keny

Hi, guys. Been looking around the forum but haven?t found anything that is actually like what im facing now.

I first embarked on my quest for more power by attacking my exhaust. I first changed the rear muffler to a Remus item (Single Muffler, Twin pipes). The sound was much better than standard but I thought that I?d ?man: it up a little more.

I then changed the stock headers to Hiop (without Cats) and then I hit a snag. The exhaust then took on an irritating rasp when the rpm was in the 2200 to 2500 rpm region. Thinking it was the resonator, I duly removed it.

Now, the rasp has lowered itself to the 1600 ? 2000 rpm region, and further up the rev range, there is a mixture of the typical Remus tone and rasping.

Seen some of the post that an X pipe might be able to solve this but has anybody here actually done a workable solution?

I don?t mind the bassy sounds but the rasp is driving me up the wall.

I drive a 2004 530i here in sunny Singapore.

Thanks in advance.

BlueMajik

Apa Kabar

Check out MacFly on the forum, he has a Remus Exhaust he just put on last weekend and it sounds great. He has a 08 535xi. I am considering getting one too. I hope all is well in Singapore. My wife and I will be there at the end of the year. We have relatives there.

keny

Hi,

I know the remus sounds great, thats why i chose it instead of Supersprint which is the preffered setup here. Actually was looking for somebody with a manifold change and De cats. This actually flows alot better than standard thats why it causes the raspy sounds that im experiencing now. Guy at exhaust shop says no cure for this.

The 535's flow would be different from mine as you know, a turbo chaged car exhaust pulses would be smoothened out by the turbo and usually turbo cars are generally softer than NA cars.

Drop me a line when you're here.

Actually, Apa Kabar is a malay greeting, but anyways, i understand it too.

info@trinityautosport

welcome. the only members that i know have that changed their headers have used the rdsport set-up. im sure others will chime in here as well but also check out the parts and mods section to see the setups that members have. some of them have videos and sound clips. enjoy the forums.

keny

Thanks for welcome. Will check out those rdsport setups you mentioned.

Never heard of this being used here in Singapore. If its that good, mabye the first in Singapore? hahaha

Will need to see that actual setup and then probably decide.

I actual design exhaust systems for ships, power stations and heavy machinery for a living but cant seem to figure out this simple problem.

keny

Had a look at the RD site and, my question really would be, if i were to just change the rear remus muffler to a RDSPORTS unit, would it stop the rasp?

I think now the only way would be to lower the velocity of the exhaust gas by adding cats and changing the harmonics present in the gas to "smoothen" the flow so as not to make it rasp that much or even at all.

Adding cats is a little difficult as there isnt any space after the manifold. Anyway along the exhaustine looks pretty daunting due to the space constraints. I had my manifold set custom made in Germany as the units normally supplied are for left hand drive cars. The car we have here in singapore are right hand drive therefore the steering column is on the right (aka next to the manifold). The set i have installed looks like a really "crushed" up version of what RDSPORT has on their site.
From just looking at the RDSPORT mufflers, i guess that they are also absorbtive units (aka, they basically have a perforated pipe from the inlet and split internally into 2 seperate outlets packed with usually a sound absorber ( normally metal wool mixed with some acoustically absorbant material) to tune (lower velocity of exhaust gas) the sound. Most sport mufflers work on this principle of tuning. Actually a Remus muffler is very similar to what i have described. I have actually opened one up to have a look.

If this is the case then i think the only way would be to install an X pipe or find some way to add a cat into the system.

Anybody here care to comment?