Test Pipes vs Stock Exhaust recording comparison

[dogbone]

I went to EAS for a Macht Schnell test pipe install and decided to record the sounds of the car before and after.

The car has a VF620 kit and the exhaust was completely stock.

I don't like a loud smelly drony car. But I did want to ease the flow of air leaving the s/c'd engine, so I decided to give the Macht Schnell pipes a try. I left the rest of the exhaust system untouched.

I brought some hi-rez microphones (QTC40) to record the sounds of the car before and after the install. I've edited some of the recording takes together into a video. There's a set of sound level meters in the video to show the levels.

There are 4 recordings:
-Dyno Before. Also, the engine idling after.
-Dyno After. Also, the engine idling after.
-Engine start and slow drive away Before install.
-Engine start and slow drive away After install.

Watch the video in fullscreen and highest resolution for best results:

Conclusion: I'm happy with the results.

-Only about 4-5 decibels louder on average, which isn't much at all.
-The tone has changed a bit once you get past 3500 rpm. It's a bit more raw and raspy. I like it. Has a nice aggressiveness to it. This rasp/growl gives a bit of attitude but isn't enough to raise eyebrows. On the freeway, no authority figure will pay you any mind---at least for noise.....
-No smell change to the car.
-There's about a 20 whp and 20 ft-lbs of torque gain in the mid-upper range of 4500-7500 rpm.
-There's ABSOLUTELY no drone in the car whatsoever. At 70 mph, 2800 rpm, inside the car sounds exactly the same as when the exhaust was stock.

Today, I had 100 octane in the car. The highest run peaked at 564 whp after the pipes were installed.

Anyway, I hope these higher resolution recordings help someone else in their decision making process. iPhone recordings can be hard to interpret.

Here's a picture of the highest pre-install dyno run (run34 - 551whp), and two post-install runs (562, 564 whp).

Thanks for a good day Tom, Steve and EAS!

[THE-FN-MAN]

Good stuff man

[Stronghammer]

Good information. Thanks for sharing

[M3PO]

It's interesting how the stock cats give a nice profile and TPs and HFCs don't (mine don't). There are two pretty distinct peaks or jumps that I wish weren't there.

[info@trinityautosport]

thanks for sharing =)

[Orange fever]

thank you for taking the time to do this .....
Next on the list

[dogbone]

Thanks guys. It's definitely a bit different. Still getting used to the new tone. Higher rpm shifts--over 4000 rpm--in S5 have a more pronounced character to them.

I understand what M3PO is saying about the jumps in sound. They come on pretty aggressively when they come on. For sure, having more "stuff" in the way of the air smoothes things out.

My friend listened and compared, and said it sounded like the stock exhaust had a pillow in front of it, and that the test pipe sounded like the pillow had been removed. He liked the test pipe.

Everyone has a different perception. I love that about sound.

[Dodge2Dub]

Thanks! I've been looking for a comparo like this....based on your outcome, I think will be switching back to OEM rear section (already have TTP's).

[tom @ eas]

Very cool, love the in-depth analysis! Glad you're happy with the new setup.

[Mmmdreamer]

Mr. Dog, thanks for taking the time and the HQ recording - that was a perfect comparison and something I've been looking for in my test pipe decision process. The rasp is perfectly captured!

[CarbonFoot]

Nice comparison. I like your low noise, big power approach.

[dogbone]

Originally Posted by Mmmdreamer

Mr. Dog, thanks for taking the time and the HQ recording - that was a perfect comparison and something I've been looking for in my test pipe decision process. The rasp is perfectly captured!

Originally Posted by CarbonFoot

Nice comparison. I like your low noise, big power approach.

Thanks!

Yeah, trying to make a car powerful, but keeping it relatively quiet is not a very common approach. Most people want to announce themselves a block or two away.

Even when the car's exhaust was stock, people in parking lots would ask me what I had going on under the hood because of the blower whine. hehe

[Munit]

That is why I love the test pipes or x-pipe/HFC option. Both essentially give you removal of primary and a 200 cc cat left. Although HFC uses metallic 200cc which significantly has more flow than the OEM ceramic 200cc. Point being the decibals may not apply exactly to a HFC setup/x-pipe which I have but I am guessing very close.

Reason I love this is because it truly is not "loud" It sounds stock in every single way in terms of drone, low rpm drone, loudness at low speeds etc. It truly only gets moderatly louder but more importantly the quality of the sound gets higher pitched, raw and raspy-sounds like a race car without being that much louder.

I think the m3 exhaust system, just like their intake design with 3 routes and a huge cone for the coolest air system ever, is reallllly hard to ever improve on. The system is so darn straight back, piping diameter is perfect, xpipe is great and the rear section despite crossing over in the middle provides extremely good flow with effective design to keep the drone out and the higher pitched sounds in.

So the only flaw which is not bmw's is the primary cats like any car robs power. So changing those, or getting an xpipe/HFC and leaving the OEM rear just makes a lot of sense to me if you want a race car sound that is not intrusive or completely overbearing if you deal with high end clients, resorts, restaurants etc. Anyone that does knows that you stick out like a really trashy person if you have an obnoxious exhaust blaring out of your car when your pulling up to meet two potential business clients at a nice restaurant. This is stealth and why I love it

[anacondatp]

will you have CEL light after installing test pipe? also did you have any tune after test pipe?

thanks,

[dogbone]

Originally Posted by anacondatp

will you have CEL light after installing test pipe? also did you have any tune after test pipe?

thanks,

On a stock setup, yes you will get a CEL. I have a VF kit, and the kit software already had the necessary adjustments in it because they figure most people that get a kit like that are gonna mess with their exhaust.

[DetroitP]

Love the data compare! Thanks for sharing.