Plenum,2925?

[racinnut15xm]

It looks like you removed the overhang on the top of the ports.
Generally that will lose power.

If you are talking about the plenum shot 5 posts down from the top of this page i agree, as far as the other pics on page 2 there is still enough roof radius to work
Tom

Can you or a schmidt use the quote function to show us which picture you are talking about? I counted and didn't see any roofs shots I would consider a number 5 down. Not sure if we can have different amounts of posts per page. And multiple people have added photos now.

[88bluestar]

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[steve cowan]

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i would leave it as is at the moment- any photo is hard to judge.
you can take material out but hard to put back if you mess up (thank you epoxy)
i would just use 60 grit flapper paper to clean up intake runners and plenum,i would be more concerned with port match with heads sitting on short block and gaskets in place.
are the heads still going to machine shop for valve job etc,if so look at intake flange to head flange for manifold angle alignment - sometimes they need to be corrected.

[SchmidtMotorWorks]

[quote="GARY

Is the size and shape of the return pressure wave entering the plenum what your concerned about here?
[/quote]

The timing of it mostly.

[SchmidtMotorWorks]

dart 215e.jpgJust an example how I do a Victor jr. tall. Thanks, Charlie

This one.

It probably flows better. But chasing flow is not the only goal.

[JoePorting]

If you are talking about the plenum shot 5 posts down from the top of this page i agree, as far as the other pics on page 2 there is still enough roof radius to work
Tom

That's so far up stream I couldn't imagine it making too much difference.

Jon, does Edelbrock do a lot of design testing with there manifolds or do they just go with the best guess? I thought they extended the four inside intake walls too far into the plenum area.

Tons of testing on the part being developed and all relevant competitive manifolds.

A single manifold will have many prototypes made and compared typically.

The testing is much more careful and controlled that what you see on YouTube videos. The dyno operators / calibrator follow test plans that are reviewed by multiple engineers. Evey pull is planned and data is carefully collected by people with engineering degrees in the subject of testing. Most have OEM experience.
This is essential for development of late model stuff.
You won't beat OEM stuff today by guessing or rules of thumb.
Frankly, unless you change the requirements there is not much on the table these days.
On the Coyote manifold I developed there were 5 major concepts and many variations of some of them. Many 100's of dyno pulls.
You need very good data management to make sense of the data. If you are just looking at power curves you might as well not even start.

Isn't the #2925 from the early 1980's? Why hasn't this design been updated? Someone told me that Brownfield designed it back then. I'd think with all the modern testing processes that this design would have been updated by how. That's what made me question Edelbrock's testing processes.

[gmrocket]

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Good thing it's marked "carb side"

[SchmidtMotorWorks]

Isn't the #2925 from the early 1980's? Why hasn't this design been updated? Someone told me that Brownfield designed it back then. I'd think with all the modern testing processes that this design would have been updated by how. That's what made me question Edelbrock's testing processes.

I suspect it had updated coreboxes made over the years.
The market for manifolds for gen1 is WAY over supplied and low cost imports prevail.

For a company that develops and manufactures parts in the USA, investing in that segment is throwing valuable resources away.
The way forward is in producing things that are difficult for importers to duplicate. Easier said than done.
That puts the focus on late model cars with supercharger and fuel injection systems.

From a business perspective gen 1 stuff is part of the past, not the future.
Even if the numbers were high, the profits are too low.

Things are done extremely different now than they were 5 years ago. Let alone 20 or 30.

[gmrocket]

Isn't the #2925 from the early 1980's? Why hasn't this design been updated? Someone told me that Brownfield designed it back then. I'd think with all the modern testing processes that this design would have been updated by how. That's what made me question Edelbrock's testing processes.

I suspect it had updated coreboxes made over the years.
The market for manifolds for gen1 is WAY over supplied and low cost imports prevail.

For a company that develops and manufactures parts in the USA, investing in that segment is throwing valuable resources away.
The way forward is in producing things that are difficult for importers to duplicate. Easier said than done.
That puts the focus on late model cars with supercharger and fuel injection systems.

From a business perspective gen 1 stuff is part of the past, not the future.
Even if the numbers were high, the profits are too low.

Things are done extremely different now than they were 5 years ago. Let alone 20 or 30.

I'm surprised the same basic lay'd over trianglur port shape hasn't changed in all those years. Maybe I'm wrong but the long wall and short wall on those cast single 4's really shouldn't be the same height from plenum to exit...yet they seem to be.

I'm talking a sbc where things have been studied and tested to death.

I've got a Vic air gap here and an ancient wiand for a sbc, they are both the same basic lay'd over triangular height dimensions all the way. Although the Vic has longer curved runners..

[BradH]

...
I gained 35 HP on 550hp engine with a geometric property that I never have never seen discussed in a forum or book.
...

Well, here's your chance!

Oh, let me guess... there's an NDA, right?

[digger]

That's so far up stream I couldn't imagine it making too much difference.

Upstream Is WHY it makes a difference.

A lot of the things that optimize a manifold are not part of the conventional discussion of CSA and flow numbers etc.

I gained 35 HP on 550hp engine with a geometric property that I never have never seen discussed in a forum or book.

A dyno room with emotional people chasing power curves and cheering about gains would NEVER find it.

And a flow bench test would not find it.

Jon,

If we ignore wetflow for a second.
Are you seeing anything in testing that you won't capture in 1D. Ie if you optimise trapped mass via area and area change and length to capture the pressure waves for maxim fill in the rpm of interest?
Naturally there will be 3D effects with bends and so forth but I deal with stuff that has a nice straight shot I.e. IR fuel injected where you can see the spark plug through entry.

[GARY C]

That's so far up stream I couldn't imagine it making too much difference.

Jon, does Edelbrock do a lot of design testing with there manifolds or do they just go with the best guess? I thought they extended the four inside intake walls too far into the plenum area.

Tons of testing on the part being developed and all relevant competitive manifolds.

A single manifold will have many prototypes made and compared typically.

The testing is much more careful and controlled that what you see on YouTube videos. The dyno operators / calibrator follow test plans that are reviewed by multiple engineers. Evey pull is planned and data is carefully collected by people with engineering degrees in the subject of testing. Most have OEM experience.
This is essential for development of late model stuff.
You won't beat OEM stuff today by guessing or rules of thumb.
Frankly, unless you change the requirements there is not much on the table these days.
On the Coyote manifold I developed there were 5 major concepts and many variations of some of them. Many 100's of dyno pulls.
You need very good data management to make sense of the data. If you are just looking at power curves you might as well not even start.

Isn't the #2925 from the early 1980's? Why hasn't this design been updated? Someone told me that Brownfield designed it back then. I'd think with all the modern testing processes that this design would have been updated by how. That's what made me question Edelbrock's testing processes.

I think your thinking the 2975, the Super Victor came out in late 90's, I bought one when they first came and was bummed because it wasn't any faster than my old Weiand 7546.

It was supposed to be designed to work better with all the new aftermarket heads.

Edelbrock Part # 2925 Super Victor 23-degree intake manifold is designed for heads with a standard port location, the runners match the "flat floor" entry of the latest 23-degree heads. Carb pad height is 5-1/2" (from end seals) and overall, this intake is about one-inch taller than our Victor Jr. intake #2975. Runners have a 2.80 square-inch cross-section.

[SchmidtMotorWorks]

...
I gained 35 HP on 550hp engine with a geometric property that I never have never seen discussed in a forum or book.
...

Well, here's your chance!

Oh, let me guess... there's an NDA, right?

Of course there is, they spent a lot of money for me to do the research. They own it.

[swampbuggy]

Question for Jon @ Schmidt Motor Works. I can see reading this topic that you worked for Edelbrock, my question to you is when people grind inside the plenum area and make quite a bit of change, mostly between the carb pad area to the roof/ceiling area of the manifold runner is this ALWAYS the correct thing to do ? Or maybe i should ask, is there more metal in that area so professionals such as.........can shape that area as they wish ? Thanks in advance for your response !! Mark H.

[BradH]

...
I gained 35 HP on 550hp engine with a geometric property that I never have never seen discussed in a forum or book.
...

Well, here's your chance!

Oh, let me guess... there's an NDA, right?

Of course there is, they spent a lot of money for me to do the research. They own it.

Then why even bring it up, if you can't/won't discuss it? It adds nothing to the discussion, other than now we know that you know something apparently nobody else does.