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My DIY Cold Air Box


jevansio
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Well, I'll never have it said that I don't listen to constructive criticism from you guys ;), so i have been on the lookout for a better filter, I think I have found it in the form of the K&N RC-4780.

 

It's a bit longer & thinner so suits the shape of my barrel better, I calculate not only does it actually give slightly more filter surface area, but the amount of volume around the filter for the air to circulate is increased. Also being cone shaped should help give more volume where it's needed (ie the end where air enters the barrel).

 

I did a quick scale pic showing the current filter & this new one to show the better volume usage :)

 

attachment.php?attachmentid=126342&stc=1&d=1296680818

g5473.png

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Well, I'll never have it said that I don't listen to constructive criticism from you guys ;), so i have been on the lookout for a better filter, I think I have found it in the form of the K&N RC-4780.

 

It's a bit longer & thinner so suits the shape of my barrel better, I calculate not only does it actually give slightly more filter surface area, but the amount of volume around the filter for the air to circulate is increased. Also being cone shaped should help give more volume where it's needed (ie the end where air enters the barrel).

 

I did a quick scale pic showing the current filter & this new one to show the better volume usage :)

 

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=126342&stc=1&d=1296680818

 

Looks magic, I haven't received your subscription notice yet though :p

 

The positioning of the box intake and the shape of the cone are PERFECT for each other IMO. The volume is at its maximum right where it needs to be.

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On a side note, I managed to fix the missfire, it was the RLTC as I suspected, removing it from the injector loom fixed it straight away. I plugged my laptop into the RLTC to see what the crack was and this is what it displayed for the sensors with the car idling on the drive:

 

attachment.php?attachmentid=126443&stc=1&d=1296929464

 

It looks like if the RLTC gets a bad connection it's enough to take out the ABS system (I checked when my warning light was on & the wheels locked up). I tweaked the RLTC pins (a bit like you tweak the coilpack connectors) and the graph went perfect again, also the ABS warning vanished. Just incase anyone else comes across the same problem/symptoms :)

RLTC.jpg

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The new filter turned up, it is perfect IMHO, not just size wise, but the way it fits, it has a bolt already at one end, which was great as I just drilled a hole in the back plate and bolted it up, it holds the thing together solid & I don't have to worry about making clamps at the other end.

 

Also it is the perfect length, you would have thunk it was custom made for me lol

 

I also replaced the bring shiney ducting with some black motorsport stuff from Merlin, much more subtle and easier to install :)

 

Hopefully this V3 item will be more acceptable :)

 

attachment.php?attachmentid=126790&stc=1&d=1297519918

 

attachment.php?attachmentid=126791&stc=1&d=1297519918

 

attachment.php?attachmentid=126792&stc=1&d=1297519918

 

attachment.php?attachmentid=126793&stc=1&d=1297519918

 

attachment.php?attachmentid=126794&stc=1&d=1297519918

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Img_6450.jpg

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Johnny, I took it out tody bud, roads are less than perfect, but the car is insane, recorded the biggest wrhp figure to date on the RLPB, 606rwhp = 721bhp (probably exactly what the last dyno showed). No idea what effect the box has had (good or bad), but suffice to say it don't seem to be hindering performance at all. A lot has changed on my car since the last run (exhaust, cams, weight), so it's hard to draw any comparsions, the fact it's faster than ever is good enough for me. A swift 5th gear pull saw 160 leptons clocked up in no time. The RLTC is still disabled while I figure out what the hell my ABS system is doing, so it was a HAIRY ride today :D

 

Cheers swampy :)

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Make of this what you will, but after I came home from the run out the other day, I opened the bonnet to find the back of the airbox had blown out, it is an EXTREMELY tough push fit into the barrel and it was also sik-a-flexed onto the back of the cone filter (but it had not completely cured). I'm not saying this is some super power boosting increase, but there are obviously times when the pressue in there is above ambient, which to me can only be a good thing :)

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Make of this what you will, but after I came home from the run out the other day, I opened the bonnet to find the back of the airbox had blown out, it is an EXTREMELY tough push fit into the barrel and it was also sik-a-flexed onto the back of the cone filter (but it had not completely cured). I'm not saying this is some super power boosting increase, but there are obviously times when the pressue in there is above ambient, which to me can only be a good thing :)

 

Would that be from the surge when you let off the accelerator? I can't think of any positive pressure situations other than during surge :)

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The new filter turned up, it is perfect IMHO, not just size wise, but the way it fits, it has a bolt already at one end, which was great as I just drilled a hole in the back plate and bolted it up, it holds the thing together solid & I don't have to worry about making clamps at the other end.

 

Also it is the perfect length, you would have thunk it was custom made for me lol

 

I also replaced the bring shiney ducting with some black motorsport stuff from Merlin, much more subtle and easier to install :)

 

Hopefully this V3 item will be more acceptable :)

 

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=126790&stc=1&d=1297519918

 

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=126791&stc=1&d=1297519918

 

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=126792&stc=1&d=1297519918

 

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=126793&stc=1&d=1297519918

 

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=126794&stc=1&d=1297519918

 

thread has been a good read - impressed by the R&D involved; the simple approach with function over form in mind. With version 3 I think you have ended up with a setup that also looks fantastic.

 

in your case the cold air feed is under the filter housing, would be interesting to hear ideas of how this would work in a single setup like mine where I choose to use a SMIC and would prefer to use the two stock cold air feeds (RAD + passenger light).

 

imi

Edited by imi (see edit history)
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