[6pack] Zenith vs SU

[Navarrette, Vance]

 	Shawn:

	I would add a couple of items for consideration in the Zenith vs. SU debate

	The SU HS series lacks temperature compensation, so if the carb heat soaks
the mixture goes way rich until enough fuel passes through the carb to cool
it. The HIF series has temperature compensation which is a distinct advantage,
as do the Zeniths. This reduces the tendency to go rich when heat soaked,
although I found them to deliver somewhat less than perfect results.
	The HS carbs do not offer a deceleration valve. The HIF carbs do, but the
deceleration valve design stinks. The SUs use a poppet valve attached directly
to the butterfly which greatly reduces air flow. The Zenith bypass valve is
much tidier, and it has no effect on air flow.
	I agree there are fewer needles around for the Zeniths, although there are
still many available (just talk to Joe Curto).  In addition, there is always
the option of hand tweaking the needle with a little 400 grit while it spins
in a drill.
	I also agree that adjusting the mixture while the car is running is a nice
little feature. It CAN be done with the Zeniths, but it is easy to stall the
engine whereas the HIF carbs will idle very sweetly during adjustment. I have
found this to be less of an issue, because with my cam the "lift the slide"
test does not work. I must read my plugs to get the mixture correct - so the
engine is off anyway.
	Your average SU has fewer and simpler adjustments, which I think is what most
people want. In the hot rod crowd, Holley is much preferred over a Quadrajet,
simply because the Holley is so much simpler. The Quadrajet is very effective,
and gives better mileage, but uses metering needles (just like our Zeniths!)
and so is more involved to tune.

	Cheers,

	Vance

    Vance Navarrette
    Knowledge is power.
    Power corrupts.
    Study hard, be evil.
    http://www.triumphowners.com/832

-----Original Message-----
From: 6pack-bounces at autox.team.net [mailto:6pack-bounces at autox.team.net] On
Behalf Of shawn loseke
Sent: Friday, March 05, 2010 12:59 PM
To: Dan Clark
Cc: 6pack at autox.team.net
Subject: Re: [6pack] Triple stromberg

<snip>

SU HS6's, with the external float bowls that sit on the side of the carb, can
be a real tight fit. HIF-44's, with an integral float bowl like the ZS, would
work very well. There are only a couple of areas that the SU's have over the
ZS's. One would be needle selection, the other would be that you can adjust
the mixture while the engine is running. Beyond that it boils down to
maintenance
issues. Both SU's and ZS's will perform fairly equally if they are in the same
condition. If you have plenty of Strombergs then I would suggest you stay with
them.

<snip>

Shawn