I don't understand this. My 04 had NO burble whatsoever with the JCW exhaust. Way too quiet. Dump that, add the Borla Race ... all kinds of burble.

No software change

So what, exactly, was causing the exhaust burble in the Borla?

 

If it serves no purpose, what does just a new catback create the burble with NO software changes?

I would add that this is also true on my Porsche. Adding a catback has created some burble where OEM it was quiet. Now this does include dropping the secondary cats.

There is something going on with the catback designs that is creating the burble ... maybe scavanging the gasses better?

 

I love the burble.

 

Love the burble.

 

Call Mini & tell them so they will bring it back

 

I like the sound too, I'm why you would want to get rid of it... Maybe, just get a Prius?

 

MINI's do not "turn off the fuel injectors" upon deacceleration. They shorten the duration of the pulsewidth telling the injector to inject so as to allow a leaner A/F mixture but to compelely shut off the injectors while the engine is running and the ignition still firing is a great way to go too lean and break something. The burble is present in almost all cars if the right combination of exhaust tubing/muffling, A/F ratio, and ignition timing is present.

 

If you completely shut off the injectors you are not going to have ANY combustion, all you are doing is pumping air. This is in no way going to damage the engine.

Shortening the pulsewidth is how you will get lean combustion.

Either way, we are talking about decel here, when the engine is not on boost, and not under any load. Going lean under this condition is not dangerous like it is when you are under load.

Jason

 

I"ve looked at the injector signal with an oscilloscope.

At the transition to lifting throttle, the ECU has to decide if your lifting or if your foot is just bouncing up and down a bit. That's why it doesn't shut the injectors off immideatly with a lifting throttle.

The change in burble with exhaust is just that, you're changing the muffleing and you hear things different (wait till you go with a header and get rid of the pre-cat!).

To make the burble or not is a question of injection and spark, and the threshold that's programmed for the ECU to interpret a lifting throttle as lifted vs bouncing. It's just software.

I can't speak to how Porsche does it, as I haven't logged the injector pulses.

Matt

 

Porsche does not burble OEM. Just changing the exhaust causes "some"

Same with the 04 MINI, changing to Borla created Burble where none existed before. So I got to figure the exhaust has "something" to do with it.

NO ECU changes to either car.

 

My Cooper, with the Megan Racing cat-back, produced just for us Cooper owners, =o) has a nice burble on trailing throttle. The higher you rev it and then let off, the better the burble. I _like_ it.

Zip

 

and the exhaust sounds like "woosh". Take off the mufflers, and it has all the fire and spit that any multi liter V8 ever had..... Changing exhaust doesn't cause it, it changes how it sounds when it comes out.

Matt

 

Changing the exhaust changes how the sound comes out.

Zip

 

You've got me all wrong, I enjoy the "Burble". I'm the guy back in the 60's and 70's that had the glass packs and let'em rap. My friends new when I arrived!

 

glasspacks = mmmm

 

Minis shut off thier fuel on engine braking EXCEPT when the car isn't up to operating temp, or if the RPMs are so low that the idle control circuit kicks in.

But like the poster above stated, for the most part, changing exhaust won't change what sounds the engine makes, just how you hear them.

Matt