I'll have an answer for everyone this summer. I'm installing 9.7 rotors w/ turbo II exhaust sleeves and will dyno my NA 20b to see what the power difference is compared to the 9.0 with stock ports. Reted and Bcool made around the same amount of hp (232 rwhp) w/ stock block and intake manifolds. I'm very curious to see what I'll get with better sleeves and higher compression. Then i'm going to install my custom made intake manifold, re-tune and dyno again. I'm going go try to give as much info about what hp one can expect with varying combinations. Then finally I'm going to open the engine again and do a half bridge and re-dyno with old stock manifold and new one.

Hey I like experimenting. What can I say.

DIY will save me a **** load of money as well.

 

http://www.wrc.no/filer/konsmo_Stein.wmv Peripheral port 20B, naturally aspirated. Gearbox about neck-and-neck with the exhaust.

http://wrc.no/filer/atle_vik_inboard..._bergen_04.wmv ?? port 13B, naturally aspirated. You can pretty much only hear the exhaust if he's in 4th gear. (5.85:1 rearend!)

Plenty other cool videos there, pretty much all hillclimbs or Euro-style rallycross.

 

peejay: Links aren't working

One of my favorite sounding 20B FD's is this one here:

http://mrec.rotary.net.nz/media/ts_bat.mpg

On the track you really only hear the yellow car right up until the FD passes it and then the 20b is louder. I read somewhere that the car was burnt in a fire.

 

I'm glad there's someone to experiment for me, hahahahaha, I'll eagerly await the results. I'm thinking of doing a 20B swap two years from now after I save up a bit and learn to weld well, so I'm trying to decide whether to use the twins or go NA.

 

Not to talk about my own setup, but last year I was running a streetport, TII sleeves, 9:7 compression, custom intake 20B, and without final tunning made 335rwhp on a mustang dyno. I have p-ports that are capped off, but will be open this year with luck. Hmmm maybe T-von and me can go hit up the streets.......

 

My favorite sounding 20B http://media.putfile.com/Mazda-LMP2

peejay, your descreptions sound good but the links both bring up the same non moving page.

 

That would be tight 20b domination baby. So you about ready to unleash the power of the semi PP's? I can't wait to see the results. I have a slightly different idea when I ultimately get underway. You guys will have to wait and see.

 

GOOD GOD THAT SOUNDS SUPREME!!! LOVE THAT HIGH PITCHED SOUND. Port?

 

I thought I had enough time/cash to finish it this month, but things have changed. I will be moving to Flordia, and its taking some time/cash from me to do it! So, maybe if I get lucky the baby will run again in a couple months.

 

Here's a question related to the original post:

Does a 4 rotor with 180 degree lobes on the e-shaft (like 2 2-rotors) sound like a pissed off 2 rotor, or like more like the 787b (it has 90 degree separation between lobes).

Does that 10 Bryan Mckewan's red 4 rotor p-port on Streefire have 180 degree or 90 degree lobeing on the e-shaft?

Any theories or thoughts?

 

WRC.NO seems to have taken down their movies, probably too many people streaming them and roasting bandwidth instead of downloading them first before viewing. A quick Tyoogle finds nothing, either.

I *have* the videos on my computer, but they're too big for me to host and certainly too big to e-mail...

 

This is a good thread. Pardon my gravedigging, but I just found it (and I don't think you guys will mind ).

God yes that car is awesome. Or, was awesome. That's a hell of a clutch too.

Fatty, I'm fairly sure that firing two rotors 180 degrees apart will sound like a twin-engined 13b car. The 4-rotor you referred to, if it's the one I think it is, is almost certainly 90 degrees phased because of the unique sound.

I do think it's interesting that some 20b's sound higher pitched (than a 13b) while some sound lower. There is definitely some harmonics coming into play on the lower pitch that can be either muffled or accentuated by the exhaust. I'm sure that the exhaust itself plays the biggest part in the tone (actually, the correct musical term would be timbre, and yes, it IS music to my ears!) of the engine.

I really love the multitude of 20b sound clips in this thread (a few I haven't heard before). T-von, your car sounds interesting and I look forward to hearing more about it. I personally am thinking about sticking an NA 20b into a Miata... that sound coming from that car would be really freaking awesome.

 

Here's an audio clip from when I was test firing it with a temporary carb setup and modded 12A dizzy. https://www.rx7club.com/forum/attach...hmentid=105273

Here's another. This time the tape recorder was placed in the garage about 20 feet from the (closed) garage door. You can barely hear the starter! That's what an open header will do for you. https://www.rx7club.com/forum/attach...hmentid=105274

 

Sorry Peejay, but the site is wring. Stein has never ran the 20B PP in competition. He was never allowed to do that. So all of the videos are of 13B PP with Volvo M45 dogshift transmissions.

I had all of the movies on my computer, but they went away on a harddisk crash. I'd love to get my hands on them again.

Regards,
Frode

 

Here's another video of my car, this time its at Auto-x but it kind of gives you a better idea of what the sound is like.

http://myweb.cableone.net/mjbless/idahorotary/autox.wmv

 

Bcool, nice vid. But in the words of one of my instructors, "If I don't hear the tires screetching, you're not going fast enough..."

~Ramy

 

Drag radials in the rear spinning off the start and it was plowing like a hoe in the corners, belive me there was enough lack of grip there. Now if only if my 5zigens would show up i'd have something to mount these Azenis's too

 

Haha....I didn't know ppl auto-xed in drag radials I hear the Azenia's are badass...I wanna see THAT video

 

Primary length, muffler type, wall thickness on pipes all have to do with what a car sounds like.

The car in the video actually has a large extend port, 2 1/2" exhaust (soon to be 3") and a single straight through 3" s/steel muffler. I think at that time I was running a stock cat though, have since pissed the cat off.

Not sure what revs it was pulling in the video but would estimate around 8500 rpm, it makes power just over 8000 rpm

I'm running 4.4 gears in it too

 

That'd be my car, shifting around 8500 rpm, no turbo, 1 single straight through 3" muffler.

I think it was running the stock cat then, didn't have it on for long, just to pass engineers.

Stock intake.

Here's another video of it from behind taking off, same day

http://www.rotary20b.com/20b-2.WMV