VR6 exhaust note not sounding like a VR6

[Kevin Bacon 5]

Easiest way to analogise the Helmholtz theory is the sound you hear when blowing across a glass bottle top. The noise you hear is a pressure differential. Same as the buffeting you get from sunroofs at low speed.

 

The roar you hear from a VR6 is basically air waves being bounced back to the airbox, so if you remove the resonator tube, or swiss cheese the bottom half, you hear it very clearly!

 

I think a lot of people only consider the intake system to be downstream of the throttle. Everything upstream (i.e MAF, pipes and airbox) is all fair game for mucking about with. Some people even take the air straighteners out of the MAF because they consider them to be a restriction! The ONLY way to increase MAF flow is to use a larger diameter housing.

 

When VW design intake systems, it's end to end, and there are actually 2 tuning tubes in the aibox. A small one where the air enters the bottom half, and the resonator tube in the top half. The entire intake system is a very carefully designed compromise between packaging and intake tuning. The air waves are contained. The whole idea of intake tuning is you want the air wave that's bounced away from the valves, to push new air in as it bounces back. If you've stuck a cone on the end of your MAF, or butchered the air box, you lose that effect.

 

I should should add that this effect is most noticeable at low to medium revs at part throttle. When the throttle is wide open, all the engine cares about is getting max air in, so peak hp numbers don't really change, but low and mid throttle response generally suffers.

[g0ldf1ng3r 13]

Kev - that is a fantastic explanation & a great level of detail

 

thank you on behalf of us all on here for continuing to share your vast knowledge & experience, i know personally i learn much from you

[sexybourbon 0]

Yep you are annoyingly clever at everything vr6 but like most on here iv learnt a fair bit from your gassing and usually listen to what you have to say basically because you have done it all

 

Get a bmc stuck on and enjoy it for what it is mate

[Kevin Bacon 5]

You guys are making me blush :oops: :D It's just my ramblings really, and I do a lot spannering and reading :study:

 

I'm glad forums are just areas for the exchange of opinions and ideas, because I'm sure loads of engineers and engine builders would probably challenge me on half of that, but the it's the basic principals :)

 

I'm not suggesting people shouldn't mess with their intake systems though. Some people like the noise and aren't bothered about optimal running. I'm too picky and like everything to run perfectly!

[Wullie 1]

. I'm too picky

 

That explains the nose then.

[g0ldf1ng3r 13]

That explains the nose then.

 

ha ha ha!!!

[st.john smythe 0]

when I said k&n style filter I didn't mean to replace your current panel filter with a k&n panel filter as that I would of thought wouldn't make any difference, I should of said cone filter http://www.ebay.co.uk/itm/RAMAIR-UNIVERSAL-INDUCTION-AIR-FILTER-VOLKSWAGEN-GOLF-VR6-/390488499892?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5aeaeda6b4

ebay search vr6 cone filter , you can pick them up for as little as a tenner , just to try them out before commiting to a better quality one, if I remember rightly even with a cone filter it still doesn't give the VR purr under light throttle , its only when you hoof it, so changing to a cone would probably just enhance the sound your already getting, idd say if your not happy with that then look more towards the exhaust side,

 

Yeah cheers for that but if I totally change airbox/filter i'd go for a bmc as from what I understand k&n cones suck in too much hot air and even if you put in another air feed they still don't give out any more power. All that's a long way down the list at mo anyway! Having driven for a couple of days without the snorkel i haven't noticed a loss of torque/responsiveness low down the revs just a slight loss of the silky smooth delivery at low revs - only really noticeable when going from 1st to 2nd gear in traffic etc. If the engine is robbed of torque for the 1st couple of thousand rpm's then it could only be a couple of lbs/ft or so at the most.

[science 0]

Has anyone got pics of the VR6 helmholtz resonator?

I'm not sure if mine is complete.