Im fabing up a dp and midpipe, and was wondering if running open dp via a electronic cutout would be worth installing. The exhaust im currently running is a RB turboback, but i got a differnt turbo, so i have to make a new dp. Would running open dp make a differnce in spool times and power? or is it not worth the extra time and money?

 

I was contemplating that also, but I was worried about the 2ft long flames my car throughs between shifts. I decided it wasn't worth melting **** and possibly igniting fuel vapors if my check valve on the tank decided to purge. If anyone else has a different opinion regarding this, I'd be thrilled and install a new catback and a cutout, Corksports catback sucks *** on a street car..

 

I tried the electric flap thing on my 87 T2 about 2 years ago. I was running a complete racing beat turboII exhaust system and got my hands on the electric cutout. I tried two variations of an open and closable system on an extra dp I had. The results I got were definitley not worth me using it.
I will explain why.
First the obvious, when it opens its freeking loud. I live in Los Angeles so I wouldn't have many oportunities to use it, if I did it would probably be at the wrong time and win me a ticket from a near enough cop.
Second, I tried opening it at different rpm's and whenever I opened it I lost power for a second do to sudden drops in back pressure then it spooled right back up. It feels tp have more power, but I haven't done it on a dyno to prove it, but throttle response lags a bit do to not having the proper back pressure. Even 1,000hp 4 cyl drag cars have the exhaust tuned for proper back pressure, no one just "runs open exhaust" it needs to be tuned to be effective.
I also tried opening it when I hit the clutch between shifts, that seemed to work best but still is not very impressive.
Third I don't care for it because of the already stated fire hazard, turbos run much richer than n/a's and pass alot more unburnt fuel into the exhaust which is ready to be ignited at anytime. I personally don't want it to happen when I'm on the road but thats just me. I'm perfectly happy with my fire coming out the back.
In my opinion it's not worth the time and the power gain is nothing to get excited about. It's cool to have and nothing else. What I did to the exhauxt that's on my car now is I cut a hole in the pipe coming out of the pre-silencer just before the flange that connects to the Y-pipe.
Then over that hole I fit a piece of 2 1/4 inch pipe around it and welded it all around. The pipe runs out to the passenger side of the car and exits in front of the rear passenger side tire. I put an exhaust flange on the end of the pipe and had a local shop cut me a 1/2 inch thick piece of mild steel to fit it perfectly so I can keep it bolted on as a cover and unbolt it when I go to the race track. The only reason I went with this setup is because when I'm at the track I turn up the boost just a little and I don't want to damage my dual main silencers hanging out in the back. I figure it will allow a little less heat to go to them.

 

Why can't I edit my above post? The edit button is missing..

 

The edit option times out.

BTW - good post - useful information - thanks..