[SuperBmw]

So I heard a BMW Performance Exhaust with stock cats and thoguht it sounded pretty damn amazing. Today my buddy brought the car over again with his downpipes added and it sounded REALLY good going upto 4000rpm on the inner streets, it actually sounded pretty exotic.

However as soon as he started redlining the gears it becamse VERY raspy up top and above 6000 rpm it sounded like TOTAL SHIT... a horrrrible metallic sound worse than a civic!!

Everyone on here seems to love this setup to death is everyone else experiencing it too up top? Maybe his Downpipes are brand new and need some carbon buildup or something? THey are AR DP's.... he has his second cats still in place.

[caliguy562]

Would you happen to know if he is running a tune? Different maps will make the exhaust sound morebor less raspy. Completely normal with this setup.

[SuperBmw]

Originally Posted by caliguy562

Would you happen to know if he is running a tune? Different maps will make the exhaust sound morebor less raspy. Completely normal with this setup.

He runs Jb4, and he's FBO + Meth so was probably running an aggressive map.
Would a different map make it sound better?

[caliguy562]

I no longer have a JB4, but I know which the v5 there are exhaust note differences between map 0, 1, and 3. 3 is defintely on the rapsy side, map 1 is the most tame and 0 is somewhere in the middle. Map 1 is almost under the radar compared to map 3. You should have your friend switch maps to compare.

[tscdennab]

It's fixable for about $100, I had the same problem with my BMW Perfomance Exhaust:

http://www.e90post.com/forums/showthread.php?t=506271

If his car is a coupe (which does not have the x-pipe resonator) than he really needs an extra pair of resonators to take out the rasp.

[SuperBmw]

Originally Posted by tscdennab

It's fixable for about $100, I had the same problem with my BMW Perfomance Exhaust:

http://www.e90post.com/forums/showthread.php?t=506271

If his car is a coupe (which does not have the x-pipe resonator) than he really needs an extra pair of resonators to take out the rasp.

I noticed you mentioned that the resonators quieted down the exhaust a lot... the reason I wanted the downpipes was to increase the overall volume.

Is your setup still a lot louder than the PE with stock downpipes? I love the high pitched exotic scream up top too, do you lose some of that with the resonators?

[645Nm]

I did not have a raspy sound with DPs only but do experience diff exhaust sounds on diff maps.

My mid cats have also been removed and the resonators do give a deeper exhaust note low down and a lovely tone at higher rpms. Resonators subdue the overall sound levels reasonably well.

[cwn23]

Originally Posted by SuperBmw

I noticed you mentioned that the resonators quieted down the exhaust a lot... the reason I wanted the downpipes was to increase the overall volume.

Is your setup still a lot louder than the PE with stock downpipes? I love the high pitched exotic scream up top too, do you lose some of that with the resonators?

Resonators basically gets rid of the raspy sound of the exhaust, it doesn't change the tone of the exhaust

[SuperBmw]

Would you guys recommend the downpipes at all then if I don't care for the perofmrance?

I was going to add them to enhance the sound a bit, but if it just makes it more raspy and causes more issues maybe I should just stick with a fully catted PE?

[only1]

Originally Posted by SuperBmw

Would you guys recommend the downpipes at all then if I don't care for the perofmrance?

I was going to add them to enhance the sound a bit, but if it just makes it more raspy and causes more issues maybe I should just stick with a fully catted PE?

If you like you can hear my car in person. I have ar catless dp's mated to two vibrant resonators number 1792, in place of the aftercats so it's fully catless mating up to the bmw pe.

[only1]

Im only mentioning it as you can compare before and after catted dp's as next week i will be putting my stock ones back on with the pe still installed.

[Lotus99]

Originally Posted by SuperBmw

So I heard a BMW Performance Exhaust with stock cats and thoguht it sounded pretty damn amazing. Today my buddy brought the car over again with his downpipes added and it sounded REALLY good going upto 4000rpm on the inner streets, it actually sounded pretty exotic.

However as soon as he started redlining the gears it becamse VERY raspy up top and above 6000 rpm it sounded like TOTAL SHIT... a horrrrible metallic sound worse than a civic!!

Everyone on here seems to love this setup to death is everyone else experiencing it too up top? Maybe his Downpipes are brand new and need some carbon buildup or something? THey are AR DP's....

he has his second cats still in place.

If he still has his secondary cats in place, then why are people above suggesting he can fix it by putting in the resonators? Those who used that "fix" I thought had their secondary cats removed too, and were getting rasp, so they put in resonators where the secondary cats used to be.

[rismo]

Check if the isolation does not touches the downpipes... I have had that after installatio, it gave quite some raspy sound....

[SuperBmw]

Originally Posted by Lotus99

If he still has his secondary cats in place, then why are people above suggesting he can fix it by putting in the resonators? Those who used that "fix" I thought had their secondary cats removed too, and were getting rasp, so they put in resonators where the secondary cats used to be.

Seems like the catless downpipes induce a lot of rasp on the BMW PE setup.

[Lotus99]

Originally Posted by SuperBmw

Seems like the catless downpipes induce a lot of rasp on the BMW PE setup.

Even with the secondary cats still in place? Seems contradictory to what was said above, as I said, because with the 2nd cats, how could you put in resonators too? I thought resonators are installed in lieu of 2nd cats.

[SuperBmw]

Originally Posted by Lotus99

Even with the secondary cats still in place? Seems contradictory to what was said above, as I said, because with the 2nd cats, how could you put in resonators too? I thought resonators are installed in lieu of 2nd cats.

I have heard 2 vehicles in person with the second cats in place and downpipes with the PE... and they were veryyyy veryyyy raspy... actually they could be considered rasp machines haha, I was veryyyyy surprised since they both told me the setups had 0 rasp.

After 5krpm, it sounded like a metallic grinding symphony.

[Lotus99]

LOL!

[tscdennab]

Originally Posted by SuperBmw

I have heard 2 vehicles in person with the second cats in place and downpipes with the PE... and they were veryyyy veryyyy raspy... actually they could be considered rasp machines haha, I was veryyyyy surprised since they both told me the setups had 0 rasp.

After 5krpm, it sounded like a metallic grinding symphony.

It is really surprising, I never had rasp with catless downpipes and secondary cats in place. The only change with catless downpipes is the exhaust loudness, everything stays the same as far as tone. If you look at how fine the ceramic catalytic converter holes are, you will realize that there is no way for rasp to not be muffled by the secondary cats (assuming it did not exist before). Maybe those guys had damaged secondary cats, it is not uncommon when pushing Stage 2 engine tunes on the car with secondary cats in place.

[SuperBmw]

Originally Posted by tscdennab

It is really surprising, I never had rasp with catless downpipes and secondary cats in place. The only change with catless downpipes is the exhaust loudness, everything stays the same as far as tone. If you look at how fine the ceramic catalytic converter holes are, you will realize that there is no way for rasp to not be muffled by the secondary cats (assuming it did not exist before). Maybe those guys had damaged secondary cats, it is not uncommon when pushing Stage 2 engine tunes on the car with secondary cats in place.

Did you hear someone else driving your car or did you hear it from inside the cabin only? The guys I asked also said there was 0 rasp, but they never heard their car from outside... and then when I heard their cars in person I was like WTFFF haha... metallic echos all through the top RPM range.

Maybe the downpipes and exhaust are too new and need carbon buildup to reduce the metallic sound? I highly doubt carbon buildup has to do with rasp though.

[SuperBmw]

As for damaged secondaries, one guy had his setup for only about a month and he doesn't push it much so I doubt he damaged the secondaries.

[RaihaX]

I just got BMW PE + AR DP (while this is a 135i) it is quite raspy but usually this goes away after it warms up, from what I can tell from one day driving it.

Need to do more testing...

[rismo]

Originally Posted by rismo123

Check if the isolation does not touches the downpipes... I have had that after installation, it gave quite some raspy sound....

Did you check your silver isolation stuff around the DP's?
I drove around for a month with raspy sound after finding isolation touching the DP's.....