H22 JDM 4th gen stainless manifold and downpipe

grant_day · Post by **grant_day** » Mon May 14, 2012 12:12 pm

Now that's what I call learning.

So I have probably got a UK/ JDM spec cat back system, with a Jap spec decat, and only need the Jdm mani and downpipe

Post by **NafemanNathan** » Mon May 14, 2012 12:21 pm

indigolemon wrote:The downpipe/cat combo sets the length. JDM cats are longer and have the temp sensor built in. Quite a few exhaust systems come with an adjustable section to connect to the cat, allowing JDM or UKDM fitment.

The issue with the fanimold is a different one however, as apparently the stud pattern for connecting them to the block can be different between JDM and UKDM H22's. This one I have yet to personally see confirmed though.

Should that first bit be Wiki'd under "UKDM/JDM Exhaust compatibility" then Lemon?

With regards to the mainfold to head bolt pattern malarky, isn't that just bullshit? I've only heard that one very recently, but I thought plenty of the members on here and else where have fitted replacement heads, not necessarily of the same ethnic background but with no issues? I can maybe understand why there's a differnence with the downpipe/cats, but not the head bolt pattern

Post by **indigolemon** » Mon May 14, 2012 12:26 pm

NafemanNathan wrote:With regards to the mainfold to head bolt pattern malarky, isn't that just bullshit? I've only heard that one very recently, but I thought plenty of the members on here and else where have fitted replacement heads, not necessarily of the same ethnic background but with no issues? I can maybe understand why there's a differnence with the downpipe/cats, but not the head bolt pattern

Yeah, I think the same. Merlin has a UKDM H22 in his track lude, with a Fuji manifold bolted to it. Macaroon has a UKDM H22 with a Fuji manifold bolted to it as well. So yeah, personally I think is is likely a load of pap

The other other place that exhausts get a bit strange is the H22A8 in the 99+ 5G's, but Merlin knows more about that than me

Post by **NafemanNathan** » Mon May 14, 2012 12:33 pm

Cool. Maybe between the two of you you could sort out a thread for Wiki-Lude

Just thought it would be useful to have the definitive possiblities written down somewhere. I know Grant's question wasn't directly about this, but it is definitely related and it always crops up

grant_day · Post by **grant_day** » Mon May 14, 2012 12:34 pm

So I can get a uk manifold but would need the jap downpipe? This is confusing as on the downpipe for the jap spec, the bores are further apart. Wouldn't this mean the manifold wouldn't fit properly onto the downpipe?

bristol_bb4 · Post by **bristol_bb4** » Mon May 14, 2012 12:35 pm

Sorry mr lemon but your wrong about the cat lengths :p

Jdm cats are shorter and catback is longer
Ukdm cats are longer and catbacks are shorter

I know from personal experience/ball ache!

All manifold/downpipes are the same up til 98 when the downpipe length was changed

There IS a difference between stud paterns on the ukdm/jdm downpipe/decat but you can overcome it by using skinnier bolts or elongating the holes a tiny bit

Have personally bolted a ukdm and a jdm decat to one of those stainless manifolds so I know it can be done

Post by **NafemanNathan** » Mon May 14, 2012 12:50 pm

And this is where the lid is off the can!

Firstly Ste. Read everything first bud

We're not on about the stud pattern of the downpipe/CAT... We're on about the stud pattern of the exhaust manifold to the head

This supposed "issue" has only popped up recently and I believe it to be a load of nonsense.

I think the man to finally confirm all of this as he has no doubt worked with every possible outcome is Rich. A lot seem to get confused when trying to fit a UKDM cat to a JDM downpipe (or vice versa) and end up blaming the length of the Catback, when it simply isn't down to the catback.

Post by **NafemanNathan** » Mon May 14, 2012 12:52 pm

bristol_bb4 wrote:All manifold/downpipes are the same up til 98 when the downpipe length was changed

This is false

bristol_bb4 wrote:There IS a difference between stud paterns on the ukdm/jdm downpipe/decat but you can overcome it by using skinnier bolts or elongating the holes a tiny bit

This is true

bristol_bb4 wrote:Have personally bolted a ukdm and a jdm decat to one of those stainless manifolds so I know it can be done

This is where you're getting confused

bristol_bb4 · Post by **bristol_bb4** » Mon May 14, 2012 1:05 pm

firstly nafe....

why would they change the stud pattern on the same engine? there is only one option for h22 head --> manifold gasket so that straight away rules that out, plus as said, the ebay mani's are uk fitment....and as ive already said ive fitted one with no problems to my jdm

secondly

post and pre 98 i believe

grant_day · Post by **grant_day** » Mon May 14, 2012 1:10 pm

http://item.mobileweb.ebay.co.uk/viewit ... 0125949719

The.collector needs modifying to fit the JDM ones?