quade throttle bodies ?? whats up with that

[jcrx]

That's wonderful and all, now show me a relavent article that has to do with Honda ITBs and boosting them. I already know about and the Skylines, and you're missing your last link.

[Moppie]

The last link is fixed.

And my point is if your have any kind of imagination and some mechanical know how its not hard to fit a plenum to independant thorttle bodys.
The example you showed a picture of would be a little more challanging, but certianly not impossible, and its by no means the only set up avliable.

Its relevancy is only to prove that it can be done.
And if you can afford it its has its advantages, mostly being more power from lower boost levels. The only reason its not done more often is that its generaly cheaper to just run more boost, and once you reach a certian level of boost the engines powerband becomes so limited that there is no longer an advantage to having ITB's.

[Tranzlogic]

it could really go either way,a gain its all a amatter of opinion and how much money you have tp throw around..id do it just to say i had a boosted quade b16a2 del sol

[jcrx]

Throttle bodies in the design of the ones I showed you, yes, you COULD fabricate an enclosure, and yes you COULD boost the motor, but the design is inherently flawed, since the runners would imped flow, and they were designed for N/A use. The Skylines have individual throttle plates, though I have never seen the inside, I HIGHLY doubt they have runners like that. You could design an intake manifold for a Honda that has the individual plates, but why?

[Moppie]

The GTR skylines actualy have a set up similar to the design you posted, its just very will hidden under the rest of the crap, fuel rail, casting shape of the manifold etc.

The idea of a quad thorrtle body is that you have the throttle plates and injectors (jets, etc if carbs)as close as you can to the intake valve with runners that can be tuned in length for each cylinder. Bascily each cylinder is able to be feed exactly the air flow it needs with out being disrubted by the needs of those around it.
The nissan engines all use that set up, short runners (for better high RPM air flow) all of tuned length. (its why when fitting NOS to an RB26 you have to use a multi port set up, or one of the cylineders runs lean due to the runner length and manifold design).
Each TB is fitted to a very short manifold that is fitted to the block (visable in the pics) and then a plenum is fitted to the backs of the TBs.
They are no differnt in design than the Honda one you showed a pic of, only theres 6 of them. On a Turbo engine things like runner length and restrictions become less important, since the air is literaly forced passed, and through such obstructions. They still have an effect on total airflow, but as a % it is much much less than on a N/A engine.
So any set up designed to work well under N/A will also work just as well with forced induction.
And a quad throttle body set up should offer a more optimum flow than a standard multi runner intake as it should have shorter, and wider intake runners, and of course anything that optimizes flow should increace performance


And on the use of plenums, most ITB set ups work best with some form of plenum chamber over the throttle bodys. Its a must have to keep a constant supply of cool air coming to the intake. Any setup with out one risks simply ingesting hot engine bay air, which of course would defeat the purpose of having an ITB set up.

[boosted331]

Originally Posted by jcrx

Throttle bodies in the design of the ones I showed you, yes, you COULD fabricate an enclosure, and yes you COULD boost the motor, but the design is inherently flawed, since the runners would imped flow, and they were designed for N/A use. The Skylines have individual throttle plates, though I have never seen the inside, I HIGHLY doubt they have runners like that. You could design an intake manifold for a Honda that has the individual plates, but why?

One of the reason's ITB's make a lot more power/better throttle reponse on N/A motors is because the velocity stacks greatly improve laminar flow of air into the motor. This same principle is used in designing the compressor housings for turbonetics Y2K and thumper turbos, as well as PTE's thumper turbos. Some good intake manifolds for hondas have velocity stacks mounted inside the intake manifold, the only one I can think off of the top of my head is Wilson's intake, but not many people have it because it is VERY expensive at around 2300 dollars. Velocity stacks help smooth out air flow, and are the main benefit you get from an ITB manifold. I'm sure a well designed manifold using some runners with velocity stacks attached to a surge tank with a single throttle body would perform nearly as good as an ITB manifold on a boosted honda.

[strodda]

the skyline does not have individuals. when its enclosed like that, its just a manifold, and what youre talking about are the runners. you can have itb's and turbo but you cant have turbo and use the itb's for what they were made for. when that guy takes the itb's and makes a plenum for them, he basically just made a real expensive IM.

at wot, everything is going to be open, there is no difference between having 4 small butterflies or one big one... and its not worth all that money just to say youre running boost on itb's.

[jcrx]

Originally Posted by strodda

the skyline does not have individuals. when its enclosed like that, its just a manifold, and what youre talking about are the runners. you can have itb's and turbo but you cant have turbo and use the itb's for what they were made for. when that guy takes the itb's and makes a plenum for them, he basically just made a real expensive IM.

at wot, everything is going to be open, there is no difference between having 4 small butterflies or one big one... and its not worth all that money just to say youre running boost on itb's.

Almost exactly my point. under boost the VS's are not doing anything. And certain designs on IM's yes have individual butterflys, and maybe even VS's inside, but there is no point to it since they are no longer building velocity, it is being made by the turbo. Indidvidual throttle bodies, like the one I posted are made for N/A applications, as they help to create airflow velocities a regular IM isn't capable of.
Yes, you could fabricate a manifold that would effectively cover and deliver air to the ITBs, but it is pointless.

[Dinasour]

JCRX: I don't know your background but I run ITBs on my car which doubles as a dailey driver and a very quick hillclimber. Over a single throttle I found on a NA engine that I actually lost top end BHP and gained alot in the mid range and throttle response is greater. And drivability is no different around town - I just have to get used to not having assited brakes but then if I suffed around enough I could have that too.
I have built a turbo motor for a freind with ITBs and it too has better mid range and part throttle performance over a single throttle.
The difference is very noticable coming off slow corners, part throttle performance is so much crisper. For drag its probably not Ideal but for circuit or hillclimbs I don't think you can go past a well sorted ITB - Turbo or not.

So yeah your right if you drive around all day at WOT then there is no advantage but then why have a throttle at all.
EDIT
Also your little speil about them no longer creating velocity or what ever it was you are trying to say is Bullshit. Think about how air gits into any engine boosted or not. the piston or rotor moves away from the inlet port creating a low pressure area. the higher pressure air from the inlet manifold moves towards the cylinder. When we add boost we are not changing the air speed rather we are increasing the density of the air. SO AIR SPEED IS STILL CRITICAL IN A BOOSTED ENGINE!