Mark Steitle wrote:
I've Attached two pictures of one exhaust port (inside and out)
from my
20B. While looking it over yesterday, I noticed a small (approx.
1/8")
slot along the top of the port. It has a diverter running
lengthwise that
forms the lower lip of the slot. The slot feeds the EGR system. My
question is what, if anything, should/could be done with this to
improve
power? It looks nothing like the exhaust port insert in my old
(junker)
'89 N/A 13B.
The second picture shows the outside view of the exhaust port,
which is a
rather odd shape. The insert has a passage inside so as to
prevent taking
a die grinder and rounding the port. Is there an improvement
waiting to
spring forth here, or should I just leave well enough alone? Does
someone
sell a replacement insert that will give me lots of free hp? ;-)
Mark S.
We usually block off the EGR elsewhere so the whole EGR system will
pressurize and
there will be little or no net flow. Now in theory it could act as a
helmholzt(s?) resonator
and affect the pressure pulse in the exhaust port but I do not know if
anything
bad is going on becasue of this.
Paul Lamar
I had figured I could block it off by tapping the EGR hole between the EGR
passage and the exhaust port and putting a plug in the hole, or maybe weld
up the slit in the exhaust insert. Also, what, if anything, should I do
with the 1/8" slit in the exhaust port insert... grind it down... weld it
shut... replace it with a different one? It appears to be blocking about a
third of the passage. Does anyone know what type of material the exhaust
port inserts are made from? Possibly inconnel or 321SS?
Mark S.
No attachment came across Mark.
I think the EGR comes out of a port in one of the intermediate housings.
I know this is the case with the 13B non turbo. Picture below. That is an
easy place
to block it off as all you need do is cut out a plate and bolt it down.
On the turbo version of the 13B center housing this port is missing.
the EGR valve is mounted someplace else.
At least on the 1988 turbo engine I have. Is it missing on the top of the
center housing on a 20B?
Those port inserts are tough but I don't know what material
they are made from. Could be Inconel or stainless.
They are also tough to get out of there. If you can avoid
messing with them.... by all means avoid it :)
Paul Lamar
I have an old '89 N/A 13B "junker" with this EGR access hole on the middle
side housing. The 20B doesn't have one there. I think the EGR comes out
below the intake ports. (see pic ...1017.jpg) I thought the objective was
to eliminate the EGR chamber. By capping the exit, you still have the
chamber connected to the exhaust port. (Is this good or bad?) My housing
has a small hole near the exhaust insert lip that I had planned on
plugging, eliminating the EGR chamber altogether. But if I welded up the
inlet "lip" that would do it too, except that it would still leave the port
partially blocked. So, I guess I will just accept the blockage as a given
and move on.
Mark S.
The jury is still out on whether the blocked off chamber is good bad or does
or does not make a difference. Perhaps the car racers know.
Those ports below the intake ports could be the EGR/manifold-heat outlet
ports.
Blocking them might block off the EGR.
BTW I like your motor mount idea what I can see of it.
Those inserts are different than both the 3rd gen. and the 2nd gen. 13B
I think. Looks like they are trying to keep the exhaust gas velocity up for
the turbo.
I can see why you are thinking of getting them out of there and welding
up the slot. Not easy.
Paul Lamar
I had the same inserts on my Cosmo 13-B. I managed to pull them out and
replaced them with full port inserts. They are a bitch to take out. You must
drill out the two roll pins with progressively larger drill bits, starting
with the smallest. You will waste many drill bits.
Than find two junk housings from late model motor and pull the inserts.
Do it by cutting around with band saw, etc. so you can save the roll pins.
They are odd size and hardened. Good Luck!
Bulent
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