Golf tee mod for M3??

[SilverSlug]

I've searched the forum, and the other threads were of no help.

My M3 is nice and loud (and super bassy) at startup, but after it goes through the warm up cycle, something happens where the exhaust quiets down.

In the 335i, you can stick a golf tee into the hose feeding the valve that closes the second exhaust tip, so it always stays loud.

Is something similar possible in the M3?

Is this bad for the car in any way??

[LastMCar]

Not a thing in the M3. Exhaust is open.

[SilverSlug]

Originally Posted by LastMCar

Not a thing in the M3. Exhaust is open.

So the cold start warm up cycle is definitely louder and much more bassy, and then you can hear it suddenly quiet down after a couple mins when it's over.

What makes it louder for those few minutes? Is it a valve somewhere that opens/shuts?

[drrust]

It's programming in the ECU. People actually have it tuned out. If you want a louder exhaust note, start looking at exhausts.

[roastbeef]

Originally Posted by SilverSlug

So the cold start warm up cycle is definitely louder and much more bassy, and then you can hear it suddenly quiet down after a couple mins when it's over.

What makes it louder for those few minutes? Is it a valve somewhere that opens/shuts?

It's the engine running rich and retarding timing to heat up the catalysts quicker to reduce emissions.
It's not your imagination, but there's no valve.

[Evo13]

The only "equivalent" would be OEM exhaust mod or ACM exhaust mod (both are the same thing)

[wyatth]

The cold start sequence holds the RPMs higher. Watch the tach/idle drop when the cycle finishes and it gets quiet. It's all done to warm up the cats quicker (they're only effective/efficient when hot).

[SilverSlug]

Originally Posted by wyatth

The cold start sequence holds the RPMs higher. Watch the tach/idle drop when the cycle finishes and it gets quiet. It's all done to warm up the cats quicker (they're only effective/efficient when hot).

All that makes sense, however still somehow doesn't explain why it has so much more BASS. It's like a subwoofer playing constant bass tone.

[Ajolives]

Originally Posted by SilverSlug

All that makes sense, however still somehow doesn't explain why it has so much more BASS. It's like a subwoofer playing constant bass tone.

2x the amount of air running thru with the secondary air pump in the initial start up; more air = more bass.

[serranot]

Originally Posted by Ajolives

2x the amount of air running thru with the secondary air pump in the initial start up; more air = more bass.

This. Secondary air pump heating the cats up.

[SilverSlug]

I figured out what was happening and wanted to follow up.

I have a Borla S-Type exhaust, which has a very low deep bass tone, it sets off car alarms of nearby cars with idle alone (no rev), not from the loudness (it's not that loud), but from how low and deep the bass tone is... as if playing two 15" subwoofers with a constant booom.

This bassy tone goes away once the car's warm up cycle finishes, but comes back if I turn on the M button

[roastbeef]

If it comes back with the M button, your car is broken.

[amrazM]

Originally Posted by roastbeef

If it comes back with the M button, your car is broken.

word





or op is broken

[roastbeef]

We were all new to this platform at one time or another. Mdm does not do anything that changes the exhaust note.
You can set it to change dampening if you have edc and throttle response ("power" mode), but that's it. There is no special mdm engine mapping.

[Not Sure]

this thread is embarrassing.

[amrazM]

Originally Posted by SilverSlug

So you're telling me that I'm the only one who thinks having the Power mode turned on (via M button) makes the engine sound different/louder?

I'll try to find some time to get record a video.

E9x M3 does not come with a valved exhaust. The only thing that happens with MDM M Power mode is different throttle mapping and that sure as shit doesnt change the exhaust tone and it also wont replicate the way the engine sounds on Cold Start

[amrazM]

Originally Posted by SilverSlug

The deep bass tone I'm referring to is present at start-up even when the engine/pipes are fully hot and warmed up.

I'm also not referring to a difference in tone that would result from valvetronic system.

I guess you just have to hear an S-Type Borla in person to understand what I mean.

As I said, I'll try to find time to post a video.

these cars sometimes idle differently when the fan kicks, its due to the dme compensating for additional load. this could be what you are describing

[roastbeef]

Originally Posted by SilverSlug

So you're telling me that I'm the only one who thinks having the Power mode turned on (via M button) makes the engine sound different/louder?

I'll try to find some time to get record a video.

mdm does three programmable things;
1. modifies traction control
2. modifies throttle response
3. modifies edc

it doesn't turn on any fans for anticipated cooling needs. the fan is electric anyways.

[Helmsman]

Originally Posted by SilverSlug

The deep bass tone I'm referring to is present at start-up even when the engine/pipes are fully hot and warmed up.

I'm also not referring to a difference in tone that would result from valvetronic system.

I guess you just have to hear an S-Type Borla in person to understand what I mean.

As I said, I'll try to find time to post a video.

Like the guys says, still the start up sequence that makes the noise. And yes, one wonder why that goes on also when the car is warm but guess it still think the cat are too cool.

Ps. Btw tried Borla S type on the M3, horrible! Atak was much better with built in resonator.

[SilverSlug]

Originally Posted by Helmsman

Like the guys says, still the start up sequence that makes the noise. And yes, one wonder why that goes on also when the car is warm but guess it still think the cat are too cool.

Ps. Btw tried Borla S type on the M3, horrible! Atak was much better with built in resonator.

Interesting... I absolutely love the S-Type, it sounds amazing to me (less obnoxious/ricey) and much better than the Atak.

To each is own, I guess.