Boing

Hi everyone,

QUestion: Does Anyone know if there is a possibility to disable the first LOUD start?
I don't want and need that first startup start when i start the car. (The Cat is also deleted, that's why the sound is too loud for me)
Got a tip, to disconnect the valve connectors, but another one tell me that wil cause faults/errors.

Hope someone has a solution for me.

Don't need the question .. Why? Just want a solution to shut this off, and want a normal V8 car start.

Thanks a lot for your help !!!

KR

superswiss

No, you can't turn off the cold start of the engine. Because the engine is cold, it revs it up higher so it cranks properly. Back in the days we had to pull the choke to start a cold engine, otherwise it wouldn't crank. Nowadays the ECU controls the air/fuel ratio precisely along with the cold start procedure to make sure the cold engine fires up. For example it holds the revs above 1000 rpm for about 30 seconds to stabilize the combustion, circulate the fluids and start heating the cats, before it drops to the normal idle rpm. Most of us whish that even a warm start sounds like the cold start. To that end AMG added Emotion Start to the 2019+ models. By pressing and holding one of the shift paddles while starting the engine, it opens the valves and briefly blips the engine for some crackling during the startup if the engine is already warm. So that gives you control over how loud you want the warm start to be, but you can't control the cold start. Disconnecting the valves isn't gonna do it. On the contrary, that will keep the valves open at all times in loud mode and as said you'll get errors and the car will go into limp mode.

Boing

Thanks for your complete answer🙏
BUT,.. it is not what a meant.

it is the start from the engine, cold, warm... allways.
that first start sounds like that the valves are opend if i push the start button. A hard sound for a second and thats it.

superswiss

Oh, I see. Yeah, you can't turn that off, either. The valves are open by default. They use vacuum to close, but the vacuum has to build up first. So during a brief moment when the engine starts the valves are open until there's sufficient vacuum to close them. That's what I was kinda getting at that disconnecting the valves will have the opposite effect. If you disconnect them, they won't close at all.

Boing

ok, thx!
is there no possibility to program/code these valves turned off at startup?
Just hardup thinking🤷‍♂️

superswiss

It's not a matter of programming. A spring holds the valves open at rest and to close them requires a vacuum. No matter of programming will magically produce the required vacuum before the engine is started and has built up the vacuum. You would have to rig something mechanical that keeps the valves closed at rest, until the vacuum is present and then revert to stock operation.

W205C43PFL

I guess you can immediately put the car in drive so the revs drop but that might not be healthy for the transmission.

Jimmy_c63s

Years ago when I was going through the whole "I NEED MORE NOISE" phase I had this coded out in my prefacelift coupe just after I did the secondary cat delete as it was annoyingly loud and I was using foam pool noodles shoved into the exhaust to quieten the loud startup boom each day as I felt bad for my nice neighbours.

Having this warm up procedure coded out made the car warm up a lot slower so after a week I got it coded back to stock and went back to using the pool noodles.

Then a couple of months later I got over the whole noise thing altogether and missed the factory sound so I got my secondary cats put back.. go figure.

My point is you can get it coded out in prefacelift cars but I don't think it's good for the car!

Facelifts are different and Superswiss has the most experience with them so I don't think it can be coded out as he said.

WadeBrookss

put the car in drive so the revs drop but that might not be healthy for the transmission.

C60 Free

Buy a valve controller, you can shut the valves using it so it’s quieter (as well as louder when you want)


Alternatively I imagine a decent tuner can map the cold start cycle out.

I doubt it’s bad for the car, the main reason cold start is there to warm the cats up to make them more efficient.

J.M.G.

All three exhaust valves on the 205 C63 are fully electric. There is no vacuum involved. The exhaust valves can be programmed to close during start up or one can use a exhaust module (ASR / Renntech) for that job.