The tachometer in my F150 goes to 6000 no redline indicated. Does anybody know what the redline for the 5.4 and 4.6 is?

 

HI!... PSYCHO : The redline on the 5.4 is 5400rpm. If you install a SUPERCHIP it will be raised to 5700rpm. But don't go by your factory tach because they have been proven to be out as much as 300rpm. I believe that the 4.6 is the same way.

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NEAL [ the horsepower freak ] NEWMAN
'99' F-150 XLT SPORT, oxford white, reg cab shortbox stepside,5.4, auto, 4.10L.S, captain's chairs, bedliner, GTS carbon fiber headlight covers, **** CEPECK clear halogen driving lights, GTS slotted tailight covers (painted oxford white), FORD locking lug nuts, tinted windows,true duel exhaust with 2.5 inch mandrel bent pipes and FLOWMASTER 3 chamber mufflers with 3' tailpipes exiting before the rear wheel like the LIGHTNING, HELLWIG rear stabalizer bar, AUTOMETER guage pod and tranny temp guage, custom fabricated air intake trac and huge K/N filter, TPS mod, BELLTECH 2-inch rear drop, SUPERCHIP

 

Neal ....5400 red line? I don't think so...you mean 4400 right? Thats what mine shifts at at wot. The chip bumped it to 4700, for awhile. My truck doesn't like the chip...at all.

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97' F150 Lariat S/C long bed 4x4 3:55LS 4.6L auto...SuperChip, 40 series Flowmaster cat back.
Colorado Springs, CO

 

the computer will not let my truck rev over 5000 rpms. Yes under wot it does shift at 4400-4500, but you can manually hold the gears down to 5000 rpms. A couple of days before I got my motor this is what I started doing. I was running 80 mph in 2nd gear at 5000 rpms according to the tach. The 4.6 should rev alot higher than the 5.4. My mothers expedition is stock with the 4.6 and at when you punch into it it goes to 5000 rpms without holding it down.

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1997 4x4 5.4 ORP XLT extended cab Dark Toreador red Westin nerf bars tint HARDER THAN A ROCK AND FASTER THAN A HEART BEAT

 

Since I got the flowmaster 40 put on last Friday, I've broke 5000rpm several times, maxing out at about 5600rpm, and I have the 4.6l

cd

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Silver 99 F150 XLT 4x2 Sport Extended Cab with Flare Sides...
Mods: K&N Air Filter, Tinted Side Windows, Flowmaster 40 Series Catback System, Reese Class 3, Airbox Mod's, Fiberglass Tonneau Cover, Alpine Deck & Subwoofer Processor, Zapco AG350 Amp, JL 10W0 (times 3) & 1 Farad Cap
Coming soon: Spray-On Bed Liner, Bell Tech Drop Kit (2" rear or 3"/4" ???)

 

HI!... Well I am sorry to burst some of your bubbles guys but the 5.4 engine has a rev limiter of 5400rpm and with the SUPERCHIP it is raised to 5700rpm with their basic program. I know of this very well because I had to send my SUPERCHIP back to have a custom program written because I kept hitting the 5700rpm rev limiter with my 4.10 gears. The reason SUPERCHIPS does'nt raise the rev limiter any higher than 5700rpm is that the 5.4 or 4.6 's camshafts are not producing any more power above that. In stock trim the 5.4 and 4.6 are not capable of going over 5400rpm. And don't go by your factory tachs because they are no where close to the proper rpm. When my truck was hitting the rev limiter of 5700rpm in 1st gear my tach was only regersting 5200rpm. Ask MIKE T if you don't believe me. Just my 2 cents.8-)

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NEAL [ the horsepower freak ] NEWMAN
'99' F-150 XLT SPORT, oxford white, reg cab shortbox stepside,5.4, auto, 4.10L.S, captain's chairs, bedliner, GTS carbon fiber headlight covers, **** CEPECK clear halogen driving lights, GTS slotted tailight covers (painted oxford white), FORD locking lug nuts, tinted windows,true duel exhaust with 2.5 inch mandrel bent pipes and FLOWMASTER 3 chamber mufflers with 3' tailpipes exiting before the rear wheel like the LIGHTNING, HELLWIG rear stabalizer bar, AUTOMETER guage pod and tranny temp guage, custom fabricated air intake trac and huge K/N filter, TPS mod, BELLTECH 2-inch rear drop, SUPERCHIP

 

These modular motors do rev higher than the older 5.0 & 5.8; they are a different design completely in terms of the valvetrain and cylinder heads, and consequently, they have an extended RPM range by comparison.

Some Ford vehicles with the same size engine will have different WOT upshift points in terms of RPMs. Some of them will do the 1-2 WOT upshift at only 4400, and some of them go all the way up to anywhere from 5250 to 5400 rpm, it isn't the same for the same size engine in every vehicle they put that engine in, you see.

Just for the purposes of clarification, the engine's redline and the WOT upshift points are two completely different functions, and will never be the same rpm figure. A rev limiter shuts off fuel flow instantly in these Fords, once that rpm has been reached, the ECU cuts fuel flow. The top speed limiter works in the same manner unfortunately, meaning a complete and total instant fuel cutoff, which if you're not ready for it can be a bit dangerous at 98-108 mph, which is the range the factory top speed limiter is set within on the F-series trucks. The top speed limiter only controls how much speed the vehicle can attain, and has nothing to do with the rev limiter, as those are two completely different and separate functions.

Another interesting point is that you have 2 different rev limiters in these vehicles; one is the "no-load" limiter, which works in Neutral and Park on automatics, and on manuals it works in any condition under which the engine is under no load. This is always the lower of the 2 rev limiters. For example, on the older 5.0 and 5.8 F-series trucks, the no-load rev limiter was set at 4500 rpm in a lot of them.

In general, the modular engines have another 600-1000 rpm of operating rpm range minimum in 2-valve form (SOHC) over their older counterparts, the 5.0 and 5.8 truck engines. The DOHC variants are capable of withstanding 7000 rpm all day long, as installed in the Lincoln Mark 8, Mustang Cobra, etc.

So there are enough differences from the factory to explain why one person's vehicle upshifts at one rpm, and someone else's vehicle has a different upshift point. Also, these factory tachs are sometimes way off, no electronic tach is very accurate to begin with. Ford has problems with the sampling rate on late-model tachs, and other variances. For example, when you are gaining rpms very quickly, like in 1st gear, say if you have 4:10 gears or a supercharger, electronic tachs in the aftermarket generally read a little bit low (slow), which can be dangerous. THe Ford factory tachs can be either high or low! In the new Lightning for example, it has a rev limiter of 5600, which is indicated on some Lightning tachs as low as 5200, and as high as 6200 rpm! They tend to be most accurate when you're cruising at a steady speed in high gear.

So before we get all heated here, I though I would drop a line or two that I hope will help to somewhat explain some of the differences that have been discussed here. I'm sure everyone is reporting exactly what they are experiencing.

Our bests to all,

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Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com

 

Typically engine redline is at or a few hundred rpm over peak horsepower. A very typical redline for truck engines is about 5000 rpm.
I'll bet this is also close for the 5.4

When we talk about raising this value, there are other structual concerns to be aware of,
If the "resonate" or structual frequency of the engine block is designed to be above the rpm range, the engine will go though the rpm range smoothly and never excite the blocks natural frequency thus vibration will be minimal. If we do increase the engines ability to rev higher without changing the engines natural frequency (stiffer block) we will notice extreme vibration at that higher rpm. be aware!

Ford did a lot of homework in designing the engines to run with-in cetain design parameters and inadvertantly changing these are an invitation to premature engine failure.

[This message has been edited by hotratz (edited 11-04-1999).]