If you want the faster quarter mile times possible turbo or otherwise... You want to gear the car to where your crossing the line at around peak HP in your final gear (usually 1:1)
In theory yes, but in practice you have to think about how the car accelerates while going down the track, not just the rpm as it crosses the line at the top end. If you can get the car to work better launching and accelerating, you may have a lower ET crossing the finish line at a more moderate rpm.
Theres no magical thing going on causing a turbo car to pull harder with higher ratio gears, what happens with you put higher gears in a N/A car, it slows down, same with the turbo, its just power.... what you are affecting is the spool characteristics and can make the boost more usable.
No, there really isn't magic. There are very significant differences in terms of:
a) How a turbo car makes power vs. an NA car or a supercharged car.
b) The torque and HP curve of a high hp turbo car looks very different
If you are scientific in how you tune, and set a car up based on that knowledge, these points become obvious. You can dyno a turbo car and observe the torque and hp curves. Granted all cars are different, but even on high hp turbo cars you will see a broader and flatter torque/hp curve then a high revving NA car. You then need to study data logs from actual passes, and observe real track behavior. Dynos aren't a true simulation of launching and accelerating down a track.
This reality combined with a car only building boost under load, makes a turbo car much better suited for less number of forward gears (for example, the use of PG's on many fast cars) and shallow gears that allow the car to stay in gear and loaded. If you view a datalog of a 3 speed car with steep gears, and vs a 2 speed car with shallow gears you will likely find that the latter is in the area of the power curve with the most power, and is making max boost for more time during the run then one with more shifts and steeper gears.
An NA car is NOT the same, it is exactly the opposite. Narrow peak power area under the curve, and a lot of value in steep gears, and stick transmission that hold the car in the narrow area of peak power.
On a street car, with limited traction on street tires, the higher gears are the ticket, better driving manners and just overall works good and can still bust off awesome times at the track.
If a pure drag car that gets awesome traction and assuming you dont have spool to worry about off the line, gear it as low as you can without running out of gear with your setup and RPM. that will net you the fastest times.
to the OP with mid 400s HP, id say 3.27s or 3.55s if its a street car. Just drive the car with the 3.73s and see how it feels, if its hooks up alright and works for your car, run that for a while. Dont just jump on the turbo high ratio gear bandwagon just because every other guy with a turbo runs em. Set your car up with what it likes.
The purpose of asking questions on a board like this is to listen to people who have done this already. I thought I had some higher knowledge on a number of things and that is why I have now changed gears twice, turbo once, and built a motor over. Now, because I really don't want to listen, I have the 4th alternator I have purchased sitting in the garage waiting to go on and a couple of amusing overspun paperweights.
My next act of stupidity is going to be spending $6k on a powerglide setup after I defiantly told everyone that I wanted to put a C4 in the car for perceived driveability reasons...
PS: 3.31 is a good alternative too, and there are a lot of these floating around now from 05+ cars.
1989 Saleen 89-425 all original + Baer 6P Brakes
1990 Saleen 90-137 heavily modded
1989 Shadow Blue Metallic Hatchback LX
-- 94mm T4 True Street Trim
Baer, Haltech, UPR, National Parts Depot, Meziere, Weldon, BBRC