Exhaust Drone
10-21-02, 04:03 AM
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Exhaust Drone
I have noticed what you described as drone....when the car is downshifting.....(highway offramp for instace....but I feel it...don't actually have any bothersome noises inside the interior...or that is just the way I percieve it. I get the same thing at idle in park on cold starts...just more of it. Still not near enought to bother me. I put the tubing from the rear section back on the car sans mufflers. Now the exhaust exits onto the rear muffler heat shields...instead of the rear diff. Haven't driven the car yet... but I am gonna guess sound should be even quieter as there is less for the exhaust gasses to bounce off of under the car. I am thinking that I might just go the whole way and do a setup similar to the one on Peter's soarer...only I would keep the X pipe closer to the stock cats and use 4 mufflers instead of two...like he suggested. Do you know of anyone who has done a setup like his on a 98-00 1UZFE? I am not sure what year his Soarer/SC is but I am wondering if the OBDII systems will adapt as well as a pre 96 4.0L setup would??
Last edited by RA40; 06-28-16 at 05:19 PM. Reason: Merged for FAQ
10-21-02, 11:53 AM
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Well, it doesn't look like you want to put those stock mufflers back on... Once that hacksaw comes out going back requires at LEAST a welder 
Anyway, I am in agreement that the whole system can be much improved. You may want to read through my earlier exhaust post:
https://www.clublexus.com/forums/sho...threadid=55774
Since that time I have been thinking about many options. Honestly, I would love to try a few different combinations... X-pipe, Y-pipe, single and dual path resonators, various final stage mufflers, different pipe diameters, different headers and cat locations... there are so many theories and it is fun to build and test things. But, at present do not have my own shop so my "testing" has been confined to simple removal of parts and mental gymnastics.
One of the things I think would be interesting would be to replace the LS cat-to-rear mufflers with the GS400 parts. The GS has the same 2" primaries with a larger ID center resonator. The divergent Y after the center res is much better than the LS and then it has twin straight through resonators vs. the LS having twin funky pre-mufflers with side inlets. My guess is the 10hp difference between these 2 factory engines is all found here. So, if you could locate this setup from a GS owner removing his parts in favor of a true cat back as talked about in the GS engine forum... could be an easy/cheap way to upgrade.
Now, if you want to build your own... my hat is off to you. I look forward to your posts and if you are ever in Houston we should get together and "test" these cars against each other
Anyway, I am in agreement that the whole system can be much improved. You may want to read through my earlier exhaust post:
https://www.clublexus.com/forums/sho...threadid=55774
Since that time I have been thinking about many options. Honestly, I would love to try a few different combinations... X-pipe, Y-pipe, single and dual path resonators, various final stage mufflers, different pipe diameters, different headers and cat locations... there are so many theories and it is fun to build and test things. But, at present do not have my own shop so my "testing" has been confined to simple removal of parts and mental gymnastics.
One of the things I think would be interesting would be to replace the LS cat-to-rear mufflers with the GS400 parts. The GS has the same 2" primaries with a larger ID center resonator. The divergent Y after the center res is much better than the LS and then it has twin straight through resonators vs. the LS having twin funky pre-mufflers with side inlets. My guess is the 10hp difference between these 2 factory engines is all found here. So, if you could locate this setup from a GS owner removing his parts in favor of a true cat back as talked about in the GS engine forum... could be an easy/cheap way to upgrade.
Now, if you want to build your own... my hat is off to you. I look forward to your posts and if you are ever in Houston we should get together and "test" these cars against each other
07-01-10, 07:52 PM
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Exhaust Delete Problem,,DRONE
Hey Guys,
Did the exhaust delete [just pulled the mufflers to try it out** and thought it was about perfect amount of sound and a sound that I rather liked for the money. I felt with the stock muffler setup I was driving an electric car!
I went ahead an had my muffler shop install pipes so it will exit in the stock location and look stock. Fine ,,they did a great job,but the problem is for me now I get a drone from 1400 to 1700 rpm's under load or complete deceleration which is rather loud inside the car. Any other rpm's or load it is fine. On the highway or punching it after the 1700 rpm's is past ,,no problem as it is rather silent. I didn't have this problem after just removing the mufflers. With the pipe extensions I now have this problem. If it can't be fixed I will just put on the stock system again.
Any thoughts on this?
Thanks
Did the exhaust delete [just pulled the mufflers to try it out** and thought it was about perfect amount of sound and a sound that I rather liked for the money. I felt with the stock muffler setup I was driving an electric car!
I went ahead an had my muffler shop install pipes so it will exit in the stock location and look stock. Fine ,,they did a great job,but the problem is for me now I get a drone from 1400 to 1700 rpm's under load or complete deceleration which is rather loud inside the car. Any other rpm's or load it is fine. On the highway or punching it after the 1700 rpm's is past ,,no problem as it is rather silent. I didn't have this problem after just removing the mufflers. With the pipe extensions I now have this problem. If it can't be fixed I will just put on the stock system again.
Any thoughts on this?
Thanks
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07-02-10, 05:21 AM
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Hmm, I did a muffler delete and went to the muffler shop and had them run pipes from the axle back and I don't get any drone what so ever. The car is still pritty quiet and sounds like a mellow mustang gt when u get on it. I recently did the delete on my newly bought sc300 and that is loud and has a lot of drone. I wonder if it could b something else caz a good amount of ppl here on cl have done the delete and I havent heard anything about it droning
07-02-10, 06:40 AM
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Lol..who are the idiots and why? Thanks for the reply though. Very informative.
I called my muffler shop and he said he will be ordering muffler clamp weights .I dont remember the exact name. They were used alot on older Lincolns etc in order to keep the pipe from singing at it's resonant frequency . This is apparently an old school device not used much anymore. He told me of a Saleen Mustang with new exhaust and complained he couldn't talk to the passenger it was so loud with drone. Put those on and it cured the problem. He is ordering some for me.
My ideal exhaust would be like LS4 said . A mild Mustang exhaust without peaks in the 1400 to 1800 rpm range. Just like it was after removing the mufflers with no pipes.
Thanks for the replies
I called my muffler shop and he said he will be ordering muffler clamp weights .I dont remember the exact name. They were used alot on older Lincolns etc in order to keep the pipe from singing at it's resonant frequency . This is apparently an old school device not used much anymore. He told me of a Saleen Mustang with new exhaust and complained he couldn't talk to the passenger it was so loud with drone. Put those on and it cured the problem. He is ordering some for me.
My ideal exhaust would be like LS4 said . A mild Mustang exhaust without peaks in the 1400 to 1800 rpm range. Just like it was after removing the mufflers with no pipes.
Thanks for the replies
Last edited by turboomni; 07-02-10 at 07:00 AM.
07-02-10, 08:12 AM
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Lexus Test Driver
07-02-10, 01:28 PM
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Just like a slide trombone changes frequency as the pipe length is changed so will exhaust systems/pipes.
Question: what size pipe was used? A different pipe size will change the frequency.
Sound deadening may help. Wrap the pipe may work but will capture dirt and moisture.
The stock exhaust on 95-00 LS400s (maybe others can't recall just now) have resonant cancelling weights installed.
See the weights bolted on ether side of the Y after the cats in pic below.
Question: what size pipe was used? A different pipe size will change the frequency.
Sound deadening may help. Wrap the pipe may work but will capture dirt and moisture.
The stock exhaust on 95-00 LS400s (maybe others can't recall just now) have resonant cancelling weights installed.
See the weights bolted on ether side of the Y after the cats in pic below.