Dyno runs with cutout valves open and closed (video)

[tlr]

The car is stock except for the cutouts, so I took it to the dyno to get a baseline, and check to make sure the cutouts don't cause any loss of power. I'm pretty happy with the results: 338 hp, 242 ft-lbs.

Here's the video:

[Stronghammer]

Where on your exhaust are the cutouts located ?

[datbimmerdoe]

sounds badass!

[SilverII]

nice

[Definitive]

Interesting. I have the same mod on my M3. What was your before HP? What kind of Dyno?

Love the soud, I just had someone in a e36 M3 lightweight follow me to home depot to ask me what exhaust I have and how he thought I was a ferrari when he heard my car.

D

[CPWINCH]

Originally Posted by Definitive

Interesting. I have the same mod on my M3. What was your before HP? What kind of Dyno?

Love the soud, I just had someone in a e36 M3 lightweight follow me to home depot to ask me what exhaust I have and how he thought I was a ferrari when he heard my car.


D

Where did you get this done and how much was it total. I want to run one right after my downpipe

[Definitive]

The shop that did the welding is now gone. I did the wiring myself. But any good exhaust shop can do this. For me it was about $800 total; including the dual cutout kit.

Not sure how it would sound on a 335 though..

D

[THE TECH]

Originally Posted by rhird

Where on your exhaust are the cutouts located ?

+1

[Definitive]

You can see where they are located on my car HERE.

D

[THE TECH]

Originally Posted by Definitive

You can see where they are located on my car HERE.

D

Ok. So yours are for sound only then.

Still wondering where the OP's are.

[Definitive]

Guessing by his gain of 1hp before and after, I would say his are in the same location. There is nowhere else upstream to put these cutouts.

D

[THE TECH]

Originally Posted by Definitive

Guessing by his gain of 1hp before and after, I would say his are in the same location. There is nowhere else upstream to put these cutouts.

D

I'm sure you're right.

[Stronghammer]

Originally Posted by CPWINCH

Where did you get this done and how much was it total. I want to run one right after my downpipe

I am also considering this. Started a thread in the exhaust section http://www.m3post.com/forums/showthread.php?t=632601 didn't get many responses. What I really want to know is if anyone has any experience with cut outs more proximal in the exhaust system.

[Definitive]

You mean closer to the engine? As you can see here, there is no where to put them any further forward than where I installed them. they would have to be under the car and I know with my 3" of clearance I would just be driving on them. Im assuming even a stock M3 could never have them hanging under the car...

[Stronghammer]

Yes closer to the engine. The shop that installed my Innotech axle back exhaust has offered to build me an X pipe. As part of this process he brought up the idea of having cut outs built in just a few feet from the headers. I know it would be insanely loud but what really worries me is having very hot exhaust come out in this location. I had not really thought about clearance issues.

[Rocksie200]

very nice!

[SchnellM3]

Sounds Bitching

[frenchM3dreamer]

FWIW, i had one on my V6 right after the Y-pipe (where our 3rd cat would be), so fairly close to the engine. dyno showed +5whp with the cutout open (same day, run 1 vs run 2)
it was a cheap one (paid $120) and the valve was leaking at high rpms when letting off the gas, giving it a nasty high-pitch noise, so i took it off...
anyhoo, it was INSANELY loud... i couldnt stand it for more than 10 minutes on the highway... and in town i was too scared of the cops pulling me over for excessive noise, so overall i barely used it !!
they do sound a lot better on V8's too

[Definitive]

Yea, for sure. I had a guy in a Dakar e36 M3 lightweight follow me into a parking lot to tell me that when we were getting off the freeway he was looking around for a ferrari trying to figure out where it was, and then he saw it was me and had to follow me to tell me. His is exact words were, "I have to say that you M3 is the most F$%^ing Bad A$$ sounding M3 I have ever heard."

And then when I pull into my garage at night when my family is sleeping, I go back to stock and dont wake anyone up.

LOVE IT!

[tlr]

Mine are in the same location as Definitive's.

I didn't dyno before installation so I don't have any comparison.

They're the Race Ready ones. Installed by Alekshop.

I'm thinking about trying to wire them up to the engine speed (open at high RPMs, etc). I've got the electronics/programming knowledge to do it, I just don't know if they'll open/close fast enough for the effect to be any good.

Or maybe just setting it up to open when the M button is pressed

[tlr]

Originally Posted by Definitive

Interesting. I have the same mod on my M3. What was your before HP? What kind of Dyno?

Love the soud, I just had someone in a e36 M3 lightweight follow me to home depot to ask me what exhaust I have and how he thought I was a ferrari when he heard my car.

D

Nice, that's like 17HP more than me. Is it stock or are there other mods?

[Definitive]

100% stock. I have one of the few high HP stock M3s. I think I'm the 3 highest HP for stock car with 91oct on Pencil Geeks Dyno Chart. My dad will almost every Dinan bolt on and tune including Dinan full race exhaust, he only dyno'd at like 387, same dyno same day. A bit confusing but maybe he started out way low, like 320's to start...

As far as the custom wiring for engine speed, the valves take about 5 seconds to fully open or close, at lease mine do. So having them pop open when you floor the car wont work. The issue with the M button concept is also that its not just open or closed, so you would have to have a timer run for about 5 seconds when you press the button. But they close/open faster and slower sometimes, so it could cause burnout on the valve.

D