[Shotimes] Interesting...porting the intake

[Steve Tatro]

You may have just found the secret solution to the 300-hp "stock"
Yamahammer!

I knew those old stories weren't just...well...stories!!!

Let us know how it turns out.  If there's only a few HP to be gained, it
may not be worth the trouble.  If you're right and there is noticeable
low-end increase, we may all be buying new Dremels very soon.

Steve "I don't yet own a Dremel" Tatro 
Red/Black '93 with 169k miles 
Cincinnati, Ohio 



-----Original Message-----
From: shotimes-admin@autox.team.net
[mailto:shotimes-admin@autox.team.net] On Behalf Of Bruce Malachuk
Sent: Tuesday, August 05, 2003 4:27 PM
To: SHOtimes
Subject: [Shotimes] Interesting...porting the intake


Well over the past few days I decided to put my dremel to the test and
port a portion of my intake. Mainly enlarging the TB area for a 69mm TB,
which I got for $40 and it turns out to be an 89 TB so it has a much
lighter return spring than the 94 one that was on my car. So I ground
out the opening and smoothed it's transition, making sure to leave a
slightly rough surface. Then I decided to look at the openings of the
runners with my new felpro set. Well we all know that there are gains to
be had from gasket matching and whatnot, but something I found that was
not expected.

The mating surfaces of the tanks to the long runners are in particular
very very mismatched. If you take a dental mirror and look thru the
front tank when the long runners attached you'll see a 1-2mm lip that is
quite mismatched. I have yet to finish, but I think this mismatch might
be considerably more important to the low end of the engine than even
gasket matching the runner to head interface. I'm just guessing here but
I'm thinking that the lip is causing a 5% or so blockage to the long
runners, and with that creating a ton of turbulence to the low end. I'm
planning on gasket matching an intake entirely other than the runner to
head mating surface, and then leaving one stock and trying to take them
to a dyno day and swapping them. I think the mating surface to the tanks
on the long runners has a ton of potential waiting to be unleashed.

Wanted to see what others had come up with or seen.

Bruce
94 Opal Frost MTX
93 Black ATX - winter beater then parts car :-)
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