secret8gent

I have vague memories of something I read a while back (was it in the courage car, or something else speedsource was running; can't remember...). Maybe you all can shed some light for me and tell me I wasn't dreaming.

Did mazda develop a three rotor renesis-style engine for racing? I seem to remember seeing the phrase somewhere, but I can't be sure. From whatever I read I don't think it was just a team running the old cosmo 20B...

[Edit: further searching of rotary news brought up this: http://rotarynews.com/node/view/871 is there any public info on this engine?]

rotarygod

It is not a side port Renesis. BK was using what was in essence an 80's 3 rotor race engine design with a few updated parts inside it. There is no new 3 rotor engine although it's not to say it hasn't been talked about.

secret8gent

So then this engine -is- different from the street 20B that people often use for conversions (but contains roughly the same time period of technology) ...
Do you know how so? Were the updated parts anything major?

Also is this engine currently for sale to some (race teams)?

I'd be curious to check out it's particulars... I assume it is side intake & peripheral exhaust; I wonder what kind of numbers they get out of it NA and FI - though I suppose would it behave basically the same as regular 20B (maybe just a higher redline). I think I remember seeing an exploded diagram of a "race 20B" a while back but the memory is just so foggy.

Thanks for the reply!

secret8gent

Lo~

https://www.rx8club.com/rx-8-multimedia-photo-gallery-6/video-grand-am-speedsource-rx-8-passes-porsche-gt3-first-homestead-112607/

peripheral port 20B.....

m477

http://www.mazdausa.com/MusaWeb/disp...=news77&bhcp=1

This article on mazdausa.com mentions both the BK motor, as well as a "3-rotor Renesis-powered Mazda RX-8" used by SpeedSource. It sounds from the article like these are two different engines?

The SpeedSource website also claims that they are running "Mazda's three-rotor 20B Renesis rotary engine."
http://www.speedsourceinc.com/index....s&news_id=2606

Renesis_8

Advertising, all the racing engines are peripheral intake and exhaust, this form is most suitable for racing.

Search through the LMP2 and the Speedsource Daytona race thread. You'll find all the answers in there.
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secret8gent

http://grand-am.com/CONTENT/Docs/PDF/2007/GTRules.pdf

see 2-14 for the basic details on the speedsource car.

Does this mean they're getting 425hp (which is what I've seen quoted on other threads) NA?? That seems like a lot considering the cosmo 20B was 300hp boosted.

here's the info:

2-14 Mazda RX8 (Prep 2)
2-14.1 20B Cosmo three rotor (Mazda Spec parts). 2.0 liter, 9.7 compression ratio, 3-52mm throttle bodies, maximum of 6 injectors, maximum fuel pressure 4.2 bar, intake manifold is free. Call Grand American for parts list 386 947 6681
2-14.2 Minimum weight 2200 lbs
2-14.3 Six-speed transmission.
2-14.4 Maximum body width is 73.5 inches.
2-14.5 Front tire 280 /640/18
2-14.6 Engine set-back 5.125 inches from spindle centerline to 1st spark plug.
2-14.7 Complete rear wing height w/ end plates cannot exceed roof height. 2-14.8 Fuel capacity 24 gallons May use oil in fuel
2-14.9 Allowed larger/higher exhaust position .
2-14.10 Tire sizes are 280/640R18 front and 295/660R18 rear

rotarygod

Yes the Speedsource engine produces that much power. You need to understand the power differences between porting styles. The Peripheral porting of the race engines is very extreme. It's like a very agressive cam on a piston engine. The standard 20B uses side intake ports which are much more mild. A peripheral port 13B can make 350 hp and they have done it. A standard side intake port peripheral exhaust port 13B by comparison makes less than 200. Don't get the idea that you can go peripheral port your Renesis to get some big power numbers. There are huge tradeoffs to going this extreme and unless you have a dedicated track car that will never see street use, you don't want to do this.

The current race engine has been marketed as a Renesis 20B. The term Renesis is highly inaccurate though as it isn't a Renesis. Since the Renesis is the current rotary engine, it makes sense to include it in the name for advertising reasons as most people don't know there is a difference.

The Speedsource engines use Racing Beat built peripheral port housings and 9.7:1 compression 89-91 RX-7 rotors. There are no major Renesis parts in it at all.

brillo

About the only thing in common with the 3rotor and the Renesis is they are both made by Mazda

pdxhak

iTrader: (2)

Stupid question but is it possible to make the Renesis a 3 rotor? I know with a lot of effort you can make a 4 rotor so could something similar be done to make a 3 rotor Renesis?

secret8gent

well the center housing would be an issue if you wanted to preserve the side-ported-ness of the renesis... (i don't think such a housing exists publicly)

the e-shaft is the other significant issue...

rotary crazy

you could, but the question is why? A 20b will make more power than the renesis 20b and be a lot cheaper

Astral

why does the SpeedSource 3-rotor RX-8 sound so much more higher-pitched when it's revving than the 2-rotor one, even though they are running the same revs?

swoope

iTrader: (5)

why does a v8 and a v 12 sound different???


beers

secret8gent

what is the sound of one hand clapping?


i suppose someone would want a renesis style 20B for street driving, it should be able to pass modern emissions requirements, no?