[Shotimes] Gasket Matching on the Intake

Thu, 13 Feb 2003 01:11:53 -0600

Bruce,

If you are using a Dremel, you will be married with a baby girl and a 6 year
old boy by the time you finish the FIRST intake. : )

I "attempted" to carve some bigger chunks of aluminum off of the trusty ol'
Vulcan intake with my Dremel.  About 20 minutes into it, I realised that it
wasn't going to happen.

Get a cheapo corded drill and a porting kit.  Jared (TCCA) has one he was
going to sell me, but I was impatient and I did the job with other tools.

Good luck sir!

Mike Kopstain
Midwest SHO Specialists
827 North Chestnut Avenue
Arlington Heights, IL 60004
www.MidwestSHO.com
Sales@midwestsho.com
----- Original Message -----
From: "Bruce Malachuk" <bmalach1@nycap.rr.com>
To: "Kurt M" <kmetros@elkhart.net>; <TechSHO@topica.com>; "'shotimes'"
<shotimes@autox.team.net>
Sent: Wednesday, February 12, 2003 9:46 PM
Subject: Re: [Shotimes] Gasket Matching on the Intake

> I'm just about to undertake my gasket matching and cleanup of the runners
> and head. I'm just getting the final parts I need for my dremel to do what
I
> want to do. I only plan to gasket match the heads and the ends of the
> runners, and if I can get up inside the long runners I will clean up any
> casting flash that I can get to with my dremel and/or sandpapers of
varying
> degrees. From everything I've been reading on the subject there is truth
in
> that porting without a flowbench or without having enough experience can
> lead to a los of power specifically because of lost velocity. other than
the
> gasket matching I don't believe I will do any enlarging to the upper part
of
> the heads or valves area. I would think that Yamaha designed this area the
> way it is based on gettin air supplied from intake matching the heads. I
> don't believe that tapering out the long runners and not being able to get
> to the middle would have much if any effect of losing HP or velocity. As
the
> air passes each of the bends the air on the inner radius of the bend moved
> faster than on the outer because of the extra distance it has to travel.
> Thats kinda why I think the long runners start straight from the tanks,
then
> go up, then curve down to make the straight shot into the heads where it
> then looks like the air is directed towards the injector. It's kinda like
> the long runners bends are "tuned" so that the air should be moving about
> the same speed as it makes it's last shot into the heads. By gasket
matching
> and tapering it out a little on the straight shot all we are doing is
> reducing the resistance in the airflow path. Making the engine breath
> easier, but not giving it more to breath in reality. Thats what the short
> runners are for.
>
> Now on the short runners I do plan to open them up to the size of the
gasket
> the whole way that I can. But again I won't be porting the head to
increase
> volume of air in the chamber before the cylinder. Just smoothing out the
> airflow restrictions. I won't even polish the upper parts of teh heads
cause
> the slight roughness induces a bit of turbulence to help mix the fuel and
> air more so than just an injector would do if spraying into a smooth
channel
> of air. I've already talked to a machine shop here locally about boring
out
> my secondaries to a specific size, and the price with new plates
> (butterflies) is very very reasonable. Just from staring at my spare
intake
> I have here, I'm sure that I can very easily duplicate what EH would do on
> the short runners. And if I really wanted to spend a long time with
> sandpaper on a stick, and possibly a mushroom shaped small polishing
bonnet
> with some aggressive grit material I could prolly come close to the EH
> results on my long runners as well. I also think that a posible change to
> the horns on the secondaries might help bump up the velocity that is lost
> via the enlarging the runners.
>
> All it seems that gasket matching, polishing and some porting takes, is a
> basic understanding of how air flows under a vaccum. And how to not
interfer
> with how it flows, just remove the restrictions. Once you start to
increase
> volume and what not then you run into tuning issues. I just can't wait
till
> I can get a little JB weld and a spare set of heads to try velocity
porting
> the final run past the valves into the combustion chamber. Mmmm that and
> some higher lift cams might be interesting.
>
> If anyone finds any good places for bits that can be used in a dremel for
> decent prices, cause I have 2 intakes to do, so I figure I'm gonna uese a
> few bits up.
>
> Bruce
> 94 Opal Frost MTX
> ----- Original Message -----
> From: "Kurt M" <kmetros@elkhart.net>
> To: <TechSHO@topica.com>; "'shotimes'" <shotimes@autox.team.net>
> Sent: Monday, February 10, 2003 6:15 AM
> Subject: [Shotimes] Gasket Matching on the Intake
>
>
> > A couple of years ago when I had my SHO apart for it's second 60K I
> > ported out the leading end of the intake runners to match the gaskets
> > between them and the butterflies.  When I was done, the opening was as
> > large as the gasket and was tapered about 1.5" into the snakes, after
> > which the went to their normal size.  I also opened the holes in the
> > surge tanks to match the gaskets.
> >
> > At that time I didn't mess with the openings between the snakes and the
> > heads.  This year, while it's apart, I am considering using a dremel to
> > port out the intake runners to match them to the size of the intake to
> > head gasket.  I am also willing to port out the heads to match these
> > gaskets.  Until yesterday, I wasn't willing to do this, but now that I
> > have the intake off and have looked at it more closely, I have a better
> > idea of how people are doing this with the heads still on the car and am
> > willing to try it out.
> >
> > In reading about porting on the web, a couple of things came up that
> > cause me to question  whether or not this would be a good or bad thing
> > to do to my intake and heads.  My main concern seems to be that of
> > velocity.  Let's say the intake opening throughout the snake is 'x'
> > (where x is some volume of air, or some unit of measurement with regards
> > to the size of the opening) until 3" before the air hits the valves,
> > then for the last 3" (the area I port out on the snakes and head) the
> > volume becomes 'y' (some measurement slightly larger than x), will there
> > be enough loss of air velocity in the last 3" due to the larger chamber
> > size to cause a negative effect?
> >
> > I'm wondering if this mod shouldn't only be done on an extrude honed
> > intake, where the size of the intake snakes are the same from the surge
> > tanks all the way through to the heads, where the size isn't going from
> > smaller to larger?
> >
> > Am I on the right track?  BTW, here's an excellent article I found on
> > porting....
> >
> > http://www.sa-motorsports.com/portdiy/diyport.pdf
> >
> > Input appreciated.....
> >
> > Kurt
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