[Shotimes] Interesting...porting the intake

[Paul Nimz]

How about 20-25% bigger valve area?  What would this do?

Paul Nimz
'97 TR
'93 EG mtx


----- Original Message ----- 
From: "Mark Nunnally" <manunnal@netheaven.com>
To: <shotimes@autox.team.net>
Sent: Tuesday, August 05, 2003 6:14 AM
Subject: Re: [Shotimes] Interesting...porting the intake


> The more I read, and talk to folks a lot smarter than me, and tinker with
> these things, it's more apparent in an n/a motor, the cams/intake runners
> are a paired team.  Basically the stock SHO runners are designed (through
> shape/size/length) to create the best resonance (ram air effect) where the
> stock cams want to make the most torque.  When you shorten the length of
the
> runner, or enlarge the ID, you are changing the resonance rpm tune on that
> runner.  You'd be moving it up higher in the rpm range.  I also think the
> shape of the runner is important as well.
>
> I think EH is probably the best (yeah it's $$$) method to "cleaning up"
the
> runners.  What I would be interested in is having somebody measure up some
> EH runners and figure up the math to determine what rpm resonance that
they
> are "tuned" for.  Then build a cam profile to suit.  And of course
> gasket/port match the runners to the heads.
>
> One of these days I'll get around to port matching the intake/head runners
> on the 3.2L (mine have a terrible mis-match, one of the worst I've ever
> seen).  I borrowed an EH intake once and lost significant low end torque
> (above 3k it would regain itself).  Never ran it at the track to see what
> top end gains might have been there, but it seemed to pull hard.
>
> Realize going much higher hp that what you can get out of a BOS 3.2L is
> probably going to be maxing out the stock injectors.  I'm getting 90% duty
> cycle on my stockers on my 3.2L now (at 216 FWHP).  If you are shooting
for
> 300 hp some 30 or 36 lb'ers probably would be needed.
>
> I think for open track work the stock cams/runners do pretty decent, as
they
> make a lot of torque over a broad range of rpm.  Personally I'd rather
build
> power through more cubes (3.4L anyone? <g>) and compression.  Ie, things
> that will pick up the whole torque curve, and not just from 6000 rpm on.
>
> I think if you EH'd a set of runners, had a cam profile built to match, on
a
> John H. type 3.4L stroker motor using about 10.75:1 (or 11:1) compression
> (running on 94 pump gas) with a little more injector, I think you could
make
> an honest 300 hp with a GOOD torque curve.  Hmm, sounds like what I want
to
> build for the track 89 :)
>
> mark
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