My tach doesn't have one. Why is this and how high can it safely go?

Cris

 

Redline was listed at 6000 RPM in the first road tests of the FEH back in 2005. This is also where peak HP occurs per Ford's specifications. I think it's safe to assume this remains the same today.

The engine can probably safely exceed this speed by a few hundred RPM for brief moments, but it's unlikely that the engine's control system would allow it.

 

Ahhh! So the computer will not allow you to over RPM the car. That explains why they feel no need for a red section on the tach.

Cris

 

That's the generally accepted theory, anyway, that it doesn't need it since the computer controls it anyway.

Keep in mind that it's omitted from a lot of vehicles now, too, not just the FEH. In these days of electronic controls and rev limiters, a lot of vehicles now have tachometers with no redline indicated. If the vehicle is at all sporty, however, it's usually marked.

 

It is my understanding that there is a rev limiter built into the computer and it will not let you rev past the "red line" point. Ford is known for having conservative tunes and I wouldn't be surprised if the FEH has an arbitrarily low RPM limit in it's tune. I make it a point to stay below/around 6,000RPM on the rare occasion that I need full power and I didn't go above 4,500 for the first 3,000 miles.

I did some looking and I see where the Duratec 2.3 I4 in the 2007 Mercury Milan has a 6800RPM red line (would the Atkins cycle affect max RPM?) and several other Duratec motors are well into the 6000s before they reach full power. In the day and age of drive-by-wire and thus fully computer controlled fuel and spark, there's no reason that an engine should go past the computer controlled limit (unless someone "tweaked" the computer).

I don't think you'll see a rush to remove the rev limit on an FEH as RPMs beyond 6000 are probably returning less power than other lower/less stressing RPM zones. If anything you'll see a tweak in the electric side before you'll see one on the ICE side.

 

There is an actual "red line" on the 2005-2007's at 6,000 RPM.

The one time I did "floor it" the Max. RPM on my digital ScanGauge registered 5960 RPM. In other words, I didn't back down to control it, but the computer did.
-John