leanest cylinder
- Thread starter thekidz
- Start date
David Neibert
SCCoA Admin
IMO it's #3 (passenger side closest to firewall).
David
David
Scott Long
Registered User
I would think that #3 would run the richest since the air technically flows past it and doesn't flow into it well, yet the injector will always spray fuel directly into the port.
TbirdSCFan
Registered User
Don't know if its related, but #5 on mine had the greatest amount of carbon build up. #3 was next.Kurt K said:
Randy N Connie
Registered User
I just checked my plugs.And they all look perfect after installing
my latest modified and ported manifold.
Randy
my latest modified and ported manifold.
Randy
Randy N Connie
Registered User
BKB said:
If your blind.Or just don't know what to look for.
Randy
Ok so as it stands 1 for number 3, 2 for number 5. The reason I was asking this is I am going to install an egt sensor in the exhaust manifold and would like to put it closest to the leanest cylinder. I know it is not the most accurate way to go but I figure if the leanest one is ok then the others must be ok to. Some more opinions would be appreciated.
Thanx
Craig
p.s. Randy you still selling intake manifolds
Thanx
Craig
p.s. Randy you still selling intake manifolds
Randy N Connie
Registered User
Craig Yes I am still doing manifold plenum mods.
But I am booked until next summer june 2006.
Others are doing this mod.But they are not
doing any balance flow testing that I have ever
read about for the manifold.And I have read of
no change of shape inside of the plenum to
promote better flow.Or testing on it.So I am
positive that they are selling parts that may
lean some cylinders out to much for my tastes.
I am only talking about manifold & plenum mods
that are with-in the stock looking design.
Some say they are doing what Chris Wise has done.
But After talking to Chris ,and looking at his parts.
And getting his permission to do a wider plenum.
He has never done the mods that they are doing.
(EXAMPLE T-BIRD 88)They are doing my mod that
was started with Mike 38 & me.This is the plenum
with the stock IC mounting flange.Chris Wise never
made a plenum like this.His had a tube welded to the
plenum.He made the manifold plenum mounting
entrance larger,But he move it forward ,to promote
flow to the number 3 & #6 port.Mine was move
back and then welded build-up & ported for the
#3 & #6 port.My test show this to be better,
And makes clearance for other makes of blowers
than just the M90 blower.
I did some wet flow testing.And now I have bought
a Aneometer to test flow balance and it seems to
work great In measuring flow volume from each
manifold port.
My testing shows the #3 & #6 port having flow problems.
#6 the most.But some welding & porting takes care of this.
But porting the number 6 manifold port to much,
with no welding.Causes the forward motion problems
of air on the drivers side of the manifold to the front ports,
if the triangle has been removed.
I you remove the triangle inside the manifold.The two
front cylinders can suffer air flow at low RPMs.
So for a manifold for mostly daily driving and some racing,
vains should be used but the inbalance is very very small
and only in the very low RPM range.
I can help you as much as I can though E-MAILS if
you are interrested in building your own manifold-plenum.
But it must be for yourself.I will not help others to do it
for profit.But I realy do don't know how to show or explain
shapes to be made short of making plexy-glass templates
for the plenum and manifold.
I have given some thought about making and selling templates
for the manifold-plenum mod and for SC head ports.For the
DIY SC people.That are proven and tested shapes.I don't
just sell cool looking unproven copied parts ,along with a line
of bull S.
The only way to measure each cylinder.Is to weld a
bung in each cylinders exhaust header tube.
This is the only balanced way.But I understand your
thoughts on installing a EGT sensor in the leanest cylinder.
My thoughts are that the air inbalance do's start in the manifold.
# 3 and # 6 manifold ports.The two worst ports in the head
that promote air flow inbalance is the two middle intake ports.
The rest of the intakes as with the exhaust ports in the
heads have the same shape and flow about the same.
With the testing your wanting to do,cylinder temps,or o2
narrow or wide band in one spot.There is not much exact
cylinder tuning you can do.You can change spark plug heat ranges.
This will help some.But the first step to take is to balance
the air flow in the intake side and exhaust side .And then
take temp or o2 readings from each cylinder to balance tune.
Hope this give you some food for thought for your goals of
installing and taking temps in the exhaust.
Thanks RANDY
But I am booked until next summer june 2006.
Others are doing this mod.But they are not
doing any balance flow testing that I have ever
read about for the manifold.And I have read of
no change of shape inside of the plenum to
promote better flow.Or testing on it.So I am
positive that they are selling parts that may
lean some cylinders out to much for my tastes.
I am only talking about manifold & plenum mods
that are with-in the stock looking design.
Some say they are doing what Chris Wise has done.
But After talking to Chris ,and looking at his parts.
And getting his permission to do a wider plenum.
He has never done the mods that they are doing.
(EXAMPLE T-BIRD 88)They are doing my mod that
was started with Mike 38 & me.This is the plenum
with the stock IC mounting flange.Chris Wise never
made a plenum like this.His had a tube welded to the
plenum.He made the manifold plenum mounting
entrance larger,But he move it forward ,to promote
flow to the number 3 & #6 port.Mine was move
back and then welded build-up & ported for the
#3 & #6 port.My test show this to be better,
And makes clearance for other makes of blowers
than just the M90 blower.
I did some wet flow testing.And now I have bought
a Aneometer to test flow balance and it seems to
work great In measuring flow volume from each
manifold port.
My testing shows the #3 & #6 port having flow problems.
#6 the most.But some welding & porting takes care of this.
But porting the number 6 manifold port to much,
with no welding.Causes the forward motion problems
of air on the drivers side of the manifold to the front ports,
if the triangle has been removed.
I you remove the triangle inside the manifold.The two
front cylinders can suffer air flow at low RPMs.
So for a manifold for mostly daily driving and some racing,
vains should be used but the inbalance is very very small
and only in the very low RPM range.
I can help you as much as I can though E-MAILS if
you are interrested in building your own manifold-plenum.
But it must be for yourself.I will not help others to do it
for profit.But I realy do don't know how to show or explain
shapes to be made short of making plexy-glass templates
for the plenum and manifold.
I have given some thought about making and selling templates
for the manifold-plenum mod and for SC head ports.For the
DIY SC people.That are proven and tested shapes.I don't
just sell cool looking unproven copied parts ,along with a line
of bull S.
The only way to measure each cylinder.Is to weld a
bung in each cylinders exhaust header tube.
This is the only balanced way.But I understand your
thoughts on installing a EGT sensor in the leanest cylinder.
My thoughts are that the air inbalance do's start in the manifold.
# 3 and # 6 manifold ports.The two worst ports in the head
that promote air flow inbalance is the two middle intake ports.
The rest of the intakes as with the exhaust ports in the
heads have the same shape and flow about the same.
With the testing your wanting to do,cylinder temps,or o2
narrow or wide band in one spot.There is not much exact
cylinder tuning you can do.You can change spark plug heat ranges.
This will help some.But the first step to take is to balance
the air flow in the intake side and exhaust side .And then
take temp or o2 readings from each cylinder to balance tune.
Hope this give you some food for thought for your goals of
installing and taking temps in the exhaust.
Thanks RANDY
Last edited:
randy hayes
Registered User
ScottScott Long said:
I do not know about the intricacies of my SC, but it is impressive stock. I could not help noticing that we seem to have a similar bent with your Big Block project. I have 2 of these also and the 91 I bought new now has an aluminum V8 and a 6spd. Much more also of course. Aircraft brakes, aluminum rear ctrl arms, radiator, etc. I am going to sell it. Perhaps you could shorten your build time. E-mail me any way and we can compare notes. Randy
SK_BlownThunder
Registered User
this is a long discussion.....i am staying out of this one
David Neibert
SCCoA Admin
Scott Long said:
Scott,
Cylinder #3 is directly across from the intake manifold adaptor (casting that connects the lower IC tube to the intake manifold). Without having a diffuser in the adaptor (like I do now) to direct the incoming air flow downward and toward the center of the manifold, I believe that the #3 cylinder receives more airflow than the others because of the direction the air is traveling when it enters the manifold.
I also believe that if you were to conduct a poll on head gasket failures asking which cylinder blew, you would find that the #3 cylinder is the one the fails the most often. I think the reason it fails more often is because it runs leaner than the others and generates more heat and because of that it has a better chance of experincing detonation.
David
Randy N Connie
Registered User
I agree with David N. his diffuser solves some big problems
in balancing the manifold air flow.
Thanks Randy
in balancing the manifold air flow.
Thanks Randy
sizemoremk
Registered User
Can this diffuser in the return plenum be described? Or is this one of those secret things?
Thanks!
Thanks!
David Neibert
SCCoA Admin
Randy N Connie said:
Randy,
As much as I would like to take credit for the difuser idea, I can't because it was ESM who first started installing them in their ported intake manifold adaptors.
David
Randy N Connie
Registered User
sizemoremk
Registered User
Randy N Connie said:
Did you make this one, or did it come form ESM?
How do I go about getitng this done to my return plenum???
I'm already welding on it so I can port into it a little bit....