Injector housing pull; Porting

[LGAFF]

Pulled the injector housing on the passenger side as I will be finishing the plenum soon and going to port match to the IH.

I noticed that the secondary TB are 37mm in the head(stock), while the primary ports are 33mm. The IH itself follows suit with the IH to head ports on the secondaries running 37mm, while the IH port that mates to the plenum is only 35mm. Head ports on primaries are also 33mm.

It seems for the poor mans port job, you might be able to focus on opening up the secondaries only to 37mm all the way through and get a pretty good bang for your buck. This way you wouldn't have to worry about the port match to the head. With the small primary ports in the head, and the limited room I wonder if you get much return as it has to neck down pretty good at some point, although I assume that you might gain some velocity going from 36-37mm as it necks down to 33 in the head.

Just a few thoughts, might generate some conversation. I'm not a professional porter, I just play one on the Registry Forum.

LGAFF
92 ZR1
#234

PS: I am surprised at the smooth finish I got from hand sanding with 100 grit and then 400 grit in the plenum runners, its pretty darn close to the extrude hone finish it had before.

[Pete]

Lee, port the primary IH port to 36mm then match port the primary head port about an 1-2"s into the primary head port for now till you port your heads.

Pete

[XfireZ51]

Pete,

The secondary head ports are 37mm stock from the factory? Does that mean there's no need to match secondary head port with the secondary port on the IH assuming you've ported all IH ports to say 36-36.5mm?

[lbszr]

Sounds like we're at the same porting steps, about two hours into the IH , not much. From what I've seen so far it might be hard to get 37 mm all the way through primary unless you have some ultrasound thickness gauger or a welder ready since the breather and coolant section are nearby, I was starting to shake while grinding, had to go get a beer and ready to go again.:cheers:

[Pete]

Dom,yes you can,you can make the primary 37mm at the buttom of the port to match the secondary port where they meet the head.


lbszr1 take your time with them.
The way i do it i go with a 35mm ball first and then slowly work with the 36mm ball,just make sure you work the IH's evenly all the way around,i'm sure you already knew that, just a reminder:thumbsup:
Don't worry if you go thru there are plenty of welders in America,if you don't know any welders let me know just in case you have an accident.

Pete

Sorry Lee, if i hijacked your thread,all this talk about porting gets me excited :-)

[LGAFF]

Thanks for the feedback Pete, learning alot as I move through the process.


LGAFF
92 ZR1
#234

[Locobob]

Keep in mind that the secondary ports at the top of the heads / bottom of the injector housings are oversized to make up for the butterfly valves intrusion - you won't actually get 37mm of air flow at this location. I gradually taper the primary ports from 36mm at the top of the injector housings down to near stock size at the head surface - unless of course the heads are ported.

[XfireZ51]

Dom,yes you can,you can make the primary 37mm at the buttom of the port to match the secondary port where they meet the head.

Pete,

I think you meant I should "match port' the secondary IH port with the secondary head port to 37mm, am I correct?

[HADI-ZR1]

Robert,
Do you need to oversize the butterfly too?

[bradslt5]

hadi, i think he is removing the secondary butterflies from the head

[Locobob]

Robert,
Do you need to oversize the butterfly too?

That could be done but it would be a lot of work and expense. If the car is modded to the point of needing that much air flow I would say just ditch the secondary system altogether.

[cuisinartvette]

I too had wondered about keeping the secondaries intact and m,aking larger butterflies. Would the larger size function the same with the actuators, would the size have any effect on how far they opened meaning strong enough??

Kind of a splitting hairs type question but Id like to see portwork and everythign work the way it should.