Headers & Exhaust for TD05H Turbos
Without a doubt, the single biggest pain in the butt during the build-up was getting the headers, O2 housings / pre-cat eliminators, wastegate dump pipes, and down pipe packaged around the TD05 turbos. It didn't have to be as difficult and drawn out as we made it but luck wasn't on my side to get this part of the build up completed quickly. Following are some of the pictures taken during the fabrication process. Although I did some of the cutting, porting, and layed out the design, almost all the credit goes to Del Glasser, owner of Custom Welding & Fabrication in Wyandotte, MI.
With that said, let's jump right into the fabrication of the headers.
Rear Bank Header
The left pic shows our starting point, a box full of 16 gage (.065" wall thickness), 1 5/8", T321 stainless bends (120 & 180 degree). $550 in raw material alone, and that's a bargain for aircraft quality T321 bends. Together with some 1/2" stainless flanges and T347 stainless welding rods, Del Glasser turned out some bitchin headers over a 2 year time span (yes it took 2 years). On the right is an early attempt at a rear bank header being compared to a Greddy header (flanges cut off). Most of the early attempts were scrapped because they didn't route quite how we wanted. Note the engine mock-up complete with half shaft etc. This together with several engine bay measurements were necessary to make sure everything would fit. Also, before the header runners could be routed, we had to determine where the TD05 turbo would sit. Jon from TRE lent us a turbo for mockup purposes. On the rear bank, we chose a position that sits higher, closer to the passenger side, and as close to the intake as possible (had to remove EGR pad). This allows for easier routing of pre-cat eliminator and wastegate dump pipes.
We had to notch the rear bank engine mount bracket to allow easy header removal. The right pic shows the rear bank header nearing completion. Note that a minimum number of bends are used for each runner, two each for cylinders 2 & 6 and three bends for cylinder 4. A low number of bends is a sign of a well thought out and free flowing design.
Del finished welding the header up to the collector and handed it over for some major league porting (aka weight reduction). It was very important to me to have a seamless transition from the cylinder head exhaust port to the header (easier said than done), many hours were spent on this endeavor. I was picking small stainless steel shavings out of my arms and hands for days.
HEY JON @ TRE! Check this out, what do you think about fitting a TD06 compressor housing on here? Will a TD06 housing even mate up with the TD05H center section and turbine housing (6cm2 I already bought)? I would like to run the big 16G with a TD06 for that extra 3% efficiency improvement.
The current rear bank header only has 7mm clearance to the cam cover worst case. Can the TD06 be modified at that location to fit without sacrificing performance? If necessary we can tilt the turbo flange a little more rearward to gain more clearance. Just let me know how much beyond the TD05H we need to allow a TD06 to fit. The front bank has a ton of room. See the two pics below to see where it is that we are tight.
Front Bank Header
OK, the rear bank header was just practice for the more complex front bank unit. Here is a pic of the front bank Greddy header (again minus the flanges) and a turbo brace to help keep the heavy turbo in position. Many people eliminate the turbo brackets to reduce complexity and weight, however, they are there for a reason. Feel the weight of your turbo (especially the TDO5s!) and you begin to understand what you are asking of your exhaust system when you're running 1650F EGTs and the engine is shaking about. If you want your headers to last, don't run your EGTs too high, don't over wrap them, and if possible take the weight off of them with braces (like the factory did, more important on the front bank).
Here is a shot of an early attempt at the front bank header and a close-up of how the turbine housing is positioned w.r.t. the engine mount bracket. As you can see, the turbo sits closer to the passenger side of the car and a tad bit lower. In this position, the turbine nestles nicely around the engine mount and the compressor housing resides outboard the edge of the mount bracket.
The header in the above pictures was completely scrapped in an attempt to shorten each runner length. Attempt #2 (shown below) looked much better except for how runner #5 entered the collector. Because I insisted on a more downward approach (feeding into turbo inlet), we cut the runner out and re-routed it.
Finally, attempt #3, the front bank header looked as good or better than anything I've seen offered for our cars.
Now for the same treatment we gave the front bank header, ie porting, add EGT bungs (& a pressure bung), normalize, and re-face.
Hey BIGKASH, here is a pic showing the line off the AC compressor I'd like:
since August 7th, 2002
Last Updated: 08/08/02 07:50 PM