***08/08/11 - I got my 2012 Rally Red Honda Civic Si Sedan.Hidden Content ***
*2nd 9thGenCivic.Com Member with a 2012 Rally Red Honda Civic Si Sedan.* 1st is 67cougar.
- 2012 Rally Red Honda Civic Si Sedan (Current)
- 2003 Satin Silver Metallic Honda Civic Si Hatchback (Sold)
- 1994 Pard Blue Green Pearl Acura Integra GSR Coupe (Stolen/Totaled)
- 1992 Super White Toyota Corolla DX Sedan (Totaled)
Make sure they include a catted version, I don't want to get screwed for that AND the straight pipe exhaust!
SiHFPClub Member #33
K24Z7Crew Member #991
The name says it all, brand new 2013 Taffeta White Civic SI HFP
Started with a '99 Civic EX, then a '09 Civic EX-L, now onto the '13 Civic SI HFP
Can you tell I'm a fan of the civic?
sorry, buddy club are not going to offer a catted dp. if you need catted dp, you will need to buy rv6
Si HFP Club Member # 4
You don't need "back pressure " lol
your only 1/2 right, less back pressure the better, but when the exhaust pipe is too large, it sometime decrease gas velocity...
it's cheaper & easier for buddy club just build a 3" straight through down pipe.. this set up is what buddy club tested to be the best cat-less down pipe for a k24.
same with their short shifter, buddy club R&D test shows full assembly ss kit is better than adapter kit for race application, so they invest $110,000 on tooling for the shifter cage. rather just spend couple thousand on cad drawing & use cnc machine to cut some aluminum adapters.
One of the most misunderstood concepts in exhaust theory is back pressure. People talk about it with no real understanding of what it is and what it's consequences are. I'm sure many of you have heard or read the phrase "Engines need back pressure" when discussing exhaust upgrades. Sadly, that phrase is completely inaccurate and a wholly misguided notion.
1. Some basic exhaust theory
Your exhaust system is designed to evacuate gases from the combustion chamber quickly and efficiently. Exhaust gases are not produced in a smooth stream; exhaust gases originate in pulses. A 4 cylinder motor will have 4 distinct pulses per complete engine cycle, a 6 cylinder has 6 pules and so on. The more pulses that are produced, the more continuous the exhaust flow. Back pressure can be loosely defined as the resistance to positive flow - in this case, the resistance to positive flow of the exhaust stream.
2. Back pressure and velocity
Many people mistakenly believe that wider pipes are more effective at clearing the combustion chamber than narrower pipes. It's not hard to see how this idea would be appealing - as wider pipes have the capability to flow more than narrower pipes. However, this omits the concept of exhaust VELOCITY. Here is an analogy...a garden hose without a spray nozzle on it. If you let the water just run unrestricted out of the hose it flows at a rather slow rate. However, if you take your finger and cover part of the opening, the water will spray out at a much much faster rate.
The astute exhaust designer knows that you must balance flow capacity with velocity. You want the exhaust gases to exit the chamber and speed along at the highest velocity possible - you want a FAST exhaust stream. (see below) If you have two exhaust pulses of equal volume, one in a 2" pipe and one in a 3" pipe, the pulse in the 2" pipe will be travelling considerably FASTER than the pulse in the 3" pipe. While it is true that the narrower the pipe, the higher the velocity of the exiting gases, you also want make sure the pipe is wide enough so that there is as little back pressure as possible while maintaining suitable exhaust gas velocity.