Jay,
What is a stub stack and where do you find them?
<Monte
----- Original Message -----
From: <ATWEDITOR@aol.com>
To: ""Matthew E. Hale"" <haleme@bellsouth.net>; ""Mg List""
<mgs@autox.team.net>
Sent: Wednesday, September 10, 2003 7:57 AM
Subject: Re: SU air filter: K&Ns and stub stacks
> I'm at work now and can't check on that dent question, but let me gas on
about the last two.Last year Grassroots Motorsports did a series of dyno
tests of bolt-on MGB engine mods. One of the huge shocks from their point
of view was the difference--around 4%--made by bolting on stub stacks to the
mouth of the SUs, and letting them reside under K&Ns, which also provided a
power gain of around 4%. Unlike standard bell-mouthed velocity stacks, the
stub stacks are about 1/2 in. high with a rounded opening edge that, as
dealer ATF products (I think that's their name--information also at home)
says, provides "a nice radius" for the SU carb opening. In short, I guess
it just fools the air flow into thinking the carb is bigger, and the flow is
increased. Cast versions of the stacks are around $19 each, and that's what
Grassroots tested. When I ordered mine, the cast versions were out of
stock, so I got the billet versions for around $30 each. I also got K&Ns at
the same time, !
> going for the open element design that eliminates the metal pots.
> I am here to tell you that the combination of K&Ns and stub stacks makes a
SIGNIFICANT difference in performance throughout the power range, from
lowest RPMs up to readline, and yes, it seems to allow the ancient B engine
to keep accelerating at higher revs where previously it seemed to run out of
gas. The bill--around $200 and 15 minutes install time.
> So here's my ultimate cheapie, no-risk, quick-install performance boost
recommendation: A Petronix ignition, K&N filters and stub stacks. Buy, bolt
and burn.
> Jay Donoghue72 B-GT66 Mustang (also with Petronix and K&N)
/// or try http://www.team.net/cgi-bin/majorcool
/// Archives at http://www.team.net/archive
|