Once again a " Would This Work" topic by no_8wire.

[RomanV]

Just something interesting to note....

An F20c (The 240hp 2 litre NA engine for an S2000) Has a throttle body diameter of 62mm.

Now... How wide is the AW11 throttle body?
It would seem that 62mm throttle is good enough to supply enough air for 240hp, so i doubt that the standard throttle would be a bottle neck for a standard 80s 4AGE.

What is also interesting, is that from memory, the throttle body from my 3sge is 75mm or so... Larger than on an S2000. Weird!

[barryogen]

Just something interesting to note....

An F20c (The 240hp 2 litre NA engine for an S2000) Has a throttle body diameter of 62mm.

Now... How wide is the AW11 throttle body?
It would seem that 62mm throttle is good enough to supply enough air for 240hp, so i doubt that the standard throttle would be a bottle neck for a standard 80s 4AGE.

What is also interesting, is that from memory, the throttle body from my 3sge is 75mm or so... Larger than on an S2000. Weird!

size doesn't necessarily matter with regards to throttle body... atleast not until your at the edge of it's limits. you can pass the same amount of air through a small one and a large one, except the smaller one the air will be travelling faster.

check out wikipedea on "d laval nozzle"s and you may see what I mean.

[Stealer Of Souls]

In theory the only thing that changes is the air velocity through different sized pipes. In practice there is also an associated pressure drop. Any pressure drop in the intake results in reduced power.
But I would be surprised if any full open TB created a pressure drop worth mentioning... Unless it was undersized....

[RomanV]

Just something interesting to note....

An F20c (The 240hp 2 litre NA engine for an S2000) Has a throttle body diameter of 62mm.

Now... How wide is the AW11 throttle body?
It would seem that 62mm throttle is good enough to supply enough air for 240hp, so i doubt that the standard throttle would be a bottle neck for a standard 80s 4AGE.

What is also interesting, is that from memory, the throttle body from my 3sge is 75mm or so... Larger than on an S2000. Weird!

size doesn't necessarily matter with regards to throttle body... atleast not until your at the edge of it's limits. you can pass the same amount of air through a small one and a large one, except the smaller one the air will be travelling faster.

check out wikipedea on "d laval nozzle"s and you may see what I mean.

Thats what Im trying to say.... You're not going to flow more air through two throttle bodies, the rate at which the engine can consume air doesnt change.

Since the air velocity will be *much* lower, it would be detrimental more than anything.

As well of the side effect of making your throttle feel incredibly twitchy.

Although S.O.S. is right, it takes energy to accellerate the air... The engine has to 'suck harder'. (Meaning less engine HP that goes to the wheels) However this is generally worth the effort, as the inertia of the air rams more air into the cylinder than would otherwise be possible.

A well tuned intake which increases air velocity into the ports will make more power than having the ports open to the atmosphere...

At the same time, a poorly set up intake can worsen the situation, if it reduces intake velocity.

[barryogen]

A well tuned intake which increases air velocity into the ports will make more power than having the ports open to the atmosphere...

So if we could just force the induction side of it, you'ld get more HP... nice..


heh, I know I know, I just had to say it.

[RomanV]

It just depends on whether you prefer 'suck' or 'blow'.

[barryogen]

It just depends on whether you prefer 'suck' or 'blow'.

I was going to reply, but now I'm not so sure I should.

[Malcolm]

can I just go off on a tangent a little here? thanks...

In theory the only thing that changes is the air velocity through different sized pipes. In practice there is also an associated pressure drop. Any pressure drop in the intake results in reduced power.
But I would be surprised if any full open TB created a pressure drop worth mentioning... Unless it was undersized....

this is not a personal attack, but a general rant - I hate it when people say "in theory" then they spout off a 1 dimensional comment about how things should behave if you only had a primary school education with which to predict them. The great thing about the physical universe is that it pretty much behaves exactly as it should theoretically, provided the theory you use completely describes the situation, with the exception being quantum physics, and chaos theory (where a system would require description so accurate that it isn't feasible to input data with enough precision to get the true outcome)


anyway, as I said on clubaw, I don't think you'll see any gains from this, unfortunately. Unless you're flowing a lot more air than the engine did when stock, or the engine is equipped with a massively undersized throttle body, enlarging it wont be of much use, whether it be by the addition of extra throttle bodies, or increasing the size of the existing one.

also I think in most cases a single large throttle body would flow more air than multiple throttle bodies of the same cross sectional area. as dave has mentioned, you get friction caused by the outside of the pipe (called a "boundary layer"), but also you would get a boundary layer forming around the throttle butterflies, not to mention a lot or turbulence due to all this (assuming you don't have air flowing so slowly as to be laminar). AFAIK the big advantage from quad throttles is the proximity to the inlet port giving much better throttle response, not a massive gain in power over a single large throttle

[Stealer Of Souls]

I feel I should defend myself...
But I won't... kinda...

I will say this... (in defense of all people who use the "in theory" statement)
Most people you will meet have only a limited understanding of physics. Take for example centrifugal force. I mean WTF is that??? It doesn't even exist, and yet everyone seems to know everything there is to know about it.
The reason people talk about "in theory" is because in order to view the greater outcome of something they need a simple model to work with. Then they do a test, and if the test results vary too significantly to the expected outcome, then they go and develop the model.
Don't forget. Most people can't model aerodynamic flows in their head right down to the nth degree.


This is a case where the most important bit of information is the fact that we're talking air velocities. I would suspect that the pressure drop created by multiple throttle bodies (vs single large) are relatively insignificant. Better to look at the rest of the inlet tract for gains there.

[barryogen]

you would probably get better gains by making the pipe less bent, I remember reading somewhere about the increases in resistance through certain degree bends, so the guy who was doing the testing made a new intake pipe with fewer, less sharp bends(same pipe diametre) and got like 2kw, now I know that it would be well within the margin of error, but it was a re-produce-able(I can't spell), old pipe, it would drop, new pipe, it would go up.

He then changed things like filters, pipe length blah blah blah, etc etc etc, ended up with pretty much a straight short CAI pulling from a bonnet vent.

Yay my mspaint skillz

I'm pretty sure that you could jerry-rig something for an MR2, I mean you would have a heap of air-flow over the roof(or along the sides), maybe a scoop there down to the filter(sorry I have no idea on the engine bay layout in an MR2).[/img]

[RomanV]

Yep, this is exactly what those horrible looking 'snorkels' are for!
(That some people put on their SW20s)

(As seen here)

To direct air down to the pod filter, sealed from the rest of the engine bay.

On the 'proper' Toms air scoop, the pod filter is sealed in a box on the left hand side of the car, under the scoop. Air comes in directly from the top of the car, down the snorkel to feed the pod filter with cold air. (EDIT: Not true, as pointed out by Revhead below)

However most are rangified versions, without the bottom half.
Since the air flow in an SW20 comes UP from under the car and out the top of the engine bay, some have theorised that in this case air will actually flow UP the scoop, as it is exposed to the rest of the engine bay.
I can neither confirm nor deny this however, since I have never considered getting a scoop. Because they look terrible.


another thing to consider with bends in pipes....
I have run a few different configs through my fluid dynamics program, and it was surprising what I saw. When the air got to a bend, it started to 'swirl' around the axis of the centerline of the pipe... spinning like a tornado, if you know what I mean.
And the air carried on 'swirling' further down the tube. So obviously the effective distance that the air is travelling increases considerably, the air isnt travelling in a straight line relative to the pipe.
I would imagine that this is the primary cause of the extra 'drag' caused by pipe bends.

[Santa'sBoostinSleigh]

they look terrible.

i'll 2nd that!

[Mr Revhead]

actually the officail TOMS part is just the scoop.. theres no air box...

[RomanV]

I stand corrected.

[Mr Revhead]

sit down, you make the place look untidy


how you describe is how it SHOULD be......

[barryogen]

they look terrible.

i'll 2nd that!

3rd'd... they do look bad.

[Stealer Of Souls]

another thing to consider with bends in pipes....
I have run a few different configs through my fluid ... considerably, the air isnt travelling in a straight line relative to the pipe.
I would imagine that this is the primary cause of the extra 'drag' caused by pipe bends.

An interesting thought relating to this... Although the turbulence may cause additional pressure drop (drag), there are certain vacuum cleaners that utilise this same principle to increase the air speed inside their chambers (dyson??). Their claimed effect is to create a spinning vortex through which the centre draws air at a greater speed than a plain straight section.
I had this thought the other day as to whether it would be possible to replicate this on the straight section of an intake to increase air velocity... I finally passed the idea off as "not bloody likely", as I feel the pressure drop will ruin the air flow.
Higher velocity but less actual mass flow.


Oh and there's an interesting point... Greater velocity with lower overall mass flow... Another possible issue of any designs...


And as a final note to this post.
Those SW20 snorkels look completely rude in my opinion. What are they trying to do? Catch a low flying bird? Or perhaps all the rain off the roof... (okay so it doesn't touch the roof... but it looks like it does.)