[Deep_Blue]

I put BMS downpipes on my car a couple weeks ago. Great results and the fittament was spot on. Boost is consistently maxing at about 17psi. My only other performance mod to date is a JB4 G5 (not ISO yet, doing that this weekend, then FMIC next wekend ).

I was expecting the result to still sound like stock, but its anything but. The exhaust note is much deeper/raspier, and when I'm either WOT or halfway on the throttle so that the car is accelerating aggressively i hear a very distinct "hiss". It sounds like a BOV (or a really angry snake). Lasts a bit longer than a BOV purge.

I had my indy look at it today. No loose bolts, no leaking lines. Everything seems to be in order. His best guess was air getting sucked through the DV lines was making the sound. Is this a standard thing for our cars? Anyone else have a similar experience?

[E90Company]

Lmao. Turbo whistle?

[Tony@vargasturbotech]

Sounds exactly like a exhaust leak to me. Have whoever put them on check them for leaks at the gaskets on both ends. A audio clip of the noise would prob help a lot.

[melenkae90]

Originally Posted by E90Company

Lmao. Turbo whistle?

+1 that would be your turbos

[farb]

damn those angry snakes, they always make their ways into our cars somehow

on a more serious note, that would be your turbos spooling.. sounds beautiful IMO

[tofu-]

Originally Posted by melenkae90

+1 that would be your turbos

sounds more like an exhaust leak...

you're not really going to hear the turbos under WOT. exhaust would drown them out

[Tiago@VRSF]

Sounds more like an exhaust leak than the sound of turbo spool. Make sure whoever installed them oriented the pipes correctly, otherwise the torque from the tightening of the rear flanges stretches the v-bands a bit or vice versa.

[Jeff@TopGearSolutions]

Sounds like an exhaust leak for sure. Most common culprit is near the v-band to the turbo. The orientation is important as well as the orientation of the clamp itself. If the clamp is on incorrectly it will hit the wastegate actuator arm (that's a different problem).

However, if the v band clamp is not seated properly it will not have a good seal but still "appear" to be sealed. Best thing to do is remove both v band clamps and re-install. They should go on smoothly and tighten down smoothly. If they give you trouble the downpipe is not seated correct and or the v band is not seated correct.

Also downpipes will not sound like stock anymore. They will have a more aggressive exhaust note and add a bit of rasp.

[Deep_Blue]

Originally Posted by melenkae90

+1 that would be your turbos

Ha! I know what turbos sound like

This noise is in addition to the regular spooling sound

Originally Posted by Jeff@TopGearSolutions

Sounds like an exhaust leak for sure. Most common culprit is near the v-band to the turbo. The orientation is important as well as the orientation of the clamp itself. If the clamp is on incorrectly it will hit the wastegate actuator arm (that's a different problem).

However, if the v band clamp is not seated properly it will not have a good seal but still "appear" to be sealed. Best thing to do is remove both v band clamps and re-install. They should go on smoothly and tighten down smoothly. If they give you trouble the downpipe is not seated correct and or the v band is not seated correct.

Also downpipes will not sound like stock anymore. They will have a more aggressive exhaust note and add a bit of rasp.

Originally Posted by Tiago@VRSF

Sounds more like an exhaust leak than the sound of turbo spool. Make sure whoever installed them oriented the pipes correctly, otherwise the torque from the tightening of the rear flanges stretches the v-bands a bit or vice versa.

I bet this is the issue. I would hope my indy would know this, but mistakes happen. He did say it sounded like it was coming from near the DVs, which are on the other side of the engine bay.

Either way, when I'm installing my FMIC (Tiago is fighting with the customs people to make that happen ) I'll have the car on ramps and will try to get a sound clip if i cant figure out what it is.

[enrita]

Actually have the same sound. Will get it checked for leaks . Sometimes i get as well a lambda code post cat. Can also smell faint exhaust gas near the turbos.

[sutter2k]

While on ramps, check for black soot where the downpipes connect to the exhaust. It could be the V-band, but an easy check would be where the dp's connect to the exhaust.

[MrRager]

you expected your car to sound the same after installing catless downpipes?

[Deep_Blue]

Originally Posted by MrRager

you expected your car to sound the same after installing catless downpipes?

Yeh i read it on here somewhere in a DP review. First DP install for me, doesnt make sense in hindsight