Decided to go 20B NA for my Rx3
 

Well I just got my Rx3 couple month ago from the body shop they did all the rust patches and I will be working on the body slowly since busy and have other priorities 😪.

I finally decided what engine I want and what set up I want, I’ve had 3 different engines I bought over the years for the Rx3 and sold them because I can’t get over wanting a 3 rotor. I decided even if it takes longer to just go for the 3 rotor and piece it out .

What I wanted to do is start buying housings , iron plates , E shaft and the rotor assembly maybe RX8 rotors and balancing .
Ive seen some parts for a good price and I’ve slacked over the years 😔. They will be picking up the 13B I just sold and I wanted to use that to start buying engine parts .

I just want to see what you guys think . I know some people who have bought a complete engine and ended up buying housing , plates rotors and it ended up paying more in the end .

Hope me you guys can help me decide if this is the right way to go , I think it is since I want to do it right the first time .

what should I look and what should I be carful getting and inspecting .?

I want ant use ITB with a Haltech and I’m not drifting or drag racing I’ll be driving to car meets and shows and weekends so it will get a lot of run time .
Thanks in advance

It's cheaper to buy an entire 20b assembly than buying parts. Also, finding a thick center iron or eshaft by itself is getting very difficult. Make sure to buy from someone reputable. I would talk to Defined Autoworks if you are wanting an NA setup. You're not going to make more than around 350WHP with the stock ports etc.

If you have any plans of reving it over 8.5k, you had better make sure the eshaft is 100% dead straight, and your rotating assembly is lightened and balanced. Anything over 9~9.5k, you'll probably want a dry sump.

RX8 rotors are not recommended. They wont give you any more power. Just use S5 9.7s

Be prepared to spend 20~30k in this adventure... hahaha

I actually just posted a thick center and e shaft up for sale and can ship em out whenever if you're ready to jump right on in.

I’m not looking for power at all , just a nice clean NA set up for my Rx3 , I really appreciate the input but even if I buy a Nice 13B it will be a nice amount of money too if I want it done right so thinking if I go a bit more at least is done to my taste , I see way to many people changing set ups , engines to upgrade and going from 13b to 20b I really can’t afford to keep switching . I built my Rx8 about 6 years and bought everything OEM and car was sold to my cousin and still turns on like day one . I know is a Rx8 not a 3 rotor but older I get the less I want to do stuff twice that’s my point .

thanks I just looked it up 🤔, got to run some numbers and see I haven’t sold my other engine yet and going waiting on some call back on some 20b’s I msg .

congratulations! you've made a good choice, if you keep your eyes open there are deals out there. the simplest intake to run is the stock Cosmo intake, but it would be super cool to chop up a couple of IDA intakes and run a 3 barrel Weber, or EFI throttle body.

if you're piecing stuff together, you should buy 3 new S5 NA rotors, and REW rotor housings, and just street port the irons, it would be plenty of power, reliable, and super simple

i'd use the Rx8 transmission, as the shifter would line up

To be more specific, I would recommend the S2 RX8 6 speed, or the 5 speed based on the additional torque from the 20b. neither of the 6 speeds are what I would call strong transmissions sadly.

I have a spare 5 speed I don't need because I bought carless's CD009/JK40C 370z transmission adapter for my 20b.

I think either S1 or S2 Rx8 transmissions would be fine for an NA 20b. They are much stronger than people give them credit for. I love mine!

thanks really appreciate it the info and the confidence . I buy car and flip them and I just sold 2 I have 1 more before I can start working on this process . But definitely Going this route , like I said I’m just wanting my Rx3 for car meets and I’m planning to drive it all over my goal is DGGR , Seven stock and any other big ones . So I have to built this right . ,6 speed from Rx8 I find them cheap in my area in the yards , I live in Florida old people town and I love it . Soon going to make a list of stuff to piece out and what to get to built it so I will be writing all this down . I got to Orlando Florida race track and a lot of racers sell engines parts for the cheap in great conditions . I want a weber look going straight up or toward the struts to show more the barrel

I’ve read about the 370z and the adapter here if I see one I’ll pick it up since yard sell all transmition around 150 😉 no matter what car

did you have to cut or do anything to make it fit on Rx3 ?

j9fd3s

you mention
3 new S5 NA rotors, and REW rotor housings, and just street port the irons, it would be plenty of power, reliable, and super simple.
so S5 rotors once I get should I try and get the balancing from 1 engine and try and get a 3rd rotor from the same year gen and have them balance it with the e shaft ?
I’ve seen I can use some irons from other generations I will just need to locate center one .
Im excited .

I would definitely have all 3 rotors, the e-shaft, and both counterweights balanced as a single unit at the same time. If you want to be extra careful/fancy than also have the rotors lightened snd clearanced.

for sure is getting balance that’s a must lightend not sure

if you're piecing something together, just buy three NEW rotors N3Y5-11-B10A. it skips all the wear and balance issues

if you find a complete 20B, i would just run it as is

Thanks , Right now I’m working on getting car ready for body work and paint and once that is set and I know what I’m working with I will start hunting down my Engine 🏁

20b housings
 

Got some used housings that’s they need some work from Goopy but I got the first 3 pieces of the puzzle . Got a good deal now wait for them to come in from across the sea . Is worth the wait for the price I paid even paying goopy to fix them is still cheaper then I’ve seen online 🏁.
Does anyone have a manual or something showing everything I need for the long block . Or a link to what I can use from other engines . I got the Rotor information but other Info for a rookie 20b guy
https://cimg3.ibsrv.net/gimg/www.rx7...31a8d2758.jpeg

Got some Iron plates , bolts , little gears behind front cover will post pictures when they come in . I couldn’t afford the thick iron or E shaft but I’m happy with my steps so far . I’m still working on this little project car I had so I can sell and buy more parts . I’m trying to focus on 1 thing at a time . The corolla is mine I need to sell and the Rx2 is my cousins
https://cimg0.ibsrv.net/gimg/www.rx7...2a29d0fad.jpeg
https://cimg3.ibsrv.net/gimg/www.rx7...9d21299b1.jpeg

Parts coming in for my Rx3 20b
 

My 20b Goal is coming along slowly but is a start

1. Front iron with gear
2. Intermediate thin iron
3. Rear iron
4. All T bolts
5. All new parts - 2 thrust bearing , 1 thrust bearing plate , oil pump sprocket, oil pump gear , oil pump chain , end play spacer C , drive gear for crank angle sensor.
   
6. used 3- 20B housings I’m having them re chrome . I’ll be a bit cheaper from new even with Rechrome .
   
7. 20b oil pump
8. 20b main pully .

and for now I’ll be on a stand still till I sell my little project car and another car I have to flip .

does anyone know if 20b stock oil pan fit a Rx3 ?

​​​​​​​thanks

no idea, but the 20B is rear sump, mostly


​​​​​​​

thanks I just PM a few guys hopefully someone can help , I don’t think I need a custom one but will see

thrust bearing NF01-11-D54 same as the FD
thrust bearing plate, the one with 8 holes that the bearings ride on? NF01-11-D51 same as FD
Oil Pump Sprocket (on the pump) N326-14-143, same as FC
Oil Pump Gear (on the Eshaft) NF01-11-D70, unique to the 20B
Oil Pump Chain, N326-14-151 same as FC/FD
Spacers, same as the FD, the parts catalog just gives a thickness not a letter...
CAS gear not in the catalog, 0839-11-531, same as everything
oil pump NF01-14-100 same as FD
​​​​​​​Main pulley NF01-11-400A

thanks
and looks like after market front and rear balance are cheaper then original ones not sure why but I’m fine with that . I’m creating a list of all parts I need so I can continue picking up small parts little by little .

cant wait. good choice on going 20B with ITB's Keep us posted.

if you need part numbers, i have the JC cosmo catalog