Exhaust

is200 Newbie · December 1, 2014

I have lived with a stainless steel exhaust now (cat back) for just over a year.

I had hoped it would have become quieter during use over time from the first install. It has but not to the point I was expecting. The only reason for replacing the original one was that it failed and the stainless one was over £2300 cheaper than replacing with an OEM one.

I know the stainless exhausts are a bit noisier than original ones just by the material that's used on them. With it being a cat back, it consists of the two back boxes and a centre box - pipe connects to the original exhaust just before the two cats.

I would like the quietness back that the original one gave ... I can live with the noise up to a point. There is a "drone" (best way of describing the noise) at 2000 revs, in cruise at 70 mph (between 65 and 75 to be exact) This doesn't really bother me as when I am in the car I can turn the music up to the point where it cancels out the drone but with others in the car and the music low its quite annoying.

I am considering what to do - to replace the exhaust or just the centre box or back boxes but I am unsure of where the noise originates from (centre box or back boxes?) if replacing one or the other halves the noise then that will do but I am just not sure what part the noise comes from?

Is the centre box also called the resonator?

Any help?

PilgrimIS · December 14, 2014

Hey,

Weirdly enough...I have the exact same issue! I had a PowerFlow catback installed a few weeks ago and around 2k rpm it's horrendous. To the point where it seems to be louder IN the car than OUT!

I too it to a local performance specialist and he said it could be down the the rear boxes being far smaller than the originals so the empty space left by the very large originals can create vibration and the louder drone inside at certain revs. Not good!

I am contemplating taking it back to the PowerFlow garage as I have also seen they have made a crappy bend in one of the pipes!

IS200D · December 14, 2014

I haven't got any answers unfortunately, but I know exactly what you mean. I've had Longlife stainless installed on 1 car and 2 vans where I asked for as quiet as possible and on each occasion I was disappointed. Its not too bad in my vito, but its definitely not as quiet as when I first bought it.

Really hope you find a solution, as my experience has made me think twice about stainless in spite of the massive savings.

noby76 · December 14, 2014

I have lived with a stainless steel exhaust now (cat back) for just over a year.

I had hoped it would have become quieter during use over time from the first install. It has but not to the point I was expecting. The only reason for replacing the original one was that it failed and the stainless one was over £2300 cheaper than replacing with an OEM one.

I know the stainless exhausts are a bit noisier than original ones just by the material that's used on them. With it being a cat back, it consists of the two back boxes and a centre box - pipe connects to the original exhaust just before the two cats.

I would like the quietness back that the original one gave ... I can live with the noise up to a point. There is a "drone" (best way of describing the noise) at 2000 revs, in cruise at 70 mph (between 65 and 75 to be exact) This doesn't really bother me as when I am in the car I can turn the music up to the point where it cancels out the drone but with others in the car and the music low its quite annoying.

I am considering what to do - to replace the exhaust or just the centre box or back boxes but I am unsure of where the noise originates from (centre box or back boxes?) if replacing one or the other halves the noise then that will do but I am just not sure what part the noise comes from?

Is the centre box also called the resonator?

Any help?

mmh is Lexus quality slipping these days that your OE exhaust only lasted 6 years..if so that's bad.. most exhausts systems last at least 10 years if one does not live near the coast of course.. most aftermarket exhast system either lack internal design in terms of resonator design which cancels out noise during cruising or most choose not to add resonators which reduces back pressure thus improving top end performance but sacrifice comfort in terms of sound due to being free flowing..

the center box is your resonator but how well its designed to cancel out noise i wont know so best to take it to the shop who fitted for some advice but not sure how much they can do to help if its designed to be free flowing exhaust.

Tango · December 17, 2014

I've got a standard cat back system if anyone wants to make me an offer. It was only on my brand new IS250 SE-L for 13 months, and as I spent most of the first year of ownership in the USA it only did about 5000 miles.

is200 Newbie · December 17, 2014

Exhaust only lasted 6 years - really disappointed with that - bit bad really and not a good reflection of the brand you are buying into - the replacement cost of £2700 floored me so I went for a stainless one.

I visited ATS yesterday just to see if there was a replacement exhaust available yet through a third party manufacturer and there still isn't.

So considering these cars are now becoming older ... this gen 2 IS is being bought and sold with high miles now and considering this is now a 10 year old car then there will be a few surprises for people having to replace these exhausts which is sure to become an issue for the people running the earlier older models of this gen.

Anyway - I have spend a bit of time on the web looking for resolutions to the drone experienced. I have found a few site (non lexus) resolving this issue and what they have done is a simple but effective job.

Just before the back box, owners of other makes in the USA have found that cutting into the pipe and welding a length of pipe which is capped (essentially a capped off tube the same diameter of the exhaust) to the system creates some turbulence in the flow of the gasses exiting the exhaust after the resonator but before the boxes and this turbulence cancels out to some degree the drone experienced. You need to get the angle of the tube right in order to get it right but in general I found a few references to the length of pipe required to be 12inches so not too excessive.

I may try this as theres a garage around the corner from my work that can do this for me.

Dean8788 · December 21, 2014

I had a powerflow on my first IS250 and it was bloody loud, of which I asked for a subtle sound. But hey back to pure bliss of silence, it was also the reason why I sold the first IS250 for the GS.