i just put in a B17 in my 88 CRX Si and i am wondering about the accuracy of the tach. since the stock tach redlines at 6200 but reads #'s up to 8000. i am wondering if that tach is still accurate in the higher rpm's, where the B17 can rev? if not is there any way to fix it? i am not too worried about it, but it is just something i've been curious about.

 

When I rev to 8k on my stock tach, my VAFC reads about 8120. The stock tach is accurate up to around 4800, falls behind from there.

 

yeah you really need to get aftermarket. Mine was really screwed up, cuz my tach showed my **** redline at 5000.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TheBestCRX &raquo;</TD></TR><TR><TD CLASS="quote">i just put in a B17 in my 88 CRX Si and i am wondering about the accuracy of the tach. since the stock tach redlines at 6200 but reads #'s up to 8000. i am wondering if that tach is still accurate in the higher rpm's, where the B17 can rev? if not is there any way to fix it? i am not too worried about it, but it is just something i've been curious about. </TD></TR></TABLE>
Hondas are pretty accurate as far as OEM tachs go, usually no more than 200 RPM or so off of the actual RPM. There's really no need for an aftermarket tach.

The tach receives signals from sensors on the engine, so the stock tach in your car would be just as accurate as the tach in a '92-93 GSR cluster with the correct 8000 RPM redline.

 

weird that we're talkin about stock tachs; mine just started going crazy today in 5th gear past about 5k rpms(S1 tranny+highway driving=yuck). it like drops down and then comes back up. I'm going Autometer as soon as i get my traction/suspension issues fixed.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Targa250R &raquo;</TD></TR><TR><TD CLASS="quote">
Hondas are pretty accurate as far as OEM tachs go, usually no more than 200 RPM or so off of the actual RPM. There's really no need for an aftermarket tach.

The tach receives signals from sensors on the engine, so the stock tach in your car would be just as accurate as the tach in a '92-93 GSR cluster with the correct 8000 RPM redline.</TD></TR></TABLE>

I agree with this - mine's pretty accurate, but a lot of users say otherwise. It's a mixed bag. You can test it by using a shift light, or the fuel cut-off.

 

doesnt the stock tach just run off of a sensor in the dizzy?

 

Usually off by about 3-400 rpms

 

aye hybrid invasion .. your ignitor/coil is goin out. get ready.

 

When my stock tach is at 6500, my autometer one is at 7. I made a post about this a while back. As it gets to 4K and up, it steadily gets more n more inaccurate. At 4000K, my stock tach is at 4K and my autometer is at 4100...after that it jus keeps gettin uglier

 

mines about like ThE bEe GuY's

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NitrousDreamz &raquo;</TD></TR><TR><TD CLASS="quote">aye hybrid invasion .. your ignitor/coil is goin out. get ready.</TD></TR></TABLE>well it JUST started doing it today. I also have a spare ignitor... hmmm...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ThE bEe GuY &raquo;</TD></TR><TR><TD CLASS="quote">When my stock tach is at 6500, my autometer one is at 7. I made a post about this a while back. As it gets to 4K and up, it steadily gets more n more inaccurate. At 4000K, my stock tach is at 4K and my autometer is at 4100...after that it jus keeps gettin uglier</TD></TR></TABLE>
Is it off that far in all gears, or just the lower gears (1st, 2nd)?

 

my tach is extremly slow. t has gotten worse from pegging it past 9 grand, but it was never up to the task of moving quickly enough to keep up

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Targa250R &raquo;</TD></TR><TR><TD CLASS="quote">
Is it off that far in all gears, or just the lower gears (1st, 2nd)?</TD></TR></TABLE>

All the gears

 

My Si tach will read almost 8000 rpm on an ECU that has a 7500 cut.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by skud_dusty &raquo;</TD></TR><TR><TD CLASS="quote">doesnt the stock tach just run off of a sensor in the dizzy?</TD></TR></TABLE>


My afternarket tach is wired directly into the dizzy, so it can't be off.

Not sure about the stock tach though.....

 

my tach its a little messed up
after 5 k it goes crazy
when my aftermarket tach reads 7200 my stock tach is on 8000 rpms

 

bump for the questions about the stock tachs and aftermarket tachs not being accurate with each other. Friend of mine has the same problem.