[acecycleins]

It's kind of hard to increase one without increasing the other.

"Tuning for torque" is sort of misleading because in that case you are not increasing the torque as much as you are just widening the rpm range of the usable torque. You get less peak torque when you widen the torque band and lower the peak HP. However the motor feels stronger because the torque is more available.

So to answer your question, "Does adding a turbo increase the hp or the torque?" Yes.

None of these rules are absolute. you can always find exceptions so they are just general rules of thumb.

BTW there are no good engineers here. If you are looking for a good engineer I hear there is one on the CW forums who knows everything.

Compression plays a role. High Compression motors will turn better over-all hp numbers but you may have peaks and valleys in the torque curve because the motors are alrady tuned for hp. If you have lower compression you will usually run lower boost but in doing so you will have a flatter, fatter torque curve or line as it were.

 

[acecycleins]

Not that I am a turbo expert, but you can't run much boost with a high-compression engine without burning holes in the pistons. The first step for running high-boost turbo applications is a cylinder spacer to lower compression and then usually C-16 gas to control detination. If you are pinging on boost, you will have a motor meltdown sooner, rather than later. Low boost and mild cam timing, and high rpm's is what makes a turbo go. Like I said, I am not an expert, but high-compression and high boost = BAD!

I'm not talking insane compression, here. More like the type you get out of your standard superstock 1000cc-1400cc bike. You can run an easy 8-10ftlbs of boost out of a stock Busa motor and get hp figures in the 240 area pretty easy without burning up to motor. But in a V-Twin application, running 7-9ftlbs of boost will trigger a torque curve that should stay above 100ftlbs from about 2500rpm (or so) to 6000rpm, usually peaking in the 130 range in or around the 4500rpm range.
I've seen v-twins running flat-top weisco pistions with 8.5to1 and get solid 150hp ranges all day and night. I know a Busa owner that does his own mapping with a stock motor hit the 260 range. He's never dropped a piston and as far as I know only runs premium 93 octane pump gas. I'm not expert, either, but If you run FI motors and have a laptop you may be in pretty good shape if you know fuelling. I don't. I'm just giving my take from what I've experienced. Personally, I'd go blower. Much more consistant air pressure in application.