Resolved port-matching idea for 1g mani on 2g head

[Lawn_ornament]

I know the question of 1g vs. 2g intake manifolds on 2g heads has been beaten to death and more or less resolved already. From what I've read, the general consensus is that if you try to port-match your 2g head with the 1g intake mani, even if you get the ports matched correctly, air flow suffers greatly and you can lose power as a result.

My question is this: what would result from meeting halfway? What if you fill and taper the 1g ports halfway to spec and make up the difference by mildly opening up the ports on the head?

When you open up a 2g head to match the 1g mani, does the power loss result from the change in angle of the airflow due to the hackjob? How do you think filling in the intake mani ports a bit would affect the airflow once it enters the 2g head?

Is the 2g head designed for max airflow velocity rather than volume? Am I getting confused here and assuming the two (velocity vs volume) are not the same?

I'm looking for some people who know a little bit about airflow and the designs of the 2g head and 1g intake mani to chime in here and straighten me out.

Nobody has any input?

 

[Lawn_ornament]

Another question: does the 2g head even have enough material to port-match it to the 1g intake mani without opening up coolant passages or irrevocably weakening the head itself?

 

[pboglio]

I don't understand the fascination with a 1g intake manifold. Do not waste your time. Pick up a used EVO3 intake manifold that'll fit the 2g like a glove, and kick the living crap out of it on the topend. If I HAD to have a 1g intake manifold, using a phenolic spacer or two or three stacked and ported would be the only way I would attempt what your trying, plus the benefits of having heat blocking.

 

[JEFFREYCASTGSX]

The 2g head is designed for max velocity and therefore flows more, size isn't what matters most. Design, angle of entry, etc. does matter. The heads on older Evos have even smaller ports. But that doesn't matter here, for whatever reason your trying to fit a restricitive 1g intake mani in place of the restrictive 2g mani, there is better. How much time (and maybe money) would it take for you to successfully match the mani with the head? The ports will all have to be the same size, and cc, the curve/angle will also have to be similiar. In my opinion a Evo3 intake mani would be the way to go.

 

[Lawn_ornament]

The ports will all have to be the same size, and cc, the curve/angle will also have to be similiar. In my opinion a EVO3 intake mani would be the way to go.

CC? Meaning what?

Also, what is a phenolic spacer? EDIT: found it. Will do more research on this.

 

[Lawn_ornament]

Somebody please explain to me what will go wrong with this:

Take a 1g intake mani. Put a solid spacer (aluminum?) between that mani and the 2g head. Carve out tapered passages in the spacer to transition from the larger intake mani ports to the smaller head ports.

Worse comes to worse, I'm out an intake spacer. No modifications to the mani or the head.


I must be missing something if nobody has ever tried doing this to put a cyclone intake on a 2g head...

edit: looks like pboglio suggested something identical to this: http://www.dsmtuners.com/forums/new...ni-stock-2g-head-will-work.html#post151819425
Either way, my question remains.

 

[JEFFREYCASTGSX]

If i read post your correctly your saying that you have a spacer that will go in between the two. IF and only IF, the transition is perfectly smooth about the only thing your gonna do is put a LONGER runner intake manifold on it, but you will hurt airflow in the sense of the differences in size and that transition will have rapid changes hurting velocity and maybe cause turbulence.

Just know that you WILL lose top-end and gain low-end.

 

[Lawn_ornament]

The car isn't going to the track/strip so I'm not interested in top-end. Low-end sounds nice but mostly I want to slap this intake on and see what kind of a difference it makes compared to the stock 2g intake mani. My priority is finding a way to do this that circumvents head porting or manifold work.

 

[pboglio]

With an aluminum plate, something like .250 thk, it sounds doable. A 1g intake manifold, complete waste of time. A cyclone manifold might be worth it if maximum low end torque where the goal. Either phenolic or aluminum would be the way I'd go.

 

[Lawn_ornament]

With an aluminum plate, something like .250 thk, it sounds doable. A 1g intake manifold, complete waste of time. A cyclone manifold might be worth it if maximum low end torque where the goal. Either phenolic or aluminum would be the way I'd go.

.250 as in .250" ? I was thinking thicker = better since it would afford a more gradual transition between mani and head. Is there some limiting factor for thickness besides firewall clearance?

And yes, it is a cyclone intake. Otherwise I wouldn't bother with all this.

 

[pboglio]

Now that I recall, I think it came down to the outer studs running out of thread engagement length on the cylinder head/intake manifold. You'd have to back out those lower outer intake manifolds threaded studs and put new longer ones in, depending on your spacer thickness. To be honest there may be room to add more spacer thickness, but it will start getting extremely tight in there.

You plan on hand fabricating this or sending it out for CNC'ing?

 

[Lawn_ornament]

Now that I recall, I think it came down to the outer studs running out of thread engagement length on the cylinder head/intake manifold. You'd have to back out those lower outer intake manifolds threaded studs and put new longer ones in, depending on your spacer thickness. To be honest there may be room to add more spacer thickness, but it will start getting extremely tight in there.

You plan on hand fabricating this or sending it out for CNC'ing?

Didn't know the intake manifold has studs, thought they all were bolted to the head? Or are you referring to something else?

I won't pretend to be an expert here. Just trying to get some ideas straightened out before I start pulling things apart. But I was working under the assumption that the intake manifold utilized bolts to attach to the head, and that in the case of a spacer, I could install longer bolts to accommodate the spacer. Is this not the case?

I'll have to pay somebody else to fab up the spacer for me. I don't know enough about using a Bridgeport to use it myself w/o worrying about screwing up 3 or 4 spacers first.

 

[pboglio]

There are two studs on the lower outer points, then bolts everywhere else. Otherwise it would be difficult to mount the intake manifold without studs in place to hang it.

I have a CNC mill in my garage actually. I'm about 1-2 months out from cutting metal with it as the tooling package, flood cooling system, and 4th axis rotary table haven't come in yet. Phenolic spacers are what I will probably start running and will be cake for this machine.

 

[Lawn_ornament]

So I'll need to extract the studs and replace them with longer ones, as well as longer bolts. When going with a longer bolt/stud, is there any adjustment to torque spec required, or should I go with the factory specs for the intake manifold?