13 replies to this topic

[Protarmic]

I heard of tis somewere.. cant remember where. But, does drilling holes in the air filter casing improve performance a little?

[daniel_johno]

I heard of tis somewere.. cant remember where. But, does drilling holes in the air filter casing improve performance a little?

i done this mod a few days ago, drilled holes the size of £2 coins in the front of my airbox. Ive not noticed a performance increase but it sounds more meatier on full throttle.

I think the mod increases airflow but how much and how effectively i dont know but you should probably get your car tuned/rolling roaded after drilling it.

Daniel

[Protarmic]

I heard of tis somewere.. cant remember where. But, does drilling holes in the air filter casing improve performance a little?

i done this mod a few days ago, drilled holes the size of £2 coins in the front of my airbox. Ive not noticed a performance increase but it sounds more meatier on full throttle.

I think the mod increases airflow but how much and how effectively i dont know but you should probably get your car tuned/rolling roaded after drilling it.

Daniel

Meatier eh.. lol. I think my mini sounds the roughest in aberdeen! I think i'll go ahead and drill some holes. Will me having twin carbs make a difference?

[Tommy Kaira]

Drilling the airbox can give you slightly better air flow and much 'better' sound.Just drill on the intake side not the carb side. That is make sure that all air getting to the carb HAS passed through the air filter. It's no substitute for a proper performance filter but it not far off and it's free! I guess you'd have to re-jet the carbs to suit the higher airflow to get the full benifit of it and then you might as well get an upgraded filter at the same time.

This is based on my bike experience but should be the same for the Mini. Someone more learned will be along to correct me if I'm wrong though I'm sure.

Hope that helps,
D

[Protarmic]

Drilling the airbox can give you slightly better air flow and much 'better' sound.Just drill on the intake side not the carb side. That is make sure that all air getting to the carb HAS passed through the air filter. It's no substitute for a proper performance filter but it not far off and it's free! I guess you'd have to re-jet the carbs to suit the higher airflow to get the full benifit of it and then you might as well get an upgraded filter at the same time.

This is based on my bike experience but should be the same for the Mini. Someone more learned will be along to correct me if I'm wrong though I'm sure.

Hope that helps,
D

Thanks man. I'll leave it for now. Im trying to get a hold of the mini service guide book so i can service my engine etc, i might just get some new air filters wit ram pipes or something. Its put me off that i cant just drill random holes all over it. I wanted to paint it yellow so it looked like a peice of cheese

[Retro_10s]

This has been covered loads,

Drilling the Housing and using a standard replacement filter element (or a K&N replacement) proved (by mr Vizard) to flow more than your boggo rubbish cone/pancake filters etc:

The picture attatched shows how the filter would look afterwards. (and yes, the filter does not sit centrally in the housing. The holes around the edge are optional and not really vital, but the four large ones are the important ones that must be drilled. You must make sure the holes are drilled around the outside of the filter,.. to make sure no unfiltered air gets through to the carb.

Attached Files

•  filterjpg.JPG   24.18K   20 downloads

[Protarmic]

This has been covered loads,

Drilling the Housing and using a standard replacement filter element (or a K&N replacement) proved (by mr Vizard) to flow more than your boggo rubbish cone/pancake filters etc:

The picture attatched shows how the filter would look afterwards. (and yes, the filter does not sit centrally in the housing. The holes around the edge are optional and not really vital, but the four large ones are the important ones that must be drilled. You must make sure the holes are drilled around the outside of the filter,.. to make sure no unfiltered air gets through to the carb.

I drew a picture of my air filter. The red bits are where i can out holes then? Do the holes go on the bottom or top side of the case?

The thing in the middle is the jesus cross.

Attached Files

•  air.JPG   11.41K   9 downloads

Edited by Protarmic, 25 March 2007 - 01:41 PM.

[Big_Adam]

Drilling the Housing and using a standard replacement filter element (or a K&N replacement) proved (by mr Vizard) to flow more than your boggo rubbish cone/pancake filters etc:

Ah, not quite Mr Retro. On bigger engines the elbow is less of restriction. On smaller engines (850-1100) the elbow on the carb is a big restriction. So on smaller engines a cone or pancake filter are better.

edit

Protarmic, when I did mine I just did them round the edge. On the front like were the regualr air hole in the box is.

Edited by Big_Adam, 25 March 2007 - 01:51 PM.

[Dan]

Please don't go drilling holes in a twin carb air box, or paint it yellow. That part is VERY NLA and actually getting fairly valuable. It was over £300 new last time it was available (only a few years back) and a Cooper S owner would pay a lot for it in good condition. If you must drill it you need to make certain that you drill the exact same size holes in the same places on each side as a mirror image. You need to keep the increased flow equal on both carbs or you could damage the engine badly. This air box is very restrictive and you would be much better getting cone or pancake filters for the carbs. Living in Aberdeen though you may get quite bad carb icing in winter if you make any serious changes to the air intake system.

[biggav]

Though that Bigmadbastard was back when i saw that pic!!!!!

Get yourself some KN pancake filters or similar. don't go wrecking that air box!!!!

[Protarmic]

Please don't go drilling holes in a twin carb air box, or paint it yellow. That part is VERY NLA and actually getting fairly valuable. It was over £300 new last time it was available (only a few years back) and a Cooper S owner would pay a lot for it in good condition. If you must drill it you need to make certain that you drill the exact same size holes in the same places on each side as a mirror image. You need to keep the increased flow equal on both carbs or you could damage the engine badly. This air box is very restrictive and you would be much better getting cone or pancake filters for the carbs. Living in Aberdeen though you may get quite bad carb icing in winter if you make any serious changes to the air intake system.

So just the box is worth a bit? Sweet. My cars turning out to be a gold mine! Yesterday someone told me that the disc brakes on the front where cooper S ones and they go for a bit too! woohoo! I think i'll just keep it intact then. Thanks for the advise.

And umm... whats wrong with my diagrams??

[Dan]

Cooper S brakes are still in production though. Yours are probably not original S but later parts because they have always been available and a common upgrade. It is a second hand set and a new set costs between £300 and £400 depending on what bits you need. As for the price of the box, delends where you sell it. You see them at Mini Shows from time to time but it would go for more in a private sale to a concourse nutter.

Edited by Dan, 25 March 2007 - 03:39 PM.

[Mini-Dave]

concourse nutter lol i like it

Dave

thats my imense input

[Dusky]

Please don't go drilling holes in a twin carb air box, or paint it yellow. That part is VERY NLA and actually getting fairly valuable. It was over £300 new last time it was available (only a few years back) and a Cooper S owner would pay a lot for it in good condition. If you must drill it you need to make certain that you drill the exact same size holes in the same places on each side as a mirror image. You need to keep the increased flow equal on both carbs or you could damage the engine badly. This air box is very restrictive and you would be much better getting cone or pancake filters for the carbs. Living in Aberdeen though you may get quite bad carb icing in winter if you make any serious changes to the air intake system.

I should sell mine lol.
If you happen to search for one, I know someone who sells a twin box.