I must have hearing issues as well. Didn't notice any difference after defeating symposium (almost forgot about this thread and my blocking it with insulation), nor do I hear any SC whine, before or after a tune.

I do hear the SC in my Tundra, and while its a cool sound, I'm ok without it in my F type.

 

+1. Never heard the SC whine except wjen I temporarily removed the air intake crossover tube. Under full gallup, the SC whine on my MINI is the only thing anybody can hear for miles, so I doubt the issue is my hearing.

 

Something strange here Lance.
We both have RWD V6S F-Type coupes.
We both have the Eurotoys lower pulley and associated VAP tune, although you have the smaller snout pulley as well (but you reckon it makes SFA difference).
So why do you hear bugger all SC whine when I hear heaps?
And I mean lots and lots, it's very pronounced especially at WOT and/or 4,000+ RPM, it sounds like a 747 taking off.
With just the VAP "no pulley" tune I still heard very little SC whine, but as soon as I fitted the larger crank pulley and put the tune on the SC whine went ballistic.
So what is going on here, enquiring minds would like to know!!!

 

That's the perfect description of what my tuned/pullied MINI sounds like. Only exhaust sound on the Jag.


This enquiring mind would like to know as well. I might even raise it to the level of on inquiry.

 

I forgot one possibly important thing - you have a manual trans whereas I have a slushbox.
I can't see how that would make such a huge difference to audible SC whine but who knows!

 

I can't see that either.

 

I have the V8 with an auto and I can also hear absolutely no SC whine.

 

Frosty, as I have explained elsewhere the big increase in SC whine only happened after I installed the Eurotoys lower/crank pulley and the associated VAP tune.
Apparently the VAP "with pulley" tune closes the SC bypass valve earlier and further and that is the reason for the SC whine going from almost nothing to lots.
Maybe the same applies to the VAP "with pulley" tune for the V8, maybe not, I can't remember any forum members with the V8 commenting on this.

 

Just chiming in here for the record 15 R, coupe, auto. I have exceellent hearing, and can not hear SC whine.

I would bet the VAP by itself would increase whine nicely because it closes that bypass.

 

Just discovered this clever little mod and will probably give it a go. Always thought that my car is almost too loud in the cabin at WOT in dynamic mode, not because of exhaust or pure engine noise but because of a kind of loud mid range drone in the cabin which I suspect is the effect of the symposer.

Not sure what to stuff in the pipe though and don't think I have anything very heat resistant at hand. I know how smoking hot the engine gets after a good run so wouldn't want to put anything in there that melts or starts a fire. Any more tips on safe material to use for the plug?

 

I always blame my passenger for that!

 

Yeah, I usually also get some extra noise on the rare occasions that I have a passenger.

 

My first instruction to passengers is "shut your eyes and scream if you want me to go faster!".

 

That's most definitely the symposer.

As noted in the first post, I used ensolite foam left over from insulating a previous car. There is no flow of gas through the tube; it only channels sound. I checked the foam a short while later and again much later and saw no signs of degradation. Look at the plastic elbow and the parts nearby and you'll see that none of that is of high-heat materials. Maybe as a public service I'll take another picture today of the condition of the plug to show what it looks like after all this time.

EDIT:

The newspaper was late this morning so I grabbed a single tool (8mm combination wrench) and popped the hood. The plug looked identical from above, so I removed it to get a picture of the underside. The plug is still resilient (the technical term, I believe, is "squishy") and shows no degradation. Here's a picture:

 

I actually took the car out for a good run tonight to check afterwards how hot that pipe gets and it was pretty hot but obviously nowhere near as hot as the engine block so I guess things in there won't melt or go up in flames. Anyway I'll try to source some similar foam as you Steve used and look forward to hearing if it makes any difference.

Thanks for all the advice and pics, great stuff!

 

PM me an address and I'll put a piece in the mail for you.

 

Top-tip:
Use a marble or ball bearing in the hose. You can then keep the OEM look.

 

It really is an undemanding application. Anything non-flammable that will block sound should do the trick. I thought about a plug of silicon sealer as a more permanent solution than the foam I used, but with no signs of degradation there was no incentive. Eventually, the symposer is coming out. Prompted by others here I'll be changing my supercharger oil, so that would be a good time to tackle it.

 

Just as an FYI...Here is a full blow-up diagram of what makes up the system.

DC

 

Thanks. That's a more complete diagram than the one up top. Number 11 is the bit that bolts to the left cylinder head. Replacing that with a blanking plate or similar and removing everything else is what I'm thinking.

An alternate means to disable the system would be to remove hose #6 and cap the port on #7 where it connects, assuming that the neutral state of the symposer is off. If it's like the valves in the muffler, the neutral state might be "loud" in which case, that would make it on all the time. That would be what I'd call a "negative outcome."