I installed a VelocityAP tune in my 4.3 Vantage last week and love it. But I've found a side effect that I hadn't noticed before. Now that the throttle response is significantly quicker off idle, I can hear the engine revs before the tach needle starts to move. It only seems to lag down around the lowest end of the Rev range. Down as low as 1500rpm the lag is already gone.

I would have expected the guys with tunes and moreso the guys with lightweight flywheels to have noted this before but I don't​ remember seeing it a here. Has anyone been else seen this,?

 

I never really noticed if it happens on my car (tune and flywheel). I only pay attention to the tach at high RPMs or when I'm cruising at a constant speed, so if mine has the lag I haven't noticed.

 

Same here. I also have the tune and flywheel. Never noticed it.

 

Why would I look at the tach while driving? The road is a much better place to look. I can hear the engine so I know where it's at in the rev range and peripheral vision tells me when it's getting too close to 12 noon.


You want slow to react try the digital spedo LOL

 

My guess is the tach is lazy for some reason. I have never heard of a street car where the tach could not keep up with the engine?

 

I imagine this is the reason for the slow reaction. The tach is not mechanically driven, there must be a lag in the signal.

 

Probably, but the signal is fine where it matters. It shows me a red light at 7000 which is 200 before the limiter, so it's accurate there or I'd already be on the limiter. If it's lagging at 2000 doesn't matter in the scope of driving, though I'm not sure mine does. The only time I ever paid attention to low revs was when trying to figure out what RPM the V12 clutch stops chattering while in a deserted parking lot, and I really don't remember any lagging. Unlike the digi speedo which can jump 5-8MPH increments with the hammer down.

 

Did you ask Velocity AP about it? You could try a test and reload the original tune and see if it acts the same.

 

Lexus practically invented the digital screen speedo for their LFA, specifically because the high revving V10 rev'd so much faster than the speedo could move