After about 1.5 weeks of unplugging the valves cables, i started to notice that black spots started to buildup on the lower chrome frame near the exhaust tips.

I never had these spots before. They are easy to remove, but I didnt expect this issue as a side effect. Did you guys notice the same thing?

Btw, I wash my car once a week

 

Do you have to unplug both plugs on each valve to keep them opened?

 

yes you do.

 

Does anyone have a before and after video clip?

 

It would be more time consuming to produce such a clip than it takes to actually unplug-try-reconnect the valves.

 

Yes I have. First thing I did when I got the car. Really easy. 2 connections on each side. Covered them with duct tape to protect them. Reconnected almost 2 years later when sold car. No issues.

 

Hey guys, I know this is an old thread, but it had the best collection of information about the stock exhaust. Just wanted to post here because I wanted to clear a few things up.
The larger connector is basically a throttle position sensor. The wires are red for +5 volts, black for negative, and white for signal (0-5 volts depending on flap position). The smaller plug is for powering the motor that moves the flap. It is connected to an H-bridge which can change output polarity depending on which direction the motor should turn.

You can just disconnect the smaller connector and the flaps will not move.

I am working on a module that will allow me to control the flaps. The problem is that Lexus has engineered some safety into the system (who would have though) and if it detects the flaps are not moving as expected, the system will stop trying until the car is restarted in order to prevent the motor from spinning into a position that is not possible.

This leaves two options: Trick the system into doing what I want, or take over control and trick the system into thinking it is business as usual.
It is looking more and more like it will have to be the latter which makes things complicated since I have to reverse engineer what the computer is trying to do. I assume this is why PPE went the vacuum actuator route...

I am very close on this and can keep you updated if you would like. At the moment I am able to lock the exhaust into full open when the car decides to do so by reading the TPS and cutting power to the motor. Next step is to integrate my own H bridge to control the flaps myself. Then I will simulate what the car is trying to do so I can switch back into default (let the car decide) mode without it going into protection mode.
I have OEM connectors from Sumitomo (TS090-2S-1) and Yazaki (090II-3S-1) on the way so I can patch my module in properly.

 

Is there a downside to having the larger connected disconnected?

And thank you so much for your hard work!

-Michael

 

No downside! If you already have it like that, there is no need to adjust.

I enjoy doing this type of "hacking" stuff! Hopefully a few other people can benefit. I will post all the designs and code once I am finished so other people can recreate it.
I will have further updates of my findings/development in this thread if anyone is curious.

 

Interested and following! Good luck

 

So I tried to mod my stock exhaust as described in this thread but my car a 2021 convertible does not have the 2 connectors, it has 1 5 pin connector so i figured they changed the connector. I unplugged it and the car starts with the valves open but then quiets down even with the the plugs unplugged it seem to quiet down. Has anyone done this mod on a 2021, am i missing something?

 

Mine starts loud and quiets down after the car runs for a few minutes. I have disconnected the valves on all my Ferraris and they do the same thing. Drive it hard and you will definitely notice it's a lot louder.

 

Interesting that they combined the plugs. The wiring looks the same.
Are you sure the quieting down you are hearing is not the car transitioning from cold start?
Our cars have dual injection and will use that in conjunction with higher rpms and valve timing adjustment to heat the catalytic converters up faster. They do this for emissions.
That process can last longer if it is colder outside/the engine is colder. Once things are sufficiently warm, it will switch to a more efficient idle ECU mapping which is also quieter.

 

Here is a photo of my 2018 valves on the stock system I replaced. You can clearly see the two connectors per side. It appears there have been revisions on your 2021. The valve body even seems a bit different. Odd that they are different. Maybe this was to cure the 'horn' sound that some people had noticed upon startup???

 

The horn sound has survived to the 2021 model. I never noticed it on the 2019 coupe. Does not happen every time, but often. Sort of a happy sound.