Blake, thanks for the reply.

Another question:

If it were possible to build a hybrid 12A or 10A using FC or FD irons, do you think that it would have improved BSFC as compared to the FC or FD 13B due to having less surface area in the combustion chamber relative to volume?

If so, it seems to me that by retaining the REnesis porting concept, but dialing back the housing thickness to 10A or 12A width, Mazda could have a 170-ish HP engine whose fuel econ might compare slightly more favorably with piston engines of similar output. This would be perfect for a back-to-basics return of the Rx-7 in the template of the 1st-generation (light, lithe, simple, fun, pure sports car).

 

Blake, any experience with WPC treatment? I have read a couple articles on its effectiveness in strenghtening components, and it is usable on nearly any metal component of a rotary engine. Is it really all it's been touted as? Any thoughts would be much appreciated. Thanks.

 

I have no experience with it, so I can't usefully comment. Never heard of it being applied to rotary engines.

 

For efficiency, nothing beats a spherical combustion chamber. The closest to that ideal we can come is a square. The 10A and 12A were at a disadvantage from having such long, narrow combustion chambers. When Mazda increased displacment by widening the rotors and housings, the power gains were out of proportion to the displacment increase. Among other things, it was the due to moving closer to the ideal combustion chamber shape. The added surface area I don't believe adversely affected BSFC to any large degree. Instead of reducing displacment by narrowing the rotor width, I think it would be more ideal to shrink the other dimentions of the engine. Unfortunately, the tooling costs and other factors makes it unlikley that will ever happen.

 

Wow, Blake! So much useful info in this thread!



What are your thoughts on Ceremet A/B coated rotor housings along with the use of ceramic(NRS/Ianetti) apex seals? I'm thinking about going this route with my 20b fd project.

 

Do you still offer your Airpump elimination kit? The one what has the bracket and pulley to give maximum contact patch on teh water pump?

 

Great combo. We built a motor for Marc at JHB a while back with Cermet A coated everything and NRS grey seals. It wasn't even broken it yet and tested over 124psi compression, IIRC. Ceramic on ceramic is a nice way to go.

 

Well, the first ones were a hard-sell, for some strange reason, so we didn't immediately make more after the first batch were gone, but then word got out and everyone wanted them. We made another small batch and those were gone in a heart-beat. Now, we are looking into making them in volume again. I thought we had eight of them left, but Rob just told me they were all spoken for.

If you want to be put on a list to reserve one, shoot me a PM with your name, phone number and address. Or, if you want to set up a Group Buy, we can do that too.

 

HI! Blake,, I am trying to find who sells the internal coolant seals, the inside one I prefer is the TEFLON encapsilated orange not the factory type. and the small oil o-rings for the dowels, I know I could get the small ones local, but if they come in a small kit OK. anyway all the internal seals kit would be nice? THX Ron dont need e-shaft seals. email ronbrothers@gmail.com or 386-295-7254 Ron

 

Those are just off-the-shelf McMaster-Carr products anyone can buy cheap and they have no special properties to recommend them in this application. Someone just invented a good story to sell them and people fell for the hype.

Our Heavy Duty Water Seals, made with a special grade of Viton, were tested for 7 years before we ever sold a set to the public. Even after several race seasons or tens of thousands of street miles, you can pull them out and re-use them again if you ever need to freshen the engine. The HDWS kit includes Viton dowel o-rings, rear stationary gear o-ring, front cover o-ring and oil filter pedistal o-rings. $199 retail or $99 as an upgrade when you buy a rebuild kit.

If you don't want the HDWS kit, then we strongly recommend the stock water seals over other offerings. And please note that while we like Viton in the water seal application, it should NEVER be used as an Oil Control O-ring material.

 

I have thiught of this myself. The one thing that would be the hardest to do I believe is getting a fabricated main drive shaft to go through both engines. Connecting to together just wouldn't be strong enough

 

Blake:

What, in your opinion, are the effects of meth or alcohol injection on a turbo'd 13B's life span? Logically thinking (without putting a lot of thought into it), I would think that the engine would be much better off, mainly because of the temperature drops associated with MI or AI...

... or is this wishful thinking and is injection a waste of time and money?

(for reference, I'm running a large streetport, 3mm Hurleys [saving for ceramics], S6 rotors with S5 housings, and a Turbonetics 62-1 .96 tangential housing @ 13psi on 93 octane.. would bump up to inbetween 16-18 with injection)

 

Well, J-rat swears by it. He got 434 on a stock mazda reman with an upgraded turbo and standalone when running alcohol injection.
I, too, would be curious as to what bruce's thoughts are.

 

If the motor is at the edge of ping, the inj. will drop the cyl pressure-reducing the load on the bearings etc. If it was not at the edge of ping, the only help is keeping the carbon build up down.

Rob doesn't like running a tune that requires water inj. because any failure in the setup (like forgetting to refill it!) is almost guaranteed to kill the motor. If you tune the engine to be safe without it and only run the injection as an additional safety measure, he's all for it.

 

Fair enough. Never enough head room with a turbo rotary anyway, huh?

Thanks for the feedback.

 

What is your reasoning?

Thanks.

 

Because every low-miles rebuilt engine that comes to us because of oil control o-ring failure has aftermarket Viton oil control o-rings. Every one. Even the ones that failed for other reasons (aftermarket apex seals, for example), if they have Viton oil control o-rings, they were really nasty looking. We never see the stock oil control o-rings fail prematurely (100K+ miles) unless the engine was overheated severely. There is absolutely no performance or longevity advantage for aftermarket oil control o-rings since the stock florinated rubber ones are GREAT; the only reason they are out there is because of cost. The good stuff is expensive. Viton is CHEAP by comparrison. Huge profit for the seller but the buyer is getting a bad deal, in my opinion.

Don't get me wrong: Viton is a good material for many other applications, but it doesn't seem to like the kind of stress associated with oil control o-rings.

 

Well, I guess I'll be rebuilding my new engine sooner that I thought!

Also, I have an unrelated question:

The main pulley has the crank angle indicator as a seperate piece behind it. I could not find any information if it is required to be put on a specific way. I know that it can only go on 1 of 2 ways (up or down), as the holes are offset, but does this have to be aligned with the rotors in some way? Or it doesn't matter? I was thinking it would matter, but I could not find any information on it.

 

Forgot to mention why I thought it was important on the position... because it's used to detect the e-shaft angle, and front rotor position (from the FSM).

 

It only goes on one way. It will sit on the pins in two ways, but the wrong way won't allow the bolts to line up.

 

Thanks! I vaguely remember putting it on (few months ago), and I was doing a once over before getting ready to start it up. That's when a little bit of uncertainty came on...

 

Hylomar is one of those over-hyped products that a lot of people apparently think is good to use for rebuilding a rotary engine, for some reason. They use it in place of Vaseline or Crisco to hold the seals in place while assembling the engine. Well, it will do the job okay but (1) it is absolutely no better and (2) it is the nastiest substance on earth to work with and clean up. I hate the stuff. If you are not familiar, Hylomar is a blue gunk that never dries out. We call it smurf snot. The problem is that it is gunk that never dries out or goes away. Even 100K miles later, the engine will be one nasty pile of smurf snot that will take 5x as long to clean up for rebuilding.

Hylomar does not help the water seals seal or have any other favorable properties to compensate for its nasty qualities. All you are trying to do is hold the seals in place during assembly. The factory originally spec'd Vaseline, which is worthy, but the best product we've ever used is Crisco shortening. We put it in a big syringe and squeeze it into the seal grooves (water seals, apex seals, side seals, corner seals, etc). When you insert the seals and springs, the Crisco hydrolics the seal in place, preventing it from falling out. The stuff is awesome. The excess that squeezes out makes a great assembly lube, as well. An odd side effect is that upon initial startup the exhaust smells a bit like fried chicken.

 

I have a customer with an RX-8 and we were talking about the 1/2 bridged motor going into my FC over the winter, and he asked me if similar porting can be done to the Renesis.

I told him I imagine so, but and EMS would be required...but I got thinking...being side port exhaust, how would you port that?

Say for example you wanted to bridge the intakes....would you have to bridge the exhuast? Wouldn't that cause too much over lap?

Im interested to hear you opinion(s) on porting the side port, renesis style engine.

 

The whole idea of the RENESIS is to get the maximum port volume without creating overlap. Introducing a lot of overlap kind of spoils the whole thing. No, bridgeporting the intake would in no way require a similar treatment for the exhaust. They are completely separate matters.

 

So, to answer the customers inquiry....

There really isn't much of any type of porting that would be very beneficial (from a purely power based standpoint) to the RENESIS style engine? even a streetport?

Or have they *pretty much* maxed out the flow capability of the porting and manifolds from the factory?