More load on engine leads to more boost?

Today I ran the race car for the first time since last season and the car felt like it had about 100 hp more than before, and that might be underselling it a little. I have the same tune as I ran at Nationals last year however, I made a couple of changes to the engine. I eliminated a 90 degree bend between the air filter and turbo, and eliminated a 90 degree turn in the exhaust after the turbo. I would expect a tiny bump in power from these two changes but the thing that I wonder about is the change from 4.10 gears to 3.70 gears. Could it be that the new gears put the engine under greater load and this allows more boost and more power? I have never driven the car with this tune in anything but 1st and 2nd gear and it always felt fast but now it feels FFFFAAAASSSTTT!!!! What say you?

I'm betting it's the gear change. A little background here, my grandfather had a 76 Oldsmobile Cutlass Supreme Brougham coupe that had a OIds Rocket 455 4BBL with 3.55's in it. Although it had all the emissions bullE36 M3 on it it still moved pretty good for a 4094 pound car. Less hp at 190 but torque was at 350. Now if it had 3.73's it would've been faster for sure but with the 3.55's and the Turbo 400 we could cruise at 85 MPH and not be straining the engine at all. Just imagine if we had an 700-R4 in there. 

I agree with the Bill above. Your gear change is letting you to load up the engine in lower gears. You will ultimately be limited to whatever your wastegate is set to but if your 410’s meant you were not getting enough load on the engine to reach peak boost then effectively lengthening each gear may let you get more boost in a specific gear.

I’ve heard from drag racers that blower cars were like this as well. Sometimes going with a lower gear would let the blower load up and the car would run faster.

I'd also say the gears did it, more load on the engine will cause the turbo to spool sooner in each gear. i imagine there is probably a sweet spot on turbo cars of what gears get you the best spool time and still good acceleration.

Verifying an actual boost change is simple enough and of course the first step, both to verifying your theory and to not blowing up. Anything that decreases backpressure behind the turbine will lead to faster spool and a higher boost level with all else remaining equal. Decrease in restriction in the inlet path will do the same thing to a MUCH smaller degree. Generally a good boost control system would catch these things but if your turbo is small enough to suffer boost spikes you could end up with WAY more boost than intended for a second or two, and if your car is fast enough that first or second gear only take 1-2 seconds to get through from boost threshold rpm to redline, well guess what you now have WAY more boost for your entire 1st and 2nd gears. 

The whole load=power thing is dubious to me. I'd have to have pretty much every other variable nailed down to even think about attributing a power gain at the same boost level to a 'load' change based on gearing. In general i think it's a myth that can always be explained by looking at boost, rpm, and time.  

One of my cars has the wastegate disconnected. The motor flows so well now that  max boost I can reach under most conditions is 15 psi. Under heavy load I can see 18 psi