Stock airbox cover removal on a IX
Jan 7, 2007, 07:36 AM
#16
I appreciate the feedback, but let me re-iterate, I just wanted some feedback from people that have actually run a IX without the stock airbox cover and without a tune.
Speculation, hear-say, should-be's, could-be's... that's all well and good, but so far there's only one response so far that I'm looking for:
Speculation, hear-say, should-be's, could-be's... that's all well and good, but so far there's only one response so far that I'm looking for:
Jan 7, 2007, 08:45 AM
#17
ShamelessCookie, I have run my IX with Walbro and 3" elbow back exhaust with AVC-R and ECUflash, with Evoscan logs and a wideband gauge. I didn't detect an AFR or timing/knock difference between stock airbox, lid removed or lid fitted but with the opposite side to the snorkel inlet opened up. They all showed similar temperature logged from the MAF sensor when moving, but with the airbox lid removed the temperature increased more quickly when idling.
However, I could run top end boost using less wastegate duty cycle with the airbox lid removed or with the modified lid. Or I could run more top end boost more easily without having to retard the timing as much as the stock airbox because of knock. This is backed up by seeing a barometric pressure recorded in the MAF sensor of 9.5-10 kPa below atmospheric (about 10%) with the stock airbox, about 5.5-6 kPa with either the lid removed or the lid modified.
In the end I run with the lid modified because I have good data that shows that at 20-22 PSI at peak power over 6000 RPM there is less restriction. FWIW, I also have dyno results that show more power with the airbox lid removed, but the bonnet was open, so I go more by the results and feel of the tests when moving.
From above the airbox looks stock, I simply cut out the coldest side near the IC spray bottle. This is away from the exhaust manifold and the heat from the radiator.
Even with the ram effect that you can actually log over 100mph with the stock airbox, the pressure in the MAF sensor is still lower than it is with the side of the airbox lid cut out.
However, I could run top end boost using less wastegate duty cycle with the airbox lid removed or with the modified lid. Or I could run more top end boost more easily without having to retard the timing as much as the stock airbox because of knock. This is backed up by seeing a barometric pressure recorded in the MAF sensor of 9.5-10 kPa below atmospheric (about 10%) with the stock airbox, about 5.5-6 kPa with either the lid removed or the lid modified.
In the end I run with the lid modified because I have good data that shows that at 20-22 PSI at peak power over 6000 RPM there is less restriction. FWIW, I also have dyno results that show more power with the airbox lid removed, but the bonnet was open, so I go more by the results and feel of the tests when moving.
From above the airbox looks stock, I simply cut out the coldest side near the IC spray bottle. This is away from the exhaust manifold and the heat from the radiator.
Even with the ram effect that you can actually log over 100mph with the stock airbox, the pressure in the MAF sensor is still lower than it is with the side of the airbox lid cut out.
Jan 7, 2007, 09:30 AM
#18
ShamelessCookie, I have run my IX with Walbro and 3" elbow back exhaust with AVC-R and ECUflash, with Evoscan logs and a wideband gauge. I didn't detect an AFR or timing/knock difference between stock airbox, lid removed or lid fitted but with the opposite side to the snorkel inlet opened up. They all showed similar temperature logged from the MAF sensor when moving, but with the airbox lid removed the temperature increased more quickly when idling.
However, I could run top end boost using less wastegate duty cycle with the airbox lid removed or with the modified lid. Or I could run more top end boost more easily without having to retard the timing as much as the stock airbox because of knock. This is backed up by seeing a barometric pressure recorded in the MAF sensor of 9.5-10 kPa below atmospheric (about 10%) with the stock airbox, about 5.5-6 kPa with either the lid removed or the lid modified.
In the end I run with the lid modified because I have good data that shows that at 20-22 PSI at peak power over 6000 RPM there is less restriction. FWIW, I also have dyno results that show more power with the airbox lid removed, but the bonnet was open, so I go more by the results and feel of the tests when moving.
From above the airbox looks stock, I simply cut out the coldest side near the IC spray bottle. This is away from the exhaust manifold and the heat from the radiator.
Even with the ram effect that you can actually log over 100mph with the stock airbox, the pressure in the MAF sensor is still lower than it is with the side of the airbox lid cut out.
However, I could run top end boost using less wastegate duty cycle with the airbox lid removed or with the modified lid. Or I could run more top end boost more easily without having to retard the timing as much as the stock airbox because of knock. This is backed up by seeing a barometric pressure recorded in the MAF sensor of 9.5-10 kPa below atmospheric (about 10%) with the stock airbox, about 5.5-6 kPa with either the lid removed or the lid modified.
In the end I run with the lid modified because I have good data that shows that at 20-22 PSI at peak power over 6000 RPM there is less restriction. FWIW, I also have dyno results that show more power with the airbox lid removed, but the bonnet was open, so I go more by the results and feel of the tests when moving.
From above the airbox looks stock, I simply cut out the coldest side near the IC spray bottle. This is away from the exhaust manifold and the heat from the radiator.
Even with the ram effect that you can actually log over 100mph with the stock airbox, the pressure in the MAF sensor is still lower than it is with the side of the airbox lid cut out.
Good testing. You left out one very importatnt thing. ambient temps during testing. cold air intake is very important here in florida.
I have logged 25 degrees difference at the throttle body with and without out cold air intake. this is in florida 90 degree heat.
Jan 7, 2007, 09:42 AM
#19
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You should ask CBRD why they did it and what it did to the car they are selling.
I really like the thinking behind their airbox. Now if only someone made that as a custom piece.
I really like the thinking behind their airbox. Now if only someone made that as a custom piece.
Jan 7, 2007, 10:20 AM
#20
94AWDcoupe, I am in Scotland. I did a lot of testing on the hottest day we've seen here for ages but that was only about 28 celcius. Even in our cool climate (vast majority of the time 5-20 C) and with uncongested roads I still don't want an open filter or the lid removed as I think that cold air intake is very important. I didn't like the amount I saw the temps go up when stopped, so cutting the side out the airbox lid is a compromise between temperature and pressure drop, I'm trying to get the highest density. The lid is quite near the hood anyway, and hot air will tend to rise. At the side where I've cut it is enough to reduce the pressure drop to within 1kPa of an open filter with less noise and less heat soak.
Jan 7, 2007, 11:10 AM
#21
You should ask CBRD why they did it and what it did to the car they are selling.
I really like the thinking behind their airbox. Now if only someone made that as a custom piece.
I really like the thinking behind their airbox. Now if only someone made that as a custom piece.
http://www.lancershop.com/customer/p...8&cat=2&page=1
There is no reason to buy it when you can simply take and cut the top off the stock airbox though. I, like JCSbanks, have tested with/without the lid. I cut away the top of the lid and get better boost earlier with less knock. I have been told there is no way I can run the timing I do at peak torque with the amount of boost, but logging shows that it does indeed give me a 3-4* advantage. That is enormous I know. All my air temps at the time of testing were 55-65* ambient and roughly that underhood (I had the rainguard out during the dry weather).
I havent logged any inconsistency in the AFR's like is reported (and I believe rightly so) with the stock MAF and most cone filters. Measured air temps (from the ECU) and barometer readings all show an improvement. Removing the rainguard can make at least a 20* difference all on its own in this regard as well. All in all, dollar for dollar, this is one of the best mods you can do for a minor power gains.
Here is a pic of my engine bay to show what I have done:
Jan 7, 2007, 12:15 PM
#24
94AWDcoupe, I am in Scotland. I did a lot of testing on the hottest day we've seen here for ages but that was only about 28 celcius. Even in our cool climate (vast majority of the time 5-20 C) and with uncongested roads I still don't want an open filter or the lid removed as I think that cold air intake is very important. I didn't like the amount I saw the temps go up when stopped, so cutting the side out the airbox lid is a compromise between temperature and pressure drop, I'm trying to get the highest density. The lid is quite near the hood anyway, and hot air will tend to rise. At the side where I've cut it is enough to reduce the pressure drop to within 1kPa of an open filter with less noise and less heat soak.
Jan 7, 2007, 12:50 PM
#26
Pics, it is raining outside and the car has been standing, note how the top of the airbox is dry but the snorkel below the vent is wet.
http://john824.fotopic.net/p37575200.html
Click next to view two more photos from the side and oblique.
http://john824.fotopic.net/p37575200.html
Click next to view two more photos from the side and oblique.
Jan 7, 2007, 02:58 PM
#28
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So FWIW, and totally disregarding my own better judgement(I have a long FUBAR history)I took out the Dremel rotary tool and had at it. Thanks, at least it was a good way to pass Sunday afternoon.
Last edited by sparky; Jan 7, 2007 at 03:05 PM.
Jan 7, 2007, 07:30 PM
#30
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Then tell us why it is so bad to do it........
Why should it be?
The airfilter will take more dirt and moisture with the cover on then with the cover of i think.
With the cover on the cold airchannel will guide any drop of water that get into it straight to the airfilter.
When you take the cover of there is no water because your hood covers it up.
Why should it be?
The airfilter will take more dirt and moisture with the cover on then with the cover of i think.
With the cover on the cold airchannel will guide any drop of water that get into it straight to the airfilter.
When you take the cover of there is no water because your hood covers it up.
Folks are running open intakes for many reasons but the ones that are doing so for performance generally have them boxed in and have cold air intakes into the box, so still very similar to the factory design.
As for John / John mod's I really cannot explain how or why they are seeing good results unless it was for short (e.g. 1/4 mile run) bursts. I will try to run some tests to determine which direction air is flowing with the hood vent (my understanding is that is flows out (engine bay to atmosphere), if air is being pulled into the bay then that would be interesting.
Finally a much better idea would be to build a true cold air ram induction setup.