Arthur wrote on 04/05/08 at 13:45:51:


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.  

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.
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.

skrapiron -FSO wrote on 04/05/08 at 19:08:22:

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.

sluggo, how many disks did you try?

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~

Strafford_Guy wrote on 04/06/08 at 07:08:50:





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?

Reelthing wrote on 04/06/08 at 06:29:00:


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.