hello guys how do you tell the difference between:
s4 and s5 na housings
s4 and s5 na irons
and s4 and s5 na rotors

the easiest and quickest way
thanks for the help guys

 

Rotor housing identification: http://www.banzai-racing.com/faq_housings_ID.htm
Rotor housing differences: http://www.rotaryresurrection.com/2n...g_differs.html

 

thanks all i need now is the rotor and iron difference and ill have it made

 

we've posted this before, several times...

S4 rotors = cast combustion recess

s5 rotors = machined combustion recess

the S4 center iron has a round freeze plug below the intake ports, and an EGR on top, the S4 and S5 t2 center iron has an extra threaded bolt hole above the intake ports. the S5 NA has neither.

the S4 and S5 rear housing are basically identical, except that the S5 has only 1 bolt hole for the top mount starter and the S4 has 2. this is to clear the NA intake. the S5 also has a different thread for the temp gauge sender.

the front irons i think the only difference is the water pump housing has the spacers machined into it, so they are interchangeable.

 

Don't forget that s4 front irons have the casting for the single rubber o-ring and the s5 and later front irons have the casting for the double teflon/rubber o-rings.

Also, the bolt pattern of all FC rear irons is identical...there are no changes due to starter location etc. as you've mentioned above.

 

the TOP MOUNT starter holes are different. S4 has both, and the S5 has the one, to clear the intake.

i've seen S4 irons with the same oring as the S5, so it might matter when the S4 iron was made. if its made in 1986 it should be the early style, if it was made in 2006 it should be the late style.

 

pic of starter flange. engine is an FD, but the S5 is the same, it has one bolt hole on that flange, which is for a top mount starter. the S4 and earlier engines have a second threaded hole on the other side...

 

its best known as the clutch inspection plate cover,, no SD engine has a top mount starter OEM

 

Yes, yes...that flange has nothing to do with the (stock, automotive application) starter, but is an inspection cover as noted. And you're correct, the early rear iron has two threaded holes while the late one only has one...but the early inspection cover did not use the extra bolt hole either.

 

I'm wondering if the exhaust port holes on the differnt housings are differnt size and timing. I'm also curious on the spark timing specs. Anyone have any info on those?

 

All 86-95 exhaust ports are identical size and position/timing. The only difference is the exhaust sleeve that is installed (which can be swapped to a different version if needed)...NA, turbo smooth, or cosmo style.

86-88 housings all had conventional plug hole location, 89 and later housings have the leading plug hole positioned 3mm lower in the housing. Though it is a matter of debate, I do not consider this to be a "timing" change, as timing is still controlled by the ecu relative to rotor position. I consider it to be a "position" change only, similar to changing the position/placement/angle of a plug in a cylinder head.

In either case, the plug hole relocation doesn't affect how the engine runs, you can switch back and forth between versions or use either version in either type of engine build, as long as you use a set of matched housings, and not mix one housing with old plug location and one housing with new plug location.

 

Ah, thanks! So I guess doing a na build would buy turbo housing if they were to buy them new.
Not I'm wondering how bad na build would be with 13bt housing and irons but with high computation rotors. Wouldn't that be like a FB 4 port build?

 

Define "how bad an NA build would be".

Cost wise?

Performance wise?

What are you saying?

Rotors now have computational abilities?

 

its probs best put that the US 86-88 turbo and NA engine has the unconventional leading plug position
this position is same as used on the MFR housings but no where else
the leading plug is closer to the centerline of the compression side of the housing

oz/jap and other markets have the odd location ONLY for the 86-88 NA
the non US 86-88 turbo ( n318 ) engine has the same positions as the the s5 and FD

the spark plug position change has minor implication to the timing lead in used , and especially the split

 

Oops I'm using my cell phone. Darn swype! I meant to spell compression.

I heard the fb 4 port irons were some of the best. I forgot, but I heard it was because there is a lot of material that allows for a good amount of porting.
So I'm wondering how a 13bt would do built NA. Comparable to an old 4 port 13b na.

 

Well, the 6 port NA irons suck for porting, there's very little room to port. So you can then use turbo II irons to convert to an NA 4 port setup. They have plenty of room for all the porting that an NA can take advantage of. To be honest I doubt it's worth the extra 2-400 bucks that a clean set of t2 irons go for, plus that much again for a custom 4 port IM to mate to it, to pick up that extra 10-15hp.

 

Still hqve the housing ?

 

Hey guys, I'm rebuilding my S5 13bt and the rotor housings may be bad. I can get a good price on some S4 turbo housings. With the different holes and everything, could I use the S4 houses on my S5 engine and S5 TMIC? Thanks.

Sorry for bringing an old thread back to life and yes I read everything on here, I just want to be safe as I can not risk wasting more money on my rebuild. I already got screwed when I bought the engine online :/ haha

 

the S4 housings have no place to put the knock sensor, and the spark plugs move, so you need to use pairs. (one s4 and one S5 is bad)

 

But could I take the two S4 housings and use them on the rest of my S5 engine?

 

Yes you can. Provided everything is in good shape. I would recommend taking some real nice photos of the insides of your rotor housings and show them to Ben [RotaryEvolution]. He just refinished mine and they look absolutely incredible. I'll post pictures in my thread when I get back to building it.

The way I have understood it, as long as everything is in pairs/sets [ie. rotors, housings, irons, stat gears, counterweight(s)/flywheel], ALMOST everything is interchangeable. More experienced guys will be able to be more specific on this.

 

you can, if you use a pair of S4 housings, you'd also have to move the knock sensor to the front of the center iron where the S4 turbo engine places it.

 

Thank you everyone

 

*** for the rear plates , My S5 t2(not thicker or reenforced) just cracked . Can I replace it with a thicker ans reenforced S5 NA plate ????

 

no..NA plate is 6 port