4age heads

[kronix]

i have a 4age 16v jdm motor and was just wondering if there is any difference between the adm and jdm as in flow wise etc

Wade

[sundee]

im guessing u have a RWD Bigport motor? most ADM 16v heads if not all are Small port of FWD engines.... BIg port heads will flow more for the obvious reason.. it has larger ports.. but some guys like to run small port heads if going under say 200hp.. anything over go bigport.. but for turbo charging i dno whats best.. havent gone down that route yet

[Trav_555]

Bigport can flow too much, but remember they have tvis

Bigport ports are too big smallport ports are too small

Bigport is better for turbo because ports are bigger, more air from turbo..

There is no difference between adm bigport and jdm bigport apart from one is rwd and other is fwd

If staying na, and want some good power from your bigport,

Go

Big cams, high compression, remove tvis, get itbs, aftermarket ecu, better internals, and more stuff but i CBF'd writing down

Travis

[Doylie]

On a slightly related note, can someone let me know if bigport and smallport heads both fit onto smallport and bigport blocks?

i.e. can I put a smallport head on a bigport bottom end? and vice versa? And what about big and small heads on GZE blocks? Do both fit? Or neither?

[Trav_555]

All 4a blocks are interchangeable,

Although with 20v some parts need modifications I believe.

So yes you can put a bigport head on a smallport block and vice versa, you can also use a 4afe block, even a 4ac block, but you need to change to 4age internals,

Even 7afe blocks.

And 4agze blocks can also be used.

BUT remember, swapping different heads onto different blocks changes your Compression ratio.

So make sure you look into that before you slap it together.

Hope that helps.

Travis.

[sun_moon]

bigport flows best, but its not all about pure flow, its about velocity and other things..... now where is SAM Q to help with this ??

[Sam-Q]

yeah here, but you should be asking jonny or frak instead of me. Well either way while I am here I migth as well give my 2 cents

as said earlier there is no difference between countries in the heads only in the generation of heads/year of make. All A series heads can be put on any A series block if you use the matching gasket.

so kronix before we say more we need some extra info on what you have planned and what your thinking

[sun_moon]

no point in having massive flow if the airspeed is not up to scratch.... hence the reason TVIS was invented

[Sam-Q]

so true, this is also why modern heads have a fairly small diameter set of ports but have a very high angle so it has both high flow and high airspeed.

[kronix]

thanx for all your replies everyone,

in my car i have a jdm 4age 16v bigport with 40thou oversized pistons, and the other day i went and bought some hks cams(264,256, 8.1 lift) and adjustible cam gears, the cams came with a head but its only a bigport adm head so what i was going to do was port and polish the adm head and set it all up so all i have to do is bolt it on, including running aftermarket computer and bigger injectors etc, but then i was thinking maby i should just port and polish my jdm head as it may flow different or something (thats why i was asking which is better)

and is there an injector other people have used that works really well or are the normal ones good enough?

so yea thats about it, let me know what you think

Wade