What do these intakes do for the engine?

[jibby]

I feel stupid asking this question but on an engine like this it appears these are each 8 little throttle bodies for each cylinder on a custom intake manifold... Am I close to right about this assumption anyone? What are the advantages to an intake setup and manifold like that? Is this setup only for track use, or can this be used in the city?.. Is there even any type of air filters on this type of setup??? I just have no clue? Anyone?

 

[Anaema]

the intakes are good for increasing the length of the intake to each port, which means more HP in the high end. shorter intake runners makes more torque in teh bottom end. and i have no clue if those have air filters.

 

[jibby]

Shorter intakes makes more torque....thanks for the definition, pretty much what I figured just haven't looked into these types of intakes....

 

[340i]

itb intakes have very direct air flow. single tb intakes with plenums and intake runners cause the air to go in many directions and around corners etc, which reduces flow and therefore power. you can buy 'sock' filters for the trumpets or run a box type air filter over all the filters or whatever setup you want really.

 

[jibby]

Where is the MAF, or MAL on these engines? I would guess it's just a raw form of intake?... Is this setup for track use only or do people run these intakes on the street? What kind of power does it create? Intake can only do so much for an engine, so being that this intake is not a form of any kind of forced air induction it would seem this intake would mostly be for show and no go? What is the difference between ITB and TB intakes? ... 340i only answer if you have the time, I can search for all this...Anyway thanks---

 

[crUZermk2]

other way around, big,short runners make high revs and top end power and longer, narrower runners make more torque and low rev response.

 

[340i]

this is being discussed extensively in this thread at the moment;
http://lextreme.com/forums/showthread.php?t=3846

i had originally decided to go for a 1uzquadcam itb setup and even bought two sets of 4age intakes, but have changed my mind to eventually run forced induction on a standard manifold due to the higher power increase per dollar spent. each setup has its advantages and disadvantages so will be better for different circumstances.

it would be interesting to compare a 1uz with itb's and the same engine with a custom designed intake and plenum with one or two throttle bodies on it. this would be my ultimate setup - a vortech and custom twin plenums and big throttle bodies on the end of each. mmm that would be nice.

 

[jibby]

Thanks 340i.......

 

[shadetree]

Have you seen this ITB 1UZ vid?
http://videos.streetfire.net/Player.aspx?fileid=7B692CB1-DB71-418E-B4D6-3B5FB0148D73&p=0
This video makes my pants tight.

ITBs have a couple of advantages.
- Each cylinder has the same air flow characteristics. Most intake manifolds do not flow evenly, so that some cylinders gettin more air than others, some end up richer and others leaner.
- Larger throttle opening. 8 little throttle bodies area is equal to one absolutely HUGE TB. ITBs generally have secondary butterfly valves, so that the huge throttle size doesn't throw off your idle and low end. Way better flow at WOT
-Allow you to run velocity stacks, better flow.
-they allow you to tune intake runner length much easier than with an intake mani

Generally due to the larger TB size you lose low end in exchange for more HP up top.

Lots of people are making ITB setups using bike itbs, on the cheap. You do need a MAP based fuel system, though.

Here's a couple of interesting threads
http://www.homemadeturbo.com/tech_projects/itb/
http://www.honda-tech.com/zerothread?id=1191757&page=1
http://www.homemadeturbo.com/forum/index.php?topic=39723.0

 

[jibby]

That is one rude intake video to say the least!!!!!!! Oh, those little throttle bodies..... No filters, no MAS/MAT either just straight intake...WOW, I like it, but I would have to wonder about debris, dirt, etc.. that might find it's way into those exposed little throttle bodies and then into the motor and potentially cause damage..also so much for the cold air intake theory as well, those throttle bodies must suck the heat in right off the engine I would assume....any thoughts on that?

 

[shadetree]

Yeah,ITBs are not a daily driver set up. Realistically, they make your TB area soo big, you really should have a high compression engine build, big cams, equal length exhaust. They definitely are to the extreme of n/a builds.

You can put little foam sport bike filters on them.

You can also fab a plenum around the velocity stacks, and run turbo charge pipes,or intake pipes as you would with a normal intake manifold. I'm pretty sure Toyota made a turbo 4banger with ITBs, that had 2 spark plugs per cylinder, related to the 4age maybe?? Do not hold me to that.
[edit- 3sge?]
http://video.google.com/videoplay?docid=555670508359773592&q=turbo

http://www.honda-tech.com/zerothread?id=1394232&page=1

Check out this Zcar. GT3540, 6 TBs, carbon plenum.

:bigeyes:
His 510 is ridiculous, too
http://www.turbomagazine.com/features/tur0801a01_free/

Mclaren F1

 

[jibby]

Shadetree - Nice motors, good pic's and links......

 

[Anaema]

ph wait, i think i got that backwards, longer and thinner runners make torgue(though i dont yet know how), and shorter fatter ones make HP. it has something to do with Volumetric Effeciency.

 

[Pro]

other way around, big,short runners make high revs and top end power and longer, narrower runners make more torque and low rev response.

i was hoping someone would pick that up!!!

 

[Pro]

ph wait, i think i got that backwards, longer and thinner runners make torgue(though i dont yet know how), and shorter fatter ones make HP. it has something to do with Volumetric Effeciency.

lifted from a miller engine site

Volumetric Efficiency

The term volumetric efficiency refers to the ability of an engine to fill its cylinders with a volume of air equal to their displacement (100 percent Ve). The greater the Ve then the greater will be the output of that engine. Engine manufacturers go to great lengths to "tune" their engine design and obtain the greatest Ve. This involves a lot of research into gas flow - including manifold and port design - as well as valve timing and lift, together with multiple valves and combustion chamber design.

The easiest way to make dramatic improvements in Ve is to add an external device such as a supercharger or turbocharger. Its job is to "force feed" as much air as possible into each cylinder. But, as with increased compression ratio, excessively high combustion pressures and temperatures may be produced by forced induction.

runner lengths are changed to modify the Ve of an engine.
Ve is a fancy term for "cylinder filling".

Mazda Miller Cycle website

have a read :veryhappy

 

[jibby]

Got it I think, correction noted. This is nice and all but should be for track only, little air filters can be used or box filter on top. Could also have a hood scoop to direct colder and clean air into the top of the engine TB's. I know what it is like taking care of one throttle body, imagine eight? This maybe called eight headaches instead. I would think they get dirty often especially if not filtered. I would also say you would need to spray the TB's regularly to keep it all clean and functioning correctly...What do I know though I am just guessing at all this anyway and going to introduce air forced induction soon anyway. I would say this type of intake just would not apply to the goals of so many on this forum....

 

[Pro]

i'm building a Datsun A14 engine with a turbo and quad TBs soon. might have to make a plenum with one TB also and test the results.

remember Nissan fitted ITBs to the RB26DETT as factory equipment...!

 

[cribbj]

Has anyone seen any recommendations or guidelines for ITB butterfly sizing and runner lengths? The Jenvey site has some general ideas, but the Honda Tech guys seem to be going with bigger butterflies and making them work.

John

 

[SCV8]

ITBs are great for the street, especially during lower rpms where a nasty engine will tend to bog with a plenum-type intake. Also, you can't just compare the throttle body area between a plenum and ITBs; the situation is different.

The foam bike filters do work very well though.

 

[Pro]

Has anyone seen any recommendations or guidelines for ITB butterfly sizing and runner lengths? The Jenvey site has some general ideas, but the Honda Tech guys seem to be going with bigger butterflies and making them work.

John

google for "david vizard inlet port runner calculation"

written for tough NA honda engines ( :lmao: ) but useful nonetheless.