GT Redline

[DivineStrike]

Please see post #46.

Divenstrike has a different definition of redline than most. Would be interested in seeing a source or two for his definition of the real 'redline' of an engine.

If you read the very first section of his link about redline, it is right there.

If you apply that definition to the new coyote, redline is higher than 7k. As the engine is very capable past 7k.

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[Norm Peterson]

Maybe we shouldn't be calling the engine's inherent rev limit beyond which it almost immediately starts taking itself apart a "redline". This would be an ultimate mechanical limit.

Any redline intended for the driver's use involves a margin, almost certainly based on some fatigue analysis. If you're willing to sacrifice some unknown amount of Ford's margin, you don't have to use their redline indication for anything more than paint on the tach face. This is a usage guideline, or an acceptable (to Ford) fatigue limit.

An ignition or fuel cut rev limiter goes in between, allowing you to reach and generally exceed (slightly) the user redline without risking immediate breakage. But long term, consistently hitting the rev limiter will almost certainly bring about failure earlier than what Ford was targeting the engine to reach during its design. This is your protection against occasional minor mistakes and carelessness, which costs a little extra in terms of fatigue usage without letting you break something right away the first few times it gets involved.


Tachometers with needles are notoriously laggy in nature. When the revs are rising rapidly, how do you know that the engine hasn't already reached 7000 when the tach is only displaying 6800? A digital tach may be accurate enough internally while flashing the numeral segments too rapidly to be useful, never mind that digital displays can be sluggish in the cold ("cold" being something that we don't have a definition for in terms of dynamic accuracy either).


Anybody trying to check what their "fuel cut rpm" might be, should at the very least work their way past about 6000 rpm very slowly to make sure that the tach isn't reading low for reasons involving its mechanical limitations. You can only check a 'static' setting by approximating static conditions as closely as possible, and here that means increasing the revs slowly.


Norm

 

[DivineStrike]

That's a good explanation norm. I have about 5k on my car and haven't seen it go near 7k...don't know why since most sources say it should go to 7k. Also if it went to 7k...0-60 app should work on pp cars even with the sensor being on the smaller front wheels.

 

[adrift]

That's a good explanation norm. I have about 5k on my car and haven't seen it go near 7k...don't know why since most sources say it should go to 7k. Also if it went to 7k...0-60 app should work on pp cars even with the sensor being on the smaller front wheels.

I wouldn't be at all surprised to find some calibration issue causing this. Have you asked the dealer to check it out? Unfortunately, I wouldn't have much expectations for a fix, if it's running within their normal parameters they're not going to look hard.

 

[15GTBEN]

FYI:

Well know coyote tuners (AED, Mike Roush...) regularly set the redline to 7200 in 2nd-5th gears in the 11-14 coyotes running the stock manifold. This motor can handle 7000rpm all day. Maybe not all day but you know what I mean.
Probably no reason to rev past 6800ish (if stock) from a performance stand point but hitting the fuel cutoff every once in a while by accident won't be hurting anything.

 

[blitzburgh]

Jimmytwotimes starting a thread about the redline?! Welcome to the dark side Jimbo! ;)

No doubt, he is a world class troll.

 

[JimmyTwoTimes]

No doubt, he is a world class troll.

I think you're confusing the words "troll" and "guy with a sense of humor who doesn't take things too seriously."

 

[blitzburgh]

No, no confusion at all.

 

[DivineStrike]

CO GT, and I'm just telling you from experience, the rev limiter occurs before 7k. And that this engines redline is higher than 6750.

I agree with you about the shift point however, with the stock intake manifold you should shift by 6700

 

[JimmyTwoTimes]

CO GT, and I'm just telling you from experience, the rev limiter occurs before 7k. And that this engines redline is higher than 6750.

I agree with you about the shift point however, with the stock intake manifold you should shift by 6700

How are you defining "redline"? Because the red line painted on the tach starts at 6500. So, by definition, redline is 6500.

 

[DivineStrike]

Jimmy, See the wiki definition under the first part of redline Wikipedia.

 

[JimmyTwoTimes]

No, no confusion at all.

Eh, loosen your tie, live a little.

Or not, I guess; up to you either way.

 

[King_V]

Side note:

This whole thread makes me want to take a look at the tach of a particular older vehicle I have... if I'm not mistaken, redline is before 5000...


In any case, I would guess that the needle on the tach isn't going to be guaranteed to be 100% spot on exact.

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