In an E-mail message from:
(Bernard Robbins) Date: Thu, Jan 9, 2003, 8:29am (PST+21) To:
6pack@autox.team.net ('6-Pack') Subject: RE: PI vs dual ZS vs triple ZS
-- dumb questions
Gentlemen,
.....I also read that injection seems more responsive than carbs because
with injection, the fuel is immediately available to the engine whereas
in a carb it takes a bit more time for the airflow to increase. Dick T,
can you confirm this as I can't remember where I saw this.
Bernard
Yes, Bernard, the Constant Depression type carbs, tho elegant in their
simplicity, don't respond to instant throttle input like FI, nor carbs
like the Weber. Especially just off idle. Before more fuel can get to
the engine from these CD carbs, engine vacuum must pull the air valve
up, and hesitation is the result. Less so, once rpm is up.
Good books, like "How to Modify & Power Tune the SU" tells of ways to
make this type of carb, and presumably the ZS, respond better, just off
idle.
While this modification has it drawbacks in terms of rich idle and high
emissions, it is said to be successful on race engines. It still does
not react as the Weber style carb, with its built-in power valve, or
accelerator pump. Or the instant-on associated with most FI systems.
Dick T.
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