Any sense behind using cutouts?

George_R

Member
Running double 2" into single 2.5" exhaust which is way too silent to my taste, with a good note however. I'd like to be able to make it sound louder from time to time, while maybe gaining a bit of extra power. Currently looking for options to install electric operated cutouts, but uncertain of two things:

1 Is it better to run 2 cutouts, one for each cylinder bank, or just one located downstream after Y-pipe? Power and sound wise?
2 Are there any commonly known low pressure places or a rule of thumb to locate one? I'd like to place the extra exhaust outlet somewhere closer to rear wheel arcs, but have no idea if the gas would be evacuated by ram air or forced into the cabin

Any thought is much appreciated
 

George_R

Member
As there've been no thoughts on the topic, tried that for curiousity.

My previous setup was a small hot-dog muffler on each side, Y-pipe, resonator and muffler on the tail. Tried cutting the resonator and tail muffler (everything down the Y-pipe) , as if I fitted a cut-out there. To my surprise, the sound was rich with middle frequencies (around 1kHz I suppose), no harsh highs, no rasp, very clean note. Too damn loud of course. Tried to record it but the mic clipped badly upon every attempt. Very interestingly, there haven't been too much bass, I even suppose no bass at all.

Overall, that experiment confirmed that a cut-out can be installed downstream after Y-pipe and the sound obtained would be definitely cleaner and more pleasant to hear than that of open headers.


Ended up with discarding the resonator, leaving only the tail dissipative-type muffler. No drone, comfortable at highway but nt as much rumble as I expected.
 

361UZ

Member
Hi George.
I was kinda hoping there would be some responses from those that have tried this?
Maybe no one has.There may be legal issues in some countries.
I was (am?) planning a similar idea on my Chev. I am using a 1UZ from a Crown, which has the exhaust cut out connection on the ECU, so why not?
I would have one output very quiet and used for quiet cruising, and the "loud" output right at the limit of legal loudness - used for rapping it out in steep canyons and tunnels;)
 

George_R

Member
4U2QUIK thanks for the response! Can you point me at some sound/video examples that sound well up to your personal preferrences?

361UZ I'd hope so, too. As stated above, I decided not to use any cutouts for simplicity. I run 2x63mm into 1x63mm behind transmission, and a single round 180mm x 400mm straight through muffler with a resonance chamber. It's barely audible when warmed engine idles, and it's still too silent in the cabin at WOT. The other thing I don't like about it is that sound is too smooth and it has higher pitch than twin exhaust at the same RPM.

Outside WOT sound is however raspy enough at low to mid rpm, and it's terribly loud. Due to the lack of a resonator and 4.1 diff ratio it's a tad droney at highway. Unfortunately I can't run a twin exhaust due to safety reasons (it's not legal here to run exhaust pipe on the same side of car with fuel lid). Maybe I'll try a small H-pipe just before the transmission to see if it's of any help when Y-pipe is installed later downstream

I have some experience with 4-bangers, where installing a small h-pipe before y-pipe helped reduce unwanted hiss and scratchy sounds due to less than optimal factory exhaust design, and additionally it helped obtain subaru-like rumble sound at low to mid rpm and WOT
 

Zuffen

Super Moderator
Staff member
I run dual 3" (75mm) with H pipe.

Have 3"offset mufflers and resonators.

Set up was originally for my supercharged engine and it is now almost silent at idle and a nice bass when driving it hard (that's most of the time).

It probably costs me some torque but I'm too idle to make a new exhaust.
 

George_R

Member
Wow, dual 3" sounds like way too much....mine works well with a single 2.5"
The car on the video above runs something like dual 2" and it feels enough for non-modified engine... no problems with the bass either

p/s the thread was started with cut-out discussion. Having listened to a number of configurations , I would only use dual cut-outs and dual system with H-pipe or no crossing at all.
 

qukae

New Member
I think H pipe is best choice for retro car, cause it's sound raw and brutal :) while Y or X more like gentle smooth tone, it make no sense of v8 for me :/
 
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