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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Pod filter HP loss? /cgi-bin/YaBB.pl?num=1207428351 Message started by Gort on 04/05/08 at 13:45:51 |
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Title: Pod filter HP loss? Post by Gort on 04/05/08 at 13:45:51 In the book, " How to Hot-Rod the Small Block Chevy", it is advised not to remove the factory engineered air cleaner housing (not the filter, the housing), due to a subsequent loss of horsepower. It says that this is a common mistake made on any automobile engine. It goes on to say that the air cleaner housing shape is engineered to eliminate turbulence or erratic air patterns, thus allowing a calm flow of air into the carb. This calm flow is required for proper atomization of the fuel. It says low profile after market housings facilitate air turbulence, with its subsequent HP loss. I wonder if the Suzuki airbox was designed to calm the air intake, and if removing the airbox and substituting a pod/cone filter will have the same HP decreasing effect as it would if you used one of the many similar designs on an automobile engine? Perhaps other mods such as a less restrictive muffler along with the usual pod filter will give the feeling of more power, with the pod filter being given partial credit for this increase, when indeed the muffler with a airbox with no filter would have given even better perfomance? |
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Title: Re: Pod filter HP loss? Post by sluggo on 04/05/08 at 15:20:37 2211170B1611630 wrote:
i'm dealing with that right now on thumper. i made that side mount air filter and intake and am having a bear of a time getting the jetting right. i've tried 150 152.5 155. added disks to the trapp and still loss of top end went from 95 mph top to just a tad over 80. that would explain things. i know it looks kewl but if i cant get it to work off it comes. next up the hand built nu foam filter. or lancers performance pod. at least i didn't have any big bucks into the project. |
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Title: Re: Pod filter HP loss? Post by T Mack 1 on 04/05/08 at 16:49:52 Gort, Makes you wonder what they are thinking when they sell those little vanes to turbulate the air for more fuel economy..... Yet the High perf. guys port & polish anything they can LOL Sluggo, Suggestion. Take some paper, wrap it around the element and cut it so that it shows you the surface area of the fancy filter (one layer of paper fully covering the elements paper part). Then.... take that paper and hold it up to your old cone filter to see if it covers it or if there is cone filter uncovered. May also want to do the same against the OEM filter if you still have it..... |
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Title: Re: Pod filter HP loss? Post by Onederer on 04/05/08 at 19:07:36 When a engine is engineered, everything is designed to work in unison. If someone does'nt completely understand how to "tune" an engine, then the end result is usually less power. Street engines are a huge compromise, because they need to operate well in a broad range of rpms and loads. When top fuelers are at a race, the crew tunes that engine for the conditions of the day, every day. Indy cars have variable length intake runners to allow maximum performance thru the revs. Most stock air filters flow more than enough air for mildly tuned engines. Also, the larger the volume after the filter allows for more institanious acceleration because of filtered air reserve. Intake volume,diameter,length all play a part. The reason for leaving the air cleaner housing on the ol' carbed engines is because the bottom is somewhat shaped like a velocity stack, and smoothes the air going thru the carb and into the intake. Porting is just mathcing the intake, exaust to the parts that conect to them to smooth flow. Polishing can be done in different stages, and something too smooth might hinder function. Reshaping ports and combustion chambers is something best left to proffesionals, because it is very sensitive work, and can have dramatic effects/consequenses. The exaust/mufflers on a lot of factory street engines are resrictive to pass noise emissions, although the end result of changing this is usually more aceleration and not top speed. From my experiance most bikes run almost the same top speed after a less restrictive muffler and re-jetted, they just get there faster. The Savage engine has a "high mass' crank for a more torquey feel, but forget about making super quick revs untile the reciprocating assembly has been lightened up. If one looks at modern high performance dirt bikes they'd see slaper pistons,titanium valves, and very light cranks, these are great for performance but not overall engine longevity or roll on power. As far as haveing the air filter stuck out in open air flow, it is normally a bad idea. As a bike is moveing at speed air has a tendency to blow thru the front and out the back of the filter, avoiding going smoothly into the intake, this causes a lot of turbulence inside the filter that upsets carb jetting and could also allow less air to enter, ergo loss in top mph. To remedy this, put some sort of shield in front of the filter.http://images.channeladvisor.com/Sell/SSProfiles/23000216/Images/2/AFH-0001.jpg These are designed for cars to keep heat away and road dirt if the filter is mounted under the bumer, but hopefully you get the point. If anyone has seen an old roadster with the louvered covers over the filter/filters that is mostly why they are used. If someone uses a open fliter that is transversly mounted on a motorcyle, it works the same. Installing a shield should help with jetting problems. Try zip tying something in front of the filer to see if it helps. Or if someone wants, the entire filter can be covered except for the front, to get a ram air effect, but they'd have to route the carb bowl vent tubes to the enclousure or the set up won't work properly because the carb will still act on actuall atmospheric pressure. There are these nifty carb enclosures for cars with centrifical superchargers or turbochargers that encloses the entire carb to keep everything balanced. It is much easier to just have a filter in a box so the air is not turbulant going into the filter. If anyone can make jelly beans from this, great, otherwise I got a little finger exercise. :) |
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Title: Re: Pod filter HP loss? Post by skrapiron on 04/05/08 at 19:08:22 On a cage, with a manifold that has to feed multiple cylinders, I can see the negative affect of the turbulent air. But on a thumper, with no manifold to speak of, I don't see how a pod would have any ill affect on the carbeurators ability to vaporize the fuel adequately. On my bike, I am still running the stock exhaust, but with the k&n pod filter, 52.5 pilot 152.5 main. I can say without a doubt, the engine accelerates much better with this setup than it did stock. Especially when I am already moving an need to pass someone. Even in 5ht gear, I can peg the throttle, and it has some serious get up and go! |
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Title: Re: Pod filter HP loss? Post by Onederer on 04/05/08 at 19:26:15 263E2734253C273A3B550 wrote:
Carbs, even fuel injectors don't vaporize fuel, tey atomize it. The only carbs I know of that vaporized fuel were catalytic carbs of the early 1900's, and those have mostly been forgoten, and the gov wants it to stay that way, besides they put lead into the fuel to foul em, and even now there are still chemicals in the gasoline that would foul em. The fuel becomes vapor in the combustion chamber when its compressed, otherwise it would'nt burn. Liquid gasoline does'nt burn well. Take a bucket of gasoline and drop a lit cigerett into it and the cigerette will just extinguish, vaporize the fuel and it will ignite. Turbulant air would even have an effect on a lawn mower. A DC-10 even gets bumpy in turbulant air.I'd hate to get caught in the jet wash of a jumbo if I was in a single engine plane. |
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Title: Re: Pod filter HP loss? Post by sluggo on 04/05/08 at 19:55:03 mines not a pod it's a cheep round job.. it is blocked from the stream by the cover.. i'll just toy with it some more.. |
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Title: Re: Pod filter HP loss? Post by Reelthing on 04/06/08 at 06:29:00 sluggo, how many disks did you try? |
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Title: Re: Pod filter HP loss? Post by Onederer on 04/06/08 at 06:41:40 Someone mentioned wraping paper around the filter and comparing that to the old filter, to measure surface area, but that is'nt accurate at all. The number of pleats in the filter media makes a difference. More pleats=more surface, taller pleats=more surface. The media material itself can have more surface area, like foam. Sluggo, if I'm correct your useing one of those very small round automotive filters, like the kind that are used on 1bbl automotive carbs. I ran one of those on an ol' Chevy 250 six cylinder. I think that if it flows engouh air to allow 250 cubic inches to propel a truck to 90mph, the it should'nt strangle the 40 cubic inch Savage at all. |
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Title: Re: Pod filter HP loss? Post by Strafford_Guy on 04/06/08 at 07:08:50 Hey Guys, pardon my ignorance but what is the differnce of a pod filter verses a k&n or one of the cone filters that Lancer has contracted to make for the Savage? Same beast ins't it? From what I have been reading on this forum for the last year with proper exhust and rejetting one of those filters should improve performance. Right? Are we talking about removing the airbox is not a good idea or is this more to the fact that the filter should not be side mounted and out in the open? I don't belve that Lancer would sell something or go through all the trouble if it was not of any benifit to use or would Savage greg or any other of the gear heads (which I am not..yet) here use one if they were not any good. Sorry but I would just like to get the facts streights on this one. Also I can't spell worth a darn so it is what it is. Thanks ~Strafford~ |
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Title: Re: Pod filter HP loss? Post by Onederer on 04/06/08 at 07:32:35 Yeah, if you use a pod/cone filter you'll have to ditch the air box. Thats fine, but there are a couple of things to consider. Some pod/cone filters are too big and the battery box will interfere with the installation., although I belive the one sold here is fine. If caught in very heavy rain, a filter without a box is prone to getting water saturated and causeing the bike to run poorly or not at all. On a plus side you could easily see if the filter is dirty. I for one don't belive in any performance gain over the stock filter, although I may use one because it seems no mater what someone does to seal around the stock filter, dirt gets by it. If I use one I'll make a shield to keep the rain out. A pod/cone/K&N cone, they're brothers, although K&N makes a factory drop in replacement, which I would'nt take if I was given one. Which way to the zipidy do da? |
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Title: Re: Pod filter HP loss? Post by Gort on 04/06/08 at 08:05:11 587F796A6D6D64796F544C7E720B0 wrote:
In the book," How to Hot Rod the Small Block Chevy", the point they were making is that it is necessary for air coming into the carburetor to first be calmed by an engineered chamber ( factory air cleaner housing). They say that if the housing is removed and a different design air cleaner housing is substituted such as the low profile after market units, the incoming air will not have the right configuration nor room to calmly enter the mouth of the carb. Instead, the carb will get air with some amount of turbulence ( a worst case scenario being no housing at all). Turbulence prevents proper atomization of the fuel and subsequent HP loss. Putting a filter close to and directly in front of a carb mouth does not allow the incoming air to calm like it would if the Suzuki airbox was left in place. The question is, how much of a HP loss does it really make on a small, single cylinder engine? |
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Title: Re: Pod filter HP loss? Post by T Mack 1 on 04/06/08 at 08:35:13 7241475B4641330 wrote:
Oh Gort..... you are such a nice person for volunteering to experiment....... ;) Kidding..... I like threads like this.... they make you think..... Thanks!!!! |
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Title: Re: Pod filter HP loss? Post by sluggo on 04/06/08 at 10:21:09 4077777E667A7B7C75120 wrote:
open end. and 10 so far. ten is all i got. need to buy a sixpack of them. at this point i'm going back to airbox. 152.5 a new foam filter and 10 disks. that should do the trick. i know it looked kewl but i need my top end. |
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Title: Re: Pod filter HP loss? Post by KwakNut on 04/06/08 at 11:38:12 I’ve modified quite a few bikes, and cars, to cone filters. Problems can arise because the range of different flowrates you get with the pod filters just goes beyond what the carb was designed for, and changing jets and needles still gives you poor mix as the carbs struggle to deal with how hard the motor is sucking. It can just mean time for a trip to the bank and a new set of carbs. Usually though, if simple jet or needle changes don’t work, it just means a bit of faffing around with needles, needle jets, main jets, pilot jets and air tubes until you get it right. Can mean getting the carbs in and out 20 times, but you get there eventually! For simple home upgrades, sticking to the factory airbox is advisory on some machines because some engines are just known for being a real turd to set up the carbs with cones – but once you get there, it’s worth the hassle. The most common complaint when going to cones is flat spots midrange– and this is invariably because the standard needles just don’t have the adjustment range to match, and/or are the wrong profile to suit cones. Needle profile is as important as needle jet size – or fuelling will only be right in a very narrow area of the midrange. I struggled to get a GSX-R1100 to run smooth some years ago and eventually went for a Dynojet kit – I knew it would work as soon as I saw the new needles because their profiles were radically different to the originals. She went from a frustrating flat midrange to standing up on the back wheel in second at ¾ throttle. Well worth the $200 for the Dynojet kt. (That said, often Dynojet is just an expensive way to buy bigger jets, depends on which bike !!) I’d be reluctant to ditch the airbox on really modern Jap stuff. High-revving race replicas get a great deal of development into optimising the airbox shape and volume to feed the motor, and I’ve known racers go back to factory setups after trying to run individual filters – sometimes with those engines even complete fuel injection remapping won’t cure the problems if you ditch the airbox. |
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Title: Re: Pod filter HP loss? Post by KwakNut on 04/06/08 at 11:39:50 73525958594E594E3C0 wrote:
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Title: Re: Pod filter HP loss? Post by Onederer on 04/06/08 at 12:46:59 I have a problem with noticable amounts of dirt getting past them. If I had a pure race vehicle that the engine was gona be torn down after x hours, then I'd run one, but on the cars and bikes I've used them on, after I run them for a while then look inside the intake, I have seen dust in there. I put on the stock filters, and no dust. I threw them all away because I felt I'd be wrong to give em to someone, well, someone I liked anyway. The K&N's were properly oiled and cared for, but still did'nt filter well. They have a place, but not on my street machines. I have'nt put one on the Savage cause that durn filter does'nt seal well anyway. Last one I put in it, I used filter rim grease all over the foam to see if it helps. If it does'nt, I'll be changing to some other type of filter. |
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Title: Re: Pod filter HP loss? Post by KwakNut on 04/06/08 at 14:45:34 6948434243544354260 wrote:
I sometimes fill out the edges of those sorts of filters with tape to make them fit more snug. |
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Title: Re: Pod filter HP loss? Post by Gort on 04/06/08 at 15:51:55 522B4B67656D37060 wrote:
Oh Gort..... you are such a nice person for volunteering to experiment....... ;) To measure the difference would take a shop with a Dynamometer along with controlled condition testing. I would assume Suzuki already did these tests when it arrived at the airbox configuration it settled on? Wouldn't there be a marketing advantage to squeeze as much HP and fuel economy out of the engine as possible, by efficient design of the air intake system? Kidding..... I like threads like this.... they make you think..... Thanks!!!![/quote] |
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Title: Re: Pod filter HP loss? Post by Gort on 04/06/08 at 16:26:33 14353E3F3E293E295B0 wrote:
There is an interesting article somewhere on the Internet about air filters. It comparison tested various brands and showed the results. It concluded that the engineers who designed the engine know what the best air filter design is, for their engine. It said that an air filter has to be a compromise which allows sufficient air-flow, while still filtering the dirt out of the air. The tests showed that the K&N design did allow more air flow into the engine, but simultaneously allowed more dirt to pass through as well. It said that there is no mystery to making a K&N style air filter, and if the engine manufacturer thought this was the best design for the engine, it would have equipped the engine with that type. But the engineers also have to take into consideration engine reliability and a K&N type filter allows too much abrasive dirt into the engine to satisfy the engineers' requirements for long component life. ( It showed a comparison test of K&N against others, and showed the difference in particulate matter that passed through. K&N ( and foam filters) let more dirt through the filter than conventional designs.) The study went on to say that you cannot have both high flow and optimum particulate filtration simultaneously. It asked that don't you think that the manufacturer would have put that design (K&N or foam) filter on the engine, if it safely increased HP? I suspect that the dirt some owners have found in the intake hose or carb mouth is the result of sloppy fit of the air filter in the airbox, due to poor quality control in the manufacturing of the airbox housing, and or from using a K&N or foam style filter. |
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Title: Re: Pod filter HP loss? Post by Max_Morley on 04/07/08 at 12:53:46 Sluggo, i ended up with a 24 hr flu bug and as I lay in bed last night waiting for the next round of hugging the throne, I thought about you carb problem. First keep it simple, re-inspect the carb slide for free travel all the way to the top of the carb body*.If it sticks 7/8 of the way up, that is all you will get regardless of where you have the butterfly plate. Could be a piece of lint from a shop towel jamming it. 2nd verify the spring on the diaphram is installed correctly and not stopping the slide from moving all the way. ? will it go WFO in 4th gear? B-i-L's came with a pod filter and it works fine so I'd look the filter being a problem last. * you should be able to raise is carefully with your finger with the inlet air elbows off. Max |
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