Fitting aftermarket air filter - what else do I need to do?

[zortonesta]

I'd like to fit a Ramair or K&N filter to my carby, obviously not looking for massive HP gains, just a nice sound and a cleaner engine bay.

So, if I fit one of these foam filters and lose the OEM metal air box where do all the hoses go that would have previously fed into the box?

Will I need a small universal cone filter that will feed into the valve cover? And simply delete all other hoses?

[Brianmoooore]

Close the bonnet and walk away.
E30 engines are designed to run with negative crankcase pressure, so your filter on the valve cover is also not a good idea, but quite what that's got to do with replacing the air filter, I'm not sure.

[DanThe]

The valve cover filter will lose as much power as removing the standard air filter box

[zortonesta]

Honestly, I don't know either.

When researching this the other eve I saw someone that had changed to a K+N filter and the hose that goes in/comes out of the valve cover also had a small cone filter attached - I figured that's what was neccesary. Here's the image

http://images.classiccars.co.uk/c/467/2 ... 9ddf9f.jpg

So you're saying forget it completely?

[Brianmoooore]

So you're saying forget it completely?

Got it in one! Your pic is of a M10 carb. engine which has had its complicated and unreliable OE carb replaced by a Weber. There should be an adaptor for the standard air filter in the kit, but this might not have been a complete kit, or the filter is for 'bling'.
That engine would definitely give more power/use less fuel if the standard filter had been retained.

P.S. I read "cabby" in your OP, not "carby", but all comments above still apply. The main problem for the filter is that it will be drawing in hot air from under the bonnet all the time, not just until the coolant gets hot, rather than cold air from around the RH headlamps.

[zortonesta]

Ah I see, you explained the info in one moment what I've been searching for days.

I do indeed have a carbed engine, had the weber upgrade fitted a month or so ago... I may also be guilty of wanting a bit of that bling in the bay too! But if I'm going to lose power, I'll forget about it as there isn't a great deal of it to begin with.

[bosers]

I've got a BMC free flow filter in my standard air box, it's a nice thing and definitely improves airflow and gives a nice noise. Have you thought of doing this? Cheers Joe

[zortonesta]

I hadn't thought of that Joe, I've been more interested in removing the standard box and replacing with one of the above. Is the BMC one for older M10 engines or more modern variants?

[Brianmoooore]

and definitely improves airflow

No it doesn't. Nothing flows better than no filter element at all, and that doesn't give any noticeable gains!
These cars were developed almost 'money no object', and BMW weren't going to save a few pennies by fitting an inadequate air filter.

[reggid]

dont worry about modifying a carby M10 you're on a hiding to nothing

[zortonesta]

Looks like I'll be spending my money elsewhere then chaps

[bosers]

Ok fair enough. I felt that there was a change compared to the standard paper filter, the induction noise was different, bit deeper. I'm sure Mr Mooooooore is correct though , (that seems to be his hobby )
I like this BMC because it lasts as you can wash it and re oil it. I had one in my old Audi sport and that also performed well.

[reggid]

the paper filter doesn't flow as well as a K&N paper, ive tested it but its a small change, same with factory stuff in general its not best for performance as the factory has alot more than performance to consider but its a good compromise