i know i get a bit cranky at times and come off as a ***** but i am curious to see how this turns out. there are a small handful of things i would change but that is my personal preference in the design of the engines.

1) i believe you will have itching issues with the pressed in sleeves around the exhaust side of the engine, even though that is where you focused the cooling passages internally on. the OEM mazda design sleeves are ribbed and cast into the aluminum so the sleeve has no way of perforating, even though the housings really do not have a ton of force applied to them, heat is the main factor to warpage.

2) the cooling on the combustion side of the housings is marginal, the spark plugs need to be cooled effectively which is where mazda spent alot of time opening the passages and even thinning the walls to cool the spark plugs more effectively as they made more power with the engines.

3) the side port intakes will work but a peripheral port works better for most turbocharged applications and simplifies the engine.


i'm assuming the engine isn't made for endurance so some of the above may not be an issue if it is only going to be run in sprints.

but if the sleeves do work you may have a good starting point for replacement housings that will be discontinued by mazda in the near future if you can build a rotor housing with replacable sleeves(simple cast aluminum, machined to accept the sleeve). but that is only if you cared to bother as it doesn't appear you're hurting for money with how much you have invested so far into this one project, heh.

i do think your figures are a bit high and i would start out with the engine as naturally aspirated to work out any timing and cooling issues and the octane versus boost and horsepower figures are at the extreme end of the spectrum.

 

what would be the price on this ??? around 60k??

 

maybe 160k.

 

I have probably three times that in it so far, but if I went into production with the engine I think I could make 10 of them for around 80-90 each.

 

I know ur market is targeted for the big offshore boating guys, where the big money is at. But sometimes u have to think small to make it big. With your level of fabricating skill, a version of the 2 rotor, 3 rotor and 4 rotor might yield you more profit! I guarantee ur motor won't sell as many as you project to sell. simple fact is... piston boys like pistons.

Make a new bad *** 2 rotor and sell the hell out of it. Or make an affordable 4 rotor and capture the market. I think guys like me who would be willing to spend 5-10k on a motor would be a great start.

Hell make me a custom 2 rotor that is smooth as a stock motor and have it proven to handle 1200hp and I would give u 8k for it.

Just my .02

 

some things to think about on price..... lets just take the sleeves for an example... You have to buy the material.. an expensive heavy chunk of high temp tool steel 3.25 thick .. then have the whole piece heat treated... I heat treated first because if it was machined first it would change dimension when heat treated.. then have it surface ground to get the piece to an exact thickness of the rotor housing to within + .001"... put it on the edm and use the edm to punch a hole through it then run the edm wire around it for around 43-45 hours... a normal place charges at least $100 per hour on the edm.. you could run it faster but not with the tolerance we wanted.. then make a jig to hold it in the mill and machine the exhaust port and the spark plug holes.. now have it cnc polished with a diamond stone... then send it out to have a coating put on the inside that is a thermal barrier coating to keep the heat from transfering to the housing.. have polished again... send to have a very hard very expensive coating put on the inside so it will not wear from the tip seal running around it.. polish the inside again.. now you have spent around 6 thousand dollars and you have one of the sleeves.. there are 12 in the engine.. and that is not counting the money to design it and writing the programs to run the machines..

No I did not spend that much on the sleeves, but they did cost alot.. And there are alot of things that people can say could be done differently but in the end that is what we did and we had reasons to make them the way we did.. I have a second set of sleeves for the second engine that are made different, but still have almost 2k each in them.

 

we are building a 4 rotor version right now. I tried to have it done by Seven stock to put it on display but were not going to be done with it. The pricing you are saying is for mass production stuff. to get to the 8k range you would have to make 10,000 engines to be able to cost out the tooling.

and a true 1200 hp one you would have 8k in just the turbos not counting the rest of the engine.

 

There are alot of little things that can be done different, but this engine was designed for a specific purpose and I wanted it to fit in the same spot as the engine that is already in my boat.. The next pair of engines were building are a little bit different in size and design.

Our sleves are alot thicker then the Mazda sleeves and what they are made out of will not warp at the temp we will be seeing, we were going to put ribs in ours too but instead went with enough press that they cannot move. we also have a thermal barrier coating in the sleeve to help keep the heat from doing damage..

The through bolts are not as big as the holes we have for them and we machined a little recess in the end housings to let water flow down the big holes around the bolts to help with cooling.. originally the engines water cooling passages looked alot different but then I was in a hurry to try to get it machined and it was alot easier to drill a couple hundred holes then spend weeks machining the water passage ways the way they were designed. this is just a test engine. the production one will be a little different on the cooling..

The side ports were a pain to machine, a peripheral port would have been alot easier to machine and made more power, but would not have had as much low end torque and efficiency. We have that drawn up also for another project where the guy wants as much hp as he can get and does not need the low end torque.. we will be starting machining that engine in about a month..

we have edm'ed a factory housing and put our sleeve in it to fix the bad one, but we could have bought a new housing for less then we had in the sleeve. if i ever went into production with the engine it may get cost effective. especially if they quit making the housings.

I talked to alot of people for a year or two to figure out what porting we would use, then we machined a factory housing using our port program and ran it to get our numbers.. so the big engine should be pretty close multiplying the number of rotors, there will be some loss from the gear box but not much.. and the octane issue.. we will be running direct injection on the next engine so it will make close to the same power on 87 or 116 octane.

 

holy jesus mary mother of baby jesus....that is sexy!!!!:i con_tup::i con_tup::i con_tup:

 

HEY! You're filling this thread with too much awesome, and I can't control it!

 

there's no reason to spend many many hours making a 2 rotor engine, because there's already plenty of 2 rotors out there, mass produced ones for much cheaper that can produce the figures you asked for.

there is definitely a hole for 3, 4 and more rotors for people who want to make more power more easily at the cost of fuel.

3 and 4 rotor engines also have that signature sound when phased properly, something that mazda really didn't mass produce aside from the 20B which was detuned and corked.

 

I may have missed it in one of the previous pages, but how are you sealing between housing and side plates? Are you using a Mazda style O-ring set up or what?

 

Yes o-rings

 

So THIS is the badassery I saw today at SevenStock. Thank you for bringing it!

 

Engineeringasm

 

Big thanks to Bigyellowcat for coming out to SevenStock!!

Taking back a little SevenStock souvenir. BEST NON-OEM Rotary award!



Thanks for coming out, and hope you guys had a good time!

-Alvaro

 

We had a good time, I think I need to buy a rx7 again now after seeing all the nice cars out there.

 

Thanks a ton for putting yourself out there for the community to grill you. It's entertaining to see pics of people stunned in awe, like observing the rotary shroud of Turin.
Then the brain locks in and the questions start flowing. We get it.
You da man.

Would've been bitchin to see it run, but it's probably wise not to rush it.

 

Just admit you've read and understand the book RE by K. Yamaguchi and we'll stop making "recommendations" for things you already know. I too expect the "spark plug hotspot" issue to be critical, but you might already have that all figured out. (If not, LMK and I'll send you a copy.)

BTW I really want to see an exploded view of this triple quad rotor beast. Presumably you've already built a 3D CAD model to get this far, but maybe not, since I'd expect to have seen some images. If no, I'd be willing to do some modeling if you send me some profile data to start with.

 

It was definately cool as hell seeing this engine at sevenstock. I read this thread a few weeks ago and was really hoping to see it here (i didnt know if u were bringing it or not)

 

I just want to know one thing. Are you coming to Deals Gap XII ?

 

You know, you're not too far away from Deals Gap Rotary Rally either. It's in the smokey mountains, about an hour form Knoxville TN. It's probably the largest east coast rotary event, and the mountain roads are fun to drive too.

EDIT:
Slevin_FD,
not sure how I missed your post...

 

I have the quietest rotary engine ever made.... The one that hasn't bee started yet. :-( Now to get off my backside and change that stupid starter so i can make some noise.

 

Thanks for coming out and great meeting you. As usual, looking forward to more news about any developments.

Btw, I also saw the engine in the back of your truck at the hotel late at night. I tried gnawing through the cable locks but quickly realized I would need teeth like these

 

sorry its been awhile since I have been on here, a couple days after seven stock we went to miami and key west for a couple weeks, I have some videos of the 12 rotor running I will put up when I get them edited so they are not 30 minuites long of us walking around. the cameras microphone is maxed out when it starts so you here the starter spinning the engine pretty loud on the video then when it starts it is pretty quiet. but you can still hear it revving up and you can see the air and flames comming out the tail pipes..