> Straight to the point, which exhaust system is better in >terms of > performance? ,> -Robert > vin 6585 "X" There's really a lot to consider when designing headers. Larger tubes are more free flowing but small tubes have a better scavenging characteristic. Longer headers maintain good scavenging and increase torque. They create a column of exhaust that actualy pulls the exhaust from the combustion chamber. As RPMs increase the velocity increases and shorter headers work better. The engines performance charateristic in regards to what RPM range that power and torque are developed has to be the deciding factor in the design. Headers also need a straight shot out of the head for at least a couple of inches to prevent exhaust gases from piling up at the exhaust port. It's also very important that the tubes are equal length. The DeLorean doesn't have a whole lot of room for headers to conform to the ideal in regards to all this but all of these things have to be considered and compromises have to be made. The whole idea is to create the right velocity of exhaust flow and if it's right it not only flows more freely, the scavenging effect actualy drags exhaust from the combustion chamber until the RPMs are high enough that velocity alone will push the gases out. Bruce Benson