Wow I mean I didnt think this engine could handle that? Did you guys get a 6500 limit too? Kinda scares me haha!

 

you can change it yourself if you're not comfy with it.

 

Is it safe? If its ok then I dont care, just seems a little high I guess?

 

sure, i can push my truck past that and it runs fine.
ive had it well over 6k lol...
but i don't have a tuner or anything :)

 

I'm not trying to jack the thread, but are the bama tuners worth the price? I've been debating whether or not to get one for awhile now. I'm not looking for huge power gains but just a little something extra when towing the boat and whatnot.

 

I think the thing here is where your HP actually starts dropping off. I'm not sure where it starts dropping but its way before 6500 unless you have a full race cam. It would benefit you to shift right @ where you reach peak HP.
Yes, the tuners are worth it!

Rick

 

Thanks Rick, I definitely trust your opinion. I like how you gave it to that guy on the other forum BTW. lol

 

Yeah I wouldnt think that a 4.0 would go to 6500 with power.... Well if it doesnt hurt anything Ill leave it there, doug must have it for a reason...

 

If its an auto it will shift before your rev limiter anyway so it shouldn't make any difference but if its a stick..well..thats a different story. I'm sure I've seen some dyno charts here that you can reflect on where the HP starts dropping off.

Rick

 

there are a few 4.0s out there running around 8k rpms

 

And nickster is one of them.

 

rick is just a trouble maker hehehe tuners i dunno, i was gonna get one but havent. whats nice about them is if u got the 4.0 at highway speeds it shuts down i think half your cylinders to save u gas. ford didnt implement that into the 4.0 but did in the 3.0 prolly cause the truck had issues at 130mph and couldnt run on half the cylinders or some bs. its kinda like how the driverside has no splash gaurd in the wheel well cause the truck over heated after having the crap beat out of it in 130F heat

 

what?!?

 

i dont think so........the 4.0 doesn't have that feature....your on

 

some serious

 

Yea, I wish we did, I know my 5.4 had that feature.

Rick

 

The 4.0L is a short stroke motor. As long as you have a good oil filter and the motor is fuly warmed up you'll be fine.

Now as far as the power curve. I've data logged this in both stock and modified states. (K&N conical kit, e-fan, and underdrive crank pulley) My 06 FX4 peaks HP at 5000 to 5100 rpms as far as I can measure doing at least 10 pulls up to 6300rpms (stock fuel cut). I would assume that exhaust mods would raise this by a little. Maybe 300-ish rpms. And maybe 500-ish with a all out headers/cats/mufflers setup.

Either way most of you guys are not into drag racing (I am) and IMO a 5500 shift point is p-l-e-n-t-y enough for these trucks with a 5 speed tranny. Anything over that and your just wasting fuel with a smile on your face.

Rich

 

5500 is as far as I would go, there is no reason for any more than that...