Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - Making 57i Induction kit even better

Some interesting stuff about improving the K&N induction kit by putting the filter in a box, and ramming air into it via the tubes (have I got that right?). Basically I was wondering what are the physics of improving airflow without turbo charging or supercharging (especially at lower speeds). Would there be a significant benefit from other induction mods, as the basic K&N kit does not seem fundamentally difficult in concept or design.

Andrew Hay

How about mounting an engine bay type fan in the left hand air vent and sucking air into a tube leading to the cone ...


It is possible to improve intake airflow at low engine speeds. The principles are based on 'ram-effects'- both inertial and wave (briefly described on -->technical--> filters)- and this is what variable length intake manifolds are all about.

Have a nice long intake tract, and you have a greater mass of air moving towards the engine. This air has inertia, and will, by its movement, suck more air into the intake manifold... this is the inertia-ram effect. This results in better engine torque low in the rev range.

Unfortunately, there is a price to pay- as long intake tracts have more frictional losses that will effect high speed air movements- and thus top end power is limited.

So 'normal' intake systems are a compromise between these two completing demands. Variable length intakes are trying to 'make the cake and eat it' but are difficult to engineer, heavy and require some kind of control device/system. Maybe a simpler system is devisable- two filters on a Y-shaped adapter with a single butterfly valve altering the the direction of airflow from the short intake tract filter to the long intake tract filter... Be my guest to have a go!

Rob Bell

>>How about mounting an engine bay type fan in the left hand air vent and sucking air into a tube leading to the cone ...<<

Nice idea, but the fan you have to move serious ammounts of air to make any kind of difference. 1796 cc 4 stroke 4 cylinder engine. 900 rpm idle with 449 mls of air drawn into the engine with each revolution = 404 litres per minute... Okay, the actual figure will be lower than that, but you get the idea that a computer CPU cooling fan ain't going to cut the mustard! ;o)

Rob Bell

What I would like to know with regard to the enclosed systems, what happens if the induction pipes end up under water? With the open cone you don't get this problem until you are up to your neck in water, by which time it will have stalled anyway :-0
Tony Smith

You're in truba.

Thats why an enclosed system would need the inlet to be up high (thanks for pointing that out Rob) which is a handicap for an F. You can use the inlets, but then you get no ram air. i would like to be able to get ram air to the filter some how.

Ram effect created from vehicle speed is irrelevant under 100 mph. Ram effect from simple air movement has far more promise. In these circulstances you need to devise the system as a one way street with 'protrusions' to trip up airflow that tries to revers flow. This may in the very best circumstances achieve positive pressures of up to about 2psi. However actually fuelling this correctly becoems a problem.

Roger Parker

This thread was discussed between 13/02/2001 and 15/02/2001

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.