SpooledupRacing

Ok I am building a turbo engine.. I planned to go with NEW FD housings.. my question is...

Why would it be worth the extra money to buy FD housings over new S5 T2 OR S4 T2 housings?
I have heard the chrome is better on FD housings but if I am using BRAND NEW housings with S5 T2 rotors etc is there any reason why the S5 or S4 T2 housings wont be just as good..


Can anyone give me a run down of the difference between

FD housings
S4 T2 housings
S5 T2 housings

and why each is better then the other.. I WONT be using a stock manifold or stock turbo if that matters. Premix over omp if that matters, I would like to see 350-400hp if that matters

THX guys!

turbodsm17

the fd housings are a tad thicker.
but with only 400hp, it doesnt matter

SpooledupRacing

ok. I was just trying to figure out if the extra amount of money was better spent elsewhere then in fd over s5 turbo housings.

arghx

iTrader: (3)

some general info:

s4 vs s5 engines: http://fc3spro.com/TECH/FAQ/ZVK/zvk.html

s5 vs s6 engines: http://fc3spro.com/TECH/SWAP/FD3S/BTvsBREW.html

I looked into this. The FD housings have some modifications for improved cooling and I think the chrome might be slightly better than the s5. S5 vs S6 isn't huge difference. S4 vs S5 is definitely different. S5 has better chrome and a different knock sensor location.

SpooledupRacing

ok so S5T deff over S4T and for the price difference I may just use S5t over FD housings..

AlexG13B

iTrader: (7)

go with s5 i think

SpooledupRacing

yeah for the $$ I think I will use S5 T2 housings.

arghx

iTrader: (3)

spark plug location is different between s4 housings and the s5/s6 housings. NEVER mix an s4 housing with an s5 or s6

demontwig

Why is that? Because the fuel would be igniting in different locations?
edit: I just read the links, and it describes a few more reasons why it's not possible.

SpooledupRacing

no I am buying NEW housings... so I am buying 2 BRAND NEW S5 T2 housings

bumpstart

ok, i have all of these housings lying about
and i want to break a myth right here right now

kouki and zenki turbo have the SAME spark location , its only the knock sensor

its the zenki NON TURBO that has the leading spark 5 mm higher towards the centreline



obviously all these housings have similar spark locations, bar the second one

- it has the normal s4 conventions ( exhaust baffle has been removed )
YET it does not have N318 cast onto the housing near the patent font stuff

this tells you it was an NA s4 housing



s4 13B NA, s5 13B T, s4 13B T, left to right




closest is the odd housing, lighting not the best , but spark location change is obvious to naked eye




n318 font tells you it was a turbo -, lack of N318 font or knock sensor = N326/ N327 NA zenki



s4 turbo


s5 turbo, the SAME



s4 NA, ODDDDD

there it is, in pictures, undeniable proof
- not simply repeating verbatim the mistruths through eternity
S4 T and S5 T have the SAME spark locations
the odd man out is the s4 NA
( the NA actually has same spark location as MFR PP housings )


okies ???

FD has a different lube process built into its chrome surface so as to need less OMP
( methinks it was teflon changed to carbon graphite coat )
it also has a relief around the spark plugs for better water cooling

but , in a rebuild extendy with all its compromises , meh differences

arghx

iTrader: (3)

I guess you learn something new every day. But what about s5 vs s6?

bumpstart

the missing s4 turbo housing pic
( the image shack logo **** cut off my limit )



s5 turbo, the SAME



s4 NA, ODDDDD

----------------------------------

AFAIK the s5T and s6 have same spark locations
the only advantage is the change in coating and spark plug cooling

go with the best deal if expecting sub 400 hp

HAI-TEK7

iTrader: (31)

I'm goin to have to argue with bumpstart. A few years ago I did build an engine (for my FD)with S4T and S6 housings. It ran fine, but I had an dowel o-ring leak. When I pulled the block I did notice that the plug holes were at different locations. So in my experience my S4T housing was different than the S6.


I found my old thread from '05...haha
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/s4-rotor-housings-diff-s5-s6-438129/

joeylyrech

iTrader: (11)

I have 2 S4 Turbo Housings on my motor(FD irons with S4 turbo housings) and the spark plugs are in the same spot as the weird NA housing on your picture(they are off a JDM motor)and i have another set of NA housings(same casting as the turbo ones)and again they dont match the S5,i guess that it depends on what casting mold they use to build the housings.

bumpstart

are you 100% they where turbo housings?
i know at least one large US supplier who has the part numbers **** about for S5/ S4
N318= s4 turbo
N370= s5 turbo
N326/7 = s4 NA ( odd numbers = auto )
N350= s5 NA

this is what the factory used to delineate


how can you argue with a housing with a cast N318 number ( it is s4T look it up )
measured alongside a housing obviously s5 housing with verniers ?

PS, i have more than 10 housings here
3 of which have no casting number, and no knock sensor
all three have the higher location

every other housing, lined up on a flat bench = same
half of which have no knock sensor hole , of those ALL have the N318 casting




show me this marking - N318
then show me the vernier measurement
then we are talking APPLES and APPLES

N318 = EXACTLY the same positions as the s5 housing
i have pics, and vernier, have you???

nitronatefc

iTrader: (2)

I don't see what you are trying to argue, since bumpstart made no claims and gave no data about S6 housings.

Great post bumpstart. This info will probably be surprising even some veterans around here. Every old post I have on read on this subject says S4t and S5t were dif. Thanks for the pics

HAI-TEK7

iTrader: (31)

S6 same as S5(spark hole location). I'm saying that S4T housing are not the same.

I have a dozen housings and none of them have a cast N3XX number on it.

i got some pics: S5 NA on left, S4T on right

Banzai-Racing

iTrader: (11)

The "318" housings are a transitionary housing, we have a few of them and the spark plug holes are in the same location as the S5 & S6. We also have some S5 N/A housings that do not have the knock sensor bung, but the plug holes are at the proper height, another transitionary part. These happen to be the exceptions to the rule.

As a standard the S4 TII and N/A have the same spark plug location which is higher than the S5 & S6. It is always a good idea to double check what you have when you start mixing and matching.

We put together a quick identification guide so that people could ID their housings. This covers the majority of housings, but as mentioned above there are always exceptions to every rule. http://www.banzai-racing.com/faq_housings_ID.htm

tegheim

I have some trouble making sense.
I have a pair of housings from a Rx7 -87 N/A-6-port. There are no knocksensor, and the waterjacket are plugged. BUT, the sparkplugs are at 137mm, and 190mm from the base.
According to the info above, they should be higher sparkplugs?
My S4 Turbo-house has 142/190mm, and my other S5 Turbo had 137/190mm??
This is my measurements.



S4 N/A:

Leading: 137mm

Trailing: 190mm

S4 Turbo:

Leading: 142mm

Trailing: 190mm

S5 Turbo:

Leading: 137mm

Trailing: 190mm

RotaryEvolution

iTrader: (30)

FD housings have the best chrome plating, worth the extra few bucks if you're buying new versus any other series.

just don't mix up series of housings and all the BS above is not an issue.

tegheim

I fill in some info on my own.

FD Housing

Leading : 137mm
Trailing: 190mm

How does we explain this along with this picture?

bumpstart

its saying same as i have .. all along,, the NA housing has leading plug higher on the block
(--note its comparing the 85 engine ( NA ) to the 86 engine
( incidently also NA in all but a very few LHD markets in 86 ,, note its definately not referring to it as a turbo 2 housing )

in the US.. for some reason the N332 turbo s4 housing has same change in location,, ...

in the rest of the world :: s4t reverts that leading plug back lower with the n318 housing with that number cast on housing top

after that.. all markets same--
s5 NA.. and s5T and FD all use the same positions as this n318 housing ( oz and jap 86 turbo2 housing )

tegheim

This is pics from today. The odd one is the S4T that have higher Leading, the other two are the same.
These cars are EU-spec.

bumpstart

well.. looks like the s4t housing you have is the n332 type... else the n318 one is bossed such near the oil injector
but what is unusual here is you are displaying a totally new type of s4 NA housing

baffle and blocked water crossover all confirm NA.. lack of knock sensor confirms s4 type.. but the patent boss writing looks different and that plug is back into the s5 position

.. i know euro NA FCs are very backward compared to oz, jap and US ones,, retaining a dizzy and simpler aux mechanisms .. am wondering if the s5 there is also a little backwards and thus is more oz/jap s4 spec in comparison