996 Turbo - Any experience with removing cats

westcoastclassic · 23 Sep 2017

I was advised by an extremely reliable source that gutting the cats on the car will transform performance. So much so that this contact further claims that simple removal of them provides more performance than a good exhaust upgrade. Apparently the standard system is highly engineered and the cats are overkill and rob it of much performance.

Question is, any experience of this?

I have a sympathetic MOT station needless to say.

I understand this will chuck the mgt light on which is a simple override on the ECU. The individual who told me this is reliable though just fishing for anyone who has done this and experienced the desired results I hope for.

westcoastclassic · 23 Sep 2017

Calling all cars, come on, where's all the expert's?

911munKy · 27 Sep 2017

Well it's certainly going to make it free to breath more without any obstructions, I think on a NA car it may reduce some of the low to mid response (due to a lack of back pressure?) but in return aid top end.
You'll probably need some ECU treaking to get the best out of it and it would benefit from a healthy air intake.
Not sure of its affects on a turbo though, just thought I'd add a response to bump the thread up the page as it's more interesting to read than ones about car prices!

New997buyer · 27 Sep 2017

PM drabux. I think he decatted his standard exhaust.

I've also been told by a reputable tuner that the standard exhaust only suffers from one flaw - weight. Apart from that with the cats removed it's actually quite free flowing.

But these are ultimately anecdotal comments. I've never seen any empirical data. Apart from lifting a standard exhaust which was indeed damn heavy. But at 85 kilos so am I

NLW73 · 27 Sep 2017

gutting the cats or putting de cats is going to make a difference to the gas flow and it will feel like the car is totally free and opened up.

it will trigger the dreaded yellow light but get it remapped to rid of that and get even more oomph.

turbos react really well to de catting.

it will be louder and boomier though but a small price to pay!

westcoastclassic · 27 Sep 2017

My has a great map from one of the top tuners. I wanted to explore how to get more power (which is not needed in all seriousness) without going the road of over priced exhausts, headers, intercoolers, change of Turbos etc. IMO there are two top tuners in the UK for Turbo cars, one of them suggested this was a bit of a little known fact that by gutting the cats you got considerable performance gains on the Turbo car. So much so that it exceeded the gains of a top exhaust system at a fraction of the cost. As pointed out in above post the standard system is heavy though apparently extremely well designed and engineered by Porsche. I would imagine that the mgt light coming on will just require a reprogram and not a remap, hopefully that's the case, as the current map I would not want to lose as the tuner is over 400 miles away and would not want any other map having owned 6Ts with other maps that just were not right.

Many thanks for your responses, it would appear that if your thread is not about how much you are making on your Porsche investment, or how much you might make by buying it, or how do I mollycoddle the value in what I might be making through winter it gets little press. It's like being back at school and playing top trumps.

plynchy · 27 Sep 2017

Drop 'ragpicker' a PM, he's done his.

I picked up a used Carnewal system for my turbo which is a re-hashed standard system with 100 cell cats fitted (allegedly), it does seem to spool up a lot faster than it did and sounds great compared to the std set up. No issues with CEL either.

I completely de-catted a Mk 1 Focus RS I had a few years ago, made a massive difference, turbos do respond well to it.

DynoMike · 27 Sep 2017

I'm fairly sure someone who posts on here and owns a rolling road did this to his car, I seem to remember him saying it freed up 12-15 hp. PM 911Tom as I think it is his guy (but can't remember his name!)

Ps; I don't give a fig what mine is worth, the real value comes when behind the wheel :thumb:

pps; extremeley happy with my 200 cell Kline :cloud9:

Hope this helps mate.

Mike

ragpicker · 27 Sep 2017

plynchy said:
Drop 'ragpicker' a PM, he's done his.

I picked up a used Carnewal system for my turbo which is a re-hashed standard system with 100 cell cats fitted (allegedly), it does seem to spool up a lot faster than it did and sounds great compared to the std set up. No issues with CEL either.

I completely de-catted a Mk 1 Focus RS I had a few years ago, made a massive difference, turbos do respond well to it.

I've got a decatted Kline plynchy, but if I were on a budget I'd decat an OE exhaust on a turbo. One of the best things I ever did was go catless - better noise, better throttle response, more power.

Makes perfect sense and not much of a secret to it really is there? Less restriction = more power, whichever way you do it. It'll take a tuner 3 minutes to switch off the post-cat lambdas. Really it should be free its that easy.

I've got a standard 6T exhaust in the garage. Reckon it'd take half an hour with a hammer and drill to de-cat it effectively enough....

HSC911 · 27 Sep 2017

Never used mine to get rid of the cats :cat:

They have been shi77ing in my garden for ages, the dog used to get rid of them but had to put her down :sad:

Could always use a :shooter:

:grin:

911tom · 28 Sep 2017

This is a bit of a secret so keep it on the quiet; No one has ever fitted a cat to increase performance

Removing them will only help performance so if you want some small gains on the cheap then it is a good idea. Obviously once done there will be there will be no going back but I bet you can buy another used exhaust fairly cheaply. Also the soundtrack could well be a little louder.

If think Mike might be right in that Rick @ Unicorn de-catted his 997 exhaust.

westcoastclassic · 28 Sep 2017

911tom said:
This is a bit of a secret so keep it on the quiet; No one has ever fitted a cat to increase performance Removing them will only help performance so if you want some small gains on the cheap then it is a good idea. Obviously once done there will be there will be no going back but I bet you can buy another used exhaust fairly cheaply. Also the soundtrack could well be a little louder.

If think Mike might be right in that Rick @ Unicorn de-catted his 997 exhaust.

Thanks for all the advice guys, going to do it, good idea as you say to buy another standard exhaust just incase I decide to move it on, doubt it though as having considered other cars there is just very few alternatives after you have gelled with a Turbo, very few indeed...

New997buyer · 28 Sep 2017

^^^^^^ you're not alone. I've a hunch the odd 997 turbo owner might be tempted by going down the same route....

911tom · 28 Sep 2017

:thumbs: had mine 5 years and even if I totalled up all that I've spent on it in that time there is literally no car that comes close! I sold my standard exhaust about 3 years ago after deciding I'd never need it and it was taking up space.

westcoastclassic · 28 Sep 2017

911tom said:
:thumbs: had mine 5 years and even if I totalled up all that I've spent on it in that time there is literally no car that comes close! I sold my standard exhaust about 3 years ago after deciding I'd never need it and it was taking up space.

what else is there really, accept its not got the wow factor of a Lambo or Ferrari, nor does it have the issues and costs involved with servicing either and can be used as car rather than a prop, plus a tuned car will match or beat most of them performance wise. Also too many narrow minded jealous people around for those exotic cars, in Scotland you will be forgiven for everything other than success

996 Turbo - Any experience with removing cats

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