Lexus LF-A vs 2012 GT-R Insideline

[MrH]

That's not what they mean.  Say you're in neutral and you rev the engine... an analog tach wouldn't be able to keep up.

Oh.  Who cares if you bounce it off the rev limiter in neutral?

[the Teuton]

My dad's 911 sounds sexy underway, but I wish it was a bit more pronounced at throttle. 

Most Porsches honestly don't sound that good. You don't buy a Porsche for the exhaust note.

[MrH]

Most Porsches honestly don't sound that good. You don't buy a Porsche for the exhaust note.

[CALL_911]

Most Porsches honestly don't sound that good. You don't buy a Porsche for the exhaust note.

Dude, go home.

[the Teuton]

Dude, go home.

http://www.youtube.com/watch?v=l0yEq0Sr8IM

[SVT32V]

The rate at which the LFA builds RPMs goes far beyond pretty much any other production road car.  How many other road cars can change RPMs so quickly that a regular analog tach can't keep up?

Maybe an analog tach that toyota builds can't keep up with engine revs but it is certainly possible to build such an analog tach, it might cost a good bit, it might be harder to build and cost more than the electronic version but it can be built.

I doubt that is what wizard was saying anyway.

It still doesn't rev anything like an F1 engine in any shape or form.

[SVT666]

Teuts is riht.  Most Porsches don't sound all that special.  The Boxster has a neat exhaust note, but nothing that stirs the soul.

[565]

The rate at which the LFA builds RPMs goes far beyond pretty much any other production road car.  How many other road cars can change RPMs so quickly that a regular analog tach can't keep up?

Actually this is more common than one would think.  For example the C5 Z06 will outrev its tach in first gear, to the point that you need to upshift slightly before 6600rpms(where fuel cut is).  It confused me when I first drove the car, cause I bounced off the rpm limiter at 6300 or so.

I imagine the same is true with most high powered engines with good throttle response.  The difference is that Lexus actually went out of their way to solving the problem rather than just accepting it.

[hotrodalex]

Teuts is riht.  Most Porsches don't sound all that special.  The Boxster has a neat exhaust note, but nothing that stirs the soul.

They sound better than a Civic with a fart can, but yeah, not all that amazing.

[Onslaught]

I agree with some of these guys. Most Porsches don't sound that great. They don't sound bad, but at the same time it's nothing to get worked up about.

[GoCougs]

Maybe an analog tach that toyota builds can't keep up with engine revs but it is certainly possible to build such an analog tach, it might cost a good bit, it might be harder to build and cost more than the electronic version but it can be built.

My 99.9% hunch is basic physics and control theory told Toyota that a mechanical tach wouldn't work.

A mechanical tach needle works by way of non-contact coupling of some sort. All such couplings (ANY coupling actually, mechanical, electrical, w/e) will have a maximum bandwidth (i.e., maximum frequency response, IOW ability to respond to input). At some point the output (tach needle) will decouple from the input (actual engine RPM); it just can't keep up because the coupling isn't responsive enough.

This is a very common control system issue - ALL systems reach a point whereby the control loop breaks down. No matter what is done; lighter tach needle, stronger non-contact coupling, etc., the system will have a maximum ability to respond to input. The physics just won't let it happen. My hunch is this is exactly the insurmountable barrier that Toyota encountered for the LF-A. Also of note F1 cars do not use an analog tach I'm sure for precisely the same reason.