Grand Rock Stack kit – ROCKS!
Joining the
“stacked” club became a priority this year.
However I wanted to retain my 4” muffled side exhaust to use while
towing and when the kids were in the back seat while also preparing for a full
5” turbo to stack flow. After casually
checking into a couple of potential manufacturers, Grand Rock products were
selected to best fulfill my requirements.
They maintain an excellent reputation and carry all the products
necessary for a complete out of box or custom solution. Given the custom design
of retaining the side pipe along with the new stacks, Josh Stewart from Grand Rock
went out of his way to visually inspect parts, take measurements, and ensure
that all the necessary parts shipped out fast so that I could complete the project
in time for the TS Performance 2007 event.
Any of the Cummins Forum sponsors that are Grand Rock dealers can help
out purchasing a system. If you have a
special requirement or question, then Josh will assist with ensuring you have
the correct part numbers to best fit your need.
Here are the products selected for this project:
|
P/N |
Description |
Qty |
|
R50-4IA |
Adapter |
2 |
|
HDT-5A |
Diverter |
1 |
|
DPU-6SK-5I |
Stack Kit |
1 |
|
SA6-36SBC |
6" Aussie Stacks |
2 |
|
AS-4A |
Accuseal Clamps |
2 |
|
SF-512 |
5" Flex Pipe |
1 |
|
WFC-5A |
5" Clamp |
2 |
Of course
the race tires/rubber prep and HTT Exhaust Manifold (from New Era Diesel) were
not included in the Grand Rock kit, but they were also part of my preparation
for the TS Performance Outlaw Race weekend.
Typically all that is needed is the Stack Kit which contains all the
necessary clamps and mounting hardware, plumbing, and to select your stack pipe
style of choice. I elected to use the 5”
cross pipe kit and diverter pipe with the new style Aussie 6” pipes. The standard kit itself comes complete with
everything necessary for a typical install including excellent written
instructions and a diagram. Adding in
the diverter pipe required a few extra bits and pieces such as clamps and flex
pipe. Upon opening the boxes, I could
immediately tell that Grand Rock sold high quality materials. The pipes are seriously stout as were all of
the clamps, flex, bolts and nuts, etc… And the Aussie style stack pipes just
simply make the “ready for serious business” statement!
I need to
take a moment here and mention that the Great Lakes Cummins Crew saved my tail
on getting this project completed in time.
John (Babyfat) loaned us his shop, tools, and
awesome hospitality in general, Brian (BBRam) did the
layout and serious fabricating - measuring, cutting, welding), Mark (wtfd6) helped
considerably with everything including screwing the slicks to the wheels, as
did Ian (ICSmoke) who also installed a custom
fabricated Air Horn and rear drive shaft loop.
Starting
out the stack install consisted of un-boxing everything and laying out the
parts. Then taking measurements and
checking where the cross pipe would reside in the box. As expected the kit was perfect with the “Y”
landing right where it should over the existing exhaust and the stacks lining
up right in the corners of the bed.
However, while so much talent was on hand… we decided to
customize the custom project. The most
significant change was to move the stacks in 5” towards center. The cross pipe is a two piece unit with the
“Y” and right side upright in one piece and the left upright “L” pipe being the
other piece. Moving the stacks in 5” required cutting the “L” piece off by
5”. The challenge came in with the right
hand side. In order to retain the
perfect alignment of the “Y”’s down section (through
the bed), we had to cut the right hand “L” off the “Y” then cut off a 5” piece
and then weld it back to the “Y” section.
Measuring from the flat end, Brian made two marks 5” apart all the way
around each pipe and then connected the segments.
After
marking both pipes, each one was placed in a vice and a clamp was installed on
the cut lines to help guide the saw blade.
After the cutting a grinding wheel was used to smooth out the pipe ends,
next it was re-measured and welded!
Now we were
back to a two piece system with the stacks moved in towards center by 5” on
each side with the bottom of the “Y” aligning right where it was supposed to
over the existing exhaust.
The other
modification was to lower the stacks into the bed as much as possible because
now with the stack pipes centered behind the cab I wanted less pipe showing
over the top of cab, and I also needed to make sure that I could fit into my
garage. It turns out the standard height
would have fit into the garage and most parking structures without any
issues. But hey, I still like the lower
look. The standard kit effectively
mounts the cross pipe to the bed with a pair of muffler style clamps. Normally you could set the cross pipe in
the bed, block up the left side so that the pipe is level, mark bottom of the
“Y” on the bed, and use a hole saw to make the cut. Brian cut out an oval section of the bed (and
a piece of the bed support) In order to lower the pipe for this project. This
allows a small portion of the ”Y” pipe’s curved area
to sink down into the bed.
