c3 tach filter
Thread Starter
Advanced
Joined: Feb 2010
Posts: 55
Likes: 0
From: Lanexa Virginia
c3 tach filter
i purchased a 81 c3 w/no motor . i instaled a 1988 L98 with tuned port injection . just read a post about the need for the tach filter . didn't know i needed one . i havent hooked the tach up yet .is it for raido supression or something to do with the tach itself ? part number or doe's someone have one they will sell . johnrodz
Instructor
Joined: Jan 2005
Posts: 172
Likes: 2
From: Cumming GA
I am not sure about your engine but in my 82 the filter smooths out the rough edges on the pulses from the distributer to avoid false triggers and also helps protect the electronics in the tach itself.
The filters can be found here:
http://ecklers.com/search.asp?action...searchHistory=
Hope that helps
Andy
The filters can be found here:
http://ecklers.com/search.asp?action...searchHistory=
Hope that helps
Andy
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
If you don't run the filter the square signal from the distributor can be interfered with.
It is not a must and some here will run their cars without the filter. About the only time we will run a car here without a filter is when we are testing the tach for problems.
We have the replacement filters listed in the forum special section at this link. http://willcoxcorvette.com/advanced_...eywords=filter
Willcox
It is not a must and some here will run their cars without the filter. About the only time we will run a car here without a filter is when we are testing the tach for problems.
We have the replacement filters listed in the forum special section at this link. http://willcoxcorvette.com/advanced_...eywords=filter
Willcox
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
No problem AT..
I just roll with the flow.. I made the boards so I've got a pretty good back ground on the entire system.
Willcox
I just roll with the flow.. I made the boards so I've got a pretty good back ground on the entire system.
Willcox
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Instructor
Joined: Aug 2004
Posts: 106
Likes: 1
tach filter
Will the tach filter affect the tach when the turn signals are blinking?...i notice that I can get a little bounce with the tach needle at idle that coincides with the blinkers going on and off.... this is on an '82.
Thanks!!
Thanks!!
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The tach signal is a stream of pulses coming from the distributor. The circuit board converts the pulse frequency to a voltage for sending to the tach gauge. If your electrical system sends some random pulses or voltage differences through the tach system (consider it 'noise in the system) for whatever reason, the board will consider it to be additional pulses/signal and include that in the tach reading. The tach filter smooths out those unwanted inputs and assures that the tach is only getting input from the distributor pulses. That filter does perform a similar function to the radio filter capacitors, but the tach filter circuit is a bit more complex. A radio capacitor [alone] will not perform the tach filtering job adequately.
