I know and I agree with you. Doesn't mean a shorter 3.5" exhaust wouldnt free up pretty good power on my set up. Hell, Tim gained 16 ponies opening the cut out on his 3.5. What's that tell you about my 3"?

 

that you should have went with bigger tubing...

 

Couldn't you wire the electric cutout to a Hobbs switch to get the same effect? Get one that ranges from 7-21psi and you can adjust it to desired psi opening

 

Sort of, but the electric ones are much slower and you dont want to keep the motor on once its fully open or closed.

 

You could still use the switch. Wire the Hobbs through the neg wire. Keep the switch off to run without it. Then flip the switch and when the hobbs reaches the desired psi it will connect the neg wires and open the cutout. At least that's my understanding of it.
And to the op. Great work modding the sp cutout to work on your truck.

 

Again, I think the bigger problem is that the electric cut outs don't open all that fast. These boost activated cut outs open very quickly.

 

You are right, it opens extremly fast. I think the electric ones take a couple seconds to fully open. This is a video Sound Performance made when they started making them. I really wish i was still driving my truck, I had completely forgot about a video. Maybe I will have to take it out one last time.

SP boost activated exhaust cutout - YouTube

 

holy **** i didnt realize these were so expensive! cool none the less. i will have to wait until one pops up used somewhere. i want one.

 

I have SP 3" cutout with boost activated gate and it works great.

The good thing is at low boost it's closed, so, there is good back pressure. Mine opens at 9psi. I can hear loud sound at 9psi.

SP web site says it starts to open at 5psi and will be fully open at 17psi.

While on the dyno after it was newly installed, it did not open. So, I foreced it open to do the dyno run and there was huge difference between the two dyno runs. Gained a lot but can remember exactly as it was couple of months back. But one thing for sure, boost jumped from 15 to 20 psi with same WG setting. So, had to adjust my boost controller down to 15psi after the SP cutout install.

 

ATP Turbo makes one with V-bands on it already. But I think it is only 3"