991.1S Very loud back fire at high revs.

[richieruss1]

Don't mean to steal Tony's thunder (sorry Tony) but I was looking into headers and sports cats a while back - either from Fabspeed or Topgear - the latter being UK based and far more cost effective!

Topgear webpage shows the 991.1 headers/sprts cats as currently out of stock but show 8 in production, so worth giving them a call.

Also worth asking for 10% discount (as they're a forum sponsor) and if you're prepared to create a before/after YT video you might get a bit more - never hurts to ask.

https://www.topgear.co.uk/porsche-911-991-gen-1-carrera-manifolds-with-sports-cat

Obviously can't promise this will fix your backfire problem but if you go down the sport cat route then they're worth a look.

PS: Don't forget, you may need to factor for replacement of the manifold bolts, which can shear and need drilling out, so that's something to be aware of! Some folk replace them with titanium studs to help removal down the line.

Thanks, those topgear ones look fantastic ... I can only dream of having a sound like this... https://www.youtube.com/watch?v=4HjXS8fG6Ow

 

[911Time]

Epic sound but I think you're gonna have to shell out for more than just the headers...
:floor: :floor: :floor:

 

[richieruss1]

Epic sound but I think you're gonna have to shell out for more than just the headers...
:floor: :floor: :floor:

Those rally GT3s sound amazing don't they probably the best GT3 sound that I can find on YouTube... I play that quite a lot and loud....

I'd just a few extra bits like a new motor, and it would be illegal on the road anyway.... :floor:

 

[OttoOtto]

Appreciate not much help to OP's problem but the Topgear website claims..

Power gains of over 25whp and ft-lbs of torque! :eh!:

Makes the PowerKit look pricey, what am I not understanding?

 

[911Time]

Appreciate not much help to OP's problem but the Topgear website claims..

Power gains of over 25whp and ft-lbs of torque! :eh!:

Makes the PowerKit look pricey, what am I not understanding?

Without wishing to go off-topic:

In essence, the design of the OEM manifold is limited by certain constraints, whereas the after-market part is not.

The original engine and any approved Porsche parts like the Power Kit need to meet worldwide legislation and perform as expected for many years.

Improving on an already efficient N/A engine isn't easy - hence why the Power Kit requires new heads, cams, plenum and sports exhaust to make fairly small gains. Also it's not just how much you gain but where in the rev range and under what conditions.

If this were solely about tuning (rather than the possibility for the OP to maybe use a problem to justify an upgrade) then I'd expect no more than 10-15whp from a change of manifold/cats and consider it just a part of a wider range of upgrades - frankly, any more from a change of manifolds/cats would be a pleasant surprise.

 

[OttoOtto]

Yes absolutely agree. It was the torque bit that raised my eyebrows, but perhaps that isn't preceded by the number '25' even though it reads like that. Anyway, mine's going in for a warranty renewal as soon as OPS mechanics stop getting 'pinged' so it's not an option.

 

[richieruss1]

Quick update I had the cat replaced today. The old one came out, and it was utterly destroyed. The new one has gone in, and the car is now sounding perfect, and it smells good too! I'd say that it's back to normal.

Again thanks for all of your help!

Happy Days!

:thumbs:

 

[Julesturbo]

Thats great news, and it also shows how good the members on here are especially deMort, Well done that man :thumb:

 

[911Time]

Glad it's sorted for you - nothing more soul destroying than an on-going problem with your pride and joy.

Happy motoring!