Intake Manifold Porting Show ‘n Tell

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Erland Cox
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Re: Intake Manifold Porting Show ‘n Tell

Post by Erland Cox »

Lloyd klem wrote: Thu Dec 01, 2022 7:35 pm
Erland Cox wrote: Thu Dec 01, 2022 6:26 pm Vanniks software would show the curves and what happens with different tapers and lengths.
The dyno would show what the result was.

Erland
There we go ,the more we do the math the less we know! Experience,r&d is everything.I have read so much expert knowledge that is no where near what goes on.People think they find something,and that's cool.Most things do not duplicate enough for us to understand.Thats why I only do what intrigued me ,I will never work on anything again that someone thinks they figured out.What happens at one rpm does not at another.The only guys that impress me have general knowledge of race engines,can produce a decent Dyno sheet and bring that to life at the track etc!!
It is a good start when you start from scratch but for developing max power you have to work on the dyno.
But an understanding on what goes on helps you to choose which way to go and saves time.
Do you understand how the physics in a manifold works?
I just want to understand all the things I see on a dyno.
By the way. 1996 I did a set of heads for an NHRA P/S engine here in Sweden, the first and last I ever did.
I had the manifold and the pistons but I did everything in between.
Dart Oldsmobile heads. 7.28-190.
The fastest American built car ran 7.16-196 something.
This is when they used 4.84 bore centers.
At a point I got tired off throwing parts on cars and tried to get an understanding of what is going on.
The gas flow and waves in the ports are very complicated because they affect each other.
Not even a perfect sim can keep up with reality but it can help you understand better.
Sadly I am to old to be any good with computers and I rather work on the dyno which by the way also has a computer though a less troublesome one.
But today I know where I would start on that P/S engine to make it better, valve gear.

Erland
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Re: Intake Manifold Porting Show ‘n Tell

Post by bobmc »

what did the 7.28 combination make on your dyno?
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Re: Intake Manifold Porting Show ‘n Tell

Post by hoffman900 »

Tom68 wrote: Fri Dec 02, 2022 2:01 am
hoffman900 wrote: Thu Dec 01, 2022 11:38 pm

Ever play with a divider down the middle?
Which picked up 7kw on the V10 but didn't work on the V8, it says they divided the front cylinders on the V8 and encouraged interference on the rear, or something to that effect. Flat plane crank anyways no doubt.

http://www.f1-forecast.com/pdf/F1-Files ... P2_10e.pdf
It worked on the V8 as it had bigger inter-cylinder interference than the V10. They just divided the middle cylinders to shape the torque curve. And yes a flat plane crank.
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Re: Intake Manifold Porting Show ‘n Tell

Post by Bigchief632 »

bobmc wrote: Fri Dec 02, 2022 8:24 am what did the 7.28 combination make on your dyno?
My estimate, somewhere in the ballpark of 1250.
Maximum power using simple logic and common sense
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Re: Intake Manifold Porting Show ‘n Tell

Post by Lloyd klem »

Erland Cox wrote: Fri Dec 02, 2022 6:48 am
Lloyd klem wrote: Thu Dec 01, 2022 7:35 pm
Erland Cox wrote: Thu Dec 01, 2022 6:26 pm Vanniks software would show the curves and what happens with different tapers and lengths.
The dyno would show what the result was.

Erland
There we go ,the more we do the math the less we know! Experience,r&d is everything.I have read so much expert knowledge that is no where near what goes on.People think they find something,and that's cool.Most things do not duplicate enough for us to understand.Thats why I only do what intrigued me ,I will never work on anything again that someone thinks they figured out.What happens at one rpm does not at another.The only guys that impress me have general knowledge of race engines,can produce a decent Dyno sheet and bring that to life at the track etc!!
It is a good start when you start from scratch but for developing max power you have to work on the dyno.
But an understanding on what goes on helps you to choose which way to go and saves time.
Do you understand how the physics in a manifold works?
I just want to understand all the things I see on a dyno.
By the way. 1996 I did a set of heads for an NHRA P/S engine here in Sweden, the first and last I ever did.
I had the manifold and the pistons but I did everything in between.
Dart Oldsmobile heads. 7.28-190.
The fastest American built car ran 7.16-196 something.
This is when they used 4.84 bore centers.
At a point I got tired off throwing parts on cars and tried to get an understanding of what is going on.
The gas flow and waves in the ports are very complicated because they affect each other.
Not even a perfect sim can keep up with reality but it can help you understand better.
Sadly I am to old to be any good with computers and I rather work on the dyno which by the way also has a computer though a less troublesome one.
But today I know where I would start on that P/S engine to make it better, valve gear.

Erland
Erland
I will start with no I'm not any math or physical science expert.I use general spread sheets I have came up with for length,size ,taper etc.I have worked on engines from about every style of racing at some point in my life.I worked with a guy for years ,when I left there we had dynoed somewhere near 2000 different engines.The thing we worked on hardest was looking at what an engine told us after it ran.We learned what to fix by color of piston on dome side and underside.What chamber and ports look like,where or if there was reversion.I work on heads and manifolds yet today.Most stuff that comes to me is already pretty well perfected design.But guys always want more.I don't get caught up in all the physic or math BS,in fact I find 80 percent of manifold or head problems are not physical outlay or design.I find that most result back to poor ring seal,valve jobs and or cam events picked.Btw I was working on prostock stuff in mid 90s as well.I would say by 96 nobody in America that was qualifying had non 4.900 Bs stuff.In fact one of guys we worked on his stuff probably was one of the last guys to qualify with 4.840 stuff.In 95 one team I worked with was running 7.11-7.12ish with at that time was 1325 hp and 785 ft lbs roughly as I recall.I really admire the guys caught up in the all the math aspect of race engines.I don't have time for that personaly.But I have fixed many of the guys that think they know it all's engines.Maybe it comes down to I out guess them.lol.
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Re: Intake Manifold Porting Show ‘n Tell

Post by Lloyd klem »

hoffman900 wrote: Thu Dec 01, 2022 11:38 pm
Lloyd klem wrote: Thu Dec 01, 2022 11:56 am Nice to use billet runners and leave a nice bell radius in plenum around each port.IMG_20221127_191150943.jpgIMG_20221127_190651537.jpg
Ever play with a divider down the middle?


26FD41E3-75EF-41C0-AB7C-58985A858A22.jpeg





91D3B677-65F7-49E1-8D7B-7D688BF911DE.png


It takes some correlation, but EngMod4t is fantastic for this stuff, but mostly is looking at dry flow. However, I put one of the virtual pressure sensors at the booster location and that’s revealing. Remember, carbs work off of pressure differentials and will work both ways as well… people who work with individual runner carburetors know this well.
Yes I have worked with dividers in plenum and dividers in runners etc.Even in ex ports trying odd stuff.
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Re: Intake Manifold Porting Show ‘n Tell

Post by Erland Cox »

bobmc wrote: Fri Dec 02, 2022 8:24 am what did the 7.28 combination make on your dyno?
At that time I did not have a dyno and it was me and 2 Danish guys that had the car so we dynoed it in Denmark.
If I remember right the old engine from Bob Ingles had 1075 hp and the one with my heads 1090 with more average.
I do not remember the torque but I can probably find it.
The Ingles engine had a US dyno sheet of 1175 hp but we didn´t deduct power lost to acceleration when we tested.
We ran 7.34 with the Ingles engine but I can´t remember the speed.

Erland
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Re: Intake Manifold Porting Show ‘n Tell

Post by Erland Cox »

Lloyd klem wrote: Fri Dec 02, 2022 10:22 am
Erland Cox wrote: Fri Dec 02, 2022 6:48 am
Lloyd klem wrote: Thu Dec 01, 2022 7:35 pm

There we go ,the more we do the math the less we know! Experience,r&d is everything.I have read so much expert knowledge that is no where near what goes on.People think they find something,and that's cool.Most things do not duplicate enough for us to understand.Thats why I only do what intrigued me ,I will never work on anything again that someone thinks they figured out.What happens at one rpm does not at another.The only guys that impress me have general knowledge of race engines,can produce a decent Dyno sheet and bring that to life at the track etc!!
It is a good start when you start from scratch but for developing max power you have to work on the dyno.
But an understanding on what goes on helps you to choose which way to go and saves time.
Do you understand how the physics in a manifold works?
I just want to understand all the things I see on a dyno.
By the way. 1996 I did a set of heads for an NHRA P/S engine here in Sweden, the first and last I ever did.
I had the manifold and the pistons but I did everything in between.
Dart Oldsmobile heads. 7.28-190.
The fastest American built car ran 7.16-196 something.
This is when they used 4.84 bore centers.
At a point I got tired off throwing parts on cars and tried to get an understanding of what is going on.
The gas flow and waves in the ports are very complicated because they affect each other.
Not even a perfect sim can keep up with reality but it can help you understand better.
Sadly I am to old to be any good with computers and I rather work on the dyno which by the way also has a computer though a less troublesome one.
But today I know where I would start on that P/S engine to make it better, valve gear.

Erland
Erland
I will start with no I'm not any math or physical science expert.I use general spread sheets I have came up with for length,size ,taper etc.I have worked on engines from about every style of racing at some point in my life.I worked with a guy for years ,when I left there we had dynoed somewhere near 2000 different engines.The thing we worked on hardest was looking at what an engine told us after it ran.We learned what to fix by color of piston on dome side and underside.What chamber and ports look like,where or if there was reversion.I work on heads and manifolds yet today.Most stuff that comes to me is already pretty well perfected design.But guys always want more.I don't get caught up in all the physic or math BS,in fact I find 80 percent of manifold or head problems are not physical outlay or design.I find that most result back to poor ring seal,valve jobs and or cam events picked.Btw I was working on prostock stuff in mid 90s as well.I would say by 96 nobody in America that was qualifying had non 4.900 Bs stuff.In fact one of guys we worked on his stuff probably was one of the last guys to qualify with 4.840 stuff.In 95 one team I worked with was running 7.11-7.12ish with at that time was 1325 hp and 785 ft lbs roughly as I recall.I really admire the guys caught up in the all the math aspect of race engines.I don't have time for that personaly.But I have fixed many of the guys that think they know it all's engines.Maybe it comes down to I out guess them.lol.
I started out with 2 stroke bikes as a kid of 13 knowing nothing.
I bought my first Chevy2 when I was 16 and had my first summer job.
When I was 17 I had another Chevy2 with a 331, Muncie M21 and 3.36 gears.
It was all the tires could take dropping the clutch at 6000 rpm.
I read Jenkins and dreamed about smallblock tuning.
Then I did some real drag racing with a 305 in a 40 Willis 4 door. 302 + .030"
After that I started streetracing with a Dodge Charger 68 and in that car I did a lot of manifold and cylinder head testing.
Just plain old cast iron heads and some where welded and epoxied.
Got around 625 hp out of a streetable 440 and used Nitrous on top of that.
In the 80:s I quit my job porting heads for another company and have been self employed.
I built my flow bench after an article in Car Craft and trying to figure out flow got me interested in math.
So I went to school for 2 years to understand more about math and physics.
But I am mostly self taught by testing but at the same time I alwaays have had an interest in deeper understanding.
I just must know why.
I have street raced, drag raced, mx:d, run bikes in roadracing and now I road race cars.
And I love it.
I have had so many cars that it would take hours to write about all of them.

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Erland
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Re: Intake Manifold Porting Show ‘n Tell

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Re: Intake Manifold Porting Show ‘n Tell

Post by frnkeore »

I have a question regarding single plane plenums.

I have noted in this thread and in other intake plenums that I've seen, that the roof of the plenums have what looks like ~3/8R entries, into the runners. Maybe on some 1/2R.

Would a larger radius promote more flow, such as at least 3/4R, if there is enough to material to do that or, you could add material by welding? Or be used to help equal the runner flow?
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Re: Intake Manifold Porting Show ‘n Tell

Post by HQM383 »

frnkeore wrote: Fri Dec 02, 2022 3:44 pm I have a question regarding single plane plenums.

I have noted in this thread and in other intake plenums that I've seen, that the roof of the plenums have what looks like ~3/8R entries, into the runners. Maybe on some 1/2R.

Would a larger radius promote more flow, such as at least 3/4R, if there is enough to material to do that or, you could add material by welding? Or be used to help equal the runner flow?
Been wondering similar myself but also how much better flow in that area matters in a running engine? I can imagine spending time in that area will increase steady state flow bench numbers but with each intake stroke of an engine how much would it contribute? Using a 383ci with a 200cc intake head and depending on volumetric efficiency one intake stroke is going to ingest low 40s to just over 50ci. A 200cc intake port is 12.2ci and a rough calculation of several sbc single plane outer runners is 17.5ci. So there is already around 29 and a half ci of volume there. So the cylinder, depending on VE only needs another 13.5 to 22.5ci of air fuel to swallow. It should easily get this from the plenum. I’d imagine a little would have to traverse the roof radius. At the same time swallowing this air fuel contributes along with every other cylinder to the overall manifold depression pulling fuel down through the carb into the plenum void. There is so much volume for an intake stroke to consume between cylinder and carb throttle blade I’m not sure the fuel’s direct path is from throttle bore directly around that roof radius.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
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Re: Intake Manifold Porting Show ‘n Tell

Post by Lloyd klem »

I like to see 3/4 " radius above ports min.But I'm not concerned if I need area and wipe that out.i will just take a spacer and incorporate my ceiling radius above port with that.The floor is important part of intake.I see so many guys don't have good width at floor.Still would rather have a tunnel ram over any other intake design.If I have to run a std manifold and no rules I Mill whole plenum off and get way out over long runners so I don't fight different runner lengths.Then I throw a teepee type top on it.
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Re: Intake Manifold Porting Show ‘n Tell

Post by Lloyd klem »

Love these Holley low rams.They have great taper and radius and area.With what's available in LS stuff ,I'm amazed anyone wants to waste time on gen 1 stuff,but to each their own.So easy to run 8500 with this stuff,Holley did the work and math for you.
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Re: Intake Manifold Porting Show ‘n Tell

Post by Lloyd klem »

Manifold that a couple of buddies had cast up and something Im working on for personal 500 inch SBC for street strip.It will end up with billet top like I posted on dart tunnel ram in here.
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Re: Intake Manifold Porting Show ‘n Tell

Post by Lloyd klem »

One of the possibility's I'm looking at for above manifold.
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