YW, not to be mushy or anything...but its only cause we care for you and your kids. Your a great guy. See you in the morning to finish up....

 

I want my freakin KEY"Z BACK Today

 

Pavement Princess!!!

 

I've heard the same thing.

In fact, a local old time rotary builder that used to build and race RX4's a long time ago said he'd take the stock balance 12A's to 17k rpms when I was talking to him. Granted the e-shaft was shorter and the rotors were slightly lighter, but still it was 17k... But you should take into account that his engines were built to last for a race or two tops. He also worked with some old style 13B's that he regularly took above 13k rpms FWIW.

I don't think 8.5k would be any problem on stock balance. I think Racing Beat suggests the same thing, might be for s5 assembly, though, can't remember. I for one am going to be taking my stock balance on my new engine I'm building to 8.5k at least, probably 9k on occasions

 

LOL, 17,000rpm!?! NO WAY. I love hearing all the old timers saying stuff like that, it just seemed like 17k rpm since all the cars in the 50s-70s had ~4k rpm redlines.

 

How is your combined secondary / aux ported motor doing?

 

Still has great compression, perfect starting hot/cold, idles great, no problems whatsoever. It pisses me off that there is a rev limiter/fuel cut, because it continues to pull up past 7500 then BAM fuel cut. Megasquirt is in my future for my s5 engine build


It actually kind of saddens me that I built this s4 motor last summer and it's still doing so well with that port, because now I'm moving on to bigger and better things with the s5 engine and will just be selling my s4 locally (most likely). Oh well, at least whoever the next owner of the engine is can be happy with it.

 

You wanna talk to him? He raced on the national circuit, and he's not lying. I've seen some of his trophies and his race built rotary he uses for display in his house.

He had custom rotors, housings, and irons all built at various times. One of his engines was completely aluminum except the rotors/balancing pieces, custom porting and he had the irons made for side port exhaust (this was in the 70's) rather than peripheral port style exhaust on the rotor housing.

He also worked with Racing Beat when they first started working with rotaries, they traded ideas and tested each others parts/plans.

 

No actually I don't want to talk to him. You said "stock balance" motor run to 17k rpms.

No way I believe it. Think about it like a skeptic.

 

ha... haha.

That's just funny.

BTW, Jeff, that sucks you sold your CYM FD. I was with the guy who bought your red R1. (Garrett)

Sounds like you have your priorities straight though.

 

Yes I was very skeptical at first as well, and argued with him for quite a long time. His reasoning was that the 12A's really were quite fine to go that high on stock balance, don't see how the shorter e-shaft and very slight weight difference mattered much, but oh well. Also like I stated, he built his motors to be good for 1 or 2 races max, these were not made to last in any way.

 

well, i take my 12a up to 10-12 alot. who cares, if it goes it goes. but i feel completly confident ot will be fine. the 12a's were built to rev more than the 13b's.

 

That's awesome! As a last resort, I got rid of the top 5mm of that bridge between the secondary and aux ports on my engine after its last side seal episode. I still have most of the secondary bowl but no bridge anymore, because it had no scissor angle with the closing seals. I think the combined secondary / aux port is a good idea.

Keep us updated on the bridgeport.

Have you ever though of beveling your rotors about 1mm on the sides? It sort of removes a corner when the port is half open and closed, which is most of the time in a running engine. The Renesis has full bevels on its rotors too, probably for this reason. I just did this to my rotors with a metal buffing pad and rotary tool, and the port timing got larger judging by how the powerband shifted up. Maybe this POS will last long enough to get a megasquirt on it.

 

I don't know if Drew and you heard this from other people as well but assuming you are saying this because I mentioned it, I just wanted to make sure I didn't give the wrong impression. I don't think they my any means encourage it but just say its about where the stock balance is generally not good enough. I don't want to make it sound like they are suggesting we all go out and run them up that high.

It would be interesting to see how high you could take one with some newer materials and good balancing. I bet you can probably pull about 20k rpms out of a 13B if you had a fat enough wallet to do it all correctly.

 

I remember when I was laughed at for my combined ports, hah! Not by you of course, but other people.

I'll keep you updated, no worries. I'm still waiting on some god damned carbide bits and sandpaper to come in so I can get the port actually done.

I thought about beveling the rotors, but between that and going to 8.5 to 9k I'd start to worry about the balance more I will most likely be beveling the part of the housing that lays over the bridge, though, for more direct flow as needed.