Chris Eimer of Eimer Engineering cuts sections of the Burns Stainless U-bends to makes the exhaust, Y-pipes and and headers. The cut sections are tacked together to form more complicated shapes like header primaries.
The X-Design program determined that the headers we previously used were too long with too small primary tubes. Burns recommended 2″ diameter primaries up from 1 7/8″ with a 24″ length, down from the previous 27″ with a long transition merged collector. With a Burns collector, these dimensions would improve bottom end and still greatly increase top end power.
The headers were mocked up from cut pieces of U-bends and tack welded together to determine the layout before welding. The header design was done to give more room around the cylinder heads to ease maintenance and to get hot pipes away from heat sensitive parts like plug wires, ignition coils and the wiring harness.
You can see the merging area of the Burns collector. The smooth merge and tapered transition helps the primary tubes have a wider rpm range of a tuned sweet spot, staying in resonance longer. The smooth non turbulent transitions are also better for flow compared to the abrupt terminations of traditional box collectors.
The Burns collectors have a 3″ exit diameter. The large 3″ in diameter Y-pipe is needed to feed the big 545 cubic inch engine. The engine is set up to run with a low boost pressure turbo and we feel that its is more reliable than revving the engine to high RPM to make competitive power. The engine can withstand boost pressure more easily than high RPM.
The engine is built to produce about 900-1000 hp with 7-8 pounds of boost by 6700 rpm rather than having to spin to 8000 rpm to make the power NA. Another 100-200 emergency hp is available by switching maps on the fly for more boost.
The headers are mostly done being test fitted and tacked together and will be ready for welding soon. Chris is getting ready to start building the Y pipe to the turbo.
The turbo is a Garrett GTX50R ball bearing turbo. It can flow enough air for as much as 1400 hp. The modern GTX aero and floating cartridge ball bearing center section is efficient and durable. This turbo has run an entire season including testing and exhibition runs without issue.
The GTX turbo is very heavy and to improve weight distribution the car was converted to right hand drive to get the turbo away from the dry sump pump. This enabled the turbo to be set over a foot back and a foot lower from its original location. This also enabled the intercooler to be set back a foot making it less vulnerable to damage and improving the weight distribution even further.
A great side effect of the turbo and intercooler relocation is that the charge piping can be made extremely short, simplifying the engine compartment greatly and saving weight. The throttle response will be increased and lag will be decreased as well. Over 90 lbs has been moved off the very front of the car and moved rearward. Since the turbo is so heavy, it is mounted directly to the chassis and the exhaust system will have flex joints to prevent different movement between the engine and turbo from causing cracks.