MEASURE TWICE, CUT ONCE

Before any cutting discs are used, or argon gas expended, a bit of basic mathematics is required. The stepped equal-length design means that each primary pipe must be of approximately the same total length, and each stepped increment of approximately the same total length. Beginning with a 1⅞-inch pipe diameter, this steps up to a two-inch pipe, which then steps up to a 2⅛-inch diameter before the primary pipe joins the four-into-one merge collector. Each step is 8½ inches in length, giving each primary pipe an overall length of 25½ inches. The tight space constraints mean the header pipes will be constructed and installed individually, as there is no way a one-piece header would be able to be installed or removed without great difficulty. The header flanges are all separate, and the pipes will use tabs to fasten to the slip-joint merge collector.

Generally, the exhaust port sitting closest to the front of the car will determine where the slip-jointed merge collector will be positioned. However, on V8 engine configurations, the team will always start with the side that experiences the tightest space constraints. The plastic header blocks are laid out to design the first header pipe according to specifications. Once that is done, the remaining three exhaust primary pipes on that side are designed, to get an idea of the final header layout, including merge collector positioning. “Once we are happy with the design and have achieved the required lengths of runners needed, we transfer the segments onto the material being used,” Mike explains.