tachometer discrepancy? - Miata Turbo Forum -Boost cars, acquire cats.

Welcome to Miataturbo.net   Members

MEGAsquirt A place to collectively sort out this megasquirt gizmo

LinkBack Thread Tools
Old 09-19-2011, 07:42 PM   #1
Senior Member
Thread Starter
iTrader: (2)
Join Date: Aug 2010
Posts: 639
Total Cats: 2
Default tachometer discrepancy?

90 1.6
stock everything else

i noticed that when i hit the rev limiter the laptop said i was bouncing around 7k and my tach said around 6k

so i decided to log it and perform a 7k shift

in the log the the rev limit bouncing was showing 7k (my tach 6k)
and when i performed the 7k shift the log showed 7k as well as my tach showed 7k

is the oem tach slow reacting?
i just dont get it cuz with my oem ecu my oem tach showed bouncing around 7k when i bounced off the rev limiter

whats going on here?
i just dont get it

jared8783 is offline   Reply With Quote
Old 09-20-2011, 08:12 AM   #2
Supporting Vendor
Matt Cramer's Avatar
Join Date: Sep 2006
Posts: 2,144
Total Cats: 41

Often it's only after installing a standalone that gives you a digital reading from the sensors directly that you find out just how inaccurate your stock tach is. The stock tach is still being driven off the factory ignition module and the readings it gets are not affected by what ECU is in charge.
Matt Cramer is offline   Reply With Quote
Old 09-20-2011, 12:21 PM   #3
Hittin' Boost & Cones
iTrader: (2)
240_to_miata's Avatar
Join Date: May 2007
Location: Cromwell, Connecticut
Posts: 2,555
Total Cats: 10

Stock tachs suck. I can bury mine to 8k and im really not even at 7 yet.
240_to_miata is offline   Reply With Quote
Old 09-22-2011, 05:09 PM   #4
Senior Member
Thread Starter
iTrader: (2)
Join Date: Aug 2010
Posts: 639
Total Cats: 2

i have never messed with revlimiters before so i had set the diypnp for fuel and spark cut, i figured why not
i googled how the miata ones work
they only use fuel cut
so i changed it to that

and now the discrepancy has vanished

the tach was hitting aprox 7400 and the data log showed a max of 7384
jared8783 is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
The Definitive "VVT swap into 90-97 chassis" Megathread. Savington Engine Performance 319 10-10-2016 10:32 PM
1997 Miata - NASA PTE/TTE Current Logbook w/Title chris101 Cars for sale/trade 2 10-27-2015 06:27 AM
Dash tachometer will not work, tach in Tuner Studio works fine... bleezy MEGAsquirt 9 12-26-2013 09:46 AM
Miata 1996 m edition BIG Crazy Car moharebusa General Miata Chat 0 03-12-2013 09:43 PM
Question about discrepancy between AFR gauge and MSPNP reading Rushin MEGAsquirt 14 07-29-2012 11:05 PM

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 03:22 PM.