fox1999

Hey so I bought an fc pre torn apart, the engine is still all together pretty much, but it came with this JMNR rebuild kit and i was wondering if anyone knew if this kit is good for boost, i plan on replacing the apex seals with carbon seals or ceramic, whatever is good for 10k rpm. Also if anyone has information on how to get these things up to 10k rpm without blowing up that'd be cool, do they go that high stock or do i also gotta change the crankshaft? Someone was talking about the crankshaft flexing and the rotor bottoming out on the housing... Idk lol. Anyway heres a pic of my seal kit.
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GtiKyle

iTrader: (5)

I don't want to come off mean, but i think you need to do a lot more research before you're ready to tear into this car.

Do you have a turbo2 engine or NA? If you're starting with a 6 port engine, and plan to turbocharge it, you have a lot of hurdles that i hope you're ready to overcome. Do some searching on this topic, it's been covered in several build threads and in the forced induction section. In general you're going to be fabricating a lot of things that aren't simply bolt-on. If you're dead set on having a turbo engine (and you don't already have a turbo2 engine), i would suggest sourcing one to start off with, it will make your life a lot easier.

First off, why do you want your engine to turn 10k RPM? Do you plan to make power up to that RPM? Are you aware that your turbo will likely run out of steam before then, or, if sized correctly, the car will be a DOG to drive around below 6k RPM so you can make boost up until 10K RPM. What are you goals with this car that it needs to turn 10K RPM?

If you're calling it a "crankshaft", i have more bad news for you. That isn't what this engine has. It's an eccentric shaft, and yes, I'm being pedantic because these details matter. If you don't have the basics down I don't have high hopes doing an engine build is right for you yet. 10k RPM will come with more expense like lightening/blueprinting rotors, clearancing of rotors, balancing the assembly and likely shorter engine life if you can tolerate the expense.

fox1999

I have an NA engine, i know its an eccentric shaft im just lazy and forgetful lol, im planning to full dive into this project, ive worked on cars on and off most my life but this is my first real project and first time rebuilding an engine entirely let alone rotary engine, ill be honest im being pretty naive about this but im ready for trial and error, i suppose I dont need 10k, im just trying to make this a beast and to my vision, i wanna do a 2 stage turbo set up, in the meantime im just replacing all the seals and springs and im gonna 6 port it, then eventually get turbos, then one day get an s5 turbo engine and get peripheral housings. Ive done alot of research but im more of a hands on in the moment experience kind of learner. But I have done quite a bit of research this past year. Everyones gotta start somewhere and this is the best way to learn for me at least, either way all i need to know is if this kit is any good, i dont wanna go spending another 500 when i have a perfectly good kit capable of withstanding like 300hp.

Dak

You don't need to spin10k rpm on a turbo car. If you dig around and look at dyno charts you'll see that even the turbo cars making big numbers generally do it below 8k. It's the n/a cars that spin that kind of rpm because they need the revs to make the horsepower due to the way the ports that make big numbers for a n/a work. You need to plan out what you want. A high revving n/a or a higher horsepower turbo. Another thing to consider is, have you looked at prices for engines lately? Current prices on Ebay have a S5 TII engine at between $1000 less than the cheapest13B-REW( 3rd Gen) engine and costing the same or more than the most expensive 13B-REW. mazda 13b engine in Parts & Accessories for sale | eBay The REW is a better engine, but that opens up a whole other can of worms as it doesn't a directly bolt into the FC chassis. To do what you want you also need a standalone ECU as the stock one(S5) won't spin past 8.5k or compensate for boost of adding a turbo.

diabolical1

iTrader: (3)

i usually only start a response this way for a member with 10 posts or less, but i'll make an exception in this case ...

welcome to the board.

okay, i mean no offense in anything i say. you're new and the one thing i think you got absolutely correct is that we all have to start somewhere. as for your question about the gasket kit you have, i can't remember seeing that particular kit before, but i've seen a number of kits over the years. instinct tells me it probably is not up to OEM quality, but i simply don't know. if you're planning on building your engine, i suppose it can't hurt to try it as long as you keep in mind the possibility/probability that you very well may have to pull the thing apart again shortly after building it, if there is a water seal failure.

now on to the other stuff ...

if you're planning on turbocharging, then this is probably not a good idea. i'm not even 100% sure carbons are available any more, even if it was a good idea. try using those terms in the search screen and get an idea of why. suffice it to say, they are more for N/A engines.

trial and error is a recipe for disaster. if you're not testing for something that there's no data already available out there, then why not do your best to use the information that is?

for the reasons stated above (Dak), 10,000 RPM sounds cool, but a turbo pretty much renders the need for it moot.

you seem to be just throwing terms out there randomly. i'm not sure what you're trying to say when you said you're going to "6 port it". then you said you want to get an S5 Turbo engine and peripheral port it. you mentioned something about paying an extra $500 for a rebuild kit (way off, by the way), so i'm guessing you're not wielding an unlimited budget. turbocharging a PP is not an endeavor for a novice. it can ruin you!

what i think is, you need to sit for a few weeks and search the board. take notes if you need to. anything that comes to mind, search it and learn it. ask whatever questions you have. i'm sure someone here will be willing to give answers and/or share insights and experiences. i don't know as much as a lot of guys here, but i know i'm willing to help if i can. at that point, you are ready to put a solid plan together, and have an increased chance of successfully executing it.

RXSpeed16

iTrader: (41)

Quote:

Originally Posted by fox1999

Everyones gotta start somewhere and this is the best way to learn for me at least, either way all i need to know is if this kit is any good, i dont wanna go spending another 500 when i have a perfectly good kit capable of withstanding like 300hp.

That's a gasket and soft seal kit. None of it impacts power potential unless it doesn't fit.
Disassemble the block you have, clean and measure everything according to the manual, buy what you need and rebuild with oem seals.
Once it drives, fix everything else that needs attention while researching the turbo swap.

Dak

If you go with rebuilding your current n/a with the plan to turbo it. Look through Aaron Cake's website. He has a wealth of information on his journey down that path.
Aaron's Homepage (aaroncake.net)
His journey The (Almost) Complete Guide To Turbocharging The Naturally Aspirated Second Generation RX-7 (aaroncake.net)

I also like his newer method of porting the TII lower intake to match the 6 port block. It makes all the turbo stuff bolt on like a TII except you still have to supply coolant and oil to the turbo.
Porting The 4 Port Turbo II Lower Intake To Fit The 6 Port NA Block (aaroncake.net)

I would also use Turbo rotor housings in your rebuild. They get rid of the exhaust diffusers in the n/a housings and have the water passages into the turbo LIM if you decided to go that route solving part of the getting coolant to the turbo problem.

Also as far as spinning to 10k. You have to balance and blueprint the rotors and eccentric shaft and I believe clearance the sides of the rotors due to flex of the eccentric shaft at those RPM's. As already mentioned, it is moot as you don't need to spin that high with a turbo.
Getting what you have running and driving like mentioned is good advice. Easier to swap an already running car than one that is in pieces.

fox1999

Thank you, all of that is very helpful, i only want 10k cause it sounds cool lol, but I can live without it. Those lada 3 rotor rally cars have inspired me. I think ive decided im gonna get am s5 motor and put peripheral port housings on it. All i really need to know is what seal kit is stronger than the oem. I will check out the links.

fox1999

But is it stronger than the oem seals? Is there any kit stronger than the oem seals?

fox1999

Thank you for the info, also what i meant was in the beginning im going to drill out 6 ports, then later when i get the money buy an s5 engine along with peripheral port housings.

Dak

What are you talking about doing? If you currently have a n/a which is the way I understand it your engine already has 6-ports (2 primary + 2 secondary + 2 auxiliary ports = 6 ports). There is nothing to "drill out" so this statement is somewhat confusing. Do you mean that you are going to port it? A street port for instance?

Dak

I think you need to determine what you want your final goals to be. Your power goals and how to achieve them. You talk of two things 10krpm peripheral ports and turbocharging. These are two different engine setups. You need to pick one or the other. I'm not saying you can't turbo a P-port you can but with a turbo you don't need p-ports to make good power and you don't need to spin to 10k to do it. So how much power to the wheels do you want to make? This somewhat determines the path you need to take.

As for seals. I haven't heard any bad things about the stock ones. At least below 8 or 9k. Above that something else may be needed. I don't know as I haven't researched how to spin that high as far as seals go. I'm pretty sure there are people with turbo motors making 400 to 500rwhp on OEM seals. Someone else please correct me if I'm wrong.

fox1999

I was planning on using a template like this.
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diabolical1

iTrader: (3)

okay, i was confused a bit by your statement earlier as well. yes, you are referring to porting the engine. in the case of the template you posted, that is bridge porting.

here's a fairly recent thread that may be of some use to you: https://www.rx7club.com/2nd-generati...build-1157395/

when i have time, i will also try to look up some threads that discuss bridge porting 6 ports.

fox1999

Thank you, i did some research earlier this year on porting, at least enough to understand i want it to be smooth and theres water jackets i definitely don't wanna drill into

fox1999

Wait, so peripheral ports allow max airflow into the engine creating more power, so wouldn't that mean it allows a turbocharger to push even more air in creating even more power?

Dak

On the surface it seems so but no it's not that simple. Someone else will have to chime in that's really know peripheral port but some searching seems to reveal turbo P-port aren't that common. Basically due to the overlap of the intake and exhaust ports on a P-port the intake and exhaust port are always open at the same time. This cause tuning/ drivability issues. This post by Blue TII
From this thread Are REW's only the right answer for high HP builds? - RX7Club.com - Mazda RX7 Forum explains it pretty well. This thread may offer additional insight as well..
Pport air-blow by to exhaust possible? - RX7Club.com - Mazda RX7 Forum

You still haven't answered what your power goals are. IIRC people are making 500rwhp with turbo street ports and the right turbo. If you want more than that you might consider a bridge port rather than a P-port for a turbo application. Though I still think more may be doable on a street port. Someone with actual high HP experience may need to chime in. I'm done searching for tonight. Maybe search the time slips and dyno section and the single turbo build section.

fox1999

Im basically just trying to get enough horsepower to drift decently without blowing up the motor really in a short period of time. So i think I probably want around 200-400 horsepower. Street porting is just grinding the ports just a little bit bigger so they overlap a little right? Cause I think thats probably what im gonna have to go for. A street port with a small turbo. Eventually ill get an s5 engine then do the same but a little bit bigger turbo and a better transmission. I wanna do a 2 stage turbo setup on that future engine

Dak

Sort of. It is enlarging the size of the port to allow more flow into and out of the engine. I may be wrong but I think the overlap is more of a side effect of enlarging the bottom of the intake port to open it sooner to get fuel/ air in sooner and closing the exhaust latter to let exhaust flow out longer. I don't think the intention is to add overlap. It just happens. So initially the stock S5 turbo may be a good starting point. It's good to about 240whp and has a better wastegate design than the S4.. You could send it to BNR 87-91 Mazda RX7 Turbo II FC3S – BNR SUPERCARS (wpcomstaging.com) and they can build a hybrid out of it good for 300 to 400whp.
Also could you clarify what you mean by 2 stage turbo? Do you mean twin turbos ran sequentially like on the FD( 3rd gen) or a stage 2 turbo upgrade. Which to be honest I don't even know what that means on an Rx-7. I'm more used to people on here talking about the amount of power they want and then being told recommendations for the turbo and the injector sizing they need to supply the fuel to support it. Most don't speak in stages on here.

fox1999

What i basically mean is like a smaller turbo for low rpm like 1.5 to 4k then a bigger one for 4k to 8.5k so theres power all round and a smooth transition between the two.
Also i got an s4 right now to practice with that im going to run until i have enough money or it blows up then ill get an s5 motor.

j9fd3s

iTrader: (3)

yes, but it adds overlap, so you need to run a HUGE turbo to have the backpressure low enough to keep the engine happy. so its also a big power setup.
backpressure in this means you're bringing hot exhaust gasses into the intake stroke, which tends to cause detonation.

so KKM has a P port turbo, 860ps
the old Scoot car was 720ps

Mazda tried P port turbo in 1981, but decided a bridge port was better and made ~530hp. 1981 is a distributor and mechanical fuel injection too, so its like a couple of sticks rubbing together to make fire!
the KSP cars were bridgeport turbo, they had them up to 730ps at 28psi, fastest drag car in Japan at the time

j9fd3s

iTrader: (3)

sounds like you just want an FD engine, which will fit

diabolical1

iTrader: (3)

just to put it our there for us all ... keep in mind that the stock ports already have overlap. porting is not creating it. the main reason we have the MSP (Renesis) is because there was no other practical way to eliminate it.

when you port an engine, you are increasing the overlap. how much you increase it will depend on whatever your final configuration ends up being. you can play around with how (particular method) you increase it though, and that may be beneficial depending on what you're trying to do.

well, you can make well over 200, easy, without porting. with porting, i don't see why you can't get to the upper half of the range you gave. just build the best engine you can, and focus on making it happy - that's making sure you have capable and reliable engine management, and increased fuel, oil and cooling (air, oil and coolant). physically reinforcing it may not be a bad idea, but ultimately it's up to you. i know you plan to get a turbo block at some point, so i don't know how far you want to go with the 6 port.

diabolical1

iTrader: (3)

do you have a link or some kind of direction to the Mazda thing you referenced?

the "sticks" comment is just funny as hell.

Dak

I hate to open this can of worms but j9fd3s already mentioned it. Mazda has already built this for you in the form of the FD engine. The 13B-REW had sequential twin turbos from the factory. It's not a direct bolt in but there are or at least were adapters available that solved the mounting issue. Rated at 255crank hp from the factory. I want to think the stock twins are good for around 400rwhp. Here is a thread from j9fd3s that should give you an idea of what's involved.
The Blue Car - RX7Club.com - Mazda RX7 Forum
Be advised complete 3rd gen engines are not cheap. $6k to $7k currently and most likely need to add the cost of a rebuild to that as well.