measuring actual RPM

[wanna-be]

not sure the tach on my 91 Glastron is accurate and want to test the rpms independent of tach. what do ya'll suggest?

 

[maxxman04]

Re: measuring actual RPM

tach/dwell meter. this is just one example

http://www.summitracing.com/search/?keyword=dwell meter&dds=1

 

[wca_tim]

Re: measuring actual RPM

A lot of timing lights register rpms off no1 firing signal and give an independant measure of rpm...

 

[wanna-be]

Re: measuring actual RPM

the acron is a nice one. can you use it while in water at WOT? i have a timing light but never noticed a RPM reading. thanks guys, keep ya'll posted

 

[bruceb58]

Re: measuring actual RPM

Most timing lights don't indicate RPM.

 

[wanna-be]

Re: measuring actual RPM

does anyone know if dwell/tach meter can be hooked up while in water at wot?

 

[mkast]

Re: measuring actual RPM

Why not?

 

[Chris1956]

Re: measuring actual RPM

The only way to verify the tach reading is to use a known accurate tach for comparison. Is the dwell/tach known to be accurate?

Seriously, if they read the same thru the RPM range, it is likely that both are accurate. if the readings diverge, one obviously is not accurate.

 

[marlboro180]

Re: measuring actual RPM

does anyone know if dwell/tach meter can be hooked up while in water at wot?

You may need to hook up some longer leads to make it reach your console so you can watch them safely. Zip tie wires to something solid and out of the way of hot/ moving parts .Some wire and a couple 'gator clips should do the trick .

 

[wanna-be]

Re: measuring actual RPM

The only way to verify the tach reading is to use a known accurate tach for comparison. Is the dwell/tach known to be accurate?

Seriously, if they read the same thru the RPM range, it is likely that both are accurate. if the readings diverge, one obviously is not accurate.

s/b...its still on the shelf at Autozone

 

[wanna-be]

Re: measuring actual RPM

You may need to hook up some longer leads to make it reach your console so you can watch them safely. Zip tie wires to something solid and out of the way of hot/ moving parts .Some wire and a couple 'gator clips should do the trick .

i'll try it....can't hurt and really want to satisfy my curiosity. tach show 4k rpms at wot but sb 4500 rpms for 5.7L merc

 

[rbh]

Re: measuring actual RPM

4000 may be all your getting anyway, everyone suggested triming up when I get on plane to achieve the 4700 rpm the engine is supposed to deliver at factory red line not the 4000 I am getting.
rob

 

[wanna-be]

Re: measuring actual RPM

trimmed up i get maybe 4.1, 4.2 rpm sb more