guitarjunkie28

this isn't so much what to do as it is letting you know what to avoid. some things you gotta find out the hard way...

have a look at the first pic. the blue line i wanted to make red--red, danger, warning... but i could only find a blue pen, so use your imagination.

the port walls are very VERY thin in these areas, otherwise the exhaust could be made to have a much better path into the runner. unless you want to weld (which i've done and it's worked), you gotta go REAL easy on these areas and not take too much out. walls are somewhere around ~1.5-2mm thick on the closing edge side, and ~2-2.5mm on the opening edge side.

second pic--

1) same as any other side port rotary--DON'T go inward

2) new one for the renesis--DON'T go outward or you'll eat side seals and end up replacing your iron. you will cease to have fun with haste.

3) the side seal is already dangerously close to the edge, and i think it might actually be slightly unsupported at the corner there. this port is blended pretty well, but i left a bit more material at the bottom of the closing edge to make absolutely sure the side seal is supported for as much as possible. look closely and you can see it come inward from where the rotor housing is so as to add support for the side seal.

this one i had to learn the hard way. on one motor, i had measured from the rotor housing, and kept the same amount of distance as it had stock with the port being drawn down a few mm's. this was wrong, and i had to buy the guy a new iron. embarrassing, yea, but i'll go ahead and admit to it so maybe you guys can learn from my mistake and avoid that one. so pay attention to where that arrow is and leave a bit of extra material there.

Razz1

Thanks

SomeGuy_sg

Mm...Great tips

Winning 8

so how much HP you gain from this little port

guitarjunkie28

~15, but the stock computer sucks.

considering the fact that i'm poor, i've made a substantial investment getting ahold of 2 renesis engines and an ems. one will be ported, the other non. i'll get a direct comparison up, but it'll tak at least a few months since i'm so busy lately.

slavearm

How can you be poor.... you must be independantly wealthy to offer such great deals for rotary work...

--or--

That is why you are poor... hahaha anyways... thanks for offering up some MSP love.

guitarjunkie28

that IS why i'm poor. i don't have a job, i just spin triangles all day

seriously though, when i start a "real" shop and pay $2k/month rent for the place, $500+ for utilities, licensing, taxes, insurance, etc etc etc.... all the prices will go up. i do stuff so cheap because i have really low overhead working out of the shack at home.

JB_Rotary

Just throwing this out there. Is it possible for you to purchase new irons port them then mail it out to people? If you can sounds like lots of money to be made. That way people will only need to dissassemble then re-assemble their engines with the new ported irons. It might keep costs reasonable for people who want porting and are willing to take apart their engine, just not willing to cut into it. Of course if 1 new Iron is like $800 then it would be more expensive then having someone do all of the work.

rotarygod

^ I had thought of doing that myself but I am so damn busy with work all the time that everyone would be on a really long waiting list!

I would like to strap a housing on the flowbench one weekend and then play with exhaust port/sleeve shapes. I have a few ideas and even access to ceramic/cast iron, ceramic/stainless steel, epoxies that can go up over 2000*F!!! I sent Dave (guitarjunkie) the info where to get these and other ceramic mold making pieces. If these products work well, we should be able to make cast ceramic pieces that will withstand 4100* temperatures but more importantly than that, make them at home for reasonable prices!!! I need to buy some, make a mold, and install the piece in my RX-7 (which has turned into a rotary guinea pig!) to verify that it will in fact work like we think it will. It will be interesting if it does.

Dave, I'm thinking that you shouldn't have to worry about a severe backcut on the exhaust ports. If it's too thin due to the water jacket, that may not be much of an issue. There is something else that can be tried and it involves casting a new exhaust sleeve. You might only have to add a very gentle radius to that sharp edge but that's it. I also have the idea for a sleeve that actually tapers in area to help with the issue. I need to somehow make a mold of it to send it to you to copy but I don't have a Renesis housing at the moment. That's a problem.

One thing I'd definitely do for a project motor is to have the apex seal grooves machined deeper to accept 13B apex seals. Use the 2 piece 2mm seals and the solid 13B corner seals from Atkins. That's my ideal setup on that motor and one that would be quite strong.

Obviously there isn't much to do to the intake. In all honesty, I wouldn't touch the port timing. I'd literally just go lightly clean up the runners a little bit and "dimple" the inner edge of the runner to port transition to help with laminar flow around that corner. In spite of what many RX-7 people say, don't worry about trying to aim or induce any air swirl going in the engine. It's not going to do anything. Since we don't have a stationary combustion chamber, it is always changing volume like any other engine but more importantly shape. This will kill any swirl you get at the intake and by the time you get combustion, the swirl effect is long gone. I actually have an SAE paper that reinforces this.

One day I'm going to have to bite the bullet and get me one of those engines to play with. I thought I had one lined up for pretty cheap last year but the deal fell through and I never got it. Oh well.

OfficerFarva

That's essentially what rotor sports did for me, minus the porting. They had the shop they use machine the rotor grooves deeper, but the 2mm seals they originally were gonna use still had a lil to much clearance they didn't feel comfortable w/ so they used the custum cut 3mm seals to fit the machined dimensions. They had done this for years on older 13b's, so it's along the same lines of what u are talking about Rotary God.

guitarjunkie28

well, i do have that spare engine with like 30k miles on it. if anyone wants to do that, i can port those irons and do it on a "trade-in" basis.

guitarjunkie28

we need to get together for a week sometime soon and **** around flow testing all this stuff.

i'm thinking the backcut can add some decent power later on down the road. i might toast a set of irons doing it, but i want to give it an edge not-quite, but similar to the older motors intake ports so the exhaust doesn't have to turn so much to exit the motor. hog it out and weld it back up, but without a huge port oriface, although, i think openining the port a bit sooner would help out in the top end. so, a bit bigger port (like the one above, or maybe a teeeeeny bit bigger), and a little smaller runner. obviously, all this stuff would get flow tested as i was doing it and before it ever got assembled.

then still later on down the road, i wanna see how it likes some overlap.

btw, you'd be proud of the intake stuff i've been doing...very conservative. i did one motor without backfilling the primaries and it didn't do quite as well below 5k as the backfilled motors, so i'll still be doing that until further notice. still need more testing with all that though.

guitarjunkie28

^drunk.
my apologies

JB_Rotary

This would make a great candidate for porting since alot of the hard work is done. Dang it why do I have to be poor!!!!http://cgi.ebay.com/ebaymotors/RX8-R...68571127QQrdZ1

guitarjunkie28

if i had the spare cash, i'd pick those up just to have another set.

swoope

iTrader: (5)

if you know the person selling these. or know the right? to ask to make sure they are legit. let me know and we can start a core exchage program...

i am assuming all the stuff you are doing would only improve the afs...

beers

guitarjunkie28

oh yea, that spare engine i have actually has 18,300 miles. not 30k, like i thought before. i can tear that down and port it anytime someone wants.

swoope

iTrader: (5)

sorry thought i was sending a pm, not drunk.... and sucks...

check pm..

beers

guitarjunkie28

i'm not drunk, i found a bunch of little white pills.

i wonder what they were... oh well, i'm very relaxed :D

swoope

iTrader: (5)

that was rude, one blue and a glass of red zine.

beers

guitarjunkie28

i can't figure out what you just said.

swoope

iTrader: (5)

rude you took white pills, i took a blue one and had a glass of red wine.. i think the results were about the same.

btw, emailed the guy with the housing about shipping.. he got back to me real fast.

emailed him for close up photos... yea never got them...

o well i tried..


beers

guitarjunkie28

ok, who bought those irons?

rotarygod

I know! Here's a hint, it wasn't me.

guitarjunkie28

richard called me and said he was gonna hit it, but he didn't end up getting them. i totally overlooked that until this morning--he needs a new intermediate anyway. missed the chance for a whole set for the price of one new housing.

non-related---i think imma do a heat rejection coating on his side seals.