Since I'm a grumpy old man now I decided to pull the Hks Hi power exhaust and swap back to the stock catback. I have to say its fantastic driving to work and being able to have the radio on 10 instead of 40 .

Was kinda bored so just figured I'd show a comparison in case someone else maybe wanted to swap back to stock and see what kinda losses they could expect. This is a mild tune on 93 octane.

The butt dyno showed about a 15-20 hp loss on the top end, the spoolup seemed about the same, so I decided to do a couple VD runs and see the difference.

Red is HKS Hipower and the other is the stock IX catback. Both with the buschur 3" downpipe and megan resonated test pipe. Both on the same exact tune.


The VD seems to confirm what I felt, I was actually fairly surprised at the lack of power loss, though this could be due to slightly varying outside temps (it's probably 5-10 degrees cooler now on the stock catback). The boost dropped 1-2lbs for the most part but not getting any knock so far.

I'm also going to run it on E85 and see the difference while running some high boost and I'll post those results as well.

UPDATE:
Here is the E85 tune with the comparison, can definitly see the stock catback struggling at higher rpms, what is still kinda weird is the lack of loss down low again. I also used a 15 degree temp correction on these as well which is probably more than what the temp variation really was. Again this is on the same tune.


I'll also be adding a mufflered electric cutouted test pipe for when I feel like being juvenile

 

Surprising, I remember seeing more gain from a catback at these power levels. I really suspect the outside temp/humidity because: from 4500 to 5500 rpm for example, you have more boost, a 3" CBE and torque is the same than less boost and stock CBE. This isn't really possible IMO.

 

I thought it a little odd as well, but it also didn't feel like it lost any bottom end, felt like it lost a bit uptop which is kinda what the dyno shows.
But your right with a couple lbs less boost I would think that certainly I would lose some torque.

 

wow very surprising. I just switched from the Buschur to the HKS for a quieter sound.

 

Buschur Racing 3"? I find it to be quiet, nice rumble, perfect.

 

Too much drone for me.

 

I have a BLITZ Nur Spec cat back and I couldn't drive the car to work because of the drone. So I found a simple solution without losing any power by switching the muffler to a Varex 3" Muffler with electronic actuator.

With the muffler in closed position, it was like I was driving my girls Yaris And with a press of a button, I can boost all I want.

Anyway I thought I would share with those looking for a solution.

 

I like this option as well but was kinda unsure about the quality. I know there have been people that have alot of problems with the regular electric cutouts, I just would hate to have a motor fail and then have to replace the entire muffler, or have to send all of it back for warranty, does the valve assembly unbolt from the muffler?

 

Varex mufflered catback ftw. Had MAP build mine 2 years ago and have no plans of swapping it.