guitarjunkie28

forgot about that point. the coolant is darker than the stuff i've seen off the shelf. anything special about it or what?

rotarygod

You'd be very surprised at how much gain little things have. One of the big secrets to improving flow on a rotary port is not necessarily making it bigger. That is the last thing you do in a series of mods. Sadly, this is what most people concentrate on. The short turn radius is the most important spot and you have addressed it. This along with blending of the port into the runner makes a huge difference in flow. I could justify pulling an engine apart just to clean up flow even if the ports weren't enlarged at all. The biggest thing to consider is how airflow behaves as the rotor is crossing the port opening. Most people just worry about flow through a fully open port. This isn't the way to do it. Most of the time there is a rotor in front of it disrupting airflow.

You'd be surprised what you can learn on a flowbench. I take 7 different flow readings and average them out. 3 readings with the rotor in various stages of port opening, 1 fully open, and 3 in different spots of the rotor closing the port. Many times I can port it my way with a smaller port and outflow a larger port done more conventionally as many others do it. You are definitely on the right track. I still feel that the exhaust port should only be enlarged just enough so the wall inside is gone. I don't think it should go any larger. Don't take this as criticism but I feel you need to concentrate more on the short turn radius than you did. It should definitely flow better than stock but get it the best you can. The hard part is getting in small areas if your bits are too short or big. This is where patience come in.

As you said, rounding off the opening edge of the port also doesn't really help airflow into it. It would seem like it would but again, it's amazing what you can learn on a flowbench. Just take the sharp edge off of it. If you want to keep porting these on a consistent basis, you really need to build a flow bench. I built mine a little more expensive than I had to and I still have less than $100 into it not including the vacuum/pressure source. I wish I'd have built one years ago. The people that say they aren't relevant tools on a rotary are just guessing. If you aren't flow testing, you are flow guessing. You have some of the best ports around with one of these and they'll be smaller and still make more power than many other people's ports.

guitarjunkie28

thanks a lot for the compliments. can you maybe shoot me a pm or give me a link to some more info on the flow tester? that's worth $100 and some time.

and i don't take that as critisism--constructive critisism at worst (which is a good thing anyway). thanks a lot. i'll make sure to give that extra effort on snoochies engine. hopefully we'll get dome dyno numbers before the end of hte year.

rotarygod

I just looked up different websites on flowbenches to understand how they work. They are extremely simplistic. There are many people on the internet that have built their own. Do a little homework and then build one. There are a few different philosophies on flow testing and a few different ways to do it. Mine may not be the best unit on the planet but it shows me what I want to know.

rx8cited

Can you post a few links for sites that you liked please?

rotarygod

You're going to want to do a little homework on the different designs. I designed and built mine so you won't find any plans for it. There are many available though. They can be made in all different sizes. To work with what I need, it didn't have to be very big. Mine fits in te backseat of a 2 door Civic.

http://www.victorylibrary.com/mopar/bench.htm This has a great schematic. Mine is based off of this design but not as big.

http://www.performancetrends.com/ez_flow_system.htm

http://www.diyporting.com/ This has other good info that is also rotary relevant.

http://www.superflow.com/support/sup...wbench-faq.htm This is Superflow's website. I linked it straight to the FAQ section. This is my favorite quote right here since it shows that bigger is not always better:

"Maximum power is obtained with the smallest port cross-section that will deliver that flow."

http://www.yawpower.com/Flow%20Testing.html This is a great article showing the importance of flow testing.

dj.stains

how much would porting my 8 actually cost?

rotarygod

It really depends on who does it. Most of the expense is just removing and reinstalling the engine. Typically porting prices are only quoted for just doing the actual port work itself. This doesn't even include disassembly/ reassembly, or replacing any parts/seals that need it. Porting alone typically runs anywhere from $200 on the very cheap side to over $2000 on the extreme porting side depending who does it. The biggest problem with this is that you don't know who is good and who isn't. All you know is that everyone makes it larger. The most expensive prices are from Paul Yaw at Yawpower. He also ports better than anyone else around. He also, coincidentally enough, is one of the only people who actually uses a flowbench on rotaries to determine flow. His porting prices start at $650. If you can remove and install your own engine and tear down and rebuild it too, you'll be looking at less money. Upwards of $1000 isn't too bad though if you can't.

If anyone wants to tear their own motor down and send me the housings, I will gladly flow test them to establish the base numbers. Then I will do the portwork and reflow them at various stages to show differences and finally get the end numbers. The relevant info is how much more average flow do they get. I take 7 different measurements and compare them all.

dj.stains

thanks alot for the info I guess I just need to find someone who works on rotaries in the Bay Area

Snoochie

Or drive down here :D

dj.stains

If I did drove down there how long would it take like if i was there thursday would i get it back saturday plus would the dealership know that i ported it?

Snoochie

It's gonna tkae a lot longer than that to port it. He need to pull the entire engine and get to the ports which will take a day assuming he has absolutely no other work to do so it's not definate. Then he has to do all of the porting and then put it back together. If he was a maniac and when all ***** out he could do it in theory. But to take time and do things right it's going to take longer. Expect a week at least.

Either way you could drive down here and drop it off, get a rental with unlimited miles on it, go home and come back later to get your car. :D but that's hypothetical.

Post something in your local section and ask them if there are reputable places in your area. Hopefully you can find one that's good.

dj.stains

yea i figured it would take kind of long but would my dealership know at all im that great on engines so excuse my noobish

Snoochie

I think we mentioned it earlier but there's 20 pages now (holy crap this got long fast). No they wouldn't unless they opened it up and found out. So don't blow up your car or do anything serious to it. Cause then they will need to "find out" what happened and they'll see the porting and blame that. Then again in theory they would need to prove that the port job caused the problem but dealerships will blame anything they can to not pay money.

And also there might be a CEL when you port. Maybe the ECU will be like "holy **** something changed and pop it up. And in that case maybe thye dealership will want to find out what is wrong. Hopefully me being the guinea pig we'll know if this happens.

I just started writing and I'm not sure where I'm going so if you have any other Q's lemme know.

guitarjunkie28

obviously we won't know until it's all back together and everything, but i don't see any reason why there would be a check engine light. the porting shouldn't effect anything that gets monitored very drastically.

Aoshi Shinomori

It won't notice an increase in flow? Maybe it would and try to change things in order to compensate, but shouldn't be a problem. I'm sure we'll find out shortly though. Good luck with the rest of the project.

NoTears316

I was talked out of getting a port done by the shop owner!!! When I called him up and explained what I wanted, he asked me how many miles it had, to which I said close to 20k. He told me that I should seriously wait until my engine actually needed some sort of rebuild. He explained that I could probably get 35 hp from a street port, but it would cost nearly $3k. When I asked him about having a bridge port done, he asked if my sole purpose for having the car was to race it... when I said, no, he told me to not even think about having it done because it will ruin the life of the engine. He finished by saying that he expects FI to be out in a few months and that if I wanted a serious increase in hp that I should wait on that. I agreed.

guitarjunkie28

i agree it is going to be expensive.
and i'm not even sure if you even can bridgeport a renesis motor--probably if you went really deep into the rotor housing, but it would have to be very narrow and i don't think the extra duration would make up for the overlap unless it was a force induction application.

but as far as reliablilty is concerned, my half-bridge fc is my commuter car. 500-700 miles a week, if that tells you anything,

Omicron

Good advice, all around. Sounds like that guy knows what he's doing. My plan is to get FI when I can, then down the road a bit I'll get the engine pulled and worked over majorly so I can really bump up the HP.

guitarjunkie28

ok, y'all remember when i said i admit when i'm wrong....well, this is one of those times.

before i said that not a whole lot could be done without going into the water jacket. i was wrong. this pic is a very rough cut (i haven't had time to get it shiny and beautiful yet) of snoochie's exhaust port.

even more of the combustion chamber is visible from the port runner than my first one!! and this is without cutting into the water jacket. of course, flow could be improved if i did cut through it, but i think even if i left this one how it is, it would outflow my first one. i'm still debating on whether or not to do it.. i'll leave it like this and sit on it for the rest of the day before i make a final decision.

first pic is the revised exhaust port, second is stock, third is the first one i ported.

RX3+5

How thin are things getting?

Vince

guitarjunkie28

good question. one i really can't answer since the other water jacket runs deeper than i can see. i may end up sticking a little bit of epoxy behind it (upper right of the pic where i ground away at the sleeve) just to bolster it up a little bit, but i'm still not sure if i'm going to poke through yet... if i did, it would almost be a relief because i'd know exactly how far i could go, then i'd just have it welded back up.

Snoochie

I would think just shave a little more for a more direct line of flow and whether you hit or not just put some epoxy up there like you said. It's not like the epoxy is going to hurt anything.

Richard Paul

iTrader: (5)

Are you working with cast iron? If you are then you must know something I don't because welding cast iron is not as easy as other stuff is. You speak about welding like it is nothing and if this is aluminum or steel I would agree.
Also epoxy can hurt something if it falls out or can't take the temp. Parent metal is always the best thing to have.
As to rotarygods comments on the little things, I concur. On poppet valve engines this is also true. The smallest changes make big differences both good and bad. I once found that a very small floor slant made a huge difference on a wedge engine.
On Superflows statement about the smallest cross section that is exactly right. It also is a fact that line of sight can be worse than a bend that points the flow in the proper direction.
this is a lesson that could be learned if you ever saw the ports on a Cosworth SCC. There is a kink in there that you would probably grind out. If you did you would go slower. So be carefull what you grind away.

Many years ago I found out there were shops that did this all day for a living. They saw lots more heads then I did and had feedback. From then on my policy for the shop was we only blend and radius existing ports, smooth chambers. If we know of something for sure then make exceptions.

Now at the moment no one knows or is talking about the Ren so the only thing to go with is the flowbench and experimenting. It's going to take some mistakes to get where you want to go. In my time we didn't have this type of communication between modifiers so to share mistakes. This should make life easier on the men that come after you.

Have at it but get a flowbench. BTW there are a couple of heavy duty NASCAR flow bench out there with my old large size superchargers doing the sucking. Sorry can't tell you who they are though.

shaolin

Wow I'm just waiting for someone to get this done and provide reliable results....judge ito did it, but keeps to himself....

I'd like to see a reputable rotary shop that I could take my car to and have this done. Don't get me wrong I love working on my own car, and have built turbo kits and such before, but I'm by no means a machinist, and I really wouldn' t know how to port a rotary engine.

Just let me know if someone does this, and I'll have money in hand...