rangerryda

Anyone with a 6 spd 5.0 notice a significant extra kick in the pants of sudden power from the short RPM range of 6k-6,700 rpms? Just seems like it's powering through then goes... "oh you're really flooring it huh? ok then here!..." Is this just the factory tune or what? Forgive my ignorance on this topic, I'm used to boosted vehicles and doing my own tuning via piggybacks or standalones so I know when or why power comes in due to timing, afr's, egt's, etc...

darksky1984

I agree that there is more power up top. Even without my tune it feels that way. With my Bama tune I let the car run to red line at WOT. When I auto-x the car I try and keep it in first rather than shift to 2nd right away b/c I can feel more power at the high rpm's.

parchisi

That's the magic of a free breathing, high revving 4-valve with Ti-VCT. It basically adjusts the cam timing and lobe seperation depending on RPM, allowing optimal power to be maintained from low RPM to the tippy top of the RPM range.

VistaBlue

The factory tune has torque limiting built in to the mid-range, which is why a simple aftermarket tune can result in gaining ridiculous amounts of torque in the mid-range. What you're feeling is the torque limiting subsiding, and full power coming on in the upper RPM.

rangerryda

Ok, so the factory "de-tunes" the mid-range intentionally then? Is there a particular reason for it? I don't mind revving to 7k because frankly it's fun and sounds amazing but I'm just used to a smoother power curve instead of such a sudden difference. I plan on getting a Bama tuned SCT down the road anyhow to assist in throttle tip in, 2nd gear lock out and most importantly the mid range torque but was curious in the meantime.

VistaBlue

I'm not personally sure of the reason, you might want to contact one of the well-known tuners for that. I think Gus (Steeda) made a post about it months ago; I think they might have been the ones who originally discovered the torque limiting, so you might try giving him a shout.

Of course, seeing as I have the memory of a goldfish, I could be fabricating all of this in my head. Who knows!

Napoleon85

You should feel the top end with the Boss intake manifold ... my redline is at 7300 and it pulls strong all the way to the limiter. I need to get forged pistons/rods and stronger valve springs so that I can go to 7500 safely.

JIM5.0

Heck, with properly designed forged pistons, you could push to 8K RPMs.

Big block guys have been doing it for decades, pushing massively long stroked engines towards 10K RPM with the right kinds of forged pistons and cylinder sleeves.

I would love to see an aftermarket company design a variable length intake manifold: long runners for low RPMs, but they shorten to promote power in upper RPMs.

The stock Coyote and the Boss manifolds are fixed length runners. The Boss manifold being suited to push to 7500 RPM maybe more assuming the right lower end rebuild.