires three times per rotation.

idk, after seeing and reading this, im convinced of what i said about the 6,9,12.

sorry guess we'll just have to agreed to disagree

djphonics

iTrader: (1)

Aaroncake, that's awesome!

ROD, I'm following your logic here...isn't this why our little 1.3 litre motors are thirsty? because there is 3 cycles per rotation?
sorry JJwalker, i'm just not following the one exhaust per rotation. if the tip of the rotor is at the top of the motor, by the time that tip gets back, 3 cycles have been completed (although not intake, combustion, exhaust, from where ever they start in that cycle, they finish)

I'm confused....

jjwalker

The rotor takes 3 revolutions of the eccentric shaft to make a full rotation around the housing. You only have one combustion event per revolution, per rotor. If you only have one combustion event, per revolution, your only going to have one exhaust event, per rotor.

Here is a link to a video that will show you this.

http://www.youtube.com/watch?v=OuId4nuxXaM


and another, skip to 1:54

http://www.youtube.com/watch?v=3UlhneTyLIc&feature=fvw

djphonics

iTrader: (1)

did you film that for us? your too sweet! lol

i follow your logic, it's a miracle, i've been converted lol

jjwalker

Sorry for going off topic and thread jacking.

Just trying to educate.

No, I didn't make that video.

Edit: I reread what you said about firing 3 times per revolution. I don't mean revolution of the rotor, I mean revolution of the eccentric shaft.

djphonics

iTrader: (1)

To be honest, the eccentric shaft's rotations didn't even play into my mind. I saw that, and was like wtf was I thinking! And i apologize for the thread jack as well.

But back onto the OP's topic:

Build a very strong 26B, that can produce 15 000 rpm plus and it'll be somewhat achievable to the untrained ear. You could pull a knock off and do a 20B at 10 000 rpm, but someone will notice lol. Tune the exhaust for the street, not the track....provided it's a street car

jjwalker

You aren't going to get that sound out of a 13b, just isn't going to happen.

Get some good stainless steel packed, straight through mufflers and enjoy the sound. I just did this and couldn't be any happier. Deep and throaty until 3500rpm+ and the car starts screaming like a banshee, without the nasty bee noise the NA tends to make.

I bought two 14" long magnaflow stainless steel mufflers and had them welded up. I bought 2.5 inch mufflers and fitted them to the stock 2 inch y-pipe. Rather large now, but I am getting a custom y pipe built this summer that will be 2.25 inches instead of the stock 2 inch. I may even go 2.5 inch, haven't decided yet.

jjcobm

iTrader: (18)

Dammit... I guess my car won't sound like a F1 engine any time soon since i'm not rocking the mullet I want yours Aaron : P


.....All in good fun, don't go mod power trip on me : )

jjwalker

Mullet madness = GT exhaust sound. Sounds plausible!

/joking!