What's the diff between the ff IMs:?

DocHudson · 07-03-2009, 04:29 AM

Fellas i really need to know the difference between the Z6 (P32), A6 (P08), and JDM D15B VTEC (P08) intake manifolds.

Those are the cast codes i see at the back of each - with some JDM ZC VTEC / JDM D16A having either P32 or P08 stamps.

It's been bugging me that they all look the same.

I think Bone had something about this somewhere but I might as well get stubborn and ask around here.

The A6 IMs we have here have those PGM-FI sign plate on top of their plenum but.. that's about it! Remove that sign plate and it looks so much the same as the JDM D15B ones aside from having a similar P08 cast code.

I'd like to believe they are all the same in terms of plenum volume, runner length and ID, flange port to head port alignment if used on other heads, etc (which is what I'm interested in knowing, actually) but,, anybody?

The_Beave · 07-03-2009, 10:13 AM

The A6 manifolds have a very long runners, very small plenum, and does not allow for mounting most larger TBs.

The Z6 manifold has a larger plenum, shorter, wider runners, a more "standard" TB setup, and internally is really good entrances to the ports as cast, though I haven't seen the inside of an A6 to compare.

I don't know about the P08 manifolds.

glenniz · 07-03-2009, 01:03 PM

One other thing about the Z6 IM. The runners maintain a consistent shape along their entire length, from the plenum to the head. Most of the other IM's will start round become flattened/oval and then round again.

Bone pointed this out a few years back.

K2e2vin · 07-03-2009, 01:30 PM

I could pull my D15B manifold and check but I don't have a manifold to compare it with; although I'm willing to bet it'll be similar to the Z6 intake manifold.

rushi · 07-03-2009, 04:03 PM

AFAIK D15B and Z6 IMs are very same casting. There might be some difference like mounting points/holes for purge solenoid.

A6 IM has OBD0 TB bolt pattern like Beave said. IIRC I measured the A6 runners being like 1/2" longer than Z6, and few millimeters smaller in diameter. I also remember that the plenum volumes were very same.

There is also differences between different year A6 IMs. Some have purge solenoid, some have just a nipple for the hose. It might be needless to say, but I say it anyway that also D15B7 IM is very different from A6 IM. Much smaller runners, and I think OBD1 TB flange.

Doc, nice to see you online for a long time

fireant · 07-03-2009, 07:19 PM

When I checked out my A6 IM vs Z6 IM, the plenum on the A6 had more of a flat back side, making it more like a D shape than the O-shaped Z6 plenum.

WhiteEgg · 07-03-2009, 10:42 PM

So which is it? Is the plenum the same size as Z6 like Rushi says, or "very small" like Beave says?

DocHudson · 07-04-2009, 12:44 AM

Reason for me asking is that I just picked up a (long neck) B20 IM yesterday.
It's got a huge plenum and a lot of meat on the walls.

I'm trying to see the diff between all those IMs I mentioned coz right now I'm trying to decide which of them will I choose for the B-to-D hybrid.

I'm dead set on the B20 plenum, the only thing left is the right info for proper runner choice.

Beave mentioned longer runner lengths with the A6. That seems like very good news to me (extra long runner with big plenum combo). Comments?

Glenniz mentioned other IMs (except Z6) has round-to-oval-to-round runner ID pattern.. Is the A6 one of them? Does this induce some sort of venturi effect on each runners' flow leading to the intake port? Seems like good news again?

I'm about to lay an egg thinkin about this thing but..I'll leave it to you guys to make the best educated guess.

As of now I only have 2 choices - either the P08 which came from the JDM D15B (and also which I am currently using) OR the P08 which came from the A6 with a steel sign plate PGM-Fi logo (i can almost get for free).

Btw, can anyone verify for me if your (USDM) A6 IM indeed is a P08 stamp with the same PGM-Fi logo plate like I've been trying to describe?

Hey Rushi! I still owe you something.. i promise it will get to you somehow.

DocHudson · 07-04-2009, 01:22 AM

Oops, i just googled (and got owned) and it looks like the USDM A6 IM is actually not the same as the A6-counterparts we have here.

http://www.hondamarketplace.com/show....php?t=2455738

It's just so different than what we have around.

Our version of the D16A6 already sports the P08 IMs which is internally the same with the JDM D15B IM ---- a P08. Except for a funky PGM-Fi badge on the plenum top.

Ok so i guess I only have one choice after all. The good ol' P08! LOL
-->this one which is exactly what i'm using: http://is.rely.net/1-2664-42091-l-hT...qwAuHgOT3g.jpg

Now, I can't run after a Z6 P32 IM anymore as they are rare here - duh!
But if they have shorter runners than a P08, then the more I'm not interested.

ps: I believe the USDM A6 IM should bear either a P27 or a P29 stamp at the back.

glenniz · 07-04-2009, 08:48 AM

All I can say Doc, is that when I switched out my D15B7 IM for the Z6 IM there was a HUGE difference in my low end response!! It was very, very noticeable!

I will soon be swapping the current Z6 IM for a ported Z6 IM.....I hope I see as much of a difference as I did with the previous swap.