Swift 1.2 VVT Airbox Questions

Posts : 18 Join date : 2012-08-22

Hi Peter i have posted this elsewhere long back. But i would love to hear your thoughts regarding this. So i'm re-posting it here.

Part 1

Many say that the function of the rubber is to make the airbox act as a resonator and at some frequencies it will help suck in more air.

Original post:

The new Swift 1.2 has a new airbox design with a small 45 degree rubber bend attached at the end of the airbox pipe. This rubber end section can be pulled out and re-fitted easily in less than a minute. I think the rubber section was put there by the manufacturer to make the opening of the pipe towards the front end of the engine from where it will get outside air through a slit on the top LHS of the grill.

But there is something else to this rubber piece. The inner diameter (ID) of the plastic pipe from the aribox is approximately 60mm. But the rubber end constricts that opening to around 40mm ID before opening with a bell mouth of around 57mm OD. Why is the ID restricted to 40mm by the rubber pipe from the original close to 60mm?

I have attached a pic of the engine bay with the rubber part marked inside red square.

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I removed the rubber and here are some better shots
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Posts : 18 Join date : 2012-08-22

Part 2

This is about the ridges/ribs inside the airbox. Does it help if the ribs are smoothened out?

Original post:

Another question hope someone could clear this as i have no idea why this kind of ridges are here inside an air box. The airbox pictured here is of our i10 1.2 and the photos were taken many days ago an uploaded to team-bhp in another thread. I'm posting this here in this thread because i found the same ridges et al in the new Swift VVT airbox too. It was not present in the older Swift airbox. Can some one tell me why is like this?

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Posts : 187 Join date : 2012-06-13

Answer for the first post:

The reduction is to gain gas speed. This will aid bottom end torque. This is obviously the product of an after thought. Bending it roughly 45 degrees forward most likely is because they faced turbulences with increasing speed - problem that is often under estimated when designing air intakes.

Answer to second post:

This again is an after thought. The air did not flow the way the original design intended. Additionally resonance problems might have occurred.

Posts : 18 Join date : 2012-08-22

Nano fan wrote:: Answer to second post:

This again is an after thought. The air did not flow the way the original design intended. Additionally resonance problems might have occurred.

But how would adding ribs to the internal structure of the airbox aid airflow. From the looks of it it should hinder airflow, shouldn't it?
Someone mentioned that its for strength, but i don't think its there for strength.

Posts : 187 Join date : 2012-06-13

crankysan wrote:

Nano fan wrote:: Answer to second post:

This again is an after thought. The air did not flow the way the original design intended. Additionally resonance problems might have occurred.

But how would adding ribs to the internal structure of the airbox aid airflow. From the looks of it it should hinder airflow, shouldn't it?
Someone mentioned that its for strength, but i don't think its there for strength.

Flow dynamics is very complex. What makes things even worse is the pulsating flow. Due to the fact that the air box is far from the optimal shape, which is due to space constraints as well as the fact that the pick-up point aren't good starting points. Additionally the gas speed constantly changes and the car moves with varying speeds.

What needs t be understood is that the shape of the car as well as the under bonnet 'landscape' have an effect on the air intake. Turbulence factors (which are plenty about) increase with speed and can change the over all pattern.

What also is often forgotten is the fact that an air filter is not used completely by the air flowing through. Usually at the edges does not occur any airflow. In the box you showed, the pipe goes into the air box. There is a number of reasons for it, which have mainly to do with drive-ability, but also sound deadening. But this comes at a price. The fins help directing and reduce turbulence and will add to further sound deadening.

Posts : 18 Join date : 2012-08-22

I made some changes to the stock airbox today since i didn't have anything better to do today. I found that i could take off the tube and the resonator along with it without damaging the airbox. So i did take out the long tube and the resonator but retained the rubber funnel end.

Went for a test drive in the evening and noticed some changes, 1) The torque curve shifted down, i expected the opposite, and it is very evident 2) throttle response is quicker and 3) the intake noise increased as expected.

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This is how the Swift 1.2 VVT airbox looks inside. The pic i posted earlier of the internal airbox is of the Hyundai 1.2 Kappa's.

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When are you bringing out the AIR for the new Swift?

Posts : 187 Join date : 2012-06-13

This is one terrible air box.

Well, the Swift I am working on at the moment and it will be finished the latest in mid September. You can have the first one if you wish.

BTW, you are as bad as me. You can't leave cars alone. I couldn;t even resist the hire car. This is the reason why we have an AIR for the i10 kappa. Smile

Posts : 18 Join date : 2012-08-22

Yes it looks badder than the old 1.2's airbox, its internals were much smoother, still the after filter area on that didn't look it would flow good.

Here's new update after driving alone on my way to office. There is a prominent push at 2k to 3krpm and then at 4k.. there is a mild flatspot after 3k though.

Mmm.. problem is i like to be doing something all the time.. and cars/bikes (not anymore) always fascinated me starting with my bicycle so been trying out what i could do on my own to see what kind of changes i brought to its performance. Sometimes it did good and often not much good Smile

Posts : 187 Join date : 2012-06-13

You should go and find a nice 1/4 mile stretch and get some acceleration testing done. run the car between 5 and 10 times stock and then with each set-up either with the ipod or any other unit. This way you will see much more of the effects and it is a lot of fun too.