A well designed exhaust can make a big difference to performance, maintaining velocity of the exhaust gases with as little restriction as possible is the key. The reason is the scavenging effect on your engine. What this means is that with an excellent system, each exhaust pulse, as it races through the piping, leaves a slight vacuum behind it to help suck the exhaust out of the next cylinder when the exhaust valve opens. This helps make your engine more efficient. You want to pump in all of the air you can, and pump all of the exhaust gases out ASAP. This is especially important at high rpm, when things are happening more quickly.
Now, as you introduce restrictions to the exhaust, you begin to reduce the scavenging effect because you don’t maintain the same velocity through the system. Mandrel bends are a great advantage over crush bends as the inner diameter of the exhaust pipe constant throughout the system.
Mandrel bends maintains the same ID all the way through the bends. Crush bends are just like they sound; the piping is crushed slightly while bending, decreasing the ID of the pipe.
Mandrel bent is the preferred method, but requires special equipment. Mandrel Bend Equipment is very expensive and most local muffler shops can only crush bend or only have access to pre bent 45, 90, 180 sections in mandrel bends. When building a custom setup ask for mandrel bends.
Xforce Exhaust systems uses mandrel bend in all its exhaust systems, restriction is kept to a minimum while flow and velocity is kept high. With a full Mandrel bend Xforce exhaust system coupled with Xforce headers power gain of 15-35rwkw (FPV FG 335 GT) has been achieved with no other supporting mods.
For a custom exhaust setup Xforce also offers a universal mandrel bends (15,30,45,60, &90 degree) in stainless and mild steel . Sizes ranges from 1” ½ – 1D bends