Weird, my 930 doesn't need a tach adapter to run with a MSD ...
07-26-2007, 10:06 PM
#1
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Weird, my 930 doesn't need a tach adapter to run with a MSD ...
The tach is happy running right off the tach out jack from the MSD box. I haven't tried it other than a few blips of the throttle, but the tach needle is smooth. I see that others are using the tach adapter. Does VDO make different versions of gauges where some run without a tach adapter and others will not?
07-26-2007, 11:10 PM
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According to Wayne Dempsey there are different tolerances within each tach. Even from the same year. Some need the adapter and some don't.... maybe you got lucky and saved a few bucks!
07-27-2007, 10:01 AM
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Originally Posted by LeonardZ
According to Wayne Dempsey there are different tolerances within each tach. Even from the same year. Some need the adapter and some don't.... maybe you got lucky and saved a few bucks!
I have installed many MSD units on 911's and have never had to use a tach adapter to get the tach to work. Do you know what tolerances Wayne is speaking about? I have never heard that before.
07-27-2007, 10:14 AM
#6
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The stock tach works off of the coil which gives 3 pulses for each crankshaft revolution. The MSD tach output works the same way. No adapter required.
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07-31-2007, 08:16 AM
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Originally Posted by Chuck Jones
Mine worked just fine without the adapter....but the MSD unit did melt the rotor in the distributor and had to change to one without the resistor in it.
Wow! you may have given me a clue!! My car suddenly quit firing on 3 cylinders shortly after connecting the MSD.... very interesting!!
07-31-2007, 10:02 PM
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My understanding was that the MSD was a square wave signal and the tach needed a sine wave signal, thus the adapter.
Originally Posted by Geoffrey
The stock tach works off of the coil which gives 3 pulses for each crankshaft revolution. The MSD tach output works the same way. No adapter required.
08-01-2007, 02:44 AM
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Nathan is right...just get a plain rotor...the additional spark heat generated by the MSD will fry the older rotors that have the resistor in them. There are some threads on this subject you mihght want to search out. There's a solution using a jumper to solve the heating issue. My rotor actually ended up with a 3 inch extruded ribbon of plastic coming out of the epoxy on the top of the rotor.
08-01-2007, 07:56 AM
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Originally Posted by Chuck Jones
Nathan is right...just get a plain rotor...the additional spark heat generated by the MSD will fry the older rotors that have the resistor in them. There are some threads on this subject you mihght want to search out. There's a solution using a jumper to solve the heating issue. My rotor actually ended up with a 3 inch extruded ribbon of plastic coming out of the epoxy on the top of the rotor.
I checked it last night and it's in perfect shape. I am going to change plugs tonight and see how it runs.
08-01-2007, 12:12 PM
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For what it is worth, I read somewhere, maybe the owner's manual, that you aren't supposed to idle the 930 excessively on start up.
What I do is idle it for maybe a 45 seconds or a minute and keep tapping the gas to get the revs up, and then I just drive away, and give it a little more throttle than usual if it feels like it wants to stall out when slowing at the end of my driveway. After 5 minutes the engine is at operating temperature (180) and after about ten minutes it runs cleanly and I can start getting into the turbo.
What you might not want to do, especially when you are running rich (which is a good thing) is to just idle the car in your driveway for periods of time on start up because you are likely fouling the plugs and you are definitely building heat up in the engine bay.
These air cooled cars don't like idling or traffic jams or stop lights nearly as much as they like being in motion. And they don't really warm up fully until you have driven the car for ten minutes, either. I would stay off the turbo until the car is warmed up.
What I do is idle it for maybe a 45 seconds or a minute and keep tapping the gas to get the revs up, and then I just drive away, and give it a little more throttle than usual if it feels like it wants to stall out when slowing at the end of my driveway. After 5 minutes the engine is at operating temperature (180) and after about ten minutes it runs cleanly and I can start getting into the turbo.
What you might not want to do, especially when you are running rich (which is a good thing) is to just idle the car in your driveway for periods of time on start up because you are likely fouling the plugs and you are definitely building heat up in the engine bay.
These air cooled cars don't like idling or traffic jams or stop lights nearly as much as they like being in motion. And they don't really warm up fully until you have driven the car for ten minutes, either. I would stay off the turbo until the car is warmed up.