Ok what are you guys shifting at with a 4.6L and a tune? One pass at the track was 104mph, VS all the rest were around 102mph...so I did something different. Whatever it was, it happened before the 1/8 mile, because that was 1.5mph higher. I was shifting around 6,000rpm. Thanks.
Dave is correct6. It's been a while but I was running 138mph in my 4.6 about a decade ago. Built motor, stage 3 heads and 15 lbs of boost put me at 643rwhp. I was running a 6 speed Tremec and 3.73 gears. An old video, before the final stage of my build. I was running about 11-12 lbs of boost here. Can't see the tach but it appears to be about 6000-6500 shift points.
So wind it out a little more? Valvetrain and everything good for it? Your car is one of the more impressive on here for the mods so I figured you'd know
I remember the new 5.0 motors being wound out to 7000-7500 and I thought that was insane. The 4.6 won't handle that. But as Dave said, it's all in your tune and where your power band is. What tune are you running? What has your tuner told you about your best RPM for shifting?
What was your et on the slower mph pass? I shift mine between 6200 and 6400. That's about as tight as I can consistently shift. You're still running 3.55's right? It's going to be much more sensitive to shift points. Also how long between runs? I'm sure you're aware of what atmospheric changes can do. At my home track, my first run is usually 125. Usually before sunset. As it cools down I'll pick up several mph.
Thanks. I have the rev limiter set at 6500 so I try to shift just before I hit it. Peak HP is at 6100rpm. You could also wind yours out to 6400rpm and you'd still be in 3rd when you hit the 1/4 mile trap. That's how you'll get the best mph. As @MrBhp correctly stated, you'll get the best ET/mph in cooler air and at the lowest elevation. A high barometer reading with cool dry air i.e. lowest DA is your friend. Also run with as little weight as you can and don't let the engine become heat soaked before you start.
