Caporegime
So, i wondered as many people do, what exactly are the benefits of a fatter, wider, straighter exhaust?
Does having a big phat pipe sticking out the tail end make a tangible difference compared to a smaller peashooter that winds its way around the back side of the car?
Yes.
My car hasd a JDM Apexi Hayabusa which is a single exit with pipework at 76mm increasing to the tail.
I also have an exhaust bung and a boost controller with which to test the setup.
being MOT day, i popped the bung into the exhaust and tried a run on the motorway. The acceleration seemed much more pedestrial than usual, and boost peakes at about 0.72 bar (Blitz DBSC).
Finish MOT, remove bung, drive home and voila, same piece of road etc same conditions, car now gets to 0.84 bar with no alterations or tweaks. Same EBC settings.
So what does this mean?
Exhaust bungs are bad. its official. MOT testing Yes, performance, No.
Fatter, straighter exhauists will help you to produce more power by reducing the pressure on the exhaust gas outflow, IF the existing diameter or smallest diameter is actually blocking or inhibiting the boost escaping quickly enough.
Sounds simple, but i was actually shocked at just how much the bung reduced the forward accel of the car itself.
Does having a big phat pipe sticking out the tail end make a tangible difference compared to a smaller peashooter that winds its way around the back side of the car?
Yes.
My car hasd a JDM Apexi Hayabusa which is a single exit with pipework at 76mm increasing to the tail.
I also have an exhaust bung and a boost controller with which to test the setup.
being MOT day, i popped the bung into the exhaust and tried a run on the motorway. The acceleration seemed much more pedestrial than usual, and boost peakes at about 0.72 bar (Blitz DBSC).
Finish MOT, remove bung, drive home and voila, same piece of road etc same conditions, car now gets to 0.84 bar with no alterations or tweaks. Same EBC settings.
So what does this mean?
Exhaust bungs are bad. its official. MOT testing Yes, performance, No.
Fatter, straighter exhauists will help you to produce more power by reducing the pressure on the exhaust gas outflow, IF the existing diameter or smallest diameter is actually blocking or inhibiting the boost escaping quickly enough.
Sounds simple, but i was actually shocked at just how much the bung reduced the forward accel of the car itself.