Golf R Observations and Questions

[DDTW]

Used the horn for the first time today and was expecting a wimpy noise but was surprised that a small car has a horn with some balls!!

I use mine all the time to honk cabbies who think the road belongs to their grandmother! Cabbies annoy the **** out of me. Never had problems with them 5 yrs ago!

[bluefrog]

unusual, and possibly dumb, question .. but I'll go ahead and ask it anyway

.. the very sexy, deep, throaty sound that you hear for the first second or so when you start up the R - what the frack is it exactly? ie. precisely what engine components are responsible for this awesome sound??

never fails to get me excited

[shakespeare]

unusual, and possibly dumb, question .. but I'll go ahead and ask it anyway

.. the very sexy, deep, throaty sound that you hear for the first second or so when you start up the R - what the frack is it exactly? ie. precisely what engine components are responsible for this awesome sound??

never fails to get me excited

All the usual components of an internal combustion engine, however on a cold start the RPM's are higher and both exhaust outlets are open, hence the deeper throatier sound (I think this is what you're referring to?)

I like this sound too, and usually start mine with the garage door closed so I get more of an echo

[PTW]

gher and both exhaust outlets are open, hence the deeper throatier sound

Both exhaust outlets open? What's the go there?

[Corey_R]

The Golf R has a "flapper valve" on the exhaust. One of the pipes only opens over a certain rpm/under a circle throttle load, thus allowing the car to have a high level of exhaust flow when needed, but also to be quiet(er) when that flow isn't needed.

[bluefrog]

very interesting and good to know .. thanks guys

[PTW]

The Golf R has a "flapper valve" on the exhaust. One of the pipes only opens over a certain rpm/under a circle throttle load, thus allowing the car to have a high level of exhaust flow when needed, but also to be quiet(er) when that flow isn't needed.

Cheers Is this unique to the R or do the GTI and Audi's have it as well?

[Corey_R]

I'm not aware of a A3 / S3 model which has it, and within the Golf range it's unique to the R.
Many manufacturers use them these days in their performance models though. Allows them to get around the noise regs but still provide a meaty exhaust sound.

[PTW]

Cheers Corey

[PTW]

Found this, it relates to the R32 but maybe the the same for the R -

That's not a vacuum pump, its a vacuum reservoir with a solenoid valve.

The MK IV Flapper gets its vacuum supply from the engines intake.

The Flapper is held closed(Quiet) by vacuum, and opens(Loud) when that
vacuum supply is shut off.

The vacuum line runs from the intake to the reservoir/valve, then to the Flapper.

The solenoid valve is electronically controlled by the ECU to shut off the
vacuum supply to the Flapper when the rpm gets above 3200-3500rpm in
3rd, 4th, 5th, and 6th gears.

I would think the MK V operates off of a similar system. Has anyone chased
down that vacuum line that runs to the Flapper to see where it goes?

And this, more of the same -

BTW, this was all discussed some time ago over on the R32 forum on tyresmoke.net.
One theory proposed there, is that the MkV R32's flapper logic is slightly different than the MkIV, as follows.
MkIV
off - flapper open
idle - flapper closed
Below 3500 rpms or 45 mph, flapper closed
Abvove 3500 rpms and 45mph, flapper open

MkV
off - flapper open
idle - flapper open
Between idle and 3500 rpms + 45 mph, flapper closed
above 3500 rpms and 45mph, flapper open

Basically they wanted to give it a little more burble at idle so
they left the flapper open. The only difference is in ECU logic.
The operation of the flapper itself is the same. No vacuum, it's open.
Apply vacuum, it's closed.

Means flapper mod is the same as well. Clamp line, or pull it off
and plug it, or interrupt the signal wire from the ECU, and it's open.