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-   -   GT inspired Exaust tone. (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/gt-inspired-exaust-tone-937866/)

AF_H1VLTG3 01-14-11 12:04 PM

GT inspired Exaust tone.
 
Morning,
Let me get the important stuff out of the way. I live in NM and have no Inspections or Sniff test to pass. Thats said I was wondering if I could get a few suggestions for a new exhaust setup. Right now I just running the following

3" Downpipe
3" pipe
Racing Beat Y
Magnaflow Domestic Fartcans.

This was done by the previous owner. I, on the other hand, am looking for a FIA GTesq Inspired sound. Something that will produce a high pitched scream and WOT. Similar to a F1 car. The REVII system is mellow which is nice for city cruising but I’m looking for aggressiveness without getting the Tinny noise I have now. The only restriction I have is the dB requirement for race tracks. I have been told that Single tip N1s are the way to go but lets face it. 3rd gear deceleration flames look much better out of two tips… :naughty:

P.S.
I did view a few Youtube vids but I value the comentariats opinion.

TIIFC3S 01-14-11 01:04 PM

I love my HKS silent high power single exhaust and have heard good things about the Apexi N1 system. And if you want duals I think you can get both systems dual. That way you can get a more aggressive sound without being too ricey

Hypertek 01-14-11 01:31 PM

Rotaries always had their own distinct sound. not sure how that could sound like a GT car

tuscanidream 01-14-11 01:35 PM


Originally Posted by TIIFC3S (Post 10414803)
I love my HKS silent high power single exhaust and have heard good things about the Apexi N1 system. And if you want duals I think you can get both systems dual. That way you can get a more aggressive sound without being too ricey

Isn't a dual exhaust rice because it's purely for looks?!

Try a system with a resonator and or a high flow cat as it might get rid of the tinny sound.?

Bamato 01-14-11 02:16 PM

Dual exhaust helps tone too. Not just looks.

I run a 3" magnaflow high flow cat, two summit 2.5" glasspacks (one per side) and finish with two 2.5" magnaflow stainless mufflers. On my T2, at high revs, it does sound quite a bit like formula cars IMHO. About as close as you could I suppose.. as we are talking about two completely different engines(pistons vs rotors, and much higher revs on F1)... And at lower RPMs, its very growly. I wouldn't have it any other way. Love it.

MK_BOT 01-14-11 06:31 PM

I have the dual apexi n1 on my 10th ae and it sounds real nice and deep even higher rpms. Btw running stock dp and straight pipe all the way Back.

misterstyx69 01-14-11 06:48 PM

Glass pack mufflers before the end of the car(tail) will Melt.So no sense in trying to use one for a Presilencer.
I'd go with something along the Lines of HKS,Apexi or try Borla XR1(?).
If you don't care about Weight then Racing Beat makes the REVII system,and it is Durable as hell,but it weighs in over 80 pounds complete.(2 mufflers,y pipe,.Presilencer,and down pipe)Get the 3 inch version.

Syritis 01-14-11 06:55 PM

I'm going to run a presilencer 40" back from my turbo then straight pipe the rest with 3" on my the track car i'll have a video up as soon as i'm done.

-Crash- 01-14-11 08:03 PM

Add two more rotors to your car, done.

jjcobm 01-14-11 08:40 PM


Originally Posted by tuscanidream (Post 10414873)
Isn't a dual exhaust rice because it's purely for looks?!

:icon_no2:

Anyway to the OP:

If your engine still has a stock port and is a 13B, you will not be getting the F1 sound, no matter how hard you try. That sound comes with an agressive port or 3 rotor engine. Working with the exhaust will only lead to a nicer 2 rotor tone.

j9fd3s 01-14-11 10:32 PM

some of the JDM systems, like the re amemyia or the knightsports are the closest i've heard to an "F1" sound, although its still pretty far away. they are higher pitched than what we are used too

we got to see the 2007 Ferrari F1 car run at laguna seca, and that did NOT sound like anything ive ever heard before... its a lot different in person than on TV too. when its coming at you, all you hear is a big sucking noise, then it passes with the shriek, which is probably the trans. after it passes you you can hear like a drumming noise, and the shifts sound like a rifle.

it had everyone, even the trophy wives, stop and watch.

oh AND its faster coming out of the corners than most cars will be at the end of the straight, its pretty nuts. they were 2 seconds off the overall track record.

Syritis 01-15-11 03:19 AM

i thought the majority of the F1 sound comes from the motor doing about, umm lets say 19000rpm?!?!?!?!

here's a perfect example of the difference rpm makes to the sound
http://www.youtube.com/watch?v=JcyvTuoslAA

jjcobm 01-15-11 10:22 AM


Originally Posted by Syritis (Post 10416003)
i thought the majority of the F1 sound comes from the motor doing about, umm lets say 19000rpm?!?!?!?!

here's a perfect example of the difference rpm makes to the sound
http://www.youtube.com/watch?v=JcyvTuoslAA

Ummm.... Yeah... that there is a 20b with an aggresive port, just like I was saying. You will never get that sound out of a 13b. Plus that is not 19,00rpm or anywhere near it.

Tofuman FC3S 01-15-11 11:50 AM

Noone said it was 19K, he was refering to F1 cars that depending on year do 18K to 23K.

Riz.

Syritis 01-15-11 08:44 PM


Originally Posted by Tofuman FC3S (Post 10416318)
Noone said it was 19K, he was refering to F1 cars that depending on year do 18K to 23K.

this. first car sounds like a turbo 13b, second car is N/A 20b at 10k rpm, and the difference of sounds it staggering. obviously the second car, the fc does not sound exactly like an F1 car, but it's a lot closer then the 13b turbo.

thus the F1 sounds comes from the engine, not the exhaust.

back in the day i had a link to a turbo 20B doing 14k rpm on a dyno, can't find it now.

MaczPayne 01-15-11 09:23 PM

This?

Not 14k but I can't find the video with it going there.
http://px5.sfstatic.com/thumbs/0000/59/97/39579.jpgMPS 3 Rotor Tac Rev test with low boost MECHANICA

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/14k-rpm-fc-cluster-790783/page2/

Bamato 01-15-11 09:55 PM


Originally Posted by misterstyx69 (Post 10415418)
Glass pack mufflers before the end of the car(tail) will Melt.So no sense in trying to use one for a Presilencer.

Melted or not, sounds great.

Spirit-RE 01-15-11 10:34 PM


Originally Posted by MaczPayne (Post 10417055)

wow.

Syritis 01-15-11 10:50 PM


Originally Posted by Bamato (Post 10417107)
Melted or not, sounds great.

only if you don't like everyone near your car.


same car, still looking for the 14k video. but still 0-100mph in 4 seconds?
http://px5.sfstatic.com/thumbs/0000/79/10/39701.jpgMPS Mazda RX7 3 Rotor 20B Peripheral Port Turbo w/

Spirit-RE 01-15-11 10:57 PM

kmh

Syritis 01-15-11 10:58 PM

yup.

Evil Aviator 01-15-11 11:12 PM


Originally Posted by AF_H1VLTG3 (Post 10414672)
am looking for a FIA GTesq Inspired sound.

3-rotor peripheral ported engine + Racing Beat "Rotor" muffler = win!

http://www.youtube.com/watch?v=oEOHn7rspsk

Your car will never sound anything close to that. However, you may like the sound of single or dual Apexi N1's on your car. Just make sure you get some high-quality mufflers. Cheapie mufflers sound tinny.

jg13b 01-16-11 11:34 AM

I agree with the others that without crazy porting and 10k+ RPM its just not going to happen but mainly since exotic rotary F1 sounds were being posted it's a must to have a good 787B in here.





http://www.youtube.com/watch?v=K1BWv7iPFUg

Syritis 01-16-11 11:51 AM

I like his helmet.

I think i know what my next project will be.

magus2222 01-16-11 12:03 PM

i know how you can get that sound........
BUY MY KS EXHAUST!

Lloyd

TIIFC3S 01-16-11 02:35 PM

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 01-17-11 10:58 AM

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 01-17-11 02:31 PM


Originally Posted by Syritis (Post 10417180)
only if you don't like everyone near your car.

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

89FC Alpino White 01-17-11 04:52 PM

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 01-17-11 05:23 PM

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 01-17-11 06:38 PM

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 01-17-11 10:01 PM

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 01-18-11 01:33 AM

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

Engines must be 2.4 litre naturally aspirated V8s, with many other constraints on their design and the materials that may be used. Engines run on unleaded fuel closely resembling publicly available petrol.[66] The oil which lubricates and protects the engine from overheating is very similar in viscosity to water. The 2006 generation of engines spun up to 20,000 RPM and produced up to 780 bhp (580 kW).[67] For 2007 engines were restricted to 19,000 rpm with limited development areas allowed, following the engine specification freeze from the end of 2006.[68] For the 2009 Formula One season the engines have been further restricted to 18,000 rpm.[69]

R.O.D 01-18-11 01:50 AM


Originally Posted by jjwalker (Post 10419905)

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.

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:scratch:

jjwalker 01-18-11 12:40 PM


Originally Posted by R.O.D (Post 10420731)
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:scratch:

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 01-18-11 04:21 PM


Originally Posted by jjcobm (Post 10415618)
:icon_no2:

Anyway to the OP:

If your engine still has a stock port and is a 13B, you will not be getting the F1 sound, no matter how hard you try. That sound comes with an agressive port or 3 rotor engine. Working with the exhaust will only lead to a nicer 2 rotor tone.

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 01-18-11 05:18 PM

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

R.O.D 01-18-11 07:10 PM


Originally Posted by jjwalker (Post 10421316)
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.



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 01-18-11 07:25 PM

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

http://www.aaroncake.net/rx-7/pictur...eccentric1.jpg

...but you can't have mine!

http://www.aaroncake.net/rx-7/pictur...eccentric2.jpg

tuscanidream 01-18-11 07:36 PM

Nice shaft dude. No homo.

jjwalker 01-18-11 07:52 PM


Originally Posted by R.O.D (Post 10421990)
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...

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 01-18-11 08:05 PM

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 01-18-11 08:11 PM

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 01-18-11 08:14 PM


Originally Posted by R.O.D (Post 10422093)
''As the rotor orbits inside the housing, it pushes the lobe around in tight circles, turning three times for every one revolution of the rotor.''


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

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

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 01-18-11 08:18 PM

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

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

jjwalker 01-18-11 08:21 PM

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 01-18-11 08:38 PM

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 01-18-11 09:49 PM

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 01-18-11 11:12 PM


Originally Posted by Aaron Cake (Post 10422020)
If you really want your car to sound F1, then you'll need to start with one of these...

http://www.aaroncake.net/rx-7/pictur...eccentric2.jpg

...but you can't have mine!

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


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

jjwalker 01-18-11 11:18 PM


Originally Posted by jjcobm (Post 10422432)
Dammit... I guess my car won't sound like a F1 engine any time soon since i'm not rocking the mullet :lol: I want yours Aaron : P


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

Mullet madness = GT exhaust sound. Sounds plausible!

/joking!


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