PRH
Well-Known Member
I read one from 4 days ago where he did a 45* seat.
Was it after that one?
Was it after that one?
David Vizard, Uncle Tony's garage, Unity motorsport. Mission impossible Dodge 302 Head porting
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Rat Bastid
Dunamis Metron
Rat Bastid
Dunamis Metron
I think this is it.
Nothing about cylinder port flow is laminar. It is all turbulent. Small port big port it's all turbulent, flow when the engine is running, especially running hard.
Rat Bastid
Dunamis Metron
Thats what the Reynolds Number is for. You can quantify turbulent flow.
PRH
Well-Known Member
Not picking on Charlie at all, but he made a comment in what I think is the latest video....... where he’s talking about the 24hrs of R&D, and how the next port got a quickie job and flowed almost as much.
The comment being....... sometimes you need to know when to stop.
I’m thinking that would have been at about hour #2 or 3 on the first port.
My feeling on the head flow situation is.......as it pertains to this particular build is....... if the heads flowed 210-215, that would be plenty........ and still way more than the intake will keep up with.
The comment being....... sometimes you need to know when to stop.
I’m thinking that would have been at about hour #2 or 3 on the first port.
My feeling on the head flow situation is.......as it pertains to this particular build is....... if the heads flowed 210-215, that would be plenty........ and still way more than the intake will keep up with.
Careful with talk like that. You might confuse some people.
From the videos is seems that there will be different phases to this project, as in a 4 bbl after the 2 bbl testing is done.
Servedio also stated that he wasn't sure if Vizard would use his heads or not. This tells me that at least Vizard (and maybe others) will have cylinder heads of their own to test/use on the project, or perhaps they'll all compare notes and prep a final set of heads.
Agree 100%
How Ever. My "personal definition" is when the flow bench SCREAMS at you so loud, it is deafening and the flow number TANK! That's turbulence in My Book.
I agree, I think the carb above all else is what restricts this motor. From memory the bbd carter is tiny compared even to a 4412 holley. We raced for years under a holley 7448 (350 cfm ) rule. A 180 or smaller head worked better than a 220 or larger head with that carb. I guessing that might be the case with this build also.Ok gave my Thoughts, at the first of this thread, ready to give a few more.
So, it was surprising, for me, that when he tried a 50 degree seat, how it flowed. I figured the 50 Degree seat would allow more cfm for the same valve size.....and it did! But exactly the OPPOSITE of what i thought it would do. Gained low lift flow and lost upper lift flow. I realize that the head has been ported in the bowl area before he started and, maybe it can't be shaped to support that valve angle. Still not what i expected of the 50 degree seat.
I think the 318 head is a much better for this project. NOW HOLD ON, don't be jumping on that high horse just yet(couldn't stop you if i wanted to any ways)
Yes 318 over 360 head, and here is why(just my lack of "experience" opinion) OK so air speed is really more important then cfm, to me. You get to much, you get turbulence(I'm not taking swirl) you get to little and you get fuel drop out. So, yes you can easily easily port a 360 head and get more flow with less turbulence. you can get 240 cfm easy there are many who can get much more then that.
Now, no one has flow tested that little two barrel manifold..........just to make my point, lets say that manifold flows 120 cfm and they get it ported out to 190 cfm(just throwing numbers in the air).
OK Now, What do you think is going to happen to the air speed that will be traveling, way to fast in the intake manifold, then slows to a crawl when it hits the 240+ capable head........Its not going to magically speed up to 240!!!!! is going to slow way down, and the fuel is going to drop out and just run down the floor of the port. end up in the combustion chamber as un burnt liquid)May get burnt but way past the Power stroke.
What make the most HP, is the most air and fuel that you can jam in to a cyl that is burnable on the power stroke. Liquid fuel is NOT THAT!!!!!
And i haven't even talked about what that tiny teen carb is going to do to the air speed/flow.
I now return you to your regular scheduled program.................................................
Wow their putting a lot of work into this, 318hp should no problem to keep the name mission impossible the might need to be bumped to 400+hp, I hope they also do 4bbl and headers along with a 2bbl and manifolds.
Vizard kind of hinted at exactly that. So there may be the 318-2 bbl build data along with whatever this thing turns out to be in the end.
So... maybe they should rename the thread....mission possible?
I can do that.
Will be interesting to see what they come up with for a stock 318 2 bbl intake manifold for their complete package flow testing, and what they consider a stock 318 manifold.
Here is a stock 1990 318 Mid Rise TBI intake manifold drilled for accepting the Chrysler 318 2 bbl carb.
This '90 318 intake manifold will surely flow better than this stock 1974 318 2 bbl intake shown below.
Both intakes are Dual Plane intakes.
Will depend on what intake will fit in the parameters of their 318 build rules.
Here is a stock 1990 318 Mid Rise TBI intake manifold drilled for accepting the Chrysler 318 2 bbl carb.
This '90 318 intake manifold will surely flow better than this stock 1974 318 2 bbl intake shown below.
Both intakes are Dual Plane intakes.
Will depend on what intake will fit in the parameters of their 318 build rules.
Rat Bastid
Dunamis Metron
Agree 100%
How Ever. My "personal definition" is when the flow bench SCREAMS at you so loud, it is deafening and the flow number TANK! That's turbulence in My Book.
100% FACT. The more quiet the port is regardless of what the flow numbers say the more power it will make.
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Amen.
Does the vacuum generated in the intake manifold and port contribute to the vaporization of the fuel?
Hmmmm welll
When you recharge the AC on your car......the first step is to put it into a vacuum, to boil out the moisture.
Being a smart arss of course.......but there may be some merit to that.
Rat Bastid
Dunamis Metron
Yes, but you can’t choke flow just for vaporization. If you use a Holley you have more choices to affect atomization and vaporization than any other carb.
You may have to do things with other carbs you wouldn’t do with a Holley.
So if i bore a 4 inch hole to the intake valve, it should be pretty quite....Right.
Sorry, I must have put my Smart Arrs jeans on today
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