The collectors were supplied to the owner as double slip collectors which are used to help alleviate thermal stresses in the headers. The header fabricator, though very skilled, was unfamiliar with how they worked, so instead, he welded them solid to the primaries (Figure 4).When testing with the downtube shown, the turbos supplied 8.9 psi boost, but the exhaust backpressure was 14.5 psi and the motor made 949 hp. When the downpipe was replaced with a 4” downpipe power came up to 1038 hp at 8.5 psi boost and 12.5 psi exhaust pressure with no other changes.Without careful planning and execution, problems can arise. In general, this system is a very good turbo exhaust system. There are many great features as well as a couple of areas that could have been done better.
The forward sweep of the headers provide a U-shaped “free-end” which minimizes stress in the header caused by thermal expansion (Figure 2). We prefer to see equal length headers, which these are not. But it is easy to criticize when it is out of the vehicle!To offer you the best selection of race quality parts. Relentless innovation in exhaust technology isn’t just a tag line, we are always improving, advancing, and refining what we offer.
A couple of items that may not be evident from the photos but are important to consider. Some of the header bolts are hard to access to remove the headers. This is with the engine on an engine stand, much less trying to reach them installed in the vehicle. Also, the header on the right side makes it impossible to remove the valve cover without removing the header (Figure 3). Combined with the hard to access header bolts, I can imagine that in the future, there will be a few curse words and wrenches sailing through the shop. It is important that the turbos are supported by something other than the headers. It has been standard practice in the import world to build exhausts from thick walled pipe which can support weight of turbos.
“Our recommendation is to expand out of the turbo using a transition” Can you give more information of why? I understand that it is not good to make an reduction, but what about the same ID of the turbine exhaust port?The turbo exhaust plumbing has a shortcoming that I would like to discuss. The turbo outlet is setup for a 3.5” OD tube. Our recommendation is to expand out of the turbo using a transition, and in this case to 4” OD tubing.Designed from scratch is an equal length seat of headers for Twin Turbo V8 builds, ideal for scale modeling (currently in 1/24 and 1/25 scale). (Gold parts in photos)You like Cults and you want to help us continue the adventure independently? Please note that we are a small team of 3 people, therefore it is very simple to support us to maintain the activity and create future developments. Here are 4 solutions accessible to all:Big Block Chevy Up and Forward Turbo Headers. All tubes are CNC mandrel bent for optimal flow. Made from 304 stainless steel for maximum corrosion resistance. Starting with a CNC cut 3/8″ thick flanges into 2-1/4″ Primaries and 3.5″ Slip Fit Collectors. Headers are fully TIG welded and back purged. These are TIG welded for strength and durability. These kits come with a lifetime warranty and proudly made in the USA.