LC Model (2018-present)

Exhaust valves

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Old 12-30-19, 07:14 PM
  #16  
hyboost
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Just to be clear, the valves are open when the car is off? In other cars, I’ve seen instructions to turn car on and put in Sport or Sport+ so the valves open and then unplug. Sounds like an easy mod, just double checking...
Old 12-30-19, 08:04 PM
  #17  
SuperGT
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Originally Posted by hyboost
Just to be clear, the valves are open when the car is off? In other cars, I’ve seen instructions to turn car on and put in Sport or Sport+ so the valves open and then unplug. Sounds like an easy mod, just double checking...
Just like I mentioned before in this thread, the default trap position is fully opened when engine is off. This is the case no matter what driving mode was set before It was turned off.
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Old 12-31-19, 12:36 PM
  #18  
pottypants
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Originally Posted by SuperGT
Just like I mentioned before in this thread, the default trap position is fully opened when engine is off. This is the case no matter what driving mode was set before It was turned off.
confirmed.

it’s just weird, majority of other cars default is closed. So I understand your concern.

works like a charm, mine has been in the shop For a balloon squeak from glass roof ever since... but I’ll get it back soon

Old 12-31-19, 03:21 PM
  #19  
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Originally Posted by pottypants
confirmed.

it’s just weird, majority of other cars default is closed.
From an engineering perspective the default closed doesn't make much sense. If something was to go wrong with the valve's electronics or pivoting mechanism, the engine couldn't run with the exhaust blocked so the whole car would be stranded...
Old 12-31-19, 03:57 PM
  #20  
nodeal
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It makes the car like 10% louder at low speeds. Sounds like a pickup truck when parked. No significant improvement imo.
Old 12-31-19, 05:06 PM
  #21  
pottypants
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Originally Posted by SuperGT
From an engineering perspective the default closed doesn't make much sense. If something was to go wrong with the valve's electronics or pivoting mechanism, the engine couldn't run with the exhaust blocked so the whole car would be stranded...
while I agree with default should be open, but having it closed wont cause the engine not to start. this is only to increase airflow bypassing the muffler or baffles.
I cant speak as to how the Lexus baffle works but it appears to be an opening before the muffler.

Please note this example of another baffled exhaust or duel mode... forgive my ignorance...


And yes id bet it doesn't provide any performance improvement by having it open... but why did we buy the V8 in the first place

ppp

Old 01-01-20, 08:14 AM
  #22  
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Originally Posted by nodeal
It makes the car like 10% louder at low speeds. Sounds like a pickup truck when parked. No significant improvement imo.
Then we agree to disagree as I'm experiencing much more than what you stated. Pick-up truck sound when parked?? WTF man.
Old 01-01-20, 08:42 AM
  #23  
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Originally Posted by pottypants
while I agree with default should be open, but having it closed wont cause the engine not to start. this is only to increase airflow bypassing the muffler or baffles.
I cant speak as to how the Lexus baffle works but it appears to be an opening before the muffler.

Please note this example of another baffled exhaust or duel mode... forgive my ignorance...
Your example shows the traps located after the muffler/silencer. Most (like the LC) have them located before the rear silencer so it would indeed prevent the engine from running as there would be no bypass through the system.
Old 01-01-20, 09:30 AM
  #24  
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^^^^Not really. The valve is located in only one tip, the straight thru pipe. When the valve is closed the gases would be forced out through the perforations in the straight thru pipe into the muffler body and into the second tip.

Lou
Old 01-01-20, 10:00 AM
  #25  
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Originally Posted by flowrider
^^^^Not really. The valve is located in only one tip, the straight thru pipe. When the valve is closed the gases would be forced out through the perforations in the straight thru pipe into the muffler body and into the second tip.

Lou
100% of our engine exhaust gases go through the two pipes that are equipped with the valves, installed right before the rear silencer.

Last edited by SuperGT; 01-01-20 at 10:33 AM.
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Old 01-01-20, 11:16 AM
  #26  
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Originally Posted by SuperGT
100% of our engine exhaust gases go through the two pipes that are equipped with the valves, installed right before the rear silencer.
my pic was just an example thanks for posting this one.

would be nice to pull one apart and see how it handles the exhaust.
i haven’t seen any oem flaps that when 100% block all the exhaust.
While it’s possible to have two pipes an one is blocked this would just
be to reduce the noise.

Hehe truck, well this is the same engine they put in the tundra
j/k


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Old 01-01-20, 12:47 PM
  #27  
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^^^^I pulled mine apart, and while I remember little about it, to me, the exhaust gases followed atortuous route. As I recall there was a pipe within a pipe, and the valve was located in the middle of the smaller pipe. When closed the gases were forced around the smaller pipe into the larger pipe.

As for my comment, I was not disputing where the valve is located on the stock LC exhaust, but commenting on SuperGT's comment about the pict. displayed by pottypants. However the comment about 100% of the exhaust gases going through the valve is false as explained above.

And, the valve on the PPE system that I have is also located after the muffler. Like the pottypants pict, there are two tips comming from the muffler. One is straight thru, the other gets gases that pass through the muffler when the valve on the straight thru tip is closed.

Lou

Last edited by flowrider; 01-01-20 at 12:52 PM.
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Old 01-01-20, 01:00 PM
  #28  
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Originally Posted by SuperGT
Yes I did and it's the only way to go on the LC original system IMO. Also tried it on my Aventador but went back to the drive-mode controlled set-up as the adrenaline pumping Corsa mode sound does get tiresome for ''casual'' drives.
Originally Posted by pottypants
awesome ! Thanks so much !

service dept gave bad info twice now, but compared to Chevy I’ll take them every day !

edit: just did the mod. I would assume only one connector on each side needs to be disconnected. It’s rainy and cold, I’m not going to play just removed all 4 and taped up the ends.

Thanks again

ppp
Can you please give us specific details on how to execute this job? Do I have to unplug wires? and if so, where are they located exactly? Thanks
Old 01-01-20, 05:41 PM
  #29  
hyboost
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I just did this mod yesterday based on the help in this post. 5 minute job, hardest part was squeezing my head under the rear diffuser on a lowered LC. Basically there are 2 plugs on each side toward the middle of the car in the back, near the exhaust tips. Unplug, zip tie hanging wires to something so it doesn’t flop around and you’re done. Start car and enjoy the sound.

Best part is that it’s quickly reversible if I don’t like it.
thanks guys
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Old 01-02-20, 06:01 AM
  #30  
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Incorrect quote Lou: I said that 100% of the engine gases run through the pipes equipped with valves. It makes sense however that there would be a pipe inside a pipe so that the valve only restrains part of the gases, not all of it.


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