LC500 - New Custom exhaust being fitted

Pritchard · March 16, 2020

hey thought i would mention some exhaust stuff in a new thread. @AJ500. as it might interest others.

So the LC500 setup (v8) looks to me, from crawling around underneath, to be 2 independent exhausts with 1 per 4 cylinder bank. i say this, as it doesnt look like the -x-pipe in the middle actually allows for gasses to flow between pipes? it looks to be only connected by a structural plate.

but, this being said - each bank flows through a manifold cat, a secondary cat, a resonator, then via the exhaust flaps to the backbox. which without being able to cut open, i am not sure if each bank crosses here or not.

I did the 'exhaust flap mod' last week to open the exhaust flaps (valves) perminantly. this is done by unplugging the 4 plugs on the exhaust found just before the backbox.
The result, in my opinion, is nothing short of amazing. the car for me was too quiet below that 4,000rpm mark.

but i am looking at getting a new exhaust. Not for chasing bhp numbers, but to get 'full volume' from the V8.
After looking online as to whats available (like the Armytrix for £5k... £5,000!! hahahahaha). and similar brands for not alot less, its clear something else is needed.
These off the shelf ones are selling steel drain pipes, for rip off prices probably because they are targetting the 'wealthy' lc500 owners. this is quite typical between car models.

After looking underneath, the backbox on our car is a very nice 1-peice, that bolts up to flanges, with 4 mounting points.
So i am going to head down to my local exhaust fabricator that i have used before for other cars. i havent yet decided if i am going to do one of two things:
- remove the backbox completely, and replace with straight exit pipes (this will be loud. but the backbox doesnt contribute to emmissions. ive never had this done before, but youtubing some US cars of varying V8s, this si bloody awesome.... sounds awful on 4-pot engines though).
- replace the backbox with 2x Single backboxes. something similar to what Cobra do for the LC (pictures available from gogle).

The estimates he has sent over its £400 and £750 for the above options. much better.
PLUS, this also means no cutting, welding, or any other intrusive works. so when i sell my car, i can swap the OEM exhaust back onto the car within 20min on ramps from home.

and i have to ask, because i have seen you mention it before AJ - what is this particular filter you keep talking about? where abouts do you think it is in the exhaust system?

hope some of this info may be of use to someone... as soon as this Quarantine stuff finishes ill be getting the exhaust fitted.

AJ500 · March 16, 2020

My understanding is that all cars ,post September 18 have to have the particulate filter,similar to the one fitted on diesels for some years.On my M2 this was a clearly visible extra can. It drastically reduces the sound.Porsche took ages to redesign theirs last year and stopped production of most models for months.All manufacturers had to comply with stricter emission regs.

I have not got under my LC500 but from your description it sounds like it’s not there or is,in some way,built into the system elsewhere.I assume that as your car is a 68 plate that the above applies.Having compared the sound of my car with the many YouTube vids,it is definitely not as loud.Most of these are overseas cars or pre late 18.

If I am wrong,I apologise but this filter has caused huge discussion and expense to most of my petrolhead pals who have tried to improve the sound of various makes by fitting aftermarket products and coding out warnings etc.This,of course,is likely to affect the warranty and future MOTetc.

I would be delighted to know Lexus got around the emissions stipulations by some other means,if that is possible.

Regardless,I am keen to hear how your proposed changes pan out.The backbox changes I have seen on YouTube have necessitated scrapping the rear diffuser to allow for larger tailpipes,which look awesome.

Hope your quarantine goes smoothly.

A J.

Pritchard · March 16, 2020

thanks (dont worry, i am fine) but i have been sent home along with half of London.

hey i am not arguing with you, i dont know these cars that well. i just dont know where i should be looking for it 🙂
i dont plan to remove or modify the rear diffuser. whatever work i have done will accomodate the current arse.

AJ if you havent already seen it, take a look at the lc review by Savage Geese (goose?), if you go to about halfway through he has it up on a car lift and pans the camera across all under parts. gives a good look.
If you freeze frame at about 22:30 in particular, there is a still shot from the side/bottom, where you can see the manifold cats, secondary cats (with lambda sensors) x-pipe (hidden under that support plate) and then the 2x Resonators. After that is the flange that bolts to the back box section.
I have a '68 plate, registered in late September if that helps, and i can confirm what you will see in that video, has the same exhaust as what i have.

if that helps in any way 🙂

@AJ500

Pritchard · March 16, 2020

Ive also done some google-woogles, and i have found 1 bloke from EU mention in a US thread that he ''has been robbed of 13bhp due to the particle filter'', making reference that the US dont have it.
But, looking at model specs on wiki, and other EU sources, it seems they were all sold with 471bhp (477ps) globally?

i cant find any model specs for this particle filter, nor can i find any other forum or blog posts about it.
i assume this guy has got 13bgp from somewhere.

What have you found? maybe i am using the wrong search terms.

AJ500 · March 16, 2020

Hi,

No worries,I know you are not arguing with me. It’s good to have some rapport with a fellow LC owner as there are so few.I am used to the Porsche and BMW forums where there are hundreds.

I will watch that vid later as it’s a while since I saw it.

Having been told about the legislation and actually having a new M2 Comp in October 18 with this filter I am assuming all systems have to have it.However,maybe they are not fitted if the manufacturer can reduce emissions in some other way.Certainly I was told that after September 18 it is illegal to make the exhaust louder than when factory fitted although I know this is generally ignored.

Maybe there is someone from the RCF forum who has better technical knowledge of the Lexus V8 engine.

In reality,it doesn’t affect your proposed changes as you are working on the tail end of the exhaust.

A J.

Pritchard · March 16, 2020

i think the uk law has always been that the exhaust shouldnt be louder than OEM, but ive never had any of my modified cars fail an MOT - unless the exhaust is blowing, or fails emmisions.
There is also no law stating that you must use OEM products if you replace an exhaust for repair....well Mr MOT man Sir, my OEM had a hole in it, and i replaced it wit this one.
So, this leaves a kind of grey area of proving grounds. But, its obviously well known aftermarket = louder! lol.

Mudbutler · April 5, 2020

On 3/16/2020 at 12:57 PM, Pritchard said:

i think the uk law has always been that the exhaust shouldnt be louder than OEM, but ive never had any of my modified cars fail an MOT - unless the exhaust is blowing, or fails emmisions.
There is also no law stating that you must use OEM products if you replace an exhaust for repair....well Mr MOT man Sir, my OEM had a hole in it, and i replaced it wit this one.
So, this leaves a kind of grey area of proving grounds. But, its obviously well known aftermarket = louder! lol.

Hey chaps, my understanding is that when the new emissions regulations came in which stopped many manufacturers building petrol car, mostly the Germans, Lexus also had to comply. The tell tale sign is moving from 471bhp to 464bhp. A simple check on the detail spec of your car will tell you if you have one with reduced BHP cause by complying with the newest regulations

check your V5 document bottom of the left hand column vehicle details. If it says 351Kw you have a pre regulations car. If it says 346kw you have a post regulations car which has the addition filters etc.

hope that helps...

malcolmw · April 5, 2020

351. 😄

BTW, on old style V5s the figure is half way down the left hand column.

Mudbutler · April 5, 2020

👍

Mudbutler · April 5, 2020

👍.

BrettMRC · July 20, 2022

Would be interesting to know who, if anyone, on here has modified the exhaust so far?

I keep looking at Armytrix as that seems to the one with the most coverage - but there must be other options?

Ruffle · July 20, 2022

The controller widget being sold on Etsy seems quite interesting but AFAIK the UK cars don't get the buttons on the rear view mirror so you'd have to go scrabbling around for the remote when you want to change the exhaust valve settings.

Pulling the connectors from the solenoids appears easy but it's not a neat as being able to turn it on or off.

In my scanning of everything LC500 I can find, I thought I saw a suggestion that in Sport+ mode the valves stay open below 4K RPM. Is this correct or am I imagining it?

BrettMRC · July 20, 2022

9 minutes ago, Ruffle said:

The controller widget being sold on Etsy seems quite interesting but AFAIK the UK cars don't get the buttons on the rear view mirror so you'd have to go scrabbling around for the remote when you want to change the exhaust valve settings.

Pulling the connectors from the solenoids appears easy but it's not a neat as being able to turn it on or off.

In my scanning of everything LC500 I can find, I thought I saw a suggestion that in Sport+ mode the valves stay open below 4K RPM. Is this correct or am I imagining it?

I have the Etsy controller, and it makes a difference in the lower RPM range... but missing some of the bark from the earlier cars.

Ruffle · July 20, 2022

So you have to fiddle with the remote or did you find some neater method?

Has your Inspiration been in for a service since you fitted the widget? Did Lexus spot it?

H3XME · July 20, 2022

5 hours ago, BrettMRC said:

Would be interesting to know who, if anyone, on here has modified the exhaust so far?

I keep looking at Armytrix as that seems to the one with the most coverage - but there must be other options?

I would literally take it to any reputable exhaust shop and let them do a back box delete. Just weld a straight pipe with a nice tip to a flange that bolts onto your stock system with the same hangers. That way you can keep unbolt the original back boxes and keep them in the garage should you need them in the future. Fully reversible solution for ~£600..

BrettMRC · July 20, 2022

39 minutes ago, Ruffle said:

So you have to fiddle with the remote or did you find some neater method?

Has your Inspiration been in for a service since you fitted the widget? Did Lexus spot it?

I've got it set to car control as it's start up/normal mode - so unless I give the remote a single click it stays in factory mode - so nothing to see or spot unless they start taking up the boot floor randomly.

Not due a service for awhile as only delivered at the end of May.

BrettMRC · July 20, 2022

20 minutes ago, H3XME said:

I would literally take it to any reputable exhaust shop and let them do a back box delete. Just weld a straight pipe with a nice tip to a flange that bolts onto your stock system with the same hangers. That way you can keep unbolt the original back boxes and keep them in the garage should you need them in the future. Fully reversible solution for ~£600..

That's a bit too much for me, I've been down that road with a lot of cars - now I like the idea of being able to easily choose between noisy and quiet! 🙂

H3XME · July 20, 2022

Just now, BrettMRC said:

That's a bit too much for me, I've been down that road with a lot of cars - now I like the idea of being able to easily choose between noisy and quiet! 🙂

That fair enough, but if it's a good garage, they'll be able to valve it too.. it's like a turn down pipe just before it goes into a backbox like this:

Obviously the cost of this is going to go up significantly but it's still a much cheaper solution than an "off the shelf system".

Malc · July 20, 2022

48 minutes ago, H3XME said:

the cost of this is going to go up significantly

when I see what exhaust fabricators can actually do I'm quite amazed and wish I'd carried on doing " Metalwork " classes at school some 60 years ago

I enjoyed it but produced mostly absolute rubbish I'm afraid ............. better with my fingers at a keyboard .... but not a music one either sadly :wink3:

Wasn't the original exhaust spec satisfactory for the LC500 then ?

Malc

H3XME · July 20, 2022

14 minutes ago, Malc said:

when I see what exhaust fabricators can actually do I'm quite amazed and wish I'd carried on doing " Metalwork " classes at school some 60 years ago

I enjoyed it but produced mostly absolute rubbish I'm afraid ............. better with my fingers at a keyboard .... but not a music one either sadly

Wasn't the original exhaust spec satisfactory for the LC500 then ?

Malc

It is a true art when it's done properly. I mean look at those welds on my exhaust. They make things up to a very high standard in Japan..

I would say that the purpose of LC500 is just a luxurious GT cruiser. It won't be winning races, it's not sporty enough by sports car standards. It's not fast enough by performance car standards, but it is a pleasure to drive.. Obnoxious exhaust just doesn't suit it for the way Lexus developed this car.. That being said I would definitely want to hear the V8 roar in a car like that. Something needs to make me deaf, right? I'd rather it be the V8 than my other half😂

BrettMRC · July 20, 2022

To be fair, I do have previous for exhaust mods on V8 Lexus...

Ruffle · July 20, 2022

2 hours ago, BrettMRC said:

To be fair, I do have previous for exhaust mods on V8 Lexus...

Hooligan 🙂 🙂 🙂

Flytvr · July 20, 2022

I don't know much about the LC500, but I've seen lots of after market exhausts fitted to IS-Fs & RC-Fs. They all have a tendancy to drone. I'd be careful what you change!

H3XME · July 21, 2022

9 hours ago, Flytvr said:

I don't know much about the LC500, but I've seen lots of after market exhausts fitted to IS-Fs & RC-Fs. They all have a tendancy to drone. I'd be careful what you change!

Very good point. Generally removing just the back boxes causes droning, but V8s aren't as high pitched as other engines so you might get away with no drone up to certain RPMs. I think if it only stars droning in RPMs higher than your cruising RPMs, it's not too bad. Nothing worse than sitting at 70mph on the motorway listening to a split bean tin. The better way is to go for removing the middle section silencer and/OR secondary cats for a better flow while keeping back boxes - this will still let you pass the emissions at MOT if tested hot.

The two silencers on the right could be fully removed and weld straight pipes in place.

However, I am not too clued up on LC500 system as these newer cars tend to be fitted with GPF (Gasoline/Petrol equivalent to DPF on diesels) as mentioned above, but again, I'm not sure if it's case on naturally aspirated cars too. I've only come across it on turbo petrol cars so far.