ive been exploring everything i can do with my new sct tuner, and i have one question: how high can i rev the 4.6 reliably? now that i can adjust the shift points and rev limiter in general, im interested in raising it a few hundred rpms, since it currently tops out at 6k rpms. the internals are all stock and i really dont want to blow anything up, so does anyone else have any experience with this?

 

frined of mine just showed me a video .. 155 mph in a 2004 cobra .. 8000 rpm .. he has run this thing wide open since the day he got it .. and it has nitrous ..

 

Damm that's scary. 6500 and I'm shifting.

 

haha ya that is scary. i should mention my particular 4.6 is just a 3v 2005, nothing fancy. 6500 is what i was thinking about... that works well for you alscobra?

 

No point over reving a stock engine until you can make power higher up. Your past peak HP & TQ at redline now. Do cams, LT's, CAI, have it dynoed then you will know your specs. I'm planning a 5.0 stroker build which should make power over 6K, the dyno will verify that. Good luck.

 

I shift at 6500, I've wound it out the most to 7000rpm, but I don't feel comfortable with that I'd say under 6800 is fine, the springs are good to 7200rpm per ford, doesn't mean you won't float a valve though, been shifting at 6500 for 3 years, all good.

You will probably get the best results shifting between 6300 and 6500.
and the "why are you shifting up there if you don't make power up there" thing is an old school myth, it's all about where you land for the next gear.

if any old schooler wants to challenge that I have TONS of evidence

 

8000?!? And only doing 155?!

I'm at only 5500rpm at 160mph. And I shift at 7200

 

So lets hear your "TONS" of evidence!!

 

Yeah. Really depends on torque curve. You may actually lose time and power revving too high. Your hp and tq will fall off at some rpm. Try 6500 then 6000 and so on with shift points. I probably would push a 2v or 3v 4.6 past 6500-7000. Shifting at red line is not always the answer to faster times.

 

i dont know what his gear ratio is .. he drags it more than anything .. mite be pretty low ..

 

Mine is 3.73s?! What does he have? 5.11s?

 

2005 Mustang Engine Horsepower & Torque

• 4.0L V6 = 210 hp @ 5250 RPM & 240 lb-ft @ 3500 RPM
• 4.6L SOHC V-8 = 300 hp @ 5750 RPM & 320 lb-ft @ 4500 RPM

So where are you going at 6500+??

 

Do you want to start with a dyno sheet or time slips?

 

well .. it was a fuzzy video ... it may have been only 7000 rpm .. i`ll look at it again next week ..

 

 

You don't really believe that you shouldn't shift past your peak horsepower do you?

you know that what matters most is the rpm range you fall back into the next gear right?
go to the track and shift at 5750 and tell me how that works out.
here is a hint: torque range, you're supposed to fall back into not UNDER it.
track tested, fdjizm approved.

 

Lots of variables to consider. First thing should be a dyno run to see peak power. I have to shift mine out of 3rd early to get all of 4th or run out of track. But my torque curve is a straight line so no worries about peak.

 

Look and see if you can see why it makes sense to shift up high...
short shift and you are landing below the torque range, lugging (or not getting the best) out of the engine on the next gear.
I went from 12.90x's to 12.72x's shifting at 6500 instead of 6100.

 

The OP asked about a stock 4.6 max shifting point, call it 7K for augment sake. You can rev to 7K, but your losing time to guy next to you.

2 equal cars, equal drivers, equal track, the guy shifting at max HP is going to win over the guy shifting at 1K over. Show me all your dyno charts your slips etc, it just won't happen.

As far as falling into torque range, thats what gears are for so you don't have to over rev your engine. Build a motor, dyno it, gear it, simple.

The only time you need to over rev an engine is to defend a position on a road or oval course, or if your not geared right for an 1/8 or 1/4 mile & you don't want to shift for a short distance to finish.

 

My real life testing at the track proves otherwise, at least on my car.
Like I said above.