DIY_EFI Digest Friday, October 29 1999 Volume 04 : Number 610 In this issue: Re: tach adapter Re: DIY_EFI Digest V4 #609 See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Fri, 29 Oct 1999 08:31:36 -0400 From: "Jim Yeagley" Subject: Re: tach adapter You may want to take a quick look at the factory tach on a Mustang, '79 up. I know the few I've had all had a switch for 4, 6, or 8 cyl right on the tach itself. I know you said he wanted to keep the stock tach, just thought maybe these might shed some light on the subject. (Or even steal the guts from one.) Jim Yeagley 1996 Dodge Indy Ram See it and many others at: www.indyram.org 1975 Pontiac Grandville Brougham Conv. jimyeagley@xxx.net webmaster@xxx.org ------------------------------ Date: Fri, 29 Oct 1999 12:16:07 -0400 (EDT) From: William T Wilson Subject: Re: DIY_EFI Digest V4 #609 On Fri, 29 Oct 1999, DIY_EFI Digest wrote: > new one. Does anybody have any ideas for a tach adapter to convert a > 6 or 8 cyl signal to a 4 or 6 cyl tach? I am hopping that I could > make one thing that can do all this, like convert a v8 or 6 cyl to a 4 > or 6 cyl signal in one package by changing some dip switches. Would a > 555 or a op-amp work on something like this. You probably can't do it by flipping dip switches, unless that same vehicle had a V6 factory option. In that case, it's highly likely that they used a configurable tachometer. Anyway, you need some sort of circuit to throw 1/3 of the pulses away. You'll need buffering and filtering so the whole thing doesn't blow. How to do it is up to you. I'd use a counter circuit set to reset at 6 and OR together the first 4 outputs. Two chips. The 555 wizards out there can probably do it with one of those, too... ------------------------------ End of DIY_EFI Digest V4 #610 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".