Ok so I got home and went right to work hacking the stock air box. I had to improvise and use a knife, which I heated up, to cut the small hole. Took me about 10 min to cut the small chunk out and another 10 min sanding the rough parts to make sure it was smooth and so that no left over chunks could get into the filter.
I decided not to reset the ecu and just started her up. I let the motor heat up and went for a quick ride. The first thing I noticed was a sucking sound followed by the woosh of the BPV. I had the biggest smile on my face, this thing sounded awesome. If your car is stock you will notice a HUGE increase in turbo and bov sound. So I proceeded to do some 3rd gear pulls and the boost stayed the same, after a buch of pull the boost still stayed the same. You guys are going to love the sound this makes!

Cliff notes:
Boost stayed the same
Turbo and BOV sound INCREASED 100%
Car felt smoother overall
No CEL or SES lights went on

I'm glad I went ahead and did this mod and the best thing is it's for free.

 

did u cut the cover on the side?? does this really works, and not hurt the car at all?

 

I did mine like this



It really works but only for turbo and bov sound. My boost and power stayed the same. The only thing that changed, other than the sound, was the car felt and did pull much smoother across the entire rev range. So far I have no problems, it idles normal and everything. I'll post more info once I clock in more miles on it.

 

nice, the cut looks clean what did u use? u should keep us updated, if it works i'll do the same to my cover.

 

x2, I want a clean cut.

***ALSO, what are you guys paying for a new stock airbox lid from Mitsu? There is no way I would take the car into the dealership with the side cut out of it like that.

 

^ Jigsaw with a smooth cut (knife edge) blade. Cuts through it like butter.

 

I payed about $40 for an OEM airbox lid...just went to the dealer and ordered one.

 

Shameless -- Nice logs....

A few questions -- (1) Any idea why the cutout lid seems to flow less air in the low RPMs? Interestingly I noticed mine would want to buck a bit if I were cruising around 2K rpm. (2) I wonder what the results would have looked like on a summer day? I guess engine temperatures would be ~ the same on a hot / cold day, so may have no impact. (3) It would be great to repeat this test and acquire more data samples to ensure the results are good throughout the power band.

Thanks again!

PS -- On your 9, you should be able to run 23 psi easy and hit closer to 300whp.....PM if you want info on how to increase and manage your boost using the stock ecu / bcs.

 

Shameless, do you have table labeled correct for knock sum? It says modified cover had higher knock.

 

It's listed correctly. It may have been phantom knock, I'm not sure. I was under the impression that 1 or 2 knock sum is normal, and 3+ means start to worry.

Also notice that w/o cover had 0 knock at redline, while w/ cover had 1.

I'm going to retest today... I think the hard drive shock protection in my IBM laptop caused EvoScan to pause when I went WOT, thus preventing log data between 4K and 7K

 

I bought an extra lid from the dealer for about $20 then hacked up that one.

Go to mitsupartsdirect.com (Rockville Mitsubishi) or Walpole Mitsubishi

https://www.evolutionm.net/forums/sh...37#post3960837

and order thru them, both great places, great service and good prices on OE parts.

 

Go buy a Dremel tool, best tool to have...I used the cutter wheels and sander wheels and made a smooth cutout. I'll get some pics but mine looks the same as My-red-rs.

 

All right, I apologize for the original set of logs - As some pointed out, they were incomplete (ie., no data from 4K to 6K RPM) and also, the "Air Volume" reading from EvoScan is apparantly not really Air Volume.

I re-logged this morning, and have updated the original pics so they now reflect a more accurate log. Please refresh the page to get the current log graphs

Keep in mind that "w/ cover" is stock cover installed, and "w/o cover" is stock cover completely removed. I have not attempted to modify the stock airbox yet. The "Air Flow" now shown in the graph is an accurate measure of Air Flow, as performed by the MAS (this is a measure of Hz, which is apparently how this sensor operates)

 

Shameless, thanks for collecting this data. Are you also planning to do future tests with a modified airbox (jcsbanks side-cut method?) I would be interested to see how that compares.

 

If you test the stock setup first then the modified setup, then you are likely to see higher temperatures on the modified setup because the car has been running longer. Whilst it is a pain, a swap back to stock so that you do stock - modified - stock would show that bias was minimised.

The differences between runs can sometimes obscure the real differences. Additionally, boost control on the stock ECU will attempt to reduce boost levels when you release a flow restriction.

That is why I prefer the more direct method of measuring the barometric pressure and then making sure that the inlet temps haven't gone up.

I could increase my boost and advance my ignition, but this is more noticeable when you are maxxing out the setup on a given turbo/octane/breathing/boost arrangement.