Exhaust upgrade on v6? You need to know this (real life experience and Lotus dealership input)

[Hell4Leather]

only if the manufacturer can prove the mod caused whatever issue you are trying to cover under warranty. Magnuson act protects us here in the US. They can't deny just because you put something aftermarket on. Believe me that they will try and I've seen some crazy examples where they tried to deny the claim but in the end it failed. There are some mods I 100% would not do until after warranty expired because it would be too easy to link even if it didn't cause the issue. Replacing exhaust would be a hard one to prove

It’s the valve control though. Like the OP states, if you close it when it shouldn’t be closed you will damage the vehicle. That's had me nervous about the VC even though I like the idea. Accidentally leaving it closed can cause a permanent problem. Dealer will have an easy time denying warranty if a potential engine safety feature was disabled.

 

[Porter]

How did you do the cat delete? And, where is the 3rd cat located?

Aren't you the one that started this thread? The third cat is right in front of the muffler, it's the short J-bend pipe that connects the rear exhaust system to the midpipe.

GRP sells a nice one.

GRP Emira Cat Delete/Race Exhaust Pipe

GRP Emira Decat/Race Pipe This is a direct replacement exhaust pipe for the third cat pipe which is installed on 2023+ Lotus Emira 3.5 V6 cars worldwide. Made from 16 gauge 304 stainless steel Precision laser cut, machined and tig welded stainless steel 3-bolt flange Welded/Made in the...

www.gregsraceparts.com

 

[crestima]

It's my understanding that the Milltek kit isn't explicitly designed for the Emira at all, it was a kit for the Ford Fiesta that just happens to fit the Emira. If I remember right, one of their UK dealers figured out the compatibility.

They still show it blended for the I4 on part number SSXFD413 (F for Ford), though they've made a new part number for the V6, SSXLO6. That number comes sequentially after the exhaust products though, and the valve controller has been available from them since before the exhaust was designed and produced.

View attachment 51037

That's certainly interesting to know and thanks for that research, however it's still a mystery as to why they would design the by-pass feature of their valve controller to potentially transmit data on a one way basis as opposed to bi-directional as suggested above by EmirOfDenmark and advised by his local Lotus dealer mechanic. It's important for those of us who like to use both OEM valve mode in addition to the Open valve one, without risking damaging the engine. Anyone know how one goes about tagging Miltek on this thread so they can provide clarity to this issue?

 

[Porter]

That's certainly interesting to know and thanks for that research, however it's still a mystery as to why they would design the by-pass feature of their valve controller to potentially transmit data on a one way basis as opposed to bi-directional as suggested above by EmirOfDenmark and advised by his local Lotus dealer mechanic. It's important for those of us who like to use both OEM valve mode in addition to the Open valve one, without risking damaging the engine. Anyone know how one goes about tagging Miltek on this thread so they can provide clarity to this issue?

I have no idea. I assume it's because the Ford Fiesta didn't require it.

I personally don't know what the objective is with the controller, except maybe opening the valve when in Tour mode? Why not just put it in Sport?

 

[EmirOfDenmark]

I have no idea. I assume it's because the Ford Fiesta didn't require it.

I personally don't know what the objective is with the controller, except maybe opening the valve when in Tour mode? Why not just put it in Sport?

In Sport mode the valves are still not fully open all the time. Big difference in the sound.

 

[EmirOfDenmark]

Is the VC required with the cat delete in order to avoid CEL?

I would not think so, as you are not decoupling the valve mechanism.

 

[EmirOfDenmark]

Aren't you the one that started this thread? The third cat is right in front of the muffler, it's the short J-bend pipe that connects the rear exhaust system to the midpipe.

GRP sells a nice one.

GRP Emira Cat Delete/Race Exhaust Pipe

GRP Emira Decat/Race Pipe This is a direct replacement exhaust pipe for the third cat pipe which is installed on 2023+ Lotus Emira 3.5 V6 cars worldwide. Made from 16 gauge 304 stainless steel Precision laser cut, machined and tig welded stainless steel 3-bolt flange Welded/Made in the...

www.gregsraceparts.com

Yes, just making sure we’re talking about the same thing. Thanks.

 

[crestima]

I have no idea. I assume it's because the Ford Fiesta didn't require it.

I personally don't know what the objective is with the controller, except maybe opening the valve when in Tour mode? Why not just put it in Sport?

This is covered in the thread entitled "Who has Milltek's Active Controller Installed?" with lots of information on the functionality, recommendations and experience by forum members who have it already installed. Also, Miltek's product description goes in to some detail as to its advantages (of course). I, myself, am pretty satisfied with its result and essentially the control of the valves allows one to open them from the onset (idle) instead of having them triggered by the higher RPM level as programmed from factory. As far as I'm concerned, the valve controller along with the 3rd Cat Delete provides an optimal combination.

 

[Porter]

This is covered in the thread entitled "Who has Milltek's Active Controller Installed?" with lots of information on the functionality, recommendations and experience by forum members who have it already installed. Also, Miltek's product description goes in to some detail as to its advantages (of course). I, myself, am pretty satisfied with its result and essentially the control of the valves allows one to open them from the onset (idle) instead of having them triggered by the higher RPM level as programmed from factory. As far as I'm concerned, the valve controller along with the 3rd Cat Delete provides an optimal combination.

I think the objection that people have is that it shouldn't come with a "force closed" mode if it can damage the car. You and I both know that people should be smart about the things they install on their cars, and have an engineer's mindset about how they use them, but in reality many people don't think a great deal about what they're doing and why. Which is why the language that Lotus uses in the warranty and the TSBs is draconian.

 

[crestima]

I think the objection that people have is that it shouldn't come with a "force closed" mode if it can damage the car. You and I both know that people should be smart about the things they install on their cars, and have an engineer's mindset about how they use them, but in reality many people don't think a great deal about what they're doing and why. Which is why the language that Lotus uses in the warranty and the TSBs is draconian.

Agree. Despite the obvious being obvious, it would behoove Miltek to just get rid of the damn Forced Closed button altogether as there's just no rational reason to have it, and it only poses risks for those who don't know better.

 

[JonathanBacon]

As many of you have been considering and trying an aftermarket upgrade of the exhaust system, I would like to share my learnings, along with the dealer advice.

The background (as explained to me by the dealer)
Here is what is going on. If you are considering about upgrading the exhaust, the last stage of the exhaust is what you are replacing. That connects to the Valve Controller (VC). The VC effectively controls a valve from a range to positions from fully open to fully closed. It is controlled by the ECU, connected to how you drive and which drive mode you are in. In Tour mode, it is mostly closed, but is still opens up slightly at higher revs (1). In Sport mode it starts somewhat opened and opens up fully in higher revs. In Track mode is behaves exactly the same as in Sport mode, but the idle RPMs are higher and the rev limiter is higher by about 200 RPM (this is why people think it is different, but what you are hearing is the higher idle RPMs). So, the way it is designed is that ECU sends a message to the valve (e.g. open up by 20%), and the valve needs to send back a response "valve opened by 20%". If the valve gets physically stuck, the valve controller will not respond, and the ECU will go "oh, the valve is not opening, that is unsafe, there is not enough respiration for the engine, I will limit it to 4000rpm".

My Initial Experience - the problems
Last year, I bought a Miltek exhaust system for my V6. I drove it to a mechanic (not Lotus), that is recommended by Miltek, and they installed it relatively quickly, no fuss.
As soon as I drove off from the shop, I got Limp mode, i.e. the engine was limited to 4000rpm. What happened was, that the mechanic has connected the Miltek exhaust with the VC in a position that was not the last recorded position in the ECU. E.g. the ECU would have thought is is in 20% Open, but the connected position would have been 30% open, by pure mechanical positioning of the valve during installation. So, the first time the ECU tried to open it up fully, it couldn't, it interpreted the valve as being stuck, and triggered limp mode.

The solution - recalibration
To solve this problem, you need to take the car to the Lotus dealer and they will recalibrate the VC to the mechanical position of the valve. Only Lotus dealer can do this, you cannot do this with a custom tool. Clearly the position of the valve is so important that Lotus doesn't want anyone to mess with it, and the moment the ECU thinks then valve is not doing what it needs to be doing, it limps the engine. So the valve is really important for the engine respiration. (2)

The workaround - the valve controller
Then I ran into the Miltek Valve Controller (MVC) that can control the valve manually (via a fob). It has three positions: Open (full open), Close (fully closed), and Stock (let the ECU decide). In any of the modes, the MVC returns an affirmative response to the ECU, and thereby the car will never go into limp mode. You are also removing an obviously important feedback loop that Lotus has built in, that when the valve misbehaves, the engine needs to be limited. (3) I installed the MVC, and the limp mode went away.

More problems - O2 sensor slow response
While I drive it fully open most of the time, I do sometimes like to close the valves, e.g. if I am on a long highway journey and want a more quiet experience. When I do that, I could get the CEL, which my OBD would read as "O2 sensor slow response". Hmmm, is it safe this? Turns out that because the air mix and air pressure is different from what is expected at certain RPMs, the error could occur. In other words, the closed valve is triggering an invalid reading from the O2 sensor.

The conclusion - as verified by the Lotus mechanic
The Miltek exhaust lets out more air flow than the stock exhaust, and generally they trust Miltek on the exhaust itself. However, the controller was a big concern for them.
Open mode - ok, you may get some O2 sensor errors there as well, but the engine can breathe properly, all good.
Stock mode - depending how the valve is calibrated. If there is a big discrepancy between the perceived position and real position you can still have the same problems as in Closed (but you would hear that).
Closed mode - this is a major risk. Do not use it. Note the points 1, 2, and 3 above. Even in Tour mode, the engine needs to open the valve to breathe (1). There is a serious feedback loop being built into the engine respiration pathway, to prevent engine from revving if there is a risk of that pathway being closed (2). Removing that feedback loop is a risk to the cats and the engine itself, it goes against the programmed behaviour (3).

Unless, you drive it in Open mode.
In other words - when you buy the Miltek Valve Controller, you are not buying a valve controller, you are buying an Open only mode, if you want your engine to be safe.

The result and the experience
I now have confidence that the Miltek exhaust itself is ok, and that the controller is safe as long it is in Open mode. That is why I basically left the fob safe at home, and the MVC in Open mode in the car. The result is a great sounding car for me. The stock car sounds good too, but with this setup, it sounds much better (for me). What is better?
At low revs - sounds deeper
At mid revs - more howl
At high revs - louder and more race-like sound
Overruns - more rumbles and pops, more drama
Final note, without the MVC, I was underwhelmed when I just had the Miltek Exhaust. It sounded a bit louder, but I was questioning whether it was worth it. If you want to do this, get the MVC as well, as that makes huge difference, but be aware you are buying an Open mode only.

TLDR; if you want a exhaust upgrade, get the Miltek exhaust AND get the Miltek valve controller, but never use it in any other mode than Open, if you want to keep your car safe.

Hope this clarifies many questions I've been seeing here.
NOTE: This is just me sharing my experience to the best of my knowledge. You take responsibility of your own car modifications.

Just to jump in here I have a FE V6 Manual and have had the Larini bypass pipe fitted (not the full System) it was relatively inexpensive to fit and my local Lotus Dealer did it - Stratton Motor Company who are excellent. The sound the car makes is absolutely amazing it really does sound like a V12 Ferrari. The cars just seems to drive so much better with it more free raving and just feels less restricted.

 

[Hell4Leather]

Larini bypass pipe

Is this the same as the “cat delete”?

 

[David s]

This is covered in the thread entitled "Who has Milltek's Active Controller Installed?" with lots of information on the functionality, recommendations and experience by forum members who have it already installed. Also, Miltek's product description goes in to some detail as to its advantages (of course). I, myself, am pretty satisfied with its result and essentially the control of the valves allows one to open them from the onset (idle) instead of having them triggered by the higher RPM level as programmed from factory. As far as I'm concerned, the valve controller along with the 3rd Cat Delete provides an optimal combination.

Sorry for the dumb question. So once the 3rd cat is installed(without the valve controller), are the valves fully open when you trigger 'track "mode? what is the difference between track mode and using the controller to trigger open mode. Does the controller delete the function of the lotus installed "touring, sport, track"" settings?

 

[crestima]

Sorry for the dumb question. So once the 3rd cat is installed(without the valve controller), are the valves fully open when you trigger 'track "mode? what is the difference between track mode and using the controller to trigger open mode. Does the controller delete the function of the lotus installed "touring, sport, track"" settings?

The 3rd Cat deletion has no effect on the valve functionality, ie when the valves open or close, as this is triggered by the RPM level that the car generates as you accelerate. The reason why the valves open earlier on Sport and Track modes, and their opening is otherwise more delayed on Touring mode, is because the gear ratio is shorter on Sport, even shorter on Track, generating higher RPM and, in turn, triggering the valves to open earlier.
As for the 3rd CAT delete, the advantage of the unobstructed replacement pipe is that the exhaust fumes can be directed from the engine towards the muffler more freely, faster and without the additional choking of sound, a job that's better left for the muffler to perform. Hope this helps to add some clarity and, by the way, no question is a dumb one.

 

[Eddmac]

I'm not sure what motivation a dealer would have to make any attempt to void a warranty, since it's the manufacturer that is providing it and any repair under warranty represents additional business for the dealer, and it's Lotus that pays for their work on the car.

Under warranty, the dealer will not make any profit. Warranty allocated times are always less than retail and depending on the manufacturer, they might have to pay for labour themselves, while the manufacturer pays for parts. I don't know the deal with Lotus, but expect it to be something similair. That's why dealers don't like warranty work.

 

[Nova]

The reason why the valves open earlier on Sport and Track modes, and their opening is otherwise more delayed on Touring mode, is because the gear ratio is shorter on Sport, even shorter on Track, generating higher RPM and, in turn, triggering the valves to open earlier.
As for the 3rd CAT delete, the advantage of the unobstructed replacement pipe is that the exhaust fumes can be directed from the engine towards the muffler more freely, faster and without the additional choking of sound, a job that's better left for the muffler to perform. Hope this helps to add some clarity and, by the way, no question is a dumb one.

Uh, how is that possible? Does Lotus know about this capability?

 

[crestima]

Uh, how is that possible? Does Lotus know about this capability?

Sorry, but how is what possible? Stay constructive please...

 

[FlashingBlade]

I'm interested in a Ti exhaust to save weight and a third cat delete but I think I'd just keep the original valve controller and put it in track mode if I want the noise.

 

[Stealthinnimbus]

Agree. Despite the obvious being obvious, it would behoove Miltek to just get rid of the damn Forced Closed button altogether as there's just no rational reason to have it, and it only poses risks for those who don't know better.

But there isnt a force closed mode
1 = equivalent of track- fully open
2 = equivalent of sport
3 = oem ie follows the vehicle mode be it road, sport or track

Personally i put it in mode 1 the dayni fitted it and havent looked back.
Its super easy to do

Lotus Silverstone noted it was fitted when it went in for another warranty issue. They have no concerns about it at all

 

[scc.131.fe]

Sorry, but how is what possible? Stay constructive please...

Changing gear ratios by ECU mode seems inaccurate. We're for more on what you meant by "shorter gear ratios".