IM manifold Design Theory - Honda-Tech

98vtec · 11-02-2006, 01:14 AM

ok so its really late, i cant sleep and i got my digital caliper in the other day. i decided to take some measurements of an h22 IM i have that had the flange hacked off from my ITB build hoping that it would just make me tired, lol. Well it actually got my brain firing.....

Anyway, everything i say is based just off speculation and i'm aiming for someone to guide me through my thoughts and critique them.

in my measurements, the #4 port was larger than the rest in diameter and height. Now, it wasnt much larger but it is infact larger.

With that runner (farthest from the TB) being larger, would it be theoretically correct to say that a larger #4 runner port could distribute more air in general and equally to the rest of the cylinders?

Once again, i am really tired and just looking to brainstorm

Master of the Universe · 11-02-2006, 09:40 AM

The runner furthest from the TB gets more air and the the one closest gets the least.

If you people thought more about it you wouldn't get things backwards.

98vtec · 11-02-2006, 12:14 PM

Quote:

Originally Posted by Don’s Lackey

The runner furthest from the TB gets more air and the the one closest gets the least.

If you people thought more about it you wouldn't get things backwards.

where did i get it backwards?

Master of the Universe · 11-02-2006, 12:21 PM

Quote:

Originally Posted by 98vtec

With that runner (farthest from the TB) being larger, would it be theoretically correct to say that a larger #4 runner port could distribute more air in general and equally to the rest of the cylinders?

What are you saying in this statement?

1. If the #4 runner was the same size, flow distribution is un-even among the runners.

2. #4 runner feeds equally to the rest of the cylinders

3. Neither, additional comments will be made.

Televator · 11-02-2006, 12:26 PM

Quote:

Originally Posted by Don’s Lackey

The runner furthest from the TB gets more air and the the one closest gets the least.

If you people thought more about it you wouldn't get things backwards.

Thinking about it to yourself leads to nothing more than assumptions no matter how long you think about it. Assumptions are assumptions because they can either be true or totally wrong. He's only trying to create a concrete idea of what happens in the manifold by openly discussing it with people who hopefully know something.

98vtec · 11-02-2006, 12:34 PM

Quote:

Originally Posted by Don’s Lackey

What are you saying in this statement?

1. If the #4 runner was the same size, flow distribution is un-even among the runners.

2. #4 runner feeds equally to the rest of the cylinders

3. Neither, additional comments will be made.

thats the thing, i dont know. I'm speculating and hoping someone would come in hear explaining why this is so.....I'm here trying to learn from people with more knowledge than me. I made this thread at 4:00am in the morning so what i said might not have been clear, but i think if someone who was knowledgeable on this topic read it, they would have an idea of what i was trying to get out of this post and be able to help me.

I'm wanting to modify my stock manifold to optimize this theory. I havent started my engineering degree considering i just changed my major from Criminology to ME, so my knowledge on this topic is limited to the physics i learned in high school.

Master of the Universe · 11-02-2006, 12:39 PM

The runner farthers from the TB gets more air because no air can over shoot it like what happens with the closet runner.

This is why ITB's generally make better power. More equal air distribution.

Here is a diagram to visualize.

98vtec · 11-02-2006, 12:44 PM

Quote:

Originally Posted by Don’s Lackey

Okay you could not possibly arrive at this conclusion.

The runner farthers from the TB gets more air because no air can over shoot it like what happens with the closet runner.

Here is a diagram to visualize.

picture doesnt work. And i understand that no air can overshoot the last runner due to it have the plenum wall to keep the air from passing by. I'm asking about ways to optimize its ability to distribute air equally by possibly enlarging all the ports a little, while keeping the farthest one larger, and changing the dimensions of the plenum so that this charge going to the farthest runner could be distributed to to the other cylinders thus providing each cylinder equally with more air and making "better" power.

edit: picture works now

Master of the Universe · 11-02-2006, 12:47 PM

Having even something like a MagnaDoodle can be a very enlightening tool.

There are already IM's available that have the proper plenum design. Cosworth is one of those companies.

Televator · 11-02-2006, 12:49 PM

In the diagram, and I know it's not acurate (no offense), do I see that the spaces between the runners are consecutively taller than the last?

Master of the Universe · 11-02-2006, 12:52 PM

The runner entrances were not intended to be lower from left-to-right, just an artifact from moving the mouse from right to left as I was drawing but I kept my right elbow fixed on the desk this creating downard arc path for the mouse resulting in what you see. This actually would help get more air to the runners that need it.

98vtec · 11-02-2006, 12:53 PM

Quote:

Originally Posted by Don’s Lackey

Having even something like a MagnaDoodle can be a very enlightening tool.

There are already IM's available that have the proper plenum design. Cosworth is one of those companies.

i'm not looking to buy a manifold. I appreciate your post with the diagram but if thats all you are going to contribute to this thread then i'd rather not reply to you.

Televator · 11-02-2006, 12:55 PM

An interesting accident I'll say. LOL! Have people ever tried something like that?

98vtec · 11-02-2006, 12:58 PM

i would think it would work better the opposite.

having the two outside ports larger than the middle, along with having the runner splitters start out tall and gradually get shorter. That just makes a little more sense to me.

WestSideDave · 11-02-2006, 12:59 PM

Televator · 11-02-2006, 01:01 PM

Actually, I take it back. The way it is drawn would seem to prevent too much air from overshooting each one. Man, I need to sleep...

98vtec · 11-02-2006, 01:04 PM

Quote:

Originally Posted by Televator

D'oh! Yeah for some reason that totally slipped me. Obviously it would seem to work better the other way around.

i mean i dont know, its all an assumption until someone with a degree or a knack for this stuff comes in and confirms it.

obviously, the first runner is going to need the most work in order for it to receive the same flow as the rest of the runners. making it the tallest at the TB port would allow it to "catch" incoming air without alot of the air passing it by.

Televator · 11-02-2006, 01:10 PM

I'll come back to this when I'm rested. You are right though we need some one with experience to spill the beans on some of this.

alterdcreations · 11-02-2006, 01:41 PM

I would think that playing with the runner walls or lenths should help nutralize the uneven flow

Master of the Universe · 11-02-2006, 01:45 PM

TB placement and plenum shape is the way to go. Having different runner lengths and runner ID would be moving away from the ideal.

alterdcreations · 11-02-2006, 01:47 PM

oh i forgot to mention
Don's lackey=Rocket

Combustion Contraption · 11-02-2006, 03:28 PM

How about a plenum that is smaller in volume at the farthest runner.

Master of the Universe · 11-02-2006, 04:00 PM

Cosworth, GM Performance Products

JerseySiPOS · 11-02-2006, 04:01 PM

Quote:

11-02-2006, 01:14 AM	#1
98vtec Tuner "replica" Join Date: Oct 2002 Posts: 13,316	IM manifold Design Theory ok so its really late, i cant sleep and i got my digital caliper in the other day. i decided to take some measurements of an h22 IM i have that had the flange hacked off from my ITB build hoping that it would just make me tired, lol. Well it actually got my brain firing..... Anyway, everything i say is based just off speculation and i'm aiming for someone to guide me through my thoughts and critique them. in my measurements, the #4 port was larger than the rest in diameter and height. Now, it wasnt much larger but it is infact larger. With that runner (farthest from the TB) being larger, would it be theoretically correct to say that a larger #4 runner port could distribute more air in general and equally to the rest of the cylinders? Once again, i am really tired and just looking to brainstorm __________________ Blake's Wiki ECU chipping and Engine Tuning Specializing in H series Engine Management

11-02-2006, 09:40 AM	#2
Master of the Universe Join Date: Mar 2002 Posts: 6,493	Re: IM manifold Design Theory (98vtec) The runner furthest from the TB gets more air and the the one closest gets the least. If you people thought more about it you wouldn't get things backwards. __________________ Semi-Retired as of April 25, 2007. Don't bother to PM me. I am tired of internet fools. Contact via RM Dealer or e-mail.

11-02-2006, 12:39 PM	#7
Master of the Universe Join Date: Mar 2002 Posts: 6,493	Re: IM manifold Design Theory (Televator) The runner farthers from the TB gets more air because no air can over shoot it like what happens with the closet runner. This is why ITB's generally make better power. More equal air distribution. Here is a diagram to visualize. __________________ Semi-Retired as of April 25, 2007. Don't bother to PM me. I am tired of internet fools. Contact via RM Dealer or e-mail.

11-02-2006, 12:47 PM	#9
Master of the Universe Join Date: Mar 2002 Posts: 6,493	Re: IM manifold Design Theory (98vtec) Having even something like a MagnaDoodle can be a very enlightening tool. There are already IM's available that have the proper plenum design. Cosworth is one of those companies. __________________ Semi-Retired as of April 25, 2007. Don't bother to PM me. I am tired of internet fools. Contact via RM Dealer or e-mail.

11-02-2006, 12:49 PM	#10
Televator Senior Member Join Date: Sep 2005 Location: Tempe/Scottsdale, AZ, USA Posts: 1,264	Re: IM manifold Design Theory (Don's Lackey) In the diagram, and I know it's not acurate (no offense), do I see that the spaces between the runners are consecutively taller than the last? __________________ 無限'93 Prelude Si VTEC BB1 Black Art

11-02-2006, 12:52 PM	#11
Master of the Universe Join Date: Mar 2002 Posts: 6,493	Re: IM manifold Design Theory (Televator) The runner entrances were not intended to be lower from left-to-right, just an artifact from moving the mouse from right to left as I was drawing but I kept my right elbow fixed on the desk this creating downard arc path for the mouse resulting in what you see. This actually would help get more air to the runners that need it. __________________ Semi-Retired as of April 25, 2007. Don't bother to PM me. I am tired of internet fools. Contact via RM Dealer or e-mail.

11-02-2006, 12:55 PM	#13
Televator Senior Member Join Date: Sep 2005 Location: Tempe/Scottsdale, AZ, USA Posts: 1,264	Re: IM manifold Design Theory (Don's Lackey) An interesting accident I'll say. LOL! Have people ever tried something like that? __________________ 無限'93 Prelude Si VTEC BB1 Black Art

11-02-2006, 12:58 PM	#14
98vtec Tuner "replica" Join Date: Oct 2002 Posts: 13,316	Re: IM manifold Design Theory (Televator) i would think it would work better the opposite. having the two outside ports larger than the middle, along with having the runner splitters start out tall and gradually get shorter. That just makes a little more sense to me. __________________ Blake's Wiki ECU chipping and Engine Tuning Specializing in H series Engine Management

11-02-2006, 12:59 PM	#15
WestSideDave Join Date: Oct 2006 Location: Cleveland, OH Posts: 42	Re: IM manifold Design Theory (98vtec) __________________ No problem at all with a RMF header 93 Civic Hatch All Motor Street Car 11.82@114 mph 2140lbs http://images.honda-tech.com/set1/smile/emthup.gif

11-02-2006, 01:01 PM	#16
Televator Senior Member Join Date: Sep 2005 Location: Tempe/Scottsdale, AZ, USA Posts: 1,264	Re: IM manifold Design Theory (98vtec) Actually, I take it back. The way it is drawn would seem to prevent too much air from overshooting each one. Man, I need to sleep... __________________ 無限'93 Prelude Si VTEC BB1 Black Art

11-02-2006, 01:10 PM	#18
Televator Senior Member Join Date: Sep 2005 Location: Tempe/Scottsdale, AZ, USA Posts: 1,264	Re: IM manifold Design Theory (98vtec) I'll come back to this when I'm rested. You are right though we need some one with experience to spill the beans on some of this. __________________ 無限'93 Prelude Si VTEC BB1 Black Art

11-02-2006, 01:41 PM	#19
alterdcreations Senior Member Join Date: Feb 2006 Location: Single camshafting for now in, N.Y. Posts: 3,223	Re: IM manifold Design Theory (Televator) I would think that playing with the runner walls or lenths should help nutralize the uneven flow __________________ http://images.honda-tech.com/set1/smile/emcocktl.gif http://images.honda-tech.com/set1/smile/emdgust.gif

11-02-2006, 01:45 PM	#20
Master of the Universe Join Date: Mar 2002 Posts: 6,493	Re: IM manifold Design Theory (alterdcreations) TB placement and plenum shape is the way to go. Having different runner lengths and runner ID would be moving away from the ideal. __________________ Semi-Retired as of April 25, 2007. Don't bother to PM me. I am tired of internet fools. Contact via RM Dealer or e-mail.

11-02-2006, 01:47 PM	#21
alterdcreations Senior Member Join Date: Feb 2006 Location: Single camshafting for now in, N.Y. Posts: 3,223	Re: IM manifold Design Theory (Don's Lackey) oh i forgot to mention Don's lackey=Rocket __________________ http://images.honda-tech.com/set1/smile/emcocktl.gif http://images.honda-tech.com/set1/smile/emdgust.gif

11-02-2006, 03:28 PM	#22
Combustion Contraption Senior Member Join Date: Jan 2003 Location: So Cal Posts: 8,534	How about a plenum that is smaller in volume at the farthest runner. __________________ EARL LASKEY, YOU WILL BE MISSED CCCylinderheads.com Check out the INDUCTION SPECIAL Matco Doublebay Toolbox FOR SALE Click Here!

11-02-2006, 04:00 PM	#23
Master of the Universe Join Date: Mar 2002 Posts: 6,493	Re: (Combustion Contraption) Cosworth, GM Performance Products __________________ Semi-Retired as of April 25, 2007. Don't bother to PM me. I am tired of internet fools. Contact via RM Dealer or e-mail.