Bigger intake manifold question

[Perry]

you can buy it? where?

hhaha Tinkerbell thats my one at adrians

[.::F[L]Y::.]

wouldnt you just want itb's? lol

[tofuR]

From what i understand intake manifolds, as many things with N/A tuning
don't follow the philosophy of .. bigger is better..

I think you'll find that lot of these intakes have a tuned length and volume,
and should recommend a duration on the cams that you would running for maximum efficiency..

For an N/A engine, it's all about pulse..
So as a very general rule of thumb as Black DC5R says..
there is the rule of of long fat runners and short thin runners generally covers quite a lot of application..

but for an exact science.. you are looking at the scavenging effects of gasses..

for those that understand the combustion cycle,
the intake valve will only be open for X number of degrees .. and closed for Y number of degrees..
for when X is open .. all is good.. waves of gas run into the chamber and are happily combusted..
but for the Y that the valve is closed.. the air that was running in at whatever velocity..
is running into the back of a valve.. and is in turn reflected back up through the head and into the runners..

This reversion of the rush of intake can actually be taken advantage of to create a scavenging effect..
to allow the next wave to come in with a nice velocity..

The tuning of the length and width of these runners really depends on the X and Y of your cams ..

So in short with such a massive manifold on a stock engine.. u will probably lose power ..

This is my understanding anyway .. maybe the REAL pros can touch up my answer..

[tinkerbell]

some measurements of intake manifolds for you:

http://www.team-integra.net/sections...ArticleID=1163

some intake manifold science/theory for you:

http://www.team-integra.net/sections...?ArticleID=466

[jansenrw]

tinker... not that I have often offered advice but the CF manifold is quite the piece of sheittt according to a very respected member of this board. It also seems to be quite over priced and does not offer substantial gains.

My quick .02. I was looking down this path. The end scenario was to go itb's. Spend your money once and once only, you'll save in the long run. The pulse effect is also known as the helmentz theory ( spelling???). So I guess, get the itb's, box em ( after careful consideration about size and dist from tb's) thats it.

[tinkerbell]

i DONT want it jansen, i just didnt believe that it was actually still for sale anywhere,

i guess it technically isn't - since it is up secondhand...

i totally agree - ITB's the whole way...

or revert back to carbies:

[tinkerbell]

I was going to put these on my 83 Prelude, before i decided to put in the B16A...

[dang]

That cf intake manifold looks pretty cool. Just go for it Perry! But you better go run your car down the 1/4 now and after or you won't even know if it made a difference or not.

[tofuR]

tinker... not that I have often offered advice but the CF manifold is quite the piece of sheittt according to a very respected member of this board. It also seems to be quite over priced and does not offer substantial gains.

My quick .02. I was looking down this path. The end scenario was to go itb's. Spend your money once and once only, you'll save in the long run. The pulse effect is also known as the helmentz theory ( spelling???). So I guess, get the itb's, box em ( after careful consideration about size and dist from tb's) thats it.

Hehe its called Helmholtz Theory..

[Wlee2]

Im going to ask here.. since its somewhat related..

IS always having a Bigger (Diameter) Runner or TB?

in this case is bigger always better ? is there a Effect on topend and Midrange like with Longer runners or Shorter runner?

and Do you think it would make a difference if lets say its a FI setup where regardless of size of runner the Boost presure in the IM is already regulated by a wategate?

[tofuR]

Im going to ask here.. since its somewhat related..

IS always having a Bigger (Diameter) Runner or TB?

in this case is bigger always better ? is there a Effect on topend and Midrange like with Longer runners or Shorter runner?

and Do you think it would make a difference if lets say its a FI setup where regardless of size of runner the Boost presure in the IM is already regulated by a wategate?

the ID (inner diameter) of the runners, is definitely not a case of bigger is better.. with most things its a precise art/science
its a measure of what RPM you want to have your power at vs the duration of your cam vs the ID of your runners vs the total length from the valves to the end of the runners ..


for a FI application .. im not so sure... not my area ..

[Wlee2]

the ID (inner diameter) of the runners, is definitely not a case of bigger is better.. with most things its a precise art/science
its a measure of what RPM you want to have your power at vs the duration of your cam vs the ID of your runners vs the total length from the valves to the end of the runners ..


for a FI application .. im not so sure... not my area ..

so umm.. if lets say umm we had same runner lengths but Bigger diameter Runners.. will that effect the car? and if it did in which direction? towards top end or Midrange?

Short Runner = more top end? right?
Longer runner = Midrange?

im sure the actual diameter should play a difference but what i was wondering is, Is it always advantageous to always have larger diameter compared to Thinner ones?

Eg.. one of the more common mods is to have a larger TB? i dont actually know what that effects..

The reason i ask is because Effectively thats what ITB are doing right? larger diamater Runners with ITB that open up as big as the runner Diameter? hence more air?

[kOncept]

Can you just bolt ITBs to any engine (obviously with aftermarket ecu) and expect good gains?

I thought you would need supporting mods like internal work?