Boxster/Cayman GTS Exhaustvalve 6500 rpm PSE?

[corvettedave]

bcr5784 said:

If you are getting neat fuel in your exhaust causing pops and bangs (which you didn't have before), then ergo your exhaust is the cause and has interfered with the fuelling. It's simple cause and effect. But I can't be bothered arguing further - if you like it that way then fine.

the point iam making is the 4 cats, factory exhaust system has hidden those noises, the reason you cant be bothered to explain your theory, is because you know iam right! lol

[nsm3]

I think the higher back pressure of the OE setup prevents the bangs in the first place, rather than "masks" them? The slightly lower resistance of the new back box creates this situation of an incomplete burn, which then ignites in the manifold. I had the same on my Exige S, when I simply changed the heavy old stock backbox/outlet, for a Larini lightweight (read less passes/wadding/resistance). The overrun bangs and crackles were significant after making that mod and there were no valves involved. Similar to a PSE being in Sport mode?

[bcr5784]

corvettedave said:

the point iam making is the 4 cats, factory exhaust system has hidden those noises, the reason you cant be bothered to explain your theory, is because you know iam right! lol

See nsm posting. The reason I can't be bothered to explain it further, is because the effect and it's cause has been so well known for 40 years (to my knowledge) with both restrictive and unrestrictive exhausts. If you were right then the normal exhaust note would be far far quieter than it is, and the pops and bangs would be the ONLY thing you would hear.

[bcr5784]

nsm3 said:

I think the higher back pressure of the OE setup prevents the bangs in the first place, rather than "masks" them? The slightly lower resistance of the new back box creates this situation of an incomplete burn, which then ignites in the manifold. I had the same on my Exige S, when I simply changed the heavy old stock backbox/outlet, for a Larini lightweight (read less passes/wadding/resistance). The overrun bangs and crackles were significant after making that mod and there were no valves involved. Similar to a PSE being in Sport mode?

I suspect you are probably right in the case of fitting aftermarket exhausts with lower back pressure. Not sure whether that is how PSE "works" - but it's certainly possible.

[nsm3]

I'm pretty sure that the PSE is no more complex than a by-pass valve(s) in the exhausts that permits a shorter route to the exit tips. Certainly has been on previous manifestations.

[bcr5784]

nsm3 said:

I'm pretty sure that the PSE is no more complex than a by-pass valve(s) in the exhausts that permits a shorter route to the exit tips. Certainly has been on previous manifestations.

If you're right, and it's a simple as that, then Porsche are NOT cutting off (all) fuel on the overrun. They could, of course, very simply, make fuel cut-off a function of PSE Sport mode. Do you know if they do?

They have (on PDK) made Coast mode the default on the overrun, rather than fuel cut-off and staying in gear. That seems to yield excellent fuel economy for me, (despite my initial misgivings) on Motorway runs, but isn't an option on manual.

[GaryF]

If you want to sample some major snap, crackle & pop this is worth a look for a laugh :-

https://www.youtube.com/watch?v=t0uzHiNYnds

Tell me that didn't make you smile just a little. It should be illegal to make this illegal...

[Trotmant]

GaryF said:

If you want to sample some major snap, crackle & pop this is worth a look for a laugh :-

https://www.youtube.com/watch?v=t0uzHiNYnds

Tell me that didn't make you smile just a little. It should be illegal to make this illegal...

1. WildWest!

[SimR]

Trotmant said:

GaryF said:

If you want to sample some major snap, crackle & pop this is worth a look for a laugh :-

https://www.youtube.com/watch?v=t0uzHiNYnds

Tell me that didn't make you smile just a little. It should be illegal to make this illegal...

1. WildWest!

Ha ha ha!

[J12KJR]

Brings back memories, mine only lasted a few days with the decats and minimal silencing it was just too loud and I never noticed the flames too busy seeing where it was heading to look for them.
The inefficiencies of the speed six fueling system do provide great ammunition for those of us with a childish disposition though.