Exhaust valves
01-10-20, 11:26 AM
#46
Lou,
not arguing the gains. headers & free flow cats ( or lack there of
do a lot ,
but swapping those headers is special. im sure toyota had their reasons for reducing
the exhaust diameter at the back as well prob for sustained flow.
honestly id go the rear gear swap and prob get the same benefits.
5K is way to much for my blood for a few stainless exhaust pipes and i haven't
even priced headers or a tune.
sorry to derail thread
ppp
not arguing the gains. headers & free flow cats ( or lack there of
do a lot ,but swapping those headers is special. im sure toyota had their reasons for reducing
the exhaust diameter at the back as well prob for sustained flow.
honestly id go the rear gear swap and prob get the same benefits.
5K is way to much for my blood for a few stainless exhaust pipes and i haven't
even priced headers or a tune.
sorry to derail thread
ppp
01-10-20, 11:44 AM
#47
Driver School Candidate
From the pics I posted, it looks like the larger connector has 3 wires and the smaller one has 2 wires. I would guess 2 wires on the larger connector carry power to the valve motor (maybe one opens the valves and one closes them?), and the other is a shared ground. The smaller connector likely has one power and one ground. A multi-meter will confirm this. So one should be able to just cut the 4 ground wires - to break all 4 harness circuits. The 4 ground wires on the connector side can be spliced together and connected to one side of a switch. The 4 ground wires on the other side can be spliced together and connected to the other side of the switch. Done, right? Not so much...
The problem is - the system needs to be energized to open/close the valves. if the switch is open and you close it while the engine is running... The valves won't necessarily move until (A) the drive mode is changed, or (B) one of the vehicle dynamics trigger valve movement. Not such a big deal. However, if you open the circuit while the engine is running, the valves won't automatically fully open like they would when one turns the engine off. They will stay in the exact position they were in when you opened the switch. They need power to open.
The problem is - the system needs to be energized to open/close the valves. if the switch is open and you close it while the engine is running... The valves won't necessarily move until (A) the drive mode is changed, or (B) one of the vehicle dynamics trigger valve movement. Not such a big deal. However, if you open the circuit while the engine is running, the valves won't automatically fully open like they would when one turns the engine off. They will stay in the exact position they were in when you opened the switch. They need power to open.
Joe
01-10-20, 11:54 AM
#48
Driver School Candidate
Lou,
not arguing the gains. headers & free flow cats ( or lack there of do a lot ,
but swapping those headers is special. im sure toyota had their reasons for reducing
the exhaust diameter at the back as well prob for sustained flow.
honestly id go the rear gear swap and prob get the same benefits.
5K is way to much for my blood for a few stainless exhaust pipes and i haven't
even priced headers or a tune.
sorry to derail thread
ppp
not arguing the gains. headers & free flow cats ( or lack there of
do a lot ,but swapping those headers is special. im sure toyota had their reasons for reducing
the exhaust diameter at the back as well prob for sustained flow.
honestly id go the rear gear swap and prob get the same benefits.
5K is way to much for my blood for a few stainless exhaust pipes and i haven't
even priced headers or a tune.
sorry to derail thread
ppp
At the end, I swapped to AMG E43 but sound was not loud, not comfortable car to drive (suspension wise) and cannot be driven relaxedly. Hence LC500, other constraints is this time I like to keep the car as close to oem as possible, for Insurance purpose.
I still have another mod on Air Filter intake flaps on both sides to remain open all the time. This open up the sound even further. Let me know if anyone is interested. Cheers,
Joe
Last edited by JoeJahja; 01-10-20 at 11:57 AM.
The following 3 users liked this post by SuperGT:
01-21-20, 01:57 PM
#50
Driver School Candidate
Thread Starter
Exhaust valves
Opened the exhaust. Now this car sounds fantastic. This is the way the factory should have made it. Car sounds great at ide and really good when accelerating. As stated 10 minute job
The following 3 users liked this post by tiger1918:
01-22-20, 03:40 PM
#51
I dont know if anyone has posted a sound clip...Tiger1918 you started this so we elect you to do so!
The following 2 users liked this post by North1Star:
ISellHomes (12-07-20),
jennypenny (07-10-24)
01-26-20, 08:27 AM
#53
Pole Position
I think I was one of the 1st to try it back in June 2018. Did it as soon as I got back from picking it up new at the dealership. Went back with the valves connected two weeks later to do a proper before and after test. I can confirm that the difference is day and night at lower speed. Louder during acceleration, pops and occasional backfires when compression downshifting. It should of been set-up like this from the factory IMO.
The following users liked this post:
ISellHomes (12-07-20)
01-26-20, 08:31 AM
#54
One of the reviewers commented on lexus engineers wanting the same loud sounds as the American V8s.
mgmt. at lexus came to an agreement, which is the current status of the exhaust with the valves.
The thing is you cant help but suspect the engineers had the default as open to allow people like us to disable.
Whatever the truth be told, im glad it ended up the way it is !
ppp
mgmt. at lexus came to an agreement, which is the current status of the exhaust with the valves.
The thing is you cant help but suspect the engineers had the default as open to allow people like us to disable.
Whatever the truth be told, im glad it ended up the way it is !
ppp
01-26-20, 09:30 AM
#55
I also did this early in 2018, but my experience was a bit different. I noticed no difference at all during acceleration in any drive mode. I suspect the valves are always fully open during acceleration to avoid backflow restriction issues. The only significant difference I recall was a louder tone during lower RPM driving. Although I liked the louder tone in Sport+ mode, I still prefer it being quieter in Normal and Comfort modes - especially when cruising with my more "well-adjusted" better half. I also wondered if the computer adjusts how lean or rich the fuel delivery is - depending on valve position. This could explain the more frequent "popping" experience. Anyway, time and user experience has shown no worrisome issues with this DIY modification - so I'm gonna try it again after winter hibernation ends. Another thing I like about this design is - the valves are not a muffler bypass, so it's never obnoxiously loud. It always sounds nicely-tuned, IMO.
Last edited by uchujin; 01-27-20 at 07:31 AM.
01-26-20, 01:43 PM
#56
Driver School Candidate
I unplugged all 4 when I seen this thread mainly because someone mentioned he/she was getting overrun. I love the sound and it's not harsh or over the top IMO. However, I have not experienced any overrun pops & crackles with this car before or after disconnecting. And was surprised the car didn't have it from the factory as most performance cars do.
01-26-20, 02:11 PM
#57
^^^ Same here. I only get occasional popping if I'm driving aggressively - typically in manual and Sport+ mode. opening and closing the throttle quickly as one would expect. I never get it if just cruising and keeping the RPMs well-below the redline. But I think that's just about right for a refined Lexus GT car.
01-26-20, 05:50 PM
#58
^^^^I've been waiting for some others to post, before I did. With my PPE Dual Mode Exhaust I also have no pops or crackles with my exhaust wide open. Those noises were common back in the day when engines were controlled mechanically. But, with the advent of electronic (computer) controls those noises are much rarer today. They would indicate unburned fuel down stream in the exhaust system.
Lou
Lou
The following users liked this post:
pottypants (01-30-20)
01-29-20, 06:55 PM
#60
Pole Position
I unplugged all 4 when I seen this thread mainly because someone mentioned he/she was getting overrun. I love the sound and it's not harsh or over the top IMO. However, I have not experienced any overrun pops & crackles with this car before or after disconnecting. And was surprised the car didn't have it from the factory as most performance cars do.
Last edited by SuperGT; 01-30-20 at 04:13 AM.