Formula 3 air intakes

[SamHH]

Why is the air intake on modern F3 cars positioned in a pod on the side of the engine cover? What are the advantages of this design over the more conventional 'over-the-driver's-head' design and are there any other single seaters that use it? Also, is the air filtration system inside the pod?

[Truckosaurus]

Is it not just because they use 4-cyl engines with the intakes out of the side, whereas bigger single seaters have V-engines with intakes in the middle?

[SamHH]

I hadn't thought of that. The fact that Formula Palmer Audi, Formula Renault and Formula BMW all use straight-4s and all have an 'over-the-driver's-head' intake goes against that theory, but maybe they are all willing to use a less efficient design for the sake of style because they are spec series.

[Eric Mc]

I thought that they were are restrictors rather than air intakes. In other words, they do the opposite to the ram-air intake on an F1 car. They reduce the airflow to the engine rather than increase it.

[Digital]

Eric Mc said:

I thought that they were are restrictors rather than air intakes. In other words, they do the opposite to the ram-air intake on an F1 car. They reduce the airflow to the engine rather than increase it.

I seem to recall a British F3 race winner subsequently being disqualified after a crash had knocked off the restrictor and thus improved the performance of their car

[Chassis 33]

4 pot formula with air intakes over the drivers head, eg F.Renault, generally have a lamb chop bone intake after a single throttle "up top" that then whisks the air round to the side of the engine, improving torque a little. F3 intakes minimise the effects of the intake restiction by making the losses through the neck to the minimum diameter as small as possible before controlling the air flow into the engine with throttle bodies after the bulging plenum.

Regards
Iain

[SamHH]

Eric Mc said:

I thought that they were are restrictors rather than air intakes. In other words, they do the opposite to the ram-air intake on an F1 car. They reduce the airflow to the engine rather than increase it.

Yes, F3 cars do have air restrictors but if they work like they do in other forms of motorsport, they are simply a hole of a specified diameter through which air entering the engine must pass. Regardless of whether an engine has an air restrictor, it must still have a system to direct air into the engine, a.k.a. an air intake system. Further, having an air restrictor does not preclude use of the 'ram effect' to force more air into the engine. What I'm asking is why is this system mounted outboard in a pod on F3 cars?

When Toro Rosso used a V10 in 2006 they had to fit an air restrictor to make it equivelant to the V8s. The restrictor can be seen in photos of the STR01.

[SamHH]

Iain: thanks for the answer.

[Eric Mc]

SamHH said:

Eric Mc said:

I thought that they were are restrictors rather than air intakes. In other words, they do the opposite to the ram-air intake on an F1 car. They reduce the airflow to the engine rather than increase it.

Yes, F3 cars do have air restrictors but if they work like they do in other forms of motorsport, they are simply a hole of a specified diameter through which air entering the engine must pass. Regardless of whether an engine has an air restrictor, it must still have a system to direct air into the engine, a.k.a. an air intake system. Further, having an air restrictor does not preclude use of the 'ram effect' to force more air into the engine. What I'm asking is why is this system mounted outboard in a pod on F3 cars?

When Toro Rosso used a V10 in 2006 they had to fit an air restrictor to make it equivelant to the V8s. The restrictor can be seen in photos of the STR01.

Tradition?

Could it be to do with not allowing any part of the car body to be higher than the highest point of the roll-over bar?

F2 and F3 cars have been fitted with these types of intakes since the 1970s from what I remember.
Is their prime purpose to act as an intake or to act as a restrictor - or both?

I've always ben fascinated by air boxes and their fashions. They have come and gone in F1 over the decades. Ferrari featured perspex ones on their 1950s cars. In the 60s they were not used, with the engines being quite exposed at the back of the car and fitted with simple intake trumpets. They made a comeback from around 1970 and then grew to preposterous sizes being eventually restricted in size from 1976. Then with the advent of turbos they disappeared again finally to re-emerge when normally aspirated engines began to be used again from 1987 onwards.

Edited by Eric Mc on Tuesday 25th March 09:35

[Racefan_uk]

SamHH said:

Also, is the air filtration system inside the pod?

Just to add to the other good replies. There isn't a filtration system on an F3 car. It would sap an already well restricted air intake so not used.

I'm no sure there are many (national level) single seater cars that run with air filters anymore. I know the older Formula Renault teams (1700, not the latest cars) used to run with them for testing, in case of anyhting getting sucked in and wecking an engine. But for races would take them off anyway for the extra air flow.

[Dunit]

I think the restrictor is fitted in the Bellmouth at the front of the airbox on both the Mercedes and VW engines .They run the airbox on different sides to each other. The reason for being on the side is to get the correct inlet tract length to aid the torque.

[NightDriver]

The rules loosely dictate that the intake could not be over the drivers head, the maximum height for any bodywork (excluding the roll hoop) must be less than 900mm. As a result there is simply not enough room to get an airbox of an acceptable size/shape in that position. Clever packaging is ruled out, as it must be possible to remove the cylinder head and intake system as a complete unit. Factor in also that the engines have to fit into different chassis' with different engine covers the air boxes end up on the side of the car.

[Mutley]

Just adding to what has already been said, the "airbox" on the side of an F3 car acts as both inlet and restrictor.

And yes about 4 years ago was when a winner was disqualified because an earlier accident had split the box therefore the air getting into the engine wasn't restricted, therefore, better performance acheived.

[superkartracer]

Also gives them that great sound :-), not bad for a 4 pot

[techman]

They do have air filters cos I had to change one the other day in testing cos a bird decided to fly into the air box!