Just wanted to see how much of a difference in power having the cut out open vs closed.

2003 evo 8
117,000 + miles
FP Red 80mm(3 years old and just under 40k on it)
GSC 280
QTP 3" Side dump,
o2 dump
Exhaust 3" downpipe > Qtp 3" cut out > stock cat back and muffler.
Boost 27psi
fuel 93oct
+ a few more misc mods..

Power is a little down(approx 20-30whp) due to a Exedy twin with about 70k on it, non aggressive tune + possible boost leak(haven't checked in a few months)..none the less, still feels great.

Noise difference is night and day with the QTP cut out closed. Now when it's showtime it gets real loud real quick.



Pic of cutout to stock catback:
Pic of QTP controller:

 

Interesting!

 

wow really? nothing else was changed between pulls? hmmmmm

 

Why is the boost higher on the open run then closed. Looks like your up about 3psi on the dump open run....

 

Nothing but pushing a button to open the side exhaust.

I guess due to the exhaust restriction ...boost was not manually dialed down. Remember this is 3" to stock cat back with resonator and muffler.

 

Same tune? Or did you get it tuned w/ it open also

 

Tune is with it open

 

thats about what i would expect.. thanks for posting

 

I wonder how would this compare to a 3" exhaust instead of the stock cbe.

 

Probably a good 10-15whp more and be crazy loud

 

I have a cutout and a 3 inch exhaust. It will damn near rattle the doors open.

 

On your Audi? ...noticeable difference with it open ?

 

I would much rather use an external dump and a quiet exhaust and acheive the same results. Any improvement in exhaust flow whether a cut out a huge diameter exhaust or an o2 dump will yeild the same results.

 

I dont know of any exhausts that are quiet as the stock one and flow as good as a 3" system.

The cut out is a good sleeper setup, im thinking about going that route cause im always getting pulled over for exhaust stuff

 

me too, stock cat back with 02 dump and cut out is a very good sleeper mod. If i was to start over again i would prob go this route. Getting pulled over for muffler stuff is getting old...(im on my 4th exahaust/muffler set up).
Nice results OP