Weber Carb Air Filter Vac lines

[BristolE30]

Hey zone,

I’m keen to remove the stock air filter setup from my engine bay. It’s bulky and makes it difficult to get to other parts so I’d like to swap it for an aftermarket airfilter.

There are however a few vac lines that come from the oil breather hose, the front of the airfilter housing near the inlet etc intertwined into it.

I’m just wondering if someone could enlighten me as to what they do? Would it matter if those vac lines were not plugged into the air filter/are they important for the operation of the carb?

Any help appreciated!
Jo

6DAC6582-F190-42B4-82AB-7A328DF17C0C.jpeg

[DavidgiDavies]

The vac lines to the air filter are used to regulate the temperature of the incoming air. If you delete this system you could get carb icing in cold damp conditions. Suggest leave it as it is,but renew the silver ducting from exhaust manifold to air filter assembly (it looks a little deformed)..

[BristolE30]

The vac lines to the air filter are used to regulate the temperature of the incoming air. If you delete this system you could get carb icing in cold damp conditions. Suggest leave it as it is,but renew the silver ducting from exhaust manifold to air filter assembly (it looks a little deformed)..

Thanks for the help. That seems fair enough...

Yes do you have any idea what that ducting is for? Emissions? I’m really keen to get rid of it, especially if it’s feeding hot exhaust into the air intake.

Do you think it’s possible to get a plate without the hole for the exhaust manifold?

Cheers
Jo

[aimlessrock]

the feed of hot air from the manifold is by design - why would you wish to remove it?

[BristolE30]

the feed of hot air from the manifold is by design - why would you wish to remove it?

Hey mate, I guess it just seems emissions orientated rather than performance. I can’t see how feeding dirty hot exhaust into my air filter would do it any good (unless I’m missing something!?). Could be totally wrong.

Plus might save me the odd air filter or two replacement.

[30316]

Its nothing to do with emissions related. Its to do with to stop icing the carburettor in cold icy weather. A 316 wasn't built for performance. If BMW fitted a part there was a good reason for it.

[BristolE30]

Its nothing to do with emissions related. Its to do with to stop icing the carburettor in cold icy weather. A 316 wasn't built for performance. If BMW fitted a part there was a good reason for it.

Ah interesting! I’ve seen a few 316’s without it (aftermarket air filter), so just wondered the reason.

No harm in trying refine the performance of an M10 tho! BMW fitted my old Pierburg carb and that wasn’t great... but I understand what you mean.

Cheers!