In a message dated 9/10/03 10:32:32 PM, mmorris@nemr.net writes:
<< Jay,
What is a stub stack and where do you find them? >>
Monte,
Go to http://www.aptfast.com/Main_Index_Page.htm, and scroll down to SU Stub
Stacks & Ram Pipes. I have a '72, so with HIF4s I needed HS4 stub stacks.
Stub stacks are amazingly small--for lack of a better word--plates that mount
on
the mouth of the carb, using existing holes, a screw-on application. Their
rounded opening apparently increases the flow of air into the carb. And the
K&Ns supply that air.
It has been stated that another lister has done testing and found that the
stock filter assemblies, with a bottom plate that serves the same function as a
stub stack, works best. I relied on the extensive dyno testing that
Grassroots Motorsports did on an a late-model MGB converted to SUs, comparing
new
things to stock, and they made strong recommendations for K&Ns and stub stacks.
They did not, however, find much benefit to most exotic exhaust systems and
headers, saying the original MG system, and especially the head pipes, already
do
a fine job of extraction. And as I said, my experience swapping from clean
stock filters to K&Ns and stub stacks, has been very exciting. The stacks fit
under the K&Ns with so much clearance I find myself wondering if the short
velocity stacks would fit, too, and if that would bring any additional benefit.
However, I'm well satisfied with what I've got now.
In passing, I find the folks at APT to be VERY responsive. I originally
ordered the wrong stack. A guy at APT noted the mis-match between my K&N order
and stack selection and e-mailed, and then called, to straighten me out and get
me the right stuff. That is exceptional service.
Jay Donoghue
72B-GT
66 Mustang
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