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

I don't think the modes you describe are right:
Mode 1 - is fully open, no stock modes are full open, they all progressively open up as you increase throttle
Mode 2 - fully closed, not stock mode is fully closed. This is the one that should never be there. It is not Sport mode. And, Sport mode and Track mode are identical in exhaust operation in the bottom and top end.
Mode 3 - is correct as you stated it. I assume road=Tour.

Bottom line is, safest thing to do is put it in mode 1, all open, the only downside(??) is that it will be always loud. Not too bad ;)
The buttons on mvc vary for 2 & 3.... grp confirms that....1 fully open BUT some controllers have positione 3 & 3 functions reversed....
 
Great post by the OP.... but few comments n Questions....

I have grp 3rd Cat bypass n MVC....

I get limp mode ,so far only when I'm going up hill hitting redline n the water temp goes upto 200F from usual 180 to 185F ,on a hot day here in so cal.... typically on full open mode... it usually resets to normal after the car cools off.... on last drive, on way down hill ,I pulled off to enjoy the view n about 10 min later, restarted the car and the RPM was back to normal range but check engine light was on this time.... will read the code later...

I heard people having their cars going to limp mode on the driveway home from the dealer after buying it brand new and so far have not heard many with limp mode on cars with third cat delete and MVC....

I don't think it's the exhaust/mvc issue. ..

I've never heard of ecu reading valve positions.... may be Louis does but .... is the VC on their exhaust truly a bidirectional signal? My huracan with aftermarket valved exhaust by fab speed and GT3 with ipe valved exhaust are uni directional signals with no issues ever having check engine light come on due to valve positions..... I doubt lotus is that advanced in terms of reading valve position....

I'm not saying that it has nothing to do wth it.... yah, the exhaust pressure can affect the flow n volume n potentially cause emission n O2 sensors to read differently and cause limp mode, yadi yadi yah.... I get that but this limp mode issue is not just due to this issue.... may be their ecu is programmed to too narrow parameters....

I just wish lotus would fix it...it's annoying when I can't drive the car at its potential....

'24 FE hethel yellow
 
Great post by the OP.... but few comments n Questions....

I have grp 3rd Cat bypass n MVC....

I get limp mode ,so far only when I'm going up hill hitting redline n the water temp goes upto 200F from usual 180 to 185F ,on a hot day here in so cal.... typically on full open mode... it usually resets to normal after the car cools off.... on last drive, on way down hill ,I pulled off to enjoy the view n about 10 min later, restarted the car and the RPM was back to normal range but check engine light was on this time.... will read the code later...

I heard people having their cars going to limp mode on the driveway home from the dealer after buying it brand new and so far have not heard many with limp mode on cars with third cat delete and MVC....

I don't think it's the exhaust/mvc issue. ..

I've never heard of ecu reading valve positions.... may be Louis does but .... is the VC on their exhaust truly a bidirectional signal? My huracan with aftermarket valved exhaust by fab speed and GT3 with ipe valved exhaust are uni directional signals with no issues ever having check engine light come on due to valve positions..... I doubt lotus is that advanced in terms of reading valve position....

I'm not saying that it has nothing to do wth it.... yah, the exhaust pressure can affect the flow n volume n potentially cause emission n O2 sensors to read differently and cause limp mode, yadi yadi yah.... I get that but this limp mode issue is not just due to this issue.... may be their ecu is programmed to too narrow parameters....

I just wish lotus would fix it...it's annoying when I can't drive the car at its potential....

'24 FE hethel yellow
Can you clarify what setting you were using for the valve? Fully open, OEM, or closed?
 
This is where you may get the limp mode problem even with the stock controller. (That is where my problems started). I.e. Even if you keep the stock controller, you need to disconnect it from the exhaust to connect the new Ti exhaust. When you do that, if you don't connect it back in the same "remembered" valve position, you will end up with limp modes. The Miltek controller mitigates that, by simply keeping the valved fully open and returning "all ok" to the ECU. I think easiest path to great sound seems 3rd cat delete, stock exhaust, but then you may have emission check issues.

So disconnect the stock valve controller before removing the third cat even if you're not replacing the stock valve controller? Then reconnect the stock controller after the new pipe is installed?
 
So disconnect the stock valve controller before removing the third cat even if you're not replacing the stock valve controller? Then reconnect the stock controller after the new pipe is installed?
Not quite. Any time you disconnect the stock valve controller you will likely end up with limp mode. Unless, you connected in the exact position where you disconnected it from. If you miss that by even a little bit, when the controller gets instruction to fully open or fully close, it will detect it has not been full opened or fully closed, because of the misalignment of the physical position of the valve and the “last remembered” position of the controller. To fix that, you need to recalibrate the controller so it knows what is “fully open” and “fully closed”. And only Lotus can do that.

Hence, whatever surgery you’re doing to the exhaust system, avoid disconnecting the controller. Or, if you do (like I did), then put the Miltek controller on it, which has an always fully open mode, that just opens up the valve fully, and returns “all ok” to the ECU - result = no limp mode and always fully open valve (great) sound.

HTH
 
Oh thanks that’s very helpful. My understanding is that you do not need to disconnect the valve controller when you perform the cat delete, so this issue should not arise.

However, if I change out the entire exhaust system with a Larini for instance, that will necessitate detaching the valve controller, won’t it? And since I’m three hours from the nearest lotus shop, that’s a risk…
 
I honestly don't know why anyone would spend $$$$ on replacing the Emira exhaust -- with the 3rd cat delete and valve controller this car sounds absolutely amazing -- it turns heads everwhere. Save the effort, try the most reasonable action first and see what you think, it's sooo nice.
 
I honestly don't know why anyone would spend $$$$ on replacing the Emira exhaust -- with the 3rd cat delete and valve controller this car sounds absolutely amazing -- it turns heads everwhere. Save the effort, try the most reasonable action first and see what you think, it's sooo nice.
I'm even questioning why you need more than just the third cat delete. Can't you accomplish the same sounds with tour/sport/track mode - is there some benefit to the valve controller besides increased customization in the different modes?
 
I'm even questioning why you need more than just the third cat delete. Can't you accomplish the same sounds with tour/sport/track mode - is there some benefit to the valve controller besides increased customization in the different modes?
The valve controller allows you to start in last used mode or valves 100% open -- set it and forget it. Although I have mine programmed to the home link buttons, I doubt I'll use the feature much...just leave them open 100%. The difference is the valve opening is controlled by both mode and RPM, the controller bypasses that so in sport at idle you can have valves 100% open, etc.
 
I'm even questioning why you need more than just the third cat delete. Can't you accomplish the same sounds with tour/sport/track mode - is there some benefit to the valve controller besides increased customization in the different modes?
Me too. I'm going to start with the cat delete, tho I have to say the full Larini sounds just like a sports car should. To be honest I don't want to mess with the valve controller or have to press a button on fob every time I go into sport mode.
 
I’ve replaced the exhaust and without the valve controller there was not much difference. With the valve controller wide open, huge difference. The stock controller never keeps the valves full open all the time.

A lot of people at talking about the cat delete and that does seem like the safest path to a great sound. However in Denmark, there are strict emissions laws and sound limits. I need to be able to put the car in “normal” mode without having to put back the cat. That was my thinking, if it is flawed, let me know?

My car sounds outstanding! I have a friend with a F12, who was down taking my v6. When I lit it up in the garage, his jaw dropped and could not believe it.
 

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