Mike,
My 99 5.4 will rev up to 5 grand and no more, when it is in nuetral or in park.....and when it shifts she shifts at exactly 5 grand, what will the limit be raised to with a chip...and are these normal rpm's in Nuetral and Park..

Thanks 5.4

 

Hi 5.4 lariet,

No, your truck will not rev up to 5000 rpm in Park or Neutral, nor should you ever do such a thing, as that's an excellent way to damage an engine!

Factory tachs are notoriously cheap & usually inaccurate, especially when revving an engine up like that. It may turn those kinds of rpms in gear (though I doubt it, your tach is just off as they are much of the time) , as the maximum factory WOT upshift point in any late-model automatic F-150 is *never* more than 5250 rpm, and usually lower, 90% of the time it's in the 4800-5000 rpm range.

All these Fords have not only an "absolute" rev limiter, which governs the highest rpms it can turn under a load, but they also have had, for almost a decade now, an additional rev limiter that will not allow the engine to run more than 4500 rpm (at most, & most are lower) under any kind of no-load condition, which is why it's called the "no-load rev limiter". This was first initiated to stop Mustang 5.0 (and later on, others) owners from dropping a brick on the throttle to blow up the engine and have it replaced under warranty, just before their 36K mile warranty ran out.

The full-throttle upshift points in the Superchip are set so that the vehicle will accelerate the quickest; in the heaviest trucks, that's around 4800-4900 rpm, and in the lighter trucks, anywhere from 5000 to a maximum of 5400 rpm. It's usually about 150 rpm more than the factory WOT setting was in most cases.

The Superchip is *not* going to defeat a rev limiter, nor should that be attempted. Any engine needs a rev limiter to protect it from overspeeding, and we do not remove rev limiters. We remove top speed limiters, but that's a completely different function.

If you'd like to go over the Superchip application in more detail, please feel free to give us a call & we'll be happy to go over all of this with you.

 

Could the tach be off that much?

I have slowly, several times taken her up to 5 grand with no rev limiter bump....I dont do this often but I read a post that someone was talking with you about theirs not revving up any more then 4 and some change, and I was curious and tried it ...all the way to 5 grand she went and stayed, and then I let off, with out a rev limiter kicking in....By no means am I saying that u are wrong, I am convinced that my truck was a special dud from the factory, after seeing the headlites of several f-150's in my rearview, and they had cat back, K&N and chip and most were short beds with no x-cab, and I have pulled away from several of them....hell if I know....maybe my tach is off that much too, but the only limiter that I have hit is at 108mph or 5 grand and a little...I dont know....and also is there a money back guarentee on the chips or not....and what are the pro's and Con's of a chip vs programmer III.....Thanks Mike..

5.4

 

You are asking for 'IT'! That's crazy--taking a factory engine up to any where near maximum RPM with NO LOAD ON IT!

Mine has been at WOT many times(see sig.) but always with a load on it.

Dan

 

If it craters then Ill just have to buy a new motor...this was initally supposed to be talking about the rev limit and how mine is diffrent from everyone elses...If the motor can't handle it then I will just have to get another...right now it has 93k in it and passes everything on the road....but this is just me talking...

have a nice day to all......

5.4

 

Hi 5.4lariat,

OK, thanks for your response.

I appreciated the humor, and it's always possible to have a "one-off". But there is indeed a no-load rev limiter, and it's never been higher than 4500 rpm on any FoMoCo vehicle with an automatic transmission that we've ever seen. The manuals have it as well of course, though we've seen higher no-load rev limiters in some manuals like Cobra's, Mustang GT's, etc., which can be easily revved veyr high for clutch-dump starts.

Could your tach be off that much? Yes, it certainly could, we've seen tachs off by that much and more at high rpms like that.

Listen, please don't take offense at us "razzing" you a bit about revving that engine up under no load like that. Trust me when I say you've only gotten away with it from luck, and I'm glad it hasn't caused an immediate problem so far. The 5.4 has a nice forged steel crank, and the rods aren't bad, but they're *very* long, so straining it with high no-load revs just is not something you want to do, trust me. Take good care of that motor & it'll give you a solid 200K+ mile service life. Keep revving it without a load on it like that and it could spin a bearing anytime, and eventually will. Then again, if it does spin a bearing that could always serve as a great excuse to build a nice strong motor with forged rods & pistons, and then slap a supercharger on that rascal & have some real fun!

Good luck,

 

If the tach was off that much would or could that mean that the WOT rev limit could be lowered between shifts, or are they normally always at 5250....just curious...and is there an aftermarket tach that you would suggest for monitoring the correct rpm's.....and while this post goes from one thing to another....what are some manufacturers of cranks and aftermarket rods and pistons etc.....just need to know for the future...(near)...driving 4k a month will catch up quick...hell I bought the truck when it was a year old and it had 39,080 on the odometer...lots of highway miles could help out... Thanks all


5.4

 

Hi 5.4lariat,

Well, there are any number of good aftermarket electronic tachs, but I like the Autometer line, as do most people here on F-150 Online & elsewhere. We're picking up that line as well.

No, if the tach is off that won't affect shift points, etc. that is all controlled by the ECU, so the only thing that tach error does is give you an inaccurate reading. The ECU usess mph (vehicle speed as reported via VSS, the vehicle speed sensor) to determine it's shift points both up and down. If the speedo is off, it will revert over to using engine rpms for shift points, but an inaccurate tach still won't affect that, you just don't get accurate readings on the tach face is all. Many of these tachs are off, that isn't rare at all. They're usually pretty close when cruising.

As far as crank, rod & piston manufacturers, wow, there are a bunch, take your pick! Your stock crankshaft is forged steel, so it's fine. For rods & pistons, there's always Calles, Weisco, Eagle, JE, etc.

 

Mike,

Where is the VSS located, I have heard that there is a sensor on the reared on the top that tells the mph and odometer reading....however I unpulgged this plug and everything still worked spedo, odometer....the only thing that happened was the ABS light came on....and whenever I try to get parts most think that the rear end has disc brakes....because it is a 99, but I have drum....Special dud she is...lol

5.4