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DarkHand

Member Since 21 May 2003
Offline Last Active Jun 22 2018 11:43 PM
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Posts I've Made

In Topic: Devac Write Up.

16 August 2012 - 11:11 AM

Just to clarify- in my devac writeup above, the "ported vacuum" that I was using to work the EGR refers to manifold vacuum taken at a spot just above where the throttle butterfly closes fully (that's why these ports are at the very base of the carb). This type of vacuum is pretty much like manifold vacuum except it is zero when the throttle is closed (at idle).


You're right, I got my terms backwards there. :) It's venturi vacuum that's needed!

In Topic: Devac Write Up.

10 July 2012 - 01:23 PM

Its been my experience that a single vacuum to the distributer on these cars does not work. But you could easily give it a shot and. See if it works for you.


Just before I sold my CRX I was on the brink of discovering this too. The theory is sound but I don't think the port we're using on the carb has enough ported vacuum to actuate the distributor diaphragm. It definitely doesn't have enough to actuate the secondary diaphragm because if it did, the throttle would stick (With the car off, pull vacuum with a hand-pump on the secondary diaphragm and move the throttle; you'll snap to full throttle with no way to get out without cutting the vacuum on the hand pump. Now imagine that happening on the highway!). That's why I came up with the zip-tie mod, to get around the two secondary issues (Secondary simply not working on devacced cars, and the throttle sticking issue).

Experiments need to be done to find a port on the carb with a strong ported venturi vacuum, i.e. low vacuum at low RPM, and high vacuum at high RPM. The distributor needs to be connected to whatever port that ends up being, but keep the secondary off it!

In Topic: Another Video 1985 Civic

09 July 2012 - 10:31 PM

Great race! :)