How to tell when turbos kick in?
Thread Starter
Junior Member
Joined: Jan 2012
Posts: 65
Likes: 0
From: Houston, TX
2012 CLS550 Launch Edition
How to tell when turbos kick in?
This my first turbo, let alone twin turbo, motor. My question seems simple but I can't find anything in the forums or the web to help. How can I tell when the turbos kick in? Is there an rpm range or does it depend on how you stomp on it? Also, could someone explain how to initiate "kick down"? Is there actually a switch or button under the pedal? While I'm at it, what is the best way to launch off of the line? Slow steady start and then mash it?
Super Member
Joined: Apr 2007
Posts: 561
Likes: 2
From: New Mexico
2014 E350, 2012 SL550
The idea behind twin turbos is to mitigate turbo lag.
A large single turbo must spin-up to achieve efficiency. You can detect this when accelerating and it is known as turbo lag.
It's not that the turbo is not engaged, it's simply that it is not yet efficient Your butt-dyno can detect the RPM where the turbo seems to "kick-in".
Twin turbo technology aims to make the turbos more efficient at lower rpm's either by using parallel smaller turbos, or by using sequential turbos. The butt-dyno effect is that turbo lag is less apparent. Ideally, you can no longer detect when they "kick-in".
Regards,
Don
A large single turbo must spin-up to achieve efficiency. You can detect this when accelerating and it is known as turbo lag.
It's not that the turbo is not engaged, it's simply that it is not yet efficient Your butt-dyno can detect the RPM where the turbo seems to "kick-in".
Twin turbo technology aims to make the turbos more efficient at lower rpm's either by using parallel smaller turbos, or by using sequential turbos. The butt-dyno effect is that turbo lag is less apparent. Ideally, you can no longer detect when they "kick-in".
Regards,
Don
Super Member
Joined: Nov 2007
Posts: 574
Likes: 7
From: Hawaii, (Texas:business)
'12 E550C, Sierra Denali
When accelerated hard (especially in Sport or M) you'll hear the turbos spool-up, the "exhaust" will get louder (inside the car), and you'll feel a distinct push against the seat back.
Starting from stop is touchy: too much throttle will cause ESP to step in.
adding a boost gauge is a great idea, but don't know where to put it: without buying and installing a new instrument panel.
Starting from stop is touchy: too much throttle will cause ESP to step in.
adding a boost gauge is a great idea, but don't know where to put it: without buying and installing a new instrument panel.
