hey everyone, well, like the title state, i'm a rotary newbie and i don't know much at all about rotary engines.

having said that, i am actually a miata guy and i'm planning on doing a rotary swap into my next miata project. i'm trying to plan everything out now before i even get the car so that i know which way to go once i actually start the project.

now, here is the BIG QUESTION for you all. i plan on doing a naturally aspirated motor, running weber 48 ida carbs. thats about all i know about whats going into the engine build. i would like to make about 250 hp to the wheels. i don't know if this is possible, but the few rotary guys i've spoken too locally, say that what i'm looking to do is very possible. i just need to know what would be the best engine setup to get the power figure i'm looking for. please take into consideration that this will be a street car and driven on a regular basis. i don't want it to be too loud, so thats another factor.

so, any suggestions as to exactly how i should go about this build? please give me some specifics. what casing? what apex seals? so on and so forth. i want something as reliable as possible.

oh yeah, i almost forgot. i have to run a 12a front cover on the engine. this is due to the mount that it has on the front, which is the easiest way of swapping in a rotary into a miata. so this is a must and i can't change that part of the build.

thanks in advance for any and all suggestions.
alex

 

A 250Whp rotary is going to be quite loud unless its turbo. This is because you will probably need a bridgeport to make that power, and bridgeport engines tend to need straight through exhaust to make their power.

There are a few kinds of 13b (probably the engine you'll want to use)

There are the older models (can't recall the particular years, but I would stay away as many parts on these were improved in subsequent generations)

The six port S3 engine (from the 84/85 GSL-SE) which is 138hp stock. Probably not the best bet as the internals would need to be upgraded anyways to get higher compression

Four port, turbo S4 engine
Six port n/a S4 engine

The S4 is probably the best bet, but I would wait for some experts to chime in.

Then there are the subsequent S5 and REW engines, as well as the Renesis, but that one is a very hard swap.

 

http://www.timeattack.com.au/forum/viewtopic.php?p=1000

 

250WHP (~287-300FWHP) in an NA is "doable" but is going to get deep into your pockets. Are you set with going NA? because going T2 swap would hit your HP goal very easily.


What are you planning for this car? autoX, daily driver?

On another note, i looked into this swap a few years ago, but turbo. What are you using for tranny? Are you going to use the stock tranny(miata) and get the input shaft machined, with turbo(rx7) bellhousing? This was the problem i was running into, there wasnt alot of info when i researched back then. So I decided just to go with a 1st gen, for my go-kart on steroids.

Keep us posted and/or do a build thread. i would be intersted in it.

 

thats pretty cool, but i'm actually doing a first gen miata. i already know how to go about getting the engine in the car. i just need help figuring out what components to use in the actual engine build to achieve what i'm looking for.

as for the loudness. i was told that i could achieve the power figures i was looking for with the right combination of engine components and just a street port making it less quite.

anyone wanna chime in with some info.

 

I figured that you knew how to get the engine in, I was just asking about the tranny setup.


Search for threads from Kahren, hes done some nice NA hp figures.