B.Rabbit put on his measuring shoes tonight figured out the volume of the stock h22 plenum.

1419cc

That is not counting the butterfly plate either.

As far as I have read, this is a bit too big for NA, according to my sources the plenum should be equal to about 50-60% of the engine's displacement for NA engines to make peak torque around 5-6k rpm. That implies that removing the IAB plate is a no-brainer on paper....

Discuss.....

Thanks Blake

 

thats about as close as i could get it. I wouldnt say its an EXACT number, but it gives us something to feed off of.

 

So does it make sense that having a larger plenum moves the powerband up?

Is this due to the fact that at low rpm the larger plenum slows down the intake charge a lot, and at the higher rpm, it can easily get as much air as it needs??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bb4ever &raquo;</TD></TR><TR><TD CLASS="quote">So does it make sense that having a larger plenum moves the powerband up?

Is this due to the fact that at low rpm the larger plenum slows down the intake charge a lot, and at the higher rpm, it can easily get as much air as it needs??</TD></TR></TABLE>

Interesting. I'd like to know more.

 

edited*

wrong calculations


Modified by B.Rabbit at 11:31 PM 12/13/2006

 

So without the AIB plate it's already too big? I'm assuming this slows down air flow as the extra air starts to swirl around in there.

BTW, what are your "sources"? Just curious, not smart mouthing.

Edit: my math was wrong...it's late.

Modified by Televator at 8:38 PM 12/13/2006


Modified by Televator at 9:15 PM 12/13/2006

 

I'd definetly like to know more about if removing the IAB plate would be worth it. In a boosted application specifically. From my understanding removing them takes away from low end torque but shows gain in top end horsepower, correct?

 

this would be only for NA applications. Boosted motors love large plenums.

 

Tele....theres an article on team-integra.net, thats what I'm referencing....

 

correction on oval IAB port sizing (damn online calculators suck ***)

38.5cc's per port = 154cc's combined

35cc per square port = 140cc's combined

294cc's in total.


cylinder volume forumla......... Pi * r^2 * height
Rectangular prism formula........side1 * side2 * side3

 

english blake?

 

for the layperson....

Matt had spoken with a certain reputable machinist who told him that in order to reach the greatest peak torque to have the plenum volume approx. 50-60% smaller than the size of the engine, ours is ~2200cc.

with this info, 1419cc + 294cc = 1713cc (with IAB plate on)

2200 / 2 = 1100

1713 - 1100 = 613cc too large by the machinist standards.

subtract the 294cc from the IAB plate and you get closer to the goal.

 

My head lol. Wow blake knows wtf hes talkn about. Learned somthing new

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ProjectBB6 &raquo;</TD></TR><TR><TD CLASS="quote">My head lol. Wow blake knows wtf hes talkn about. Learned somthing new </TD></TR></TABLE>

there is no empirical evidence on this. Just one person giving us some info to work with, then me and matt who are number crunching.

empirical meaning that there isn't any evidence i could give you showing this. Jdogg posted that he gained 5whp and 5ft lbs of torque everywhere when he removed the IAB plate. I take his word for it because he is very reputable and tunes for a living. Not to mention it goes hand in hand with the machinists info.


Modified by B.Rabbit at 1:46 PM 12/14/2006

 

yeah and people say "when will i ever use this" in math class... I would like to learn about this as well I wish i could be of some help. But time to watch another thread

 

Sweet read. I just wanted to be sure that it's supposed to be a general rule for all 4 cyl motors. It appears to state that it is. I just wonder why Honda would do that even when documenting the H22's VE against the F2XC.

Okay I think I got it: 1.419/2.156= .658. Wich is obviously over said optimum range.


Modified by Televator at 9:43 PM 12/13/2006

 

i'd like to hear word by the "sources"

 

Just a reminder, Brad did not tell me this, I got if off team-integra.net

There is an article on there

from the looks of john's manifold I'm not sure Brad would agree...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by M2B4 &raquo;</TD></TR><TR><TD CLASS="quote">yeah and people say "when will i ever use this" in math class... I would like to learn about this as well I wish i could be of some help. But time to watch another thread </TD></TR></TABLE>

There are a few things even an engineer like me would say are pretty worthless, matrices being one of them, and discrete math is right behind it.....but I always thought the social studies classes and such were the worst....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bb4ever &raquo;</TD></TR><TR><TD CLASS="quote">Just a reminder, Brad did not tell me this, I got if off team-integra.net

There is an article on there

from the looks of john's manifold I'm not sure Brad would agree...</TD></TR></TABLE>

wtf i must have been seeing things then, coulda swore you said brad, lol.

.....damn mushrooms

 

I would like to see the Euro R manifold with its single runner setup specs in regard to the volume of the pendium, and if its closer to the optimal volume.

 

You guys forgot to account for the size of the plenum with the IABs closed.....

From what i gathered by reading your post, just with the IAB plate in place ( not closed ) it adds an extra 2xxcc's due to the fact is increases the overall height... what about with the iabs actually closed and working properly? Doesnt it do exactly what you are saying and decrease overall plenum volume?

 

Good thread. Here are the relevant pages from the SAE F20c article. Might also want to post this in the NA and Tech forums.


___

 

I wonder what the cc's of the stock manifold are with the volume of the area the IABs close up. I forgot which ports are the ones the IABs close up, the longer ones or the shorter ones.

I would also like to know the cc's of The Birdmans manifold, we all know that thing is HUGE. Unless the pictures are exagerated.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98TypeSH &raquo;</TD></TR><TR><TD CLASS="quote">You guys forgot to account for the size of the plenum with the IABs closed.....

From what i gathered by reading your post, just with the IAB plate in place ( not closed ) it adds an extra 2xxcc's due to the fact is increases the overall height... what about with the iabs actually closed and working properly? Doesnt it do exactly what you are saying and decrease overall plenum volume?</TD></TR></TABLE>

Subtract roughly 50cc and you will have that volume, but know that when the air has to flow that irregular *** path through the plenum, hitting closed butterflies and around the plate and all, that it loses velocity, so that is a disadvantage to the plate.
Also, when they're open, the butterflies also cause turbulence, which is another slight disadvantage.

It is definitely worth noting that we were wrong in calling the IAB plate part of the plenum, it is not. Once the air is in the IAB plate it is now into the runner, so removing the IAB plate actually shortens the runners, it doesn't decrease plenum volume.

One disadvantage I see to just removing the IAB plate is that you're left with the sharp edges underneath where it used to mount....I wonder if the plenum matches up with those edges perfectly or not, they would cause a good amount of turbulence....

This really needs to be dyno tested.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vinuneuro &raquo;</TD></TR><TR><TD CLASS="quote">Good thread. Here are the relevant pages from the SAE F20c article. Might also want to post this in the NA and Tech forums.

</TD></TR></TABLE>

great article

thank you

I'd like to measure the volume of the runners as well. That would let us use that chart they have of engine disp. vs intake manifold size to figure out how the h22 one compares to the f20c.....they said that the direct runner design is better for VE, IE the euro R mani