Hi guys now here is something I discovered recently which has me scratching my head a little.

Long story short is that the exhaust in my near new 2022 has a flattened section in the midpipe, close to the muffler, just before the exhaust valve actuators, that simply does not exist on earlier model LC500s

Here is a pic of the 2018 exhausts I have found online (and from Savagegeese's 2018 LC500 review video where he has extensive shots of the undercarriage)



And here is a picture of mine from basically the same view



Heres another comparison from the other side, top one being a picture of a 2018 muffler i found on ebay with mine being the one below it



I'm guessing they did this to reduce noise? Emissions? Might there even be a gas particulate filter installed on the later exhausts that did not exist on the earlier model ones?

Anyway, does anyone have a part number for the muffler assembly without the restriction? I cant tell what I am getting just by looking at online catalogs/diagrams. I might want to swap to it if i can. I can't modify my own exhaust system or go aftermarket because of the laws we have here but swapping to an earlier year muffler is possible for me, and very enticing if it helps derestrict the engine or improve the sound

 

Wow good to know the LC-2018s are faster! ha!

 

My guess is that it was notched (flattened) to clear the extra hardware just forward of the differential. I'm not sure what that is, but I would think it's related to the Yamaha Performance Damper.







Note - I had the rear section with the muffler, but I destroyed it when I installed my PPE Dual Mode Exhaust. I was checking to see how the OEM valve mechanism worked

 

That was actually a great guess but those mounting points you mentioned are actually for the rear differential that is common across all LC500 models regardless of year. There is adequate clearance to run an unrestricted midpipe there without the need to flatten it. Here's a closeup of the differential and its mounting wings with the exhaust out of the way on my car (i was actually swapping out the rear differential on my car which is a story for another post lol). I was looking everywhere for the yamaha performance damper too, for the life of me i did not see it. My guess is its buried deep in the chassis somewhere



This is a pic of the differential from a different angle from savagegeese's 2018 LC500 with the unrestricted exhaust, shown here able to clear the same differential mounting point:



Definitely not a clearance issue IMO unless I am missing something. I'm still of the opinion it was either to restrict noise output or where they installed a gas particulate filter but i was hoping for some definitive confirmation about that, or at least a part number for the unrestricted muffler so i can order it and investigate it further

 

I can confirm that I as well have the compressed exhaust pipe on my 2022

 

i'll look on my '21 when i get home.

 

My 21 convertible is crushed too

 

Some updates on parts numbers from what I have been able to find trawling through parts catalogs

17430-38050 -I believe this is the restricted exhaust. It is listed to fit 2020-2022 LC500s. This must be the one with the kink in it (and probably the OPF)

17405-38041 - I managed to find this on a google image search but the ebay listing is gone. Listed to fit only the 2018-Nov 2019 LC500s. Later models not included. It looks unrestricted, so this is the best guess?



17430-31E50 - There are literally no pictures of this one on the internet. One one website this is listed as compatible with the LC500. But on another website it is listed as compatible only with the LC500h. The part diagram looks unrestricted but it also looks like it has no provision for exhaust valves. Maybe it is in fact for the LC500h which might not have exhaust valves since it is already much quieter than the V8?



17430-31E51 - Same deal as 17430-31E50. Based on the sequential part number there might have been a minor update to it

So my preliminary guess is:

17405-38041 is used on LC500 V8 coupes 2018 to late 2019 production models (so i guess up to model year 2020)
17430-38050 is used on all LC500 V8 coupes and cabriolets after that day (model year 2021 and up) - these are restricted

The findings are consistent with when (around 2020) I believe lexus decided to impose either an exhaust restriction or worse yet, a gas particulate filter on LC500 models, in line with the release of the LC500 cabriolet, all of which I believe have the exhaust restriction

I am guessing the the exhaust part numbers with the E designation 31E50 and 31E51 are meant for the LC500h. They dont appear to be valved/filtered at all and might even fit the LC500 V8 (in fact I strongly believe they are interchagable). At idle the LC500h is 27db vs 43db on the LC500. On a full throttle flyby the LC500h is 83db vs 93 on the LC500. Assuming the LC500h exhaust worked, there might be even more gains to be had since the V6 hybrid would require far less surpression in the exhaust, but it would depend on a host of factors and i would need to see them side by side

I'm going to see if I can get a second opinion (maybe you guys can help) and if it looks good I will try to get my hands on a 17405-38041 part and fit it to my 2022 and report the difference, if any

 

Thank you very much breplica for this information, very interesting. Really looking forward to the test if you chose to do it!

 

Thank you very much, I do hope I get something interesting or useful out of this too

May I also ask anyone reading the thread up to this point, has anyone in the US listened to, or been in a pre 2019 LC500 and a post 2021 LC500 and noticed any difference in the sound or performance between the two? I have been on youtube but its really hard to tell from a video recording

 

^^^^Since you'll be using the stock muffler, why not just have a muffler shop cut off those two crush straight pipes and weld on new ones. It looks like a pretty straight forward simple job

 

Not an option for me I'm afraid. Regulations here are very strict and undercarriage inspections are carried out yearly. When fresh welds are seen on exhausts, its an immediate fail with heavy fines. Just how it works in this part of the world. I have to use a factory part to escape scrutiny

 

breplica,

I have this that I removed from my 2018 at around 3K miles when I installed my Tom's exhaust and is in perfect condition. They are the unrestricted pipes (see the photo below).

If you're interested, I'd be willing to sell it to you if we can make a deal. You can send me a message here on the forum or email me at Hello@RickGibbons.com.

 

^^^^I thought of that too, I believe I can I know where I can pick one up. But shipping to Singapore would be extremely expensive as well as customs

 

Thanks very much friends for the offer. You guys are right, the shipping to Singapore would be murder. I actually just placed an order for one from Japan (a little closer to where I am) already. But I am very grateful for trying to help me out!! Will post my findings about any differences I notice (if any) when i install the older unrestricted mufflers