5.0L General Discussion This section is for non-tech specific information pertaining to 5.0L Mustangs.

Shift light question

Thread Tools
 
Search this Thread
 
Old 06-06-2011, 01:23 PM
  #1  
g3mustang
3rd Gear Member
Thread Starter
 
g3mustang's Avatar
 
Join Date: Sep 2008
Location: mo
Posts: 810
Default Shift light question

In another thread i think we came to some conclusion that my factory tach might be a couple hundred rpm higher then it really is. I really dont like the look of the big tachs and i cant afford a florida 5.0 cluster. So my thinking was, What about just a shift light? But does my factory rev limiter stop me from doing this. if my tach is indeed couple rpm higher then it really is and i set the shift light at 5800 rpms wont the rev limtier take over b/c of the stock tach reading above 6300 rpm
g3mustang is offline  
Old 06-06-2011, 02:21 PM
  #2  
g3mustang
3rd Gear Member
Thread Starter
 
g3mustang's Avatar
 
Join Date: Sep 2008
Location: mo
Posts: 810
Default

i guess what im asking is does the factory rev limiter go off what the tach is showing, or off a different signal
g3mustang is offline  
Old 06-06-2011, 03:27 PM
  #3  
AdderMk2
Banned
 
AdderMk2's Avatar
 
Join Date: Dec 2005
Location: Lil' Rhody
Posts: 22,376
Default

factory rev is driven by the same signal as the tach.

get a stand alone shift light
AdderMk2 is offline  
Old 06-06-2011, 03:45 PM
  #4  
g3mustang
3rd Gear Member
Thread Starter
 
g3mustang's Avatar
 
Join Date: Sep 2008
Location: mo
Posts: 810
Default

i understand by getting a stand alone shift light but when i put the shift light to 5500 rpm and what if my tach is off and showing 6300 rpm then im going to hit rev limiter before i really am. im sorry if this is confusing im trying the best i can to make sense lol
g3mustang is offline  
Old 06-06-2011, 06:47 PM
  #5  
g3mustang
3rd Gear Member
Thread Starter
 
g3mustang's Avatar
 
Join Date: Sep 2008
Location: mo
Posts: 810
Default

Try to explain better lol

If my tach reads 500 more rpm then it really is and I set timing light at 5800 then that would mean my factory tach would read 6300 rpm which is past rev limiter

Spat shifting point is the car going to bounce off rev limiter??
g3mustang is offline  
Old 06-06-2011, 09:35 PM
  #6  
AdderMk2
Banned
 
AdderMk2's Avatar
 
Join Date: Dec 2005
Location: Lil' Rhody
Posts: 22,376
Default

its the tach itself thats ****ed up, not the electrical system

stop overthinking things
AdderMk2 is offline  
Old 06-06-2011, 09:49 PM
  #7  
g3mustang
3rd Gear Member
Thread Starter
 
g3mustang's Avatar
 
Join Date: Sep 2008
Location: mo
Posts: 810
Default

Lol sorry buddy I just want to try to make things ok
g3mustang is offline  
Old 06-07-2011, 12:26 AM
  #8  
AdderMk2
Banned
 
AdderMk2's Avatar
 
Join Date: Dec 2005
Location: Lil' Rhody
Posts: 22,376
Default

It's ok... just don't give the car too much credit. It's not nearly as complicated as some people think it is.

The ECM reads the signals coming from the distributor (PIP). It has a direct link. The factory rev limiter is triggered by the ECM, not the tach.

The tachometer is a piece of what can be referred to as I/O device. The unit is driven by reading pulses, and converting them into the rotation of the needle. If the calibration is off even slightly... the tach will read wrong. Whereas the ECM is only counting pulses, not converting them into a different output.

Think of it like the coolant temp gauge. it says "normal" because its not a finely calibrated piece. its just there to get you in the ballpark.
AdderMk2 is offline  
Old 06-07-2011, 07:15 AM
  #9  
g3mustang
3rd Gear Member
Thread Starter
 
g3mustang's Avatar
 
Join Date: Sep 2008
Location: mo
Posts: 810
Default

Thank you so much for that description.
g3mustang is offline  
Old 06-10-2011, 12:29 PM
  #10  
nitrous_bob
6th Gear Member
 
nitrous_bob's Avatar
 
Join Date: Oct 2005
Location: st clair shores MI
Posts: 6,028
Default

if you have the stock cam.... even 5500 is way too high so it's not an issue.

i consider myself a pretty good driver, and use a 5200 chip

by the time you react and complete the shift, you'll be around 5500 which is perfect. if you start the shift at 5500 you'll probably kiss the limiter once in a while.

i like msd over the others, dont get the cheap one with the dial.... plugin chip is way better imo
nitrous_bob is offline  


Quick Reply: Shift light question



All times are GMT -5. The time now is 10:05 PM.