Mixed messages on Test pipes and Rasp

[US///M3]

I want to get some test pipes and keep the secondary cats and the rest of the exhaust OEM but so far I've seen some conflicting info on the matter regarding rasp as a result.
I cant stand a raspy exhaust. So will the exhaust note get raspy or not with the test pipes?

Thanks!

[flipm3]

Technically, I am sure rasp does increase.
Realistically, chances are most won't really detect the increased rasp.

I installed a XPipe with a primary cat delete, but it retained aftermarket secondary cats and resonators. With my OE Muffler, I did not notice any increased rasp during my daily commute.

I installed test pipes on another E92 M3 that has an Eisenmann Race. In-cabin, any potential increase in rasp is fairly minimal and pretty much imperceptible.

My tolerance of rasp may be different than others though since I also have an E46 M3 with catless headers. The E46 M3s are NOTORIOUS for absurd rasp, so my perception of rasp may be skewed.

[W Cole]

It's slightly more raspy. I believe this will occur anytime you remove a resonator/cat? I am very picky but quickly got used to it and it's definitely worth the extra hp.

[spool twice]

it may sound raspy at heavier throttles when the exhaust/muffler is still cold. the raspy essentially quiets to an almost undetectable amount once warmed up.

[gatorfast]

If you can't stand raspy exhausts then you absolutely do not want test pipes with the oem rear. Search for some vids as there are plenty and it will give you an idea of the rasp you would get.

[W///]

Originally Posted by US///M3

I want to get some test pipes and keep the secondary cats and the rest of the exhaust OEM but so far I've seen some conflicting info on the matter regarding rasp as a result.
I cant stand a raspy exhaust. So will the exhaust note get raspy or not with the test pipes?

Thanks!

It completely depends on what muffler you have. I paired it with the ACM mod and wasn't a fan of it (tons of rasp at 3k rpm). Switched to Borla S-type and it was a deep and throaty exhaust, but it just wasn't loud enough for me. Now paired with Eisenmann Race and there's a bit of rasp, but I love it.

So in summary, completely depends on muffler. But with completely stock muffler, you'll be fine.

[s85e90]

Rasp is dependent on resonators and can me eliminated by adding additional resonators if it's (rasp) is introduced once you remove the primaries.

[Dave07997S]

Test pipes with the rest of the exhaust OEM will result in more rasp with the rear oem silencer. Its not that bad but it is there, I ran the OEM rear muffler for awhile with my testpipes and yes there was some rasp but mainly when the exhaust was cold. As it got to operating temp it did diminish a tad.

Dave

[coloradoe92m3]

Xpipe with HFCs and resonators with OEM rear sound refined, high pitched and to me a natural rasp. Sounds close to a CSL only a few tones deeper. If you like CSL sound you will live it. If you hate CSL sound you won't like. To me its a raw engine nouse

[swamp2]

A classic raspy exhaust to me is E46 M3. My test pipes did not increase that particular sound quality.

[Honda]

Sorry for stupid question. What does rasp mean? Is it the sound that exhaust produce when you remove the Cats? If yes, how come I did not notice that when I installed BMS DP on my ex-car 335i.

[US///M3]

Originally Posted by e90-NEBO

Sorry for stupid question. What does rasp mean? Is it the sound that exhaust produce when you remove the Cats? If yes, how come I did not notice that when I installed BMS DP on my ex-car 335i.

It's a metallic, tinny type sound you get at WOT, like something you'd get from a cheap , thin exhaust system.

When I had my 335i I had a slight rasp with the catless downpipes that was gone when i heat wrapped the downpipes.

[dogbone]

I do sound for a living and did a high-quality before/after sound recording when the test pipes were installed. It is more raspy than stock. The recording shows the difference pretty well on the dyno.

Here's the thread where you can find the video:

http://www.m3post.com/forums/showthread.php?t=767814

[swamp2]

Originally Posted by dogbone

I do sound for a living and did a high-quality before/after sound recording when the test pipes were installed. It is more raspy than stock. The recording shows the difference pretty well on the dyno.

Then of course you realize that the play back equipment is just as important as the recording equipment/technique...

[dogbone]

Originally Posted by swamp2

Then of course you realize that the play back equipment is just as important as the recording equipment/technique...

Of course, but what helps here regardless of the playback system is that you have a direct side by side comparison recorded from the same source. So even on a limited playback, you can still compare the tones. That rasp will show itself on pretty much any playback setup. It's a very mid-range frequency sound. And most cheap playback systems tend to emphasize the mid-range. They suffer when trying to replicate quality highs and lows. But that's not what we're listening for in this case.

[US///M3]

Originally Posted by dogbone

I do sound for a living and did a high-quality before/after sound recording when the test pipes were installed. It is more raspy than stock. The recording shows the difference pretty well on the dyno.

Here's the thread where you can find the video:

http://www.m3post.com/forums/showthread.php?t=767814

This is what I mean by rasp, it's not the growl sound but the tinny sound you hear.

[swamp2]

Originally Posted by dogbone

Of course, but what helps here regardless of the playback system is that you have a direct side by side comparison recorded from the same source. So even on a limited playback, you can still compare the tones. That rasp will show itself on pretty much any playback setup. It's a very mid-range frequency sound. And most cheap playback systems tend to emphasize the mid-range. They suffer when trying to replicate quality highs and lows. But that's not what we're listening for in this case.

Agreed, A vs. B on an equivalent recording set up should exhibit the features. However, that being said, I don't really hear an increase in rasp. I hear a different frequency content and volume but not rasp. Rasp to me is this and I seriously doubt this being present or absent could be masked by even a mobile phone recording. Maybe some very small increase/decrease might not get picked up...

[swamp2]

Originally Posted by US///M3

This is what I mean by rasp, it's not the growl sound but the tinny sound you hear.

I agree, its much less intense than in the video I just posted above but it is the same essential rasp.

[tareemaa]

I had the stock exhaust with an acm mod with test pipes and it was extremely raspy, that same mod without test pipe sounded great. But when I switched to Megan almost all rasp was gone.

[Mmmdreamer]

Dunno if it's raspy...it's rippy =) Here's mine recorded with an external mic I put on the rear license plate with my gopro. Test Pipes + Dinan Rear.

https://www.dropbox.com/s/yozqgkl3x5...tto2ndGear.mp4
https://www.dropbox.com/s/4ffskwd09a...dto3rdGear.mp4

[US///M3]

Originally Posted by tareemaa

I had the stock exhaust with an acm mod with test pipes and it was extremely raspy, that same mod without test pipe sounded great. But when I switched to Megan almost all rasp was gone.

Thanks, a few members have said that about their Megan axle back +TP's.

[Sered]

As others have said, it comes down to what muffler/axle-back you're running if its just test pipes and not a full x-pipe.