Redline At 3k?!?
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Elder User
Joined: Nov 2005
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Redline At 3k?!?
Ok here goes another one. I've got a 94 F-150 4x4 with the 4.9L in it, 5 speed manual tranny, and 3.08 gears. Just tuned it up (cap, rotor, plugs, wires, PCV, air filter, oil change), and its running GREAT! even with 190,450 miles on it. Well, I installed a SunPro Super Tach II on the truck yesterday (it works great), but it seems that my truck redlines at around 3,000 rpm. Now, yes, the tach is set for 6 cylinders, and yes, its hooked up correctly, and YES it reads up to 8000 rpm. But at 3000 rpm the engine is just ROARING. She idles around 750-775 rpm, I shift around 2500 rpm and all is fine, but something just doesn't quite seem right about that number... 3000 rpm. A buddy of mine said his redlined at 5500. I don't know, what do yall think. Maybe its just a stump puller... lol.
Postmaster
Joined: May 2004
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You could run it up higher, but you won't get much benefit. The 300 is a high torque/low rpm/decent mpg/"easy to work on" engine. It doesn't produce much additional horsepower at high rpms. I shift mine at like 2200 rpm. The manual tranny ratios seem a little too far apart, but I think the engineers knew what they were doing...the high torque at lower rpms allow it to recover quickly to a normal powerband.
I think you're looking for horsepower, a V8 would be a better choice.
I think you're looking for horsepower, a V8 would be a better choice.
Elder User
Joined: Jan 2004
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From: houston
Just a thought. If you can, try to hook up another tach just to be sure. But with almost 200K, I might consider the exhaust being clogged. Try un-bolting the muffler and going for a spin. The cat could also be clogged. Sometimes just taking the O2 sensor out will relieve enough pressure to tell you if the exhaust is the problem. God luck.
Mountain Pass
Joined: Aug 2004
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From: Roswell, GA
I think the actual rev-limiter is set for around 5500 on a EFI truck (i know i've hit mine once or twice, but without a tach) But other than that, when i installed a tach in my truck, i was very surprised at how low in the RPM range i had actually been shifting (judging by engine sound) versus how strained the engine sounded at 3000, 3500 RPMs. My educated guesses on my shift points were really about 500 - 700 RPM+ off.
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From: Spokane WA
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I know what you are talking about! Your not alone. It must be the tach because I also have a Sunpro Super Tach (old one meant for my dads '71 Mach 1) in an '85 2wd F250 300 I-6 and have also thought it was weird that I thought it would blow up if l took it over 3000 RPM's. that's like what a diesel redlines at. the thing that gets me is that the tach says the truck idles at about 600 RPM's wihich is about right isn't it
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New User
Joined: Jul 2004
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Got a '96 with 300 and m5od. Not sure it even redlines...lol. I'm sure it does, but never seen it go that high. Even when racing the ricers, 3500 would be tops, and yes, the 300 does roar at those rpm's. Nature of the beast.
New User
Joined: Jan 2005
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Same redline
I drive an 86 f150 with a factory Tach in the dash and it sounds like it is going to explode at 3,000 rpm. I have also wondered about this. I think the computer has a problem because if I let the rpm go to 2,000 or higher for longer than 2-3 seconds the timing jumps about 20 degrees and stays there (even when the rpms drop back down) until I turn the swithch off and back on. It makes no difference what gear. It does this in neutral. I shift aroud 1,500 and reset the switch if it screws up. I have replace so many parts I have to save up to replace the computer. Ignition module is on distributer. No vacuum advance. All timing is controlled by the computer.
Postmaster
Joined: Feb 2003
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From: Muskegon, MI (home)
When I'm wheeling in the dunes and I'm climbing the big hills (I run 4 high/ 2nd gear) and hold it to the floor all the way up. I consistantly hit 4k with my 300 and doesn't seem to mind it, I try not to do this too much if I can help it. I like to shift mine @ 1800 - 2000 sometimes...usually 2200rpm, it doesn't mind it at all...plenty of power way down low. If I'm getting on the expressway, I'll buzz er up to 3k before putting it in 4th gear. With 4.10 gears and 33s I try to stay below 70mph (3k @ 70mph) if I'm on a long trip or cruising for a longer period of time, I like to run 60-65mph @ 2600-2800 rpm. Had up to 5200 once, scared the hell out of me...never again!
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Elder User
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Great, thanks for the info guys! I knew I wasn't crazy or anything. As far as the tires, they are stock, and as for the exhaust...
I'm throwin' a set of dual 2.25" pipes with 3" Chrome tips under there as soon as I get my dual in dual out V-Force Muffler (sounds Beeutiful). And yes, the cat will be gone
. Thanks again.
I'm throwin' a set of dual 2.25" pipes with 3" Chrome tips under there as soon as I get my dual in dual out V-Force Muffler (sounds Beeutiful). And yes, the cat will be gone . Thanks again.