I started to just follow up on this great question in the same thread but decided it needed to be in a new thread, so, thanks 051fdrof, for kicking me into a new thread.

What are safe limits on some of the things we CAN monitor?

What the heck is the redline RPM on a 5.4L engine, for instance? With tuners, it looks like we can override any safety limits for the engines (and they all have them). If we go with ANY custom tunes, we are at the mercy of whatever hack dreamed them up (and please, I'm not talking about everyone's "favorites" here, but my Sister, for instance, "knows a guy in Colorado Springs, who has a chip, and he says he can make her truck...'). You get the picture I hope! (By the way, the redline question was asked in another thread, but never answered).

And, since these programming devices seem to let us "great unwashed" twiddle with all kinds of settings, where do we get in trouble?

So, in our defense, at what CHT should we begin to get worried? What about EOT and TFT? These fluids break down fast above certain temperatures and I'd like to stay comfortably below those limits - whatever they are!

I'd like a few certified mechanics or some or our "expert" tuners (Bill, Mike, Justin? - and I know you're ALL busy) to chime in here with some information please. I'm a complete ignoramous when it comes to these values. They don't seem to exist in any of the maintenence manuals I use.

Back when I was flying, I KNEW the redline speed of my aircraft, the stall speed, the max EGT, max RPM, min oil pressure, etc., etc.. To not know these things was a ticket to a peaceful patch of ground in a quiet resting place.

So, while the stakes are not quite the same, most of us would not like to see our trucks self-distruct due to our blind dependence on the skill of whoever set up our PCMs - or our lack of skill in modifying the setup.

On behalf of everyone, any information would be eternally (well, maybe not that long) appreciated!

- Jack

 

from prior reading of posts from TP and others on the site the stock torque converter for my model year was good to about 5400 RPM, that's the only question I can anwer with any certainty of the ones you posted. good thread

 

Thanks, BSL. That's the RPM limit I came up with too, and for the same reasons.

But, it makes me "queasy" not knowing for sure!

- Jack

 

Has anyone besides me noticed that there are no answers to my questions posted here?

Could this mean, that there are no answers? Or is it that all our "experts" simply don't know anything after all?

I thought my questions were straightforward and clear.

Is it that the real answers are unknown?

Maybe "limits" are all a myth! Bring your transmission fluid temperature up to 1000 degrees! It's OK! Crank the engine RPMS up to 20,000! No sweat, the thing's just "turning around". While we're at it, let's put 120 volts on the battery to charge it - real quick!

What's going on guys? It's no disgrace to admit you don't know. I don't know a lot, and that's why I asked this question. Maybe there is no "published" information on the limits I asked about. And, if that is the case, why aren't you all rioting to get this information? I''ve just recently joined this forum, and all I see are a bunch of half-baked opinions on power options. No real discussion of tradeoffs in engine wear, economy, and impact on the environment.

Don't you care about your rides? Don't you believe knowledge is power? What are you, a bunch of "Whatever big brother sells me is OK", kind of wimps?

Anyone out there with guts?

- Jack

 

On the 2v 5.4's the torque converter starts to balloon after 5400 rpm. The redline for the engine is 5800.

 

Good on ya! Someone who is willing to express an opinion and give us an answer!

Of course, I have the 3v 5.4 and others do too. Does that make a difference?

I'm really sick of "fence sitters". Let's get some more input!

- Jack

 

all the answers are posted here several times over; give search a try

 

Who cares? It is a electronically control vehicle: It has safeties and strategies to control limits/heat via the PCM. Just drive it.

 

Thank you, jpdadeo, for your useful input. The world would be a much better place if only everyone was as helpful as you.

Since you know everything already, just ignore the rest of this post. It's meant for people like me who are interested in these things and are hoping maybe someone can quickly enlighten us.

The RPM limit seems to be 5800 but torque converter damage may start to occur at 5400. This was from a post that quoted Mike Troyer on the subject.

According to the New Jersey Forest Fire Service, using f350 and f450 trucks, if transmission fluid is operated at no higher than 175 degrees, it should last about 100,000 miles. Prolonged operation at 195 degrees, it's good for only 50,000 miles. At 240 degrees, it breaks down rapidly, ruining it for further use. Deteriorated fluid can and will cause transmission failure.

The only thing I can find on Ford's recommended oil is that its flash point is 365 degrees. The owner's manual says to change it every 3000 miles or 3 months if used in severe service.

I can't find anything on CHT. I suppose the engine will go into "fail-safe mode" before anythng gets damaged though. I have not been able to find the coolant temperature where this happens, but it appears to be around 250 degrees from one article I read about off-road driving in the desert.

If anone has anything to add, feel free.

- Jack

 

That will be for the 4r100 and not the 4r70/4r75

Also the fail safe temp is listed in the owners manual i think.

 

so what are you trying to say, you're to good to search?

well then I guess the rest of us will have to do it for ya and spoon feed ya

 

I'm probably just dumb, Gotts2BMe, but I don't understand what you mean by "4r100" or "4r70/4r75". And, I did not find any mention of the actual fail-safe temperature in the owners manual, only that if the engine overheated, the temp gauge would go to full hot and half the cylinders would shut down. It's possible, of course, that I just missed the temperature reference.

I also found another reference to breakdown in transmission fluid at or near the temperatures I cited. It wasn't Ford-specific, but it gives me confidence in these values.

Something else I found in my searching is that failure of sensors is a fairly common problem. It looks like they fail in such a way that they indicate trouble (where none exists), but I would not like to bet my life on this. From all the posts in the electrical forum, these trucks are fairly prone to electrical problems.

And, I've never been one to rely on some device's fail-safe "features". An engineer can only design something to be fail-safe if he/she has correctly anticipated ALL the possible ways the device can fail.

- Jack

 

The 4r100 is the tranny found in the superduty's, f250 light duty's, lightnings, and 7700 series f150's. It is their heavy duty transmission and holds ~19 quarts. The 4r70w is the lighter duty tranny found in the older 2v f150's, mustangs, crown vics, etc and holds about 14 quarts. The 4r75 is found in the newer 3v f150's and is basically just an up dated 4r70, they are basically identical except for some electric solenoid i believe.

 

JnJ - I believe that your year truck does not have a coolant temp sensor, but infers the coolant temp from the CHT.

 

Thank you Gotts2BMe, for enlightening me. I knew there was something familiar about those numbers, but I couldn't bring it up out of my feeble little brain. Now that I know what you meant, I understand your post. But, unless the heavier transmissions use different fluid, the breakdown temps wouldn't be different would they? I'm going to guess that Ford would design them to use the same fluid, but I could be way wrong.

And, ONELOWF, I'm sure you're right about the CHT and inferring coolant temp from it. Several of the sources I looked briefly at were about inferring coolant temp from CHT. Since that wasn't what I was looking for at the time, I didn't actually read them.

Using the CHT this way seems to be true for several year models, and the CHT sensor seems to like to fail.

Thanks to you both for adding to this discussion.

- Jack