actually after playing with it for a while I think the actual air box mods are where the improvment is. The stock rubber pipe is fine unless you remove the baggage off the side of the air box (this is what I did for other reasons) and then you have a large hole to try and plug. I may try and plug that hole and reuse the stock rubber part if I can make it sanitary enough. The only draw back I can see to using 3" pipe is that you lose some velocity when you come through the AFM and then jump into a 3" pipe. Much like an expansion chamber only in exactly the wrong spot.


On the subject of exhaust. There is an optimum size and there is also extremes on either side. Im also about tired of people talking about back pressure like its some sort of requirment.... ITS NOT!. The reason you use a select size pipe is for scavanging or in more common terms siphoning. You want the exhaust to flow as easily as possible so the engine spends no extra power pushing the exhaust gasses out (AKA.. NO Back Pressure!). The compromise here is that you also want a small enough pipe so that as the exhaust gas pulse leaves its trying to draw more exhaust out of the cylinder or create a vacuum in the cylinder for the intake charge. So in essance the vacuume is aiding the intake charge. We could also go into exhaust gas velocity and the speed of heated air VS cold air but I think people who didnt know before will have the right idea now. If im wrong here some one jump right in but I dont know how much longer I can take "the back pressure excuse" for exhaust pipe size.