V-6 intake modifications

[Tim_K]

I got a 1989 intake manifold assembly out of a 224,000 mile minivan. I plan to port the upper part of the intake (that the throttle body bolts to).

I've seen the sites that show to cut the center divider out completely, and I'll do that. But inside the intake top, it has cast in lines or bumps that go in different directions.

Should I smooth those down some also? I wonder how much effect they have on anything. They had to be put there for a reason. I'm using a 52mm throttle body with it also.

Also, using the intake upper half to lower half gaskets as a pattern, I was thinking of getting 2 spacers cut out of 1/2" plywood. I know plywood has been used as a spacer on 1960's / 1970's V-8's to keep heat away, and I've read how these spacers help the airflow turn in the V-6 intake.

Ideas, thoughts, comments?

[mwinkle353]

Smooth the entire thing down. Then port the holes up to the gasket ports. Then put some JB Weld on the underside of the areas before the lower ports. Then radius them into the ports. That's basically what I did. And I noticed great gains above 5k rpms


Wink

[Ondonti]

just remove all that crap. also try to radius all the square edges around each port. I feel my intake porting was probably my biggest gain and is the difference between 150-160whp 3.0's and 180-190 whp 3.0s like mine and Joshes (his high compression motor making more power and also a lighter car).

Its no wonder that the Australian guys have gains 30WHP!!!!!!! by building a stock manifold. Our head may flow like crap, but if you put a good intake on then the heads can actually flow to their crappy potencial, rather then being hampered even more.

[93sundance]

I am working on porting my plenum even better. Stay tuned for results using the Diamante cams.

_____________

Josh

93 Sundance Duster: 3.0L A543 - 14.345 @ 93.77
95 Spirit: 3.0L A670
90 Shelby Daytona: 2.2 VNT A568

[Boogieman142]

ok, so what effect does removing the center divider and taking out the swirls make, i just took mine off and smoothed the corners out a bit.

[93sundance]

Quote:

Originally Posted by Boogieman142 ok, so what effect does removing the center divider and taking out the swirls make, i just took mine off and smoothed the corners out a bit.

More top end power

[irocelectric93]

oh yeah after 3 grand...you notice a good amount of kick that wasnt there before...at least i did with my plenum ported and a 55mm throttle body

[93sundance]

Quote:

Originally Posted by irocelectric93 oh yeah after 3 grand...you notice a good amount of kick that wasnt there before...at least i did with my plenum ported and a 55mm throttle body

55mm TB?

[Boogieman142]

yeah, i was told that porting it losses a bunch of top end so i just smoothed out some corners to keep my bottom end.

[irocelectric93]

I have a 55mm or at least thats what i was told from the guy who i bought it from...its pretty big compared to stock. Oh and uhh you gain top end...not lose it.

[Harvii]

just ditch the upper plenum and buy/complete this setup =)



Harv

[93sundance]

did u get that working yet?

[mwinkle353]

Quote:

Originally Posted by Boogieman142 ok, so what effect does removing the center divider and taking out the swirls make, i just took mine off and smoothed the corners out a bit.

Hella more top end power. But you do loose a little bit of low end grunt in the process. But the high end overshadows the losses.


Wink

[Tim_K]

Who has used those 1/2" thick spacers between the upper and lower halves of the intake? Did they make any noticeable gains?

[Jetson8294]

The porting and smoothing may be my next project... could anyone tell me how long this will take?