LT1-LT4 Modifications 1993-97 Gen II Small Block V8

factory tach calibration?

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Old 06-04-2011, 09:51 PM
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Default factory tach calibration?

97 ws6 a4
Can I adjust the factory tach on this to read accurately. I have Jet DST and it shows a tach pulse (or something like that) variable that can be adjusted. Can I use this to make the factory tach read correctly or is it going to mess something else up in the tune??

I have MX Scan so I can see what the engine is actually doing rpm wise and make the stock tach work if the setting in DST will do it.

Has anyone done this before?? I am just afraid to start tweaking things that I am not sure what they do. Don't want to freak out the pcm and cause other problems obviously I can put it back to where it started but I don't want to mess something up that is not real obvious and cause problems down the road.
Old 06-04-2011, 11:08 PM
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anyone???? someone has to know the answer to this.......

Old 06-05-2011, 08:25 AM
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I would not mess with it. Factory tach often don't read linearly. It might be high at low RPMs and low at high RPMs or vice versa. It's just not a super precise instrument. Since you have an A4, you have perfect control of programming and shift points, so you know that the computer is going to accurately deliver the same thing every time, regardless of what the tach says.
Old 06-05-2011, 02:00 PM
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I know it will never be right i was just hoping to get it closer then the 400 rpms its off now idle.
Old 06-05-2011, 03:08 PM
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That's a good reason to get a shift light. I hardly use my tach when shifting, just the shift light, at wot of course. The only way to make the tach more accurate would be to get an aftermarket tach.
Old 06-06-2011, 06:19 PM
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I am not worried about the tach at high rpms for shifting I just would like to have it at least close when at idle/low rpms.

Oh well I guess I will just not worry about it as I will likely be selling it anyways as I need to pay off some debt. I just thought out of all the people on here someone would have had an idea on this matter. But I do have mad respect for the shoe so I guess I will just listen to what he says and not mess with it.

And what made me think it was worth looking into is the fact that I can adjust both low and high tach pulse. So if I use mx scan and see how far its off you should be able to adjust the tach so it reads pretty close to actual low and high rpms. But since I am not sure if it will effect other things in the tune I guess I will just leave it alone.

Last edited by Enforcerws6; 06-06-2011 at 06:33 PM.



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