Exhaust valve fully open
#26
IDK about that...with the renntech module my car starts significantly louder and idles louder on cold start or warm start than without it...the only explanation i can think of is the position of the valves. Even in Race mode once the car is warmed up all the valves arent completely open until 4K RPM.
I think that I understand what you are saying; however, I cant verify with the RENNtech set up.
Factory default on start up is valves open and, to your point, COMFORT mode. After oil is distributed through the motor and the safety warm up is complete, the valves close - RENNtech may do this too but louder due to the 100% open override. With CETE, it eliminates this start up feature, and the car will always start (in COMFORT) with the valves in the closed position.
Factory default on start up is valves open and, to your point, COMFORT mode. After oil is distributed through the motor and the safety warm up is complete, the valves close - RENNtech may do this too but louder due to the 100% open override. With CETE, it eliminates this start up feature, and the car will always start (in COMFORT) with the valves in the closed position.
#27
MBWorld Fanatic!
Join Date: Nov 2016
Location: California
Posts: 1,291
Received 623 Likes
on
369 Posts
2020 McLaren 720s Spider
IDK about that...with the renntech module my car starts significantly louder and idles louder on cold start or warm start than without it...the only explanation i can think of is the position of the valves. Even in Race mode once the car is warmed up all the valves arent completely open until 4K RPM.
With CETE or RENNtech, the purpose is largely to fully open the exhaust values when they are opened. From the factory they have been limited (moreso in the 2020 models). In the factory 2018 I have, during a cold start, the exhaust values will be default open similar to the EVM settings (100% vs <100%), and then once oil is distributed through the motor and an acceptable temp is reached, they close (usually about a minute).
For the CETE module, it changes that - the default cold start opening is over-ridden and the EVM is controlled via the button or engine settings only - so it always starts with valves closed. I'm not sure how the RENNtech works during cold starts, not to be confused with regular operation. For me, I didn't like the idea of a remote that I could misplace so I opted for the CETE.
#28
Multiple perspectives converging.
With CETE or RENNtech, the purpose is largely to fully open the exhaust values when they are opened. From the factory they have been limited (moreso in the 2020 models). In the factory 2018 I have, during a cold start, the exhaust values will be default open similar to the EVM settings (100% vs <100%), and then once oil is distributed through the motor and an acceptable temp is reached, they close (usually about a minute).
For the CETE module, it changes that - the default cold start opening is over-ridden and the EVM is controlled via the button or engine settings only - so it always starts with valves closed. I'm not sure how the RENNtech works during cold starts, not to be confused with regular operation. For me, I didn't like the idea of a remote that I could misplace so I opted for the CETE.
With CETE or RENNtech, the purpose is largely to fully open the exhaust values when they are opened. From the factory they have been limited (moreso in the 2020 models). In the factory 2018 I have, during a cold start, the exhaust values will be default open similar to the EVM settings (100% vs <100%), and then once oil is distributed through the motor and an acceptable temp is reached, they close (usually about a minute).
For the CETE module, it changes that - the default cold start opening is over-ridden and the EVM is controlled via the button or engine settings only - so it always starts with valves closed. I'm not sure how the RENNtech works during cold starts, not to be confused with regular operation. For me, I didn't like the idea of a remote that I could misplace so I opted for the CETE.
The following users liked this post:
Orcbolg (10-28-2020)
#30
#32
Sorrry maybe I didn't explain it well. Regardless of what EVM you have the car always starts in COMFORT mode. With the Renntech EVM, the car will stay int he setting you have the EVM set to you. So the car will start in comfort mode but the vales will be open so it'll be louder. That being said, you can tell it idles significantly louder when you switch it to RACE mode rather than comfort...even with the EVM.
#33
Cete = true
RENNtech = not true
That said, Its obnoxiously loud on start up with the valves 100% open (not to be confused with the stock setting open on startup like it comes from the factory). I opted for the Cete - I just wanted the option to decide whether I want to wake up the neighbors or leave the house without the fanfare.
RENNtech = not true
That said, Its obnoxiously loud on start up with the valves 100% open (not to be confused with the stock setting open on startup like it comes from the factory). I opted for the Cete - I just wanted the option to decide whether I want to wake up the neighbors or leave the house without the fanfare.
The following users liked this post:
Saudio (10-30-2020)
#35
#36
#39
Just realize that your default starts in 'C' mode...so your start ups will be the same as stock.
#40
Member
That’s what you’re saying. If so then the Renntech one is better because of the key fob function? The CETE one is basically the same thing as Renntech without the key fob and uses the factory switch. I think both of them will start in C mode regardless of the EVM.
#41
Correct me if I'm wrong: With Renntech, the control changes the valve between 100% open and factory (when off, the factory control acts normally).
The Cete control changes the valve between 100% open and 100% closed. No middle ground.
The Cete control changes the valve between 100% open and 100% closed. No middle ground.
#42
MBWorld Fanatic!
Join Date: Nov 2016
Location: California
Posts: 1,291
Received 623 Likes
on
369 Posts
2020 McLaren 720s Spider
I believe the difference is that RENNtech allows you to turn off the modification vs CETE is just hardwired. @BBS63 cold starts under factory settings last about 20 seconds or so and as a previous comment said, we all start in 'C' so valves are closed.
The following users liked this post:
BBS63 (11-02-2020)
#43
When set to fully open, neither the exhaust button nor changing modes does anything to the valves. I also just noticed that the Renntech version of the ASR module is missing the silent option, which completely closes the valves.
The following users liked this post:
BBS63 (11-01-2020)
#46
Super Member
Not sure if this will help lol
My GTC is very loud on cold startup in C. Always was hopeful always will be. When I installed the EVM I noticed a bit more bark in the volume on cold startup. That said I can only tell if it’s on by going back to C and playing with the button on the remote as the car is pretty loud all the time anyways.
To answer the other question, the valve button on the centre console still works because it only controls the valves in the mufflers. The module opens the centre valve that opens in Race all the time leading to the additional volume at idle and around town. Hope that helps.
To answer the other question, the valve button on the centre console still works because it only controls the valves in the mufflers. The module opens the centre valve that opens in Race all the time leading to the additional volume at idle and around town. Hope that helps.
The following users liked this post:
BBS63 (11-01-2020)
#47
To answer the other question, the valve button on the centre console still works because it only
controls the valves in the mufflers. The module opens the centre valve that opens in Race all the time leading to the additional volume at idle and around town. Hope that helps.
controls the valves in the mufflers. The module opens the centre valve that opens in Race all the time leading to the additional volume at idle and around town. Hope that helps.
Here is the exhaust from the GT/S/C, and the R:
The EVM keeps the valves open 24/7. When you start the car after it's already warmed up it has a tendency to start with the valves closed for some reason, leading to quiet starts when out and about. That no longer happens with the EVM installed. Also, unless you are in Race AND pushing the car past a certain RPM threshold, the valves never fully open without the EVM. So the EVM makes the car louder throughout the entire rev range.
Last edited by Orcbolg; 11-01-2020 at 07:30 PM.
The following users liked this post:
BBS63 (11-01-2020)
#48
Super Member
My mistake
Thought I read somewhere there was a centre flap somewhere that opened under full throttle
in race mode. Your probably right then as I’ve never really paid much attention to the exhaust system. Makes sense. Sorry for the mistake.
in race mode. Your probably right then as I’ve never really paid much attention to the exhaust system. Makes sense. Sorry for the mistake.
#49
No worries, you had me second guessing myself for a second there. What they were talking about is what I described in the second part of post, where the valves will never fully open, stock, even in Race, until pushed past the RPM threshold, that I believe is 4500 rpm.
Last edited by Orcbolg; 11-01-2020 at 08:07 PM.
#50
Member
I appreciate the explanation. That’s what I assumed it did otherwise there would be no point in having the module.
What center valve are you referring to? I'm almost certain there are only 2 valves that either direct the flow into the muffler or allow the exhaust gasses to bypass the muffler.
Here is the exhaust from the GT/S/C, and the R:
The EVM keeps the valves open 24/7. When you start the car after it's already warmed up it has a tendency to start with the valves closed for some reason, leading to quiet starts when out and about. That no longer happens with the EVM installed. Also, unless you are in Race AND pushing the car past a certain RPM threshold, the valves never fully open without the EVM. So the EVM makes the car louder throughout the entire rev range.
Here is the exhaust from the GT/S/C, and the R:
The EVM keeps the valves open 24/7. When you start the car after it's already warmed up it has a tendency to start with the valves closed for some reason, leading to quiet starts when out and about. That no longer happens with the EVM installed. Also, unless you are in Race AND pushing the car past a certain RPM threshold, the valves never fully open without the EVM. So the EVM makes the car louder throughout the entire rev range.