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Registered
Join Date: Apr 2001
Location: Haleiwa, HI USA
Posts: 153
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Older vs Newer Tachometer
Hi
As I approach starting the engine in my 3.2l conversion I have been trying to figure what to do about the tach. What is the difference between the 914 tach and the 911 tachs. How is it that they process the tach signal, for a four vs six? While looking for a tach to buy I have seen similar looking vdo guages that are referred to as early vs late. Like "for all 911s after 1974". " Early type 911 Tach" What really is the story about early vs late? Can the Motronic DME tach signal from my 88 3.2 run the earlier types? I have gotten some conflicting advice. One 3.2 conversion owner said he just hooked the DME up to the 914 tach and it worked. Another said it wouln't work and I need a carrera Tach. Can the amassed experience and technical knowledge of the group massage this confusion into some clear info? 73 914 88 3.2 best Mark |
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04-22-2001, 08:31 PM
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Registered
Join Date: Aug 1999
Location: Denver, NC
Posts: 1,391
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Hi Mark:
The 914 Tach will definetly not work... I do not know the internal difference between 4 vs 6 pulses per minute but that is the main difference on how the RPMs are clculated. The 914 Tach may appear to work but is not correct in the reading that it giving. You need to get the tach from a 911. I would try to locate the tach from a 3.2 that matches the year that you have. On the back of the tach there is usually a stamp that indicates the year. This can also be found in a little Blue triangle on the Tach. The main differnce in the early and late tachs I believe has to do with the type of ignition system that is used, but I am not 100% sure on that. Good Luck ------------------
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04-23-2001, 09:28 AM
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Registered
Join Date: Aug 1999
Location: Denver, NC
Posts: 1,391
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Hi Mark:
The 914 Tach will definetly not work... I do not know the internal difference between 4 vs 6 pulses per minute but that is the main difference on how the RPMs are clculated. The 914 Tach may appear to work but is not correct in the reading that it giving. You need to get the tach from a 911. I would try to locate the tach from a 3.2 that matches the year that you have. On the back of the tach there is usually a stamp that indicates the year. This can also be found in a little Blue triangle on the Tach. The main differnce in the early and late tachs I believe has to do with the type of ignition system that is used, but I am not 100% sure on that. Good Luck ------------------
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04-23-2001, 09:28 AM
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