Factory Tach. on 02' Z06

[REDROCKET02Z06]

Please see the compressed version of mods. in my signature. The shop that built the motor says that the engine with the forged internals, bearings, blower cam, etc... is out running the capabilities of the factory tach. The car starts bouncing off the rev limiter at 6,000rpm's and the builder said according to his Dyno-Jet Dyno it was actually pulling 6,500rpm's. I do not want a big "look at my moster tach" sitting on my dash. The current boost and fuel pressure gauges are on the A-pillar and cloke pretty good behind the tinted windows. Any suggestions would be appreciated.

[RocketSled]

The factory gages all have some "latency", they average the actual input reading over a short span of time to smooth out the motion of the needle. The engine will rev faster than the tack can track, even with a stock motor. My solution was a Raptor shift light. Mounts to the A-Pillar right along side the middle gage of my 3 gage cluster (my fuel pressure gage). Set to light at 6200RPM to give me a little time to get off the gas before I bang the limiter.

[REDROCKET02Z06]

Originally Posted by RocketSled

The factory gages all have some "latency", they average the actual input reading over a short span of time to smooth out the motion of the needle. The engine will rev faster than the tack can track, even with a stock motor. My solution was a Raptor shift light. Mounts to the A-Pillar right along side the middle gage of my 3 gage cluster (my fuel pressure gage). Set to light at 6200RPM to give me a little time to get off the gas before I bang the limiter.

That was the option that I was considering. Just buy a three pod A-pillar and add a shift light. I would have to set it at 5,800rpm's and that just seems crazy but the rpm's vs mph's seem to be right so unless someone else has a better idea or solution I guess a new shift light is on the to do list. Does it wire in to the factory tach. and come with different shift point modules?

Thanks man.

[RocketSled]

The shift light needs to hook up to the tach signal. You can grab it from under the dash somewhere, or from the PCM (which is behind the front passenger side wheel well liner). You'll have to search the forum for details. I did my hookup to the PCM, seemed easier than taking the dashboard apart. The Raptor is programmable with a set of small rotary switches. No modules needed. Set it and forget it. I think the only "challenge" I had with the setup was figuring out to set the 4-cylinder mode instead of 8. The tach signal fires at 2x the engine RPM.

[REDROCKET02Z06]

Originally Posted by RocketSled

The shift light needs to hook up to the tach signal. You can grab it from under the dash somewhere, or from the PCM (which is behind the front passenger side wheel well liner). You'll have to search the forum for details. I did my hookup to the PCM, seemed easier than taking the dashboard apart. The Raptor is programmable with a set of small rotary switches. No modules needed. Set it and forget it. I think the only "challenge" I had with the setup was figuring out to set the 4-cylinder mode instead of 8. The tach signal fires at 2x the engine RPM.

Thanks man. I guess we're the only ones that ever noticed huh?

[Z O SICK]

Go with the raptor, it's small and you can mount it anywhere. I had mine on the A-piller.

[RocketSled]

Originally Posted by REDROCKET02Z06

I guess we're the only ones that ever noticed huh?

Well, truth be told, the engine will spin up a lot faster on a Dyno than on the street (and the engine will free-rev even faster still). The load the Dyno places on the engine is much less than the weight of the car itself, and the engine doesn't have to fight air resistance as the wheels speed up. In practice, on a stock configuration with the engine pushing the weight of the car and the tires hooked up, the engine can't spin up fast enough and the tach will track well enough it doesn't matter.

So for most, it's not an issue.