04
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. 

 

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Comments
8695Beaters
8695Beaterslink
Tuesday, April 05, 2016 5:53 AM
That is some seriously TIGHT packaging! It's also very tidy, almost like that huge engine and turbo belong there. I'm curious, with all the cooling issues this car has had, was there any consideration for water/methanol injection, or spraying the intercooler with water or even nitrous? I suppose running methanol in the fuel is against the rules, so that wouldn't be an option.
Mike Kojima
Mike Kojimalink
Tuesday, April 05, 2016 8:38 AM
The engine itself runs very cool, the problem was things in the engine compartment getting damaged by the heat generated by the exhaust. Most aftermarket turbo kits would cook the engine compartment under track conditions. The engine runs on ethanol, has a huge rear mounted radiator and oil cooler which really keeps things cool internally
theneil
theneillink
Tuesday, April 05, 2016 3:04 PM
Such good articles this week! I'm wondering are those slip joint springs extra sturdy to handle the back pressure from the turbo, is it such low boost its not a concern, or are they special joints? Nice plumbing work it looks great!
malibuguy
malibuguylink
Tuesday, April 05, 2016 5:33 PM
Ive used Burns bends several times in the past and as soon as 2 weeks ago. Have not been impressed. Most of them were ovaled. I really like the Vibrant bends. I have better sucess with them.
Mike Kojima
Mike Kojimalink
Tuesday, April 05, 2016 6:55 PM
Thats contrary to what my fabricator friends tell me. I am not a fabricator but I work with lots of them.
erikl
erikllink
Wednesday, April 06, 2016 8:29 AM
I would love to see some b4 and after dyno and seat of the pants and/or lap time. Fabulous work
cartechs
cartechslink
Wednesday, April 06, 2016 9:46 AM
Hats off to Chris for such nice work. Looks like you solved a lot of issues, many being possible by the switch to RHD. Still, taking those rocker covers off looks like a chore....
Mike Kojima
Mike Kojimalink
Wednesday, April 06, 2016 10:59 AM
theneil, slip joints secured with springs are common with race type exhausts and the fit is very tight so they won't blow apart.

cartechs, the valve covers come off.

ericl, the dyno stuff is classified but we did see a big increase in both bottom end power and having the power not fall off after 5900 rpm like it used to. The power stays flat to the rev limit now.
Ivo
Ivolink
Wednesday, April 06, 2016 11:22 AM
The fab work and the Burns stuff are indeed top quality, but do we really need to spend so much money on "smooth and non turbulent transitions" when watching this US made video:
https://www.youtube.com/watch?v=azPKIjxmmdU
My answer is NO, but probably just because no one wants to have hammered headers in his engine bay.
...Where are the Myth Busters..?
Mike Kojima
Mike Kojimalink
Wednesday, April 06, 2016 11:31 AM
Ivo, I have designed my own headers many times and with Burns I have always had the same results, more bottom end power and a little more peak power with the power not falling off past the peak. I have done this on about 5 different engine projects.

Burns collectors work and I have proven this to myself many times with race engines and dyno testing. The Burns collectors are good at increasing area under the curve.

Also denting primaries isn't the same as how collectors work as the acoustic end of a pipe and how a merged collector works is different with a wider acoustic sweet spot.

Denting a header tube won't change it's tuned length. Most of a primary tubes length and diameter is based around harmonics rather than flow and this video proves that.

It's an awesome video.
Vince @Burns
Vince @Burnslink
Wednesday, April 06, 2016 1:11 PM
Thank for sharing that video. I had not seen it before. But what that tells me is that the header is too big to begin with. I wish they had specified the the size of the header in the video.
Mike Kojima
Mike Kojimalink
Wednesday, April 06, 2016 5:11 PM
Or it's a very mild street type engine. I have experienced that mild engines with small cams are relatively insensitive to header design while more serious engines with big cams and lots of overlap in particular are very sensitive to header design.
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