I could only find one other thread on this through searches, and it was from four years ago: https://www.northamericanmotoring.co...ead.php?t=4684

Anyone else tried this? When I look at the Dinan and the JCW (without the flap), it sorta seems like it would be a lot easier and cheaper to just cut your own hole with a dremel. Of course, you don't have the nice cone filter from the purchased intakes, but replacing the panel filter with something from K&N or ITG would certainly get it pretty close, for a fraction of the cost. (With the added benefit of not being noticed during service, unless they are specifically servicing the intake...)

Any comments?

 

I've done this. Except I went one step further and modified the stock air box lid to accept a cone filter. See my gallery for pics of the mod.

See this thread: https://www.northamericanmotoring.co...ad.php?t=76946

 

A lot of effort for very little gain, IMO. If you look at the lower air box, the rear is a very small area and already has an inlet from the cowl. Also you'll need to cut through the cowl partition in an area loaded with brake lines. Not a place you want to "oops".
If you are on a tight budget, it's something to do, but don't expect much of a result.
For a few dollars more, keep an eye on the Marketplace and pick up a used CAI. I got my Alta for $100 less than retail and am pleased with it.

 

Your right on both counts - a do it yourselfer can dremel out the back and replacing the flat panel w/ a cone filter pretty much equals many of the aftermarket CAI. Peter of MinSpeed (aka myminiparts.com) - either has or was getting an ITG cone/round filter that would fit in the stock box.

One thing you didn't mention was that the stock box has good thermal efficiency.

 

great suggestion

 

Well, I went ahead tonight and cut a hole in the back of my air box and partition!

Because of the risk involved with the brake lines directly behind the partition, I found an old license plate hanging around that I shimmied in between the back of the partition and those lines. It turned out to be the perfect item, since it was rigid, but just bendable enough to be able to wiggle it in the narrow space.... Now with the license plate in place, if I go too deep with the dremel, I'll have plenty of leeway and an audible alarm (loud metal-on-metal!).

I took off the top of the air box and made a rectangular outline on the partition where I'd roughly be cutting. I tried using the disk-like cutting attachment, but found that one of the carving attachments worked much better in that tight spot. Once I finished that hole, I cut a reciprocal hole in the back of the air box top. Reattached the top and we were good to go....

I took it out for a quick five minute run around the block, and WOW! I love the WWHHHHIIIIIIIIIIIIIIIIIIIINNNNEE!!! And this is with a stock filter! (I'll be getting a K&N panel filter to replace that.)

All in all, I'm very happy so far... I got that big whine I was looking for and hardly any of the loud sucking sound. (For the most part, I only hear a slight sucking sound when I initially hit the accelerator.)

The best part, though, was the cost: $0

 

So with all this cutting, is the air going into the TB still being filtered? Which firewall partition is being cut here--above, or below, the filter?
A photo would help to understand, thanks.

 

If you cut any holes in the top half of the air box, you are getting unfiltered air into the engine.

 

Well, crap....

 

Duct tape works wonders until you can get another top.

 

Not any more! Pretty expensive mod for debatable gains compared to a CAI and other mods presented here on NAM. Ooops.
Still, a new box top and repair of whatever you cut in the firewall facia and all will be good.

 

Here's one possible solution:
https://www.northamericanmotoring.co...ad.php?t=95314

 

Here is a used intake box cover for $10.
http://www.helix13.com/mini/products/used

 

well it sounded like a great plan
i was already to say nice job

 

OK, I just ordered a K&N cone filter online. I actually tried going to an Advance Auto Parts and an Autozone, but neither of them stock it.... Two day shipping. Then I'll be incorporating ignote's ideas from his homemade CAI. It should only cost me about $60-$70 overall...

 

The cone filter should definitely be better than a panel one anyways. You'll be able to use that big ol' hole you made and there's more filter to go around.

FYI, there is a .pdf I found somewhere here on NAM that details what you were doing, making a bigger hole and staying with a panel filter.. I'll upload it to my webspace.. For the next person who finds this thread in four years.

EDIT: Here, copyright and thanks to "Martin Intemann"

 

Here is the glue I used for the pipe.
http://www.appliedimaginationinc.com...ick/index.html

 

btw, I just modified my stock airbox to accept a cone filter similar to what Ignote did, and even though I didn't increase the cowl hole I still notice a difference... the engine seems to "breathe" a lot better and I get much better throttle response especially from a stop. I hear more supercharger whine too but not so much that it will freak out the neighbors, esp. when seeing a greying middle aged lady behind the wheel, hehe.

Even with the air restrictions of the stock box it's a little better than the HAI configurations I tried first. Though as the weather goes from warm to oppressive here in South Louisiana I may see less of a difference. Since I don't intend to race but do drive a lot in stop and go city traffic it was well worth it, and the way I did it using a male PCV pipe adapter rather than glue makes it totally reversible w/o my having to buy a new stock box top. I just got an Alta panel filter as well and I may just try that out to see if there's any difference between this mod vs. just using a better panel filter. (I couldn't believe how nasty the paper filter got after 10,000 miles since my last scheduled maintenance)!!!

Also, if I want to get a little more *real* performance out of the set up I can get a heat shield w/o filter (Pilo Racing and Megan Racing both sell MCS specific heat shields for DIY intakes) and be able to mix and match CAIs with the ability to go back to stock as needed... Reason going back to stock is important is b/c my hubby has gotten a little concerned with my tinkering esp. since I *was* originally going to drill a larger hole like Ignote did, and was afraid I'd mess something up so he'd rather that I keep it close to stock... I think any additional mods I do from here on out also need to be bolt-on/reversible, so that any problems with the car can't in any way be traced to anything that I did, lol. (He was concerned I caused an OIL LEAK!!! by working on the stock box, b/c coincidentally we checked the oil and it was a quart low. No matter how much I reassured him I was no where near anything oil--or anything else--related by changing out the air filter, he didn't believe me.) Ms. Fix-It here fixed our dying washer for $25 and that was cool, but working on our "good" car that ain't broke, I just want to make it work a little better, well, that's a bit different... I'll just have to install Shoe's engine damper while he isn't looking, not to mention hope that I retrieve it from the mail before he sees it.

I'm using a K&N RU-3130 which I think is the same size as the Airaid filter Ignote is using. Fits perfect in the stock box.

 

Can you post a picture of how you used a male PCV pipe adapter? I'd sure like to see your work.

 

Here you go... I posted it in my gallery.

https://www.northamericanmotoring.co...45122&cat=1829

from underneath... looks a lot like yours

https://www.northamericanmotoring.co...45123&cat=1829

As you can see, I inserted the 2" male PVC adapter *into* the hole going out of the top of the airbox. Due to the angle of the pic it's actually more flush than it looks like in the picture - it's a snug fit. I didn't have time to totally disassemble it this AM as I needed the car to go to work, but I additionally am using a rubber boot along with the hose clamp to make a tight seal between the filter flange and the PVC adapter.

Pros:
(1) more easily reversible on the fly than glueing PVC to the box.
(2) just as cheap as yours. Filter ran me $25.60 through Amazon.com (free ship) and the other materials around $5.

Cons:
(1) While it seemed "snug enough" when I first installed it a couple days ago (I had to "screw" it in), I'm not 100% convinced now it was snug enough going into the box without some additional sealant/adhesive. I was initially more concerned about how I used a rubber boot inside the filter flange but that connection has proven very secure and airtight. But in the process of taking the top of the airbox out of the car this morning to take pics the adapter pulled out of the hole a bit too easily. Fortunately I wasn't driving it around long and I doubt if much if any unfiltered air got in the engine but that's not a chance I want to take, especially as our roads around here are like washboards and I'm driving an early build (stiffer) MCS. I put silicone sealant on the adapter threads before reinserting into the box. There are no leaks but I will check it later today to make sure it's still secure. If not, I'm definitely going with your method.

(2) I'm obviously trading off some airflow out of the box for reversibility. Because of the angle of pic #2 it's really not as bad as it looks in the pic but I know it's a tradeoff. Though the fact that I'm getting any improvement at all over stock means that the extra filtration area of the cone filter over panel is increasing the flow enough to make a difference despite this tradeoff. As I said before, if I want *real* performance and not just mere improvement over stock I'll get a heat shield similar to Pilo's.

Though like you, I think the stock airbox w/mods has some definite advantages in keeping out heat. I initially drove with top of the airbox out and the filter clamped directly to the hose, and while that was also an improvement over stock, this is a bit better than even that despite my "tradeoff" so the stock box is obviously doing something.

I'm not dynoing this btw. Not worth it to me as it's probably not a measurable enough difference to warrant it.

 

Nice job. My only concern is that by sticking the threaded pipe in the outgoing whole, you have reduced the overall size of the inlet into the engine causing some restriction. Hard to tell for sure from the photo.

Also, unless you sand the plastic in the airbox top, I'm not sure that the silicone will hold. Even then it may not. You definately should keep a close eye on it.

 

Sorry for resurrecting a zombie thread, but I just did this change to my MCS's stock airbox over the weekend since I was in there anyway to install an Alta drop in foam panel filter. This was my first performance enhancement effort on my mini.

Unlike Martin, I did everything insitu, sliding a piece of sheet steel between the bulkhead wall and the brake lines. I ended up opening up the 1.375" diameter hole to a 1.5" x 2.8" long rectangle, which provides better than 2.5 times as much crossectional area as the stock hole. Cuts to the airbox bottom's back surface and bulkhead were defined by drilling starter holes in each corner of the enlarged rectangle and were made using a box cutter w/fresh blade. I sealed the airbox to the bulkhead using some LDPE I salvaged from computer packing materials being disposed at work.

Results. I'm guessing the supercharger noise about doubled...going from hardly noticeable to noticable. It feels like it pulls a bit better from 4,500 rpms up, but that might just be because I can hear it pulling now. I figured for the zero cost and 30 minutes it took for me to make this change, it was a worthwhile effort and good preparation for that 15% reduction pulley...

Cheers,

--Rich

 

just cut the bottom out...directly below the panel filter....

 

How hot does it get below the airbox? I didn't know and didn't want to suck hot air into the intake...

 

Dunno