Right guys. you seem to know your stuff come n/a rotary.i know the basic and coming from a single turbo 13b im lacking big time in the n/a department. and being from Ireland there is little or no specialists.

heres what i want. A hi revving all top end race motor. it will be going into my FD race car witch i will be racing in the ITCC (www.itcc.ie) this year. im aiming for the championship.

From looking around i think a peri port 13b on about 60mm(ish) throttle bodies is what im going to need. it will be run on 95octane. i want to have as close to 350 fly wheel hp.(is this achievable?) i want to build this motor on a small budget. the crowd building my car (Jomo Engineering) will be doing all the fab work along with the build. they havent yet touched a rotary but johnny the owner is a very smart man and is well up for the job.

A few questions.

could i run a peri port n/a on my apexi power fc with some modifications?

what size throttle bodies will i need?

what revs can i get the engine to?

what parts should be used while building the engine (the races are 15 mins)

ive heard of using some rx8 rotors to help with n/a?

removing the oil pump and running 2 stroke. safer option for race use?



im here to learn.


this is the car at the min

 

you can run the PFC, but i think something that can do an TPS based fueling would be better. getting a stable map or afm signal on a PP is going to be tricky

60mm throttles sound fine, the older carbed setups ran 51 IDAs, but these are too small.

provided the right exhaust tuning the engine could make power up to and over 10,000, although if you need to run mufflers, tuning for a lower peak rpm might be good. obviously the lower you rev it the longer its going to last.

the FD stock internals are up to the competition specs, so they are fine up to 9000+

i'd just buy NEW stock parts, and build it really carefully. i'd be running the carbon apex seals.

i haven't seen anyone make more power with the rx8 rotors vs the 89-91 NA 9.7's, but i haven't seen everything either

i'd leave the metering pump AND premix a little. the metering pump will give you lubrication on decel, and at other points that premixing doesn't. however the stock pump doesn't run enough oil, so you need to add some

cool car, i have a 12A pp in a 1st gen and its FUN

 

Don't forget lightening, clearancing, dynamic balancing, hardened stationary gears, and a 2-piece e-shaft to help mitigate flex.

 

1. not really trying to get into your business, but it might help you a bit if you give a ballpark figure of what you have to put into this. most of us here can give you a laundry list of suggestions, but choices/sacrifices may have to be made to fit your bottomline.

2. i've seen as large as 62 mm. given that this is a racecar, you might want to look into them.

3. i think the better questions are where your setup's usable powerband will be, and how long you need to go between rebuilds. i know you said the races are 15 minutes each, but remember the higher you rev, the more wear and tear on the engine. also, consider dry sump lubrication as i would tend to think the factory oil pump may have an effective RPM limit.

4. based on what i've seen (read) it seems prudent to skip them and just use the 9.7s - maybe get them lightened even more than stock.

i thought the REW gears were already hardened. are there better gears out there?

 

to give you an idea theres a guy over here with a fd 13b pp race car,hes probly the fastest 13b n/a car ive seen round a race track thats not a big dollar build,he runs 45mm pports and 55mm throttle bodys controled by a motec,rx8 rotors and seals(all factory)its making 305 rwhp on a dynopac dyno,he revs it to about 9500rpm,he runs at about 1 second a lap down against a couble of 450hp turbo fds,when i asked him a few questions about his car he said the two critical areas of making good car speed(aside from driving!)was intake and exauast design to make good hp and gearbox ratios to keep it in the power!

 

Any pics or dyno of this beast floating around? It would be interesting to see the mid range with the slightly smaller PP's.

 

no i havnt found too many photos or vids of the car,the only thing ive seen on the net is http://www.youtube.com/watch?v=UE0aiOkRlHA which shows the car idling in a car park(the power numbers given in the vid are wrong)other than that there isnt much else about it,when i was askig him about the size of the ports he said the reason they had them at 45mm was to keep the air speed as high as possible!

 

Just to make sure we (or at least myself) are looking at this the same, is the 45mm the ID or the OD of the tubing used for the port? I only ask since a 2" OD aluminum pipe usually has an ID of 44-45mm.

 

45mm id,the engine started out with 43mm id and the machined it out to 45mm,hope that helps!

 

Wow!!! Every experimental pp I've cut into my damaged housings have been that size. Even my TB's are the 55mm size. I guess I did some great research over the years because I too was looking more for higher velocity and more midrange than top end for my future PP experiments.

 

Thanks, its also nice to see that an even smaller port had been tested.

 

thanks for all the replies. huge amounts of knowledge on this site. i will get back to all the above points and questions.




few quick questions. im buying up a few damaged 13bs to build this engine. a 13b n/a from an fc(hi comp rotors?). will it just be the rotors that are of any use to me? or can the housing also be used.

will also have a 13b from a fd.


what im pretty much asking is what parts from what engine should i use?




rebuilt kit. ive searched around and what i seem to be looking for is this? i like the heavy duty water seals. http://www.pineappleracing.com/13b-r...ebuildkit.aspx


also these

http://www.mazdatrix.com/getprice.as...m=01-9103-0000


what other parts would you guys recommend and what carbon seals should i go for? have been looking at the mazdatrix seals.


thanks again guys. much appreciated

 

[QUOTE=irishrx7;10436626
few quick questions. im buying up a few damaged 13bs to build this engine. a 13b n/a from an fc(hi comp rotors?). will it just be the rotors that are of any use to me? or can the housing also be used.

will also have a 13b from a fd.


what im pretty much asking is what parts from what engine should i use?

what other parts would you guys recommend and what carbon seals should i go for? have been looking at the mazdatrix seals.


thanks again guys. much appreciated[/QUOTE]

preferably you want to use the FD front iron, oil pump and rotor housings. the FD has the best oil pump and it only works on the FD iron. the FD or S5 rotor housings have better spark plug placement too.

other than that the FC engines have smaller ports, so they might be easier to fill

the carbon seals are made by mazda, anyone you buy em from is just a reseller, so price/willing to ship to the wonderful country you live in.

 

I would use just the fc rotors and the rest FD, like previously stated, the FD oil pump is the best so u must retain the FD irons. Also, u want the FD bellhousing when shopping for a good close ratio box. I don't know what your budget is on trannies, but its much easier to fit other trannies up to the FD. Most cheap tranny swaps require u to use a 26 spline disc, in which case u will need the bigger ring gear of the turbo(unless u plan to use a 5.5 or 7.25 multi disc) I have found the RX-7 ratios to be terrible for pp's, i have used a g-force t-5 which was a little better and now a Mid Valley Engineering that i am finally happy with. I have as much $ in my clutch+flywheel+tranny+custom driveshaft as i do in my whole motor. Come up with a tranny plan before u waste money on different clutches and stuff. The RX-7 FD trans is 3.48,2.01,1.39 - not very close. And Trannys are so expensive.