stock tack not accurate (TACH) t-a-c-h - Miata Turbo Forum - Boost cars, acquire cats.

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Old 03-13-2008, 11:17 PM   #1
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Default stock tach not accurate

When i got my car dynoed a few months ago on the stock ecu the dyno tech. told me my stock tach was very inaccurate and the dyno showed a big difference high end. Today when i was doing some tuning i was watching my computer screen and noticed it too. my tach is OFF... megasquirt shows 3750 rpm which is obviously correct while the stock tach shows 4000 or more. Is there any way to calibrate the stock tach ???

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Old 03-13-2008, 11:18 PM   #2
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sounds normal...everyone knows the stock tach is off.
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Old 03-13-2008, 11:22 PM   #3
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The tach doesn't really need to be spot on. It would be nice, but you'll survive as long as it is repeatable. If you hit an actual 7000rpm at an indicated 7300rpm, who cares as long as it is always indicated at 7300rpm. As long as it is repeatable, you should know where fuel cut is and all that good stuff.
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Old 03-13-2008, 11:28 PM   #4
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Mine reads 7800rpm when my shift light comes on and megasquirt reads 7200. Does it matter that much to you? 90% of factory meters are less accurate than autometer's gauges (which are pretty far off aswell) cause they're budget cheap... Hense why oil pressure and volt meters are normally just idiot gauges which don't actually show pressure/charge.
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Old 03-13-2008, 11:31 PM   #5
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I hit the 7200 rpm rev limiter at an indicated 8000 rpms.
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Old 03-13-2008, 11:33 PM   #6
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Quote:
Originally Posted by Bryce View Post
I hit the 7200 rpm rev limiter at an indicated 8000 rpms.
7500 fo me
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Old 03-13-2008, 11:33 PM   #7
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haha... thanks for editing the title. i was on the phone with my gf trying to "listen" to her and type at the same time.

Guess ill live with the inaccuracy....... or get a huge ricer gauge




jk
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Old 03-13-2008, 11:36 PM   #8
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Well I hope you learned a valuable lesson today: posting correctly on the internet is more important that talking to your gf on the phone.
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Old 03-13-2008, 11:40 PM   #9
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7600 RPM is an indicated over 8k on my car
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Old 03-13-2008, 11:51 PM   #10
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good to know that its natural. The dyno tech made it seem like there was something wrong with my car... he was dynoing a variety of cars that day and only commented about my tach. I guess i don't have to fear going into the red so much any more, haha.
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Old 03-13-2008, 11:54 PM   #11
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Interesting, mine reads 7250 at most at the factory rev limter of 7200.
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Old 03-14-2008, 12:48 AM   #12
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Quote:
Originally Posted by 240_to_miata_OWNER View Post
good to know that its natural. The dyno tech made it seem like there was something wrong with my car... he was dynoing a variety of cars that day and only commented about my tach. I guess i don't have to fear going into the red so much any more, haha.
Cause an inaccurate tachometer is the mark of a terrible car... So whats that make 98% of Fords that don't HAVE a tach?
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Old 03-14-2008, 01:04 AM   #13
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Quote:
Originally Posted by elesjuan View Post
Cause an inaccurate tachometer is the mark of a terrible car... So whats that make 98% of Fords that don't HAVE a tach?
Well since they don't have a tach, then they certainly can't have an inaccurate tach, so maybe it reinforces the saying that "ignorance is bliss".
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Old 03-14-2008, 01:35 AM   #14
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Quote:
Originally Posted by jasonrobo02 View Post
Well I hope you learned a valuable lesson today: posting correctly on the internet about Miatas is more important that talking to your gf on the phone.
fixed it for you
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Old 03-14-2008, 01:37 AM   #15
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fixed it for you
Thanks.
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