jevansio Posted January 30, 2011 Author Share Posted January 30, 2011 Ah feck it, took it out and the car started missing like feck, swapped coilpacks, plugs, ignitor and it's still doing it, I'm off for a skinfull, no doubt there'll be a for sale thread tonight when I get in Quote Link to comment Share on other sites More sharing options...
mikeyh Posted January 30, 2011 Share Posted January 30, 2011 sorry to here this mate i hope its an easy fix Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted January 30, 2011 Share Posted January 30, 2011 That looks like it is going to be the business bud. Personally I would have increased the volume of air around the filter (between filter and perspex tube) as that may cause a bit of a restriction, basically you want the volume that the filter can handle to be equal to the volume outside the filter. Unless the perspex is actually larger than it looks, I know pics can throw you off Im with Scott, a bit sceptical. I dont see how it can outperform a filter exposed in a large volume airbox. But looks like nice work Quote Link to comment Share on other sites More sharing options...
neo2810 Posted January 30, 2011 Share Posted January 30, 2011 lol... Jay and the car sale merry-go-round. I missed this thread, but everything you've done is mega innovative mate, love the work! You can't sell the car, who will I steal all my ideas from?! Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 Well that sambuca is great stuff, had a bit of a brainwave when I was sloshed yesterday, when i went out on the morning my ABS warning light kept flashing on, I figured my brake fluid may have been low but when I got home and check it it was at the max. Anyway I'm putting money on the RLTC plug keeping on dropping the ABS sensors, triggering the fuel cut and messing with the ABS system. The RLTC plug has given me issues in the past and was the cause of a missfire. When I was out yesterday I was really pleased with the noise difference the airbox has made, I no longer have that "jet taking off" suction sound from the filter, it's made the car a bit more refined again, and you can really appreciate the exhaust note now. WRT to the airbox performance. I understand you guys sceptism, so the best I can do is peform a back to back test with the box on and off, and use my RLPB as a measuring tool. I figure if power is unaffected then it's obviously not a restriction. I will have to wait until the weather picks up though as ATM I got no traction in 4th when the turbo spools. I will also log AFRs, but my gut is telling me you guys are overthinking how much of a restriction this thing is Quote Link to comment Share on other sites More sharing options...
johnny g Posted January 31, 2011 Share Posted January 31, 2011 Well that sambuca is great stuff, had a bit of a brainwave when I was sloshed yesterday, when i went out on the morning my ABS warning light kept flashing on, I figured my brake fluid may have been low but when I got home and check it it was at the max. Anyway I'm putting money on the RLTC plug keeping on dropping the ABS sensors, triggering the fuel cut and messing with the ABS system. The RLTC plug has given me issues in the past and was the cause of a missfire. When I was out yesterday I was really pleased with the noise difference the airbox has made, I no longer have that "jet taking off" suction sound from the filter, it's made the car a bit more refined again, and you can really appreciate the exhaust note now. WRT to the airbox performance. I understand you guys sceptism, so the best I can do is peform a back to back test with the box on and off, and use my RLPB as a measuring tool. I figure if power is unaffected then it's obviously not a restriction. I will have to wait until the weather picks up though as ATM I got no traction in 4th when the turbo spools. I will also log AFRs, but my gut is telling me you guys are overthinking how much of a restriction this thing is Am so glad to see that it's not back up for sale buddy. Concentrate on the RLTC next I take it, make sure it's ok! Quote Link to comment Share on other sites More sharing options...
Scott Posted January 31, 2011 Share Posted January 31, 2011 TBH I'm maybe underthinking it however my understanding is this: The volume outside the filter must be equal to the volume inside the filter. So if you have a 6" diameter filter (not sure what it is just an example) and it is 8" long (again guessing) the volume of the filter is 226.1"cubed. You want the volume outside this filter to be the same. 220mm = 8.66", obviously it's a bit longer so call it 10" long so the volume of the tube would be 588.71"cubed. This is clearly more than double the volume of the filter so in this case it would be absolutely fine (as it is double the volume if you subtract the volume of the filter this will give you the volume of the box outside the filter, as long as it is more than double it's fine). The box itself is causing no restriction. You also want the intake diameter to be the same if your filter has a 5" out to the turbo, you want the intake to the induction tube to be the same or that will case a bit of a bottle neck. I'm guessing this is probably what you did though Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 I think due to the fact that none of us are experts in this field that the only way we're going to agree on the suitability of this is when I run some real tests and get some real data, until then it's just a bunch of clueless guys making assumptions on things they know nothing about Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted January 31, 2011 Share Posted January 31, 2011 until then it's just a bunch of clueless guys making assumptions on things they know nothing about Lol welcome to the world of car tuning Quote Link to comment Share on other sites More sharing options...
Scott Posted January 31, 2011 Share Posted January 31, 2011 I think due to the fact that none of us are experts in this field that the only way we're going to agree on the suitability of this is when I run some real tests and get some real data, until then it's just a bunch of clueless guys making assumptions on things they know nothing about Ahem, I'll have you know I do know a little something about this Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 Ahem, I'll have you know I do know a little something about this That makes one of us Quote Link to comment Share on other sites More sharing options...
Scott Posted January 31, 2011 Share Posted January 31, 2011 That makes one of us As I said I might be over simplifying it but here goes on how I came to my conclusion..... Having the intake setup without the tube means that the only restriction on the intake of the turbo is the filter itself. The bigger the filter surface area the less of a restriction the intake will be, but there will come a point when the filter doesn't act as the restriction.... it will be the intake pipe itself. I might be wrong but I would say that given the size of your filter this is possibly the case. Regardless, you have chosen your intake size and your filter size, all you want to do now is enclose the filter away from engine bay temps without increasing the restriction. First thing you need is an intake diameter size the same or bigger than the intake diameter on the turbo. By doing this you are ensuring that the amount of air flowing into the box is the same as the amount of air that was flowing into the original intake (minus the filter). If you want to be absolutely sure you could increase the box intake size, as obviously the longer the intake length the more resistance the system will have. If you made it a half inch bigger it would make all the difference IMO. Next you want to make sure that the restriction of the box is less than the restriction of the filter. Very simple to do that, measure the volume of the filter and the volume of the box, as long as the volume of the box is more than double the volume of the filter, the amount of air that the box can occupy at any given time is more than the filter can occupy. This would guarantee that, as per the original setup, the most restrictive thing in the whole intake system will be either the intake pipe, or the filter. If you want to get really serious about removing the restriction you could adapt the intake size to a larger diameter all the way through to the end of the box. A 5" intake would be magic and the pressures would be non existent Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 (edited) As I said I might be over simplifying it but here goes on how I came to my conclusion..... Having the intake setup without the tube means that the only restriction on the intake of the turbo is the filter itself. The bigger the filter surface area the less of a restriction the intake will be, but there will come a point when the filter doesn't act as the restriction.... it will be the intake pipe itself. I might be wrong but I would say that given the size of your filter this is possibly the case. Regardless, you have chosen your intake size and your filter size, all you want to do now is enclose the filter away from engine bay temps without increasing the restriction. First thing you need is an intake diameter size the same or bigger than the intake diameter on the turbo. By doing this you are ensuring that the amount of air flowing into the box is the same as the amount of air that was flowing into the original intake (minus the filter). If you want to be absolutely sure you could increase the box intake size, as obviously the longer the intake length the more resistance the system will have. If you made it a half inch bigger it would make all the difference IMO. Totally agree with you on these points, and I have infact done exactly this for exactly those reasons. My filter to turbo pipe is 4", the hole into the box is 5", I'm pretty sure we all agree upto this point that my system will not cause additional restriction vs the old one. Next you want to make sure that the restriction of the box is less than the restriction of the filter. Very simple to do that, measure the volume of the filter and the volume of the box, as long as the volume of the box is more than double the volume of the filter, the amount of air that the box can occupy at any given time is more than the filter can occupy. This is where I disagree with your logic. I don't see how the "volume" of the filter has anything to do with the size of the box. IMHO what is more important is that the airflow entering the box is not restricted as it needs to get to every point on the filter surface. I likened it to a FMIC endtank, the endtank goes from wide to narrow as at the widest point it not only needs to flow the air to that part of the core, it needs to flow air up the endtank to the rest of the core, obviously the end of the endtank is shallowest as it only needs to flow air for that part of the core. I used the same logic on my box design. As the air enters the "side" of the barrel that needs most volume. The reason the filter is closer to the barrel at the top vs bottom is that any airflow that circulates the filter to the top only has one place to go, through the filter, bit like the shallow end of the FMIC endtank. IMHO the volume needed around the filter is nothing to do with how much "volume" the filter has, rather it's related to how well it can disperse the inlet volume of air (in my case 4", or 5" if you use the box opening), and in my case I believe the volume around the filter is more than enough. The reason I doubt your "volume" theory is that I could take your argument to an extreme, and have say the worlds biggest filter, say 6 million litres, which had a 4" outlet. Reason it's 6 million litres is the filtration system is sooooo fine it is almost solid, BUT allows enough flow given it's surface area for the 4" outlet. Using you theory, you would need a volume around that of another 6 million litres, but I hope you can see that in reality that wouldn't be the case. Worst case scenario you would need to take your 4" inlet flow and supply it to every part of the filter, bit like adding 4" onto the radius of the thing, but that is overkill, bit like having an endtank the same thickness all the way up. You see what I'm saying? Also airbox design is far more important, where the air enters, the volume needed would totally change IMHO if the air entered from the flat box end (bit like that BMC link earlier) vs entering from the side, this is another reason IMHO why your "volume" methodology doesn't hold up or give you the more efficient box size. Edited January 31, 2011 by jevansio (see edit history) Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 More food for thought while I'm typing. You realise that the K&N filter is shaped like that to get the largest surface area of filter in the given overall dimensions. You seen the tapered cone filters , they're bahaving a lot more like the endtank on the "other" side of a FMIC. The air exiting the core at the narrow entank end is narrow for exactly that reason, it only needs to flow that air, as the endtank goes up the side of the core it grows as it not only flows the air coming from that row of the core, but every row below it. Same principle for the airfilter, the air entering the end furthest away from the turbo only has to flow that air, yet as you go down the filter it needs to flow the air it has let in at that point (and every point before it). You can see my airfilter is wasting a lot of space in that way, but obviously it makes up for it in filter surface area, the cone filters don't have the same surface area given the same overall dimensions. I just don't see how your "you need double the filter volume" theory works, IMHO it is a lot more complex than that, and you can get a smaller overall box if you look at what the airflow is doing. Quote Link to comment Share on other sites More sharing options...
mikeyh Posted January 31, 2011 Share Posted January 31, 2011 id love for you to get some data for this just to see if it does work. my single still has the standard airbox that has been modified a very good job seems to have been done but several people have suggested that it will be very restrictive and the more info i try and dig up for this suggests just that, i think ill have to do away with mine but id love to know if it is actually restricting my setup before i do Quote Link to comment Share on other sites More sharing options...
Scott Posted January 31, 2011 Share Posted January 31, 2011 I understand exactly where you are coming from, and it's going to be quite hard to explain my reasoning. It is all down to the pressure (well actually vacuum) around the filter where it is closest to the enclosure. At the intake area it will be absolutely fine and make no difference, but in order to get the optimum volume of air through the filter you can't have one area with a lower pressure than the other. There is a VERY simple experiment you could do that kind of shows what I mean. Take a straw and suck air in through it, next take that same straw and put your finger really close to the end of it but not touching any part of it. Have half of the straw covered closely by your finger and the other half free. Try sucking again and you will notice a restriction. Now, around the straw is completely open to the atmosphere so it is the distance between the top half of the straw and your finger that is causing the restriction. If you want to make this experiment easier use 2 straws, have your finger closely over 1 of them and open with the other. imagine that is the upper and lower halfs of your filter. The lower half of your filter can easily draw the air from the intake, the upper half of the filter is restricted by how close the box is to it (mimicked by your finger being close to the straw). In both instances, no finger and then finger, the intake size is the same... open to atmosphere. If we section your filter into sq" and say that 1sq" of it will draw in 100ml of air per second the surrounding space when the filter is located in the cover will need to be able to accomodate that rate. Obviously the area of the filter closest to the intake will manage this no problem, but the upper half of the filter will really struggle as the static volume in that area is FAR less than the filter can take in. This means that the upper area needs to draw the air from the lower half of the air box creating a drop in pressure and a restriction on the system. The more volume inside the box to begin with, the easier it is for the air to circulate and the less of a pressure drop you will see in the upper end of the filter. It isn't as simple as an intercooler, with the intercooler the air goes in one end and out the other. The intake and outlet are the same sizes, yes but the air is always moving in the same direction. With the box with the filter in, the air must travel in one end, go around certain parts of the filter and then out through the filter. Basically if the volume of air around the filter matches the volume of the filter it will create next to no added resistance. If the volume of air around the filter is less than the filter itself then you will be relying on certain areas of the filter to work harder (the parts nearest the inlet as that is the easiest path for the air) and that in itself will create a restriction. It is almost like taping up the first half of your filter, although not quite to that extreme lol. Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 Dude, we are never going agree, it's the reason why I wanted to let the performance stats speak for themselves, it may prove me wrong, I doubt it, but it'll save me hours of my life trying to convince you Quote Link to comment Share on other sites More sharing options...
Scott Posted January 31, 2011 Share Posted January 31, 2011 Dude, we are never going agree, it's the reason why I wanted to let the performance stats speak for themselves, it may prove me wrong, I doubt it, but it'll save me hours of my life trying to convince you Without knowing the volume of the box I won't know if there will be any difference or not. The pressure in the upper half of it is going to be far lower than in the lower half of it if it is tight, that's for certain. The air will try to make its way mostly from the lower half of the filter due to where the intake is, the upper half won't be able to draw the air as fast due to the lack of volume up there (the way an aeroplane takes off). What I am saying is correct, you won't convince me otherwise Whether it will apply any REAL difference remains to be seen. I don't think it will have any effect on the arse dyno at least lol. Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 Without knowing the volume of the box I won't know if there will be any difference or not. The pressure in the upper half of it is going to be far lower than in the lower half of it if it is tight, that's for certain. The air will try to make its way mostly from the lower half of the filter due to where the intake is, the upper half won't be able to draw the air as fast due to the lack of volume up there (the way an aeroplane takes off). What I am saying is correct, you won't convince me otherwise Whether it will apply any REAL difference remains to be seen. I don't think it will have any effect on the arse dyno at least lol. I will use my RLPB, it gives a rwhp figure based on acceleration and weight, whether it's accurate is debatble, but it reliably gives me similar reading run to run so one thing is for sure it'll prove any percieved performance increase/decrease. Also next time it's dyno'd I'll be sure to get a run with & without the box Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 PS you know the actual volume of air around the filter in my new setup is approx the volume of the filter? Filter 8" x 7" diam = 307" cubed (and I know for one the 7" is the outside of the silver end not the filter and the filter inner volume will be less than this) Box 9.8" x 8.6" diam = 580" cubed Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted January 31, 2011 Share Posted January 31, 2011 Subscribed for the figures Quote Link to comment Share on other sites More sharing options...
Scott Posted January 31, 2011 Share Posted January 31, 2011 PS you know the actual volume of air around the filter in my new setup is approx the volume of the filter? Filter 8" x 7" diam = 307" cubed (and I know for one the 7" is the outside of the silver end not the filter and the filter inner volume will be less than this) Box 9.8" x 8.6" diam = 580" cubed No, that's why I asked you ages ago Being pedantic I would opt for it to be slightly over double, and I would also have a slighlty larger gap at the top to the bottom for flow purposes. Being really pedantic 9.8" by 8.6" diam = 568" cubed I doubt it will make much difference in that case. You are only 0.4" off it on the diameter. Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 No, that's why I asked you ages ago Where? Being pedantic I would opt for it to be slightly over double, and I would also have a slighlty larger gap at the top to the bottom for flow purposes. I don't have much choice bud, the tube comes in pretty specific sizes, and it's not possible to have an infinitely large barrel in there due to space with the bonnet closing Being really pedantic 9.8" by 8.6" diam = 568" cubed I truncated the measurements when I converted from cm, the volume is ok for the unrounded numbers Quote Link to comment Share on other sites More sharing options...
Scott Posted January 31, 2011 Share Posted January 31, 2011 Where? I didn't really, I just stated that I didn't know... presumed you would have said after I threw in guestimate sizes Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 31, 2011 Author Share Posted January 31, 2011 I guess I didn't throw the numbers in as I don't subscribe to the theory, I only worked it out at the end to when you said "Without knowing the volume" and I thought I wonder what the volume actually is Quote Link to comment Share on other sites More sharing options...
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