Which plate should I install in my Borla for best power delivery for autocrossing.

I bought this car last year, the guy gave me all three plate. He was running it wide open, and I've noticed the low end torque at wot isn't as strong as I would expect it to be, plus there's a rush of power at about 3K or so.

I'm assuming adding a tuning plate will increase back pressure and therefore torque (?). Question is, which one? Thanks.

 

What is the rest of the setup?

I'll give mine.

LT1. ESP engine build. Hooker short tube headers. Gutted cat. Borla.

I noticed a SIZEABLE increase in torque when I went from wide open to the plate that has a small (1" 'ish hole). I never tried he completely closed plate.

But my guess? The closed plate would have been best. If I still had the cat converter I'm guessing the small hole would have been best.

Borla mufflers are not that restrictive so even in blocked off form your gonna still have power.

Also my butt-o-meter is pretty numbs. So I'm calling the torque gain from going to the more restrictive plate signifigant.

I've got a new custom exhuast I'm working on, and I'm going with the same kinda plate system as a Borla. Should be about 40lbs lighter.

 

The car is completely stock, plus I'll be putting the stock intake back on for events only. What you said is what I suspected concernignthe torque/plate relationship.