That's how I figured you would *have* to do it.

And then it gets more expensive than a casting, taking away the engineering advantage. (But "billet" and "CNC" *sound* sexy so it's worth it)

Why not forged housings? Ram 'em with a hundred tons or so to get the grain structure how you want it, and then mill away everything that doesn't look like a side housing. But that WOULD be expensive.

 

Yeah baby!

 

There wouldn't happen to be a pre-order list for that 2 piece one, would there? Their website is down so I assume you have to know the guys...

I can't believe it, but the obvious issues with the turbosmart water jacket didn't even occur to me.

The prospect of a half weight 20B made from almost all aluminum sounds perfect to me. Granted the block I have in mind will suck down 30K before its even in a car, but parts like that make it worth it.

 

I know exactly what you mean. It's like damn these really aren't necessary but ****, you just gotta have them. Personally I'm just really glad the after market is finally stepping up and fabricating upgraded rotary parts. For far too long we've been at the mercy of mostly factory stuff. Rotary R&D is finally starting to take off.

 

I am curious how durable this two piece design will be. The internals look very thin and fragile. Personally I would leave the ribbed sections a little bit thicker.

 

wonder how they are going to cool the rotor, cant see any way for the oil jet
spray to get to the inside of this rotor for cooling.
matt

 

All of these parts are develop for drag racing, where they don't need to run for long periods.. I'm sure as time passes and more R&D is done, we will see a streetable version so as of right now I suggest you wait till that day arrives... I wouldn't like to see someone go out and purchase a billet plate for a 800hp motor, that would be stupid IMO.... These parts are made to go where the stock parts can't take you, so if you plan on having a street car with less than 1000hp then stick with the factory stuff for now.... Also be realistic with your goals.. Don't aspire to make 1100hp when your chassis & driveline can't even handle 700hp without breaking or wheelspin

This Plate was intended for a 1500whp, methonol buring all out race motor

 

Why doesn't the 2 piece plate work for <1000hp cars? I'm considering it for an N/A 20B PP at around 450HP. A track engine, not a strip engine.

Hell, I'll pay the extra $9,000 and buy all aluminum plates if it means an additional 75lbs off the front of my car.

 

I'm not saying it wouldn't work, but I think its a overkill for a 450hp NA motor.... There are talks of the Guru plate being tested on a race car, but i'm not sure if its a road race or drag vehicle... Wanna save some weight & money?? Buy a short crank 3rotor and you will save a few lbs, you might even be able to rev it a little higher than the 20b.... If you have money and wanna save some serious weight then go with the short crank 3rotor and RB aluminum plates... IMO I think the 20b is a bad design, the 13b base 3rotor is a far better engine..IMO

 

It's not just wanting the plate for hi hp purposes. To me their more valuable in saving weight with 3 and 4 rotor blocks.

 

I disagree. Your not taking into account that the stock porting makes the original 20b a overall better/more usable engine. If you compare the two versions, the factory 20b will make more hp with the side ports than short version which uses mostly all primary ports. Also both engines will make similar amounts of hp with PP's. The original 20b has a much wider range of function than the short 20b your so fond of.

 

I don't know for sure but isn't the short crank 3 rotor e-shaft supported in both midplates?

 

He was not talking about the power output attainable with both powerplants but more about the reliability of both motors when the power levels are being pushed.
You will and cannot make the same power per rotor with a factory 3-rotor vs a 2-rotor with the same reliability. The mechanicals of a factory designed 20B will not support it.
Even the NA guys(550rwhp+) well the ones I know that make real power cannot acheive the same reliabilty for some of the very same reasons as do the boosted ones.
I have allready been looking into billet end housings that are solid in design with no water jackets to solve some of these very same problems that high power bring on. Only time well tell.

 

So with that said, is the 13b based (short-crank) 3-rotor more reliable in the mechanicals dept. than the 20b and if so, why?

 

if you really look close at the factory thick plate, its a really intense casting. theres a lot going on with cooling and the oil feed and drains...

 

I perfectly understand that but we all know Mazda originally didn't design the 20b for that purpose. The 20b was designed as a pure side port engine, so the center plate had to be wider to accommodate both primary and secondary ports. But you already knew that. Personally I think the stock engine could be even more reliable if Mazda would have engineered the e-shaft to have multiple journal e-shaft bearings at each plate to keep the e-shaft from flexing. All piston engine cranks have the support, why not the longer 20b? Look at the 13b! Ever since the newer 2 piece e-shafts came out with center support bearing, 13b drag engines have started becoming more reliable. The 20b could really benefit from having the extra support between the center and rear rotor but it doesn't. Also if those snazzy billet rotors start showing any promiss, think of how much lighter the rotating assembly would be and how much less stress the e-shaft will have at stratospheric rpm's.

 

Thanks for the clearification Cris..
I think the main problem is having the front rotor spaced further apart from the other 2 rotors... Maybe that "balance" problem is putting to much stress on the center plate, hence the reason for premature failure... I've herd stories of up to 0.025" Eshaft flex at 8k rpm. This info came from someone that knew the builder of Pepe Loco's motor...
Heaps of testing was done on the short crank motor for Dennis Marquise and non of the engine failures was caused by this new design... This was a PP motor on alot of boost, some 6-7+ years ago and it was revved well above 10K rpm... The same thing with Major League... The engine design was so good, that the team ordered a spare engine from New Zeland.. I also believe Gaby Chassis has one of these motors in his full chassis truck..
It would be nice if Abel could voice his opinion concerning the design of both engines... A few people are running 4rotor engines without problems... Mazsport made a 4rotor engine from 12A & s4 Rx7 spare parts and it made well over 1600hp.. I think the issue is not so much the length of the shaft but its the location of the rotors on the shaft... I'm not expert on the matter, but Im just relaying what I was told in conversation by various people in the sport.

 

It wasn't very long ago that many inline sixes had 4 main bearings, and not much further back that fours and V8s had three main bearings.

Chrysler got their start by buying the troublesome Maxwell company and improving their 4 cylinder engine. The Maxwell had *two* main bearings, Chrysler added a third, and this made the engine reliable...

 

well what i heard was a 4 rotor engine cant take anymore than 15 psi before it cracks the modified centre plate/s with the bearing.that motor that made 1600 hp did break on that run aswell.somebody needs to come up with a better design for the bearings.but it wont be easy.
these new plates are the start of good reliable motors to come....

 

Hey guys, to avoid any confusion and speculation here is the official press release from Turbosmart....

Oh, and yes, the product has been designed and manufactured by Turbosmart, so it is not the same as other products out there. Competition is good for the industry as a whole though - think of it this way; the more companies get behind the rotary technology the better for everyone

Product Description
Centre Plate for the 20B triple rotary engine. Manufactured from Billet Aluminium with electroplated wear faces. Currently approved in Australia by ANDRA for use in competition drag racing.

Application
Replacement for factory Mazda part NF01-10-D50D used in 20B engine

Key Features
• 1kg lighter than the factory item
• Built under strict quality control to precise tolerances
• Solid bearing support for high boost and high RPM engines
• Tougher wear face with excellent oil retention properties for side seal longevity
• Increased engine rigidity
• Dry sump compatible
• Direct bearing oil feed or through traditional dowel oil system.

This component has undergone extensive testing on several race cars, including the PAC Performance’s 6-second drag car. The product produced excellent results under all circumstanceses including methanol and the traditional water cooling system.

Manufactured by Turbosmart Pty Ltd
For more info contact 1300 33 55 06
or www.turbosmartonline.com

 

Turbosmart, what's the price on that peice?

 

In Australia, the RRP will be $4400 (including GST).
Keep in mind each of these is pretty much a custom job.

 

In USA and Canada the price will be slightly lower (exchange rate works in your favor there). Most likely about US$4000.

 

TurboSmart, welcome to the RX7club... Thank you for posting this info

The price seems fair for what it is, but this looks like a track (alcohol) only solution.... when did PAC start using it?
Are there any plans to reproduce the rear plate in Billet??
Im guessing there's no internal coolant vains like the original plate, how are you keeping the face cool ?? Is that where the use of Alcohol comes in??

 

Also, are these repairable in case of side seal damage?