you know how people say the tach reads 7900 rpms when in actuality you are doing 7300 rpms or somthing like this...?

also

how the people say that at 150mph on the speed-o-meter is really around 140-146mph?

when does this disparity occur, does it occur always at a certain rpm no matter if off the line or when at 146mph?
is 80 miles at 4000 rpms actually lower?
is 110 miles actually lower?

just wanted to know the answer/truth cuz i don't.

thanks!

 

As best I remember, the tach is always off by 2-300 RPMS (reads high) - the speedo is off by a certain % - I think 100 KPH on the Field unit was @ 103-4 or so on the in-dash speedo. It's been a while since I had the Field tho, so I won't swear to the speedo #s.

Paul

 

ive had my buddy next to me running at 79 and mine showed 85?

 

I recently installed an Autometer Ultimate Playback tach, and compared to stock BOTH are the same, only difference is at idle. The stock RPM readout at idle is very low (clost to around 5000RPMS), where on the tach they are sitting right around the 8000-8500 RPMS.

As for the speedometer, I don't know.

 

my tach is off about 300 when it goes towards redline....but i have a monster tach...now i shift at 8200 in my gsr....fuel cutoff! and mange a tenth off my 1/4
but im thinking of gettin a jdm cluster...and gettin rid of my stock one....and monster tach...the monster tach is just showy....kinda ricey....

 

120kph on the fields unit is 125kph on the dash. and the rpms are off by a couple hundred. the faster you go the more inacurate the speedo is gonna be

 

so basically everyone can agree that all together the rpm and speedometer are slightly off no matter if off the line, at idle, or at 120 mph...but the higher in speed you go, the more inaccurate???

 

yes

 

Most are off, but every car is diffent as in how off it is...

WHY, WHY, WHY do people put another tach in their car when they already have one? Yes, I would like something else blocking my view please...