man i rekon go the buddy club if u wanna here it scream in vtec espec bc spec II. sure it mite cause a lil chaos on da road wit cops nd stuff but dats wats its all about man. my m8 got 1 on his, nd its only a d series vtec nd its freakin screams man. up 2 u tho.
it's not back pressure you want to produce low end torque, it's a balance between flow and inertia. Back pressure is evil in every way and is to be eradicated
Large pipes mean the gas flows slower (try blowing air through a straw, then a toilet roll), and as the gas at the outside of the pipe sides encounter friction from the pipe walls, it slows, the faster gas running on the inside causes eddies to form along the pipe wall, which actually encourages the gas to start flowing back up the pipe (fill a sink with water and pull your finger straight through it, some water will go in the opposite direction). In that situation, the exhaust coming out of the motor is basically encountering a very small area it can flow through, hence no torque.... but at high RPM the sheer volume of gas doesn't allow this backwards flow to occur, the larger pipe allows more gas to be pumped out of the engine, so better performance
A smaller pipe will allow more flow at low RPM because the overall speed of the gas doesn't allow the eddies to form.... the exhaust coming out of the port encounters a larger area to flow through...
Now, add on to that the inertia aspect - the gas flowing out of the pipe must push something out of the way - resistance from the air already in the exhaust, and actual back pressure caused by restrictions in the system - but as it pushes through, it creates a vacuum behind it, effectively sucking the exhaust out of the head. The bigger the pipe, the less inertia the flowing gas has, so less vacuum...
exhausts for turbos are a different story
I'd like to know more about the mugen twin loop and the valve thingy, I've searched and searched and the only mention of it is fokelore on forums like this. The twin loop design seems to be all about soundwave tuning - using special sizing and angles for the pipes to eradicate unwanted sound waves, while allowing the gas to flow.
yeah...do a search in the mugen website...you will find out more...as I am using twinloop on mine....
got a link? the only one I can find is www.mugen-power.com, and the japanese version is pretty useless, and the english version says "Sorry. English pages are currently under the constriction" lol...
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Originally Posted by yourfather
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