Here is my current idea, I decided that I'm going to build from the E-shaft out with new parts. Will these parts fit together without machining and is there anything important I'm missing?

Factory 20B irons
http://www.mazdatrix.com/r-20.htm housings
'90 13B N/A rotors (9.7)
Guru E-shaft

I haven't found 10.2 rotors anywhere, I heard they were custom REN motors and not really available.

Is this motor "built" or is it "assembled"? Meaning can I with a few tools assemble the core/housings at home myself? I know it's not just snap together and go, but how much can I do without specialized equipment?

 

the 89-2003 rotors are all the same balance weight, so the 9.7 1990 rotors interchange directly with the s5t2/20b rotors.

rx8 is 10:1, not sure where they came up with 10.2, suspect math errors

PP housings at this point, either need to come from japan, or be built

i just built a PP 12a from new parts in my garage, i got all the parts, checked all the clearances, sent it out for balancing, and then assembled it.

3 rotor na rx8 would be pretty sweet, btw

 

Do you have a link to better PP housings? I can't find any.

I think I'll go with the 9.7s anyways unless someone manufactures 20B capable 10.2s. I'm aiming for 450hp to overcome the extra weight of the 20B which I'm hoping is possible with the 9.7s and a good PP. I just want to take all the fabrication work out of this as possible, as my fabrication skills are limited, and I don't want to screw up a $1000 set of 3 RX-8 rotors because I milled a fraction of a millimeter too far.

And yes, an N/A 20B RX-8 would be amazing, but any time anyone breathes "20B" on the RX-8 forum everyone rips their throat out. Saying "20B RX-8" over there is like saying "W16 RX7" over here. There are a few turbo'd 20B 8s over there but so far as I know no N/A ones, except the speedsource cars (which is sort of what I am aiming for engine-wise).

 

speed source is using the 13G engine, straight up.

racing beat makes PP housings, if you search on this forum, the guy who made ken sheepers housings does better.

the oem PP housings, would almost need to come from japan, like they might cast a run for you. $$$$$

 

https://www.rx7club.com/rotary-car-performance-77/building-peripheral-port-housings-144200/page2/

That guy?

 

http://www.rotaryeng.net/intake.html

 

Went to a big meet yesterday and learned a lot. Thoughts on this:

450HP can be developed at 9,000RPM with a big street port N/A.
PPs are meant to rev much higher than that.
The front iron will be big bucks because it's unique to the 20B
Only the GURU shaft is expensive, stock 20B Eshaft is much less.

Question.

If 450hp is good at 9k with an SP, why does the 13G have similar numbers with a PP? What's the point of PPs if I can make power at high revs with just an SP?

 

450 with a street port is way high. hp/per rotor, a 2 rotor would be making 300hp, and they dont. street port should be in the 100-120hp per rotor range, which puts the 20b in the 330hp area.

also the re-amemyia gt300 car is 420ps, speedsource rx8 is 450hp, my 1997 mazdaspeed catalog say 450@8500rpms. all PP's.

the 20B front iron is cheap ($350ish, theres one in my garage), its the FAT center iron thats expensive

the stock 20b shaft WAS cheaper, but mazda hasnt made them for at least 5 years, if you call mazdacomp they sell you the guru shaft for like 5k

do some digging, what ive found so far has been pretty consistant.

 

Seemed high to me too. PP it is than. Almost had my hopes up

Racing beat told me that 450hp is fairly easy to develop depending on desired RPM. I told him peak at 9k with redline of 10. Is that reasonable?

I know that gas mileage is thrown out the window with a PP. Can I expect 50 miles/tank?

 

EDIT: Racing beat PP housings: $998 each

 

rpms are about right, imo its better to loose 5-10hp at 9k to have a broader powerband in the 5-7k area, especially for a street car, but 450 engine hp with a PP 3 rotor should be no problem, if you're lucky it'll do 445-450hp from 8-9k.

also keep in mind the stresses on the motor go up with the square of rpm, so while 8k isnt a big deal, 10k is, the faster you spin it, the faster it'll wear out.

not sure what to expect for mileage, i know of one fellow in canada, with a small 13b PP, that gets better mileage than stock, but its a 20b... tough to say, id expect high teens on the freeway, although it could go either way. roadrace it should be around 3mpg

 

How about stationary gears. They have to be hardened and than permanently affixed to the rotor via a snap ring, correct?

 

actually if you're buying new rotors, buying the RB rotors with the snap ring, and balanced and lightened, is not much more than buying new stock ones.

the stat gears in a 20b are hardened already, you would want to upgrade to the FD/competition style bearings though.

 

Well I'm considering using 10:1 Rotors which racing beat does not sell pre-modified. I think they'll have an easier time getting 400 to the ground.

 

so far results seem to be mixed, but the good thing is that gordon should have some numbers soon. if they do work, then use em.

if you can make the intakes a little smaller, it'll be more streetable.

 

Its not that I don't want streetability, its that the car can't be street legal anyways, since its an RX-8. So I might as well go all out. I would think about smaller intakes but that would require custom housings which I cannot fabricate nor fund the fabrication of.

Can you link me to those bearings? I cant find these either. My google skills aren't the best.

 

http://www.mazdatrix.com/b4.htm

actually with 3 rotors instead of 2 it might be a moot point anyways, its going to idle better, and be quieter

 

~90 NA Rotors or RX-8 Rotors
Guru E-shaft
RB PP Housings
Stock side housings (filled in ports of course)
FD bearings ....

What else do I need within the engine itself?

 

maybe ceramic apex seals, NRS makes affordable ones.

 

I need to know about fuel. What are the most commonly used fuel systems, what works best for this engine? Come to think of it, I know very little about the stock fuel system anyways. Google has again failed me