itschrisfoo

are they interchangeable. let say im using s5 irons and use s4 housing, will it work

Skidtron

iTrader: (1)

It depends on if you have that intake manifold.

texFCturboII

iTrader: (17)

^^ housings and intake manifolds don't mix.

OP, a 13b housing is a 13b housing. As long as the housing is designed for a 13b type mazda wankel rotary you can use it. That being said, there are different variants between the housings; but as long as you are willing to do any necessary modification to match things up than you can do whatever the hell you want.

There are a couple of differences between housings from turbo to N/A and from series to series:

Turbo housings have a water outlet that feeds water from the jacket to the turbocharger via the turbo intake manifold, on the N/A manifolds this outlet is plugged. The turbo housings also have a different exhaust diffuser than the N/A housings.

From series to series I believe the only difference is the amount of space between the spark plugs. It is a general rule of thumb to match housings as a pair of the same series, although I'm sure the engine would run with mismatched series housings, it's a better idea to match it up.

So yes, you can use s5 irons and s4 housings.

This has been covered before, search frankenrotor or something of the like.

bumpstart

housings don't care which inlet or exhaust manifolds are to be fitted
for factory applications - some are mildly different in the internal passage routing front and rear
- on purpose -
( FD front and rear housings are marked either blue and red dot to encourage you to identify them and place them front and rear correct positions so as to align ACV passages correctly )

this however is irrelevant to many builders who are not interested in maintaining the factory ACV operation

-------------------
yes , mostly,, the s4/s5 FC and FD housings are interchangeble, with a few reservations especially as noted above

essentially s5 turbo housings are the same as s4 turbo housings , aside the knock sensor location

essentially s5 NA housings are the same as s5 turbo ones,, but lack the coolant crossover in one of the housings to supply turbo cooling water
and also have a different exhaust port baffle

similarly FD housings,, asides some detail changes to the water flow around the plug casting and the unique surface treatments,, is essentially same as the s5 turbo housing


its s4 NA housings you must be wary off,, or use a matched pair
at least in JDM, and aus markets ,, these n326 housings have odd leading spark locations to any other commonly available housing
( and also have the exhaust baffle and coolant crossover mismatches )

they can be used in turbo applications , as long as paired with a similar one,, and the exhaust port inserts and the coolant crossover addressed

to identify them is easy enough
if you have a housing with no knock sensor above the spark hole check that it has N318 bossed near the oil injector
if so,, its actually a japanese or aussie s4 turbo ,, i believe your code may well be N332 ( but still stamped n318 on the housing )

if there is instead no bossing,,, treat with caution,, as the source originally may have been n326,, the odd housing

matching them up on a flat bench will soon tell you it has a higher leading plug, close to TDC

Skidtron

iTrader: (1)

LOL I read that exactly backwards. In that case disreguard my stupid post. These guys are right.

Dyslexia? Maybe.

itschrisfoo

so basically itll work if i pull out both the s5 housing off the s5 block and put two s4 housings in

Nick_d_TII

iTrader: (6)

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/rotor-housings-fd-vs-s5-t2-vs-s4-t2-816116/

texFCturboII

iTrader: (17)

...

RotaryEvolution

iTrader: (30)

Jspec rotor housings all use S5/S6(FD3S) spark plug timing/location in the housing.

S4 USDM housings are the only housings you must not mix with any other series.

Skidtron

iTrader: (1)

Wait for it....wait for it.....

Are you sure? LOL just kidding man.

This is the exact answer. Do what the tiger says or die by a horrible mauling

2slow4stock

iTrader: (18)

Someone failed to mention that only s4 n/a rotor housings have the spark plug 5mm lower on the leading plug then s4 tii/s5 n/a-tii.

You can mix and match S4/S5 TII housings. Minor difference is knock sensor hole on housing or not. But.. factory knock sensor is garbage anyways.

OP you can use s4 housings on s5 irons. It will work. But your question said it was paired, so it doesn't matter your fine to go. Just make sure flywheel, rotors, front counter weight stay the same. Don't mix s4/s5 internal parts.

RotaryEvolution

iTrader: (30)

S4 rotor housings have the leadings 5mm higher, the split difference we mentioned earlier, the Turbo and n/a S4 housings share the same spark plug timing. S5/6/Jspec(all series Jspec) all use the same timing.

you CANNOT mix and match the S4 USDM and later rotor housings. the porting on the S5 irons is also slightly larger and more offset than the series 4 is.

if you mix a S4 USDM rotor housing and a S5/S4 Jspec/REW rotor housing, the timing difference will likely result in a broken side seal and slightly erratic idle(don't ask me how i know this..).

the easy way to tell is lining them up side by side and looking at the spark plug gap between the plugs with a micrometer or tape measure. S4 USDM gap is 23mm, the Jspec/S5/6 are 28mm apart(top of the leading hole to the bottom of the trailing on the outside of the housing, not center to center) and all have some sort of boss for a knock sensor above the trailing plug.

bumpstart

i am going to set it straight,, you are actually on an international forum , not a US only one
( the world isnt centred over the US you know ,, and since this is an international forum, my answer is world specific )

Jspec housings,, actually more accurately NON US world spec s4 turbo housings
are N318 and NOT N332 engines
( genuine bossed n318= non US s4 turbo housing )
they even come with ECU's marked N318/N319
DO NOT HAVE A KNOCK SENSOR location in the housing
they DO NOT HAVE THE NARROW SPARK SPLIT



maztrix quote N318 as a s5 housing
when the entire world knows this is a 1986 s4t ( world ) part number
and the revised s5 housings ( with knock sensor ) retrofil any order as they are listed as the correct reverse compatible housing and are thus supplied as N318
thus new purchase "n318" housings will be actually supplied the part that was originally numbered N370 but has now , many years down the track been re-assigned N318
( the knock sensor location is the only difference and does not effect reverse compatibility )
- this is to maintain the mazda parts number strategy where they reproduce the parts capable of total retrofit but re-issuing it the original numerical key
by same strategies,, you still order oil control cases with 10 A part number,, and there is not separate numbers for every evolution of engine since then


in WORLD terms, N326 ( s4 NA ) is the odd housing
( as no where else gets a N332 )
and it is clearly distinguished from a GENUINE N318 housing
cause real N318 housings have it bossed onto the casting
( and has the wide spark spacing )

if your in the US or not,, your taking a gamble on any housing that lacks the knock sensor,, and lacks the N318 boss moniker
as it is odds on a N326 or perhaps the uber rare ( in world terms ) n332 US only s4T housing

that is why i have told all to final check on the flat bench

clearly,, this stack reads as a whole bunch of s5 housings , then three genuine n318 bossed s4t housings ( bossed right next to the oil injector ),, then two n326 housings on the end

clearly pictured and with the housings that the rest of the world has
,, only N326 has the odd spark locations







and thats before we get to porting

in world terms
and i have stripped many s4 and s5 turbo engines,, and 6 ports for that matter-

there is no difference between s4 and s5 turbo,, and s4 and s5 6 port internally in any of the porting
comparing real world N318 to real world N370, comparing a real world N326 to a real world N350
in world terms,, the only difference is in the change in compressions and the bolt on manifolds/ turbo and ECU




which is why ,, when you order a s4 rear "iron" you now get one with the bigger boss and wedge around the dowel
-- its an s5 world item, supplied as retrofit, on exactly the same terms as the s5 n370 housings being re-labelled and sold as n318 ones


if you have pics of different US porting from the factory and pics of N332 housings then post them up
they are US quirks,, not world ones

j9fd3s

iTrader: (3)

good post! you're 100% right.

N332 housings don't look any different from the N318's except the plug location. it may be a small problem across the oceans, but in the US the N332/n326's are more common than anything else, so the mix and match is actually a big problem.