200 cell cats! "Porsche" sound at last!!

So I finally did it..

After the best part of six months in a constant effort to get the sort of sound I wanted from my Porsche 911 (we are close to supercar territory, after all..) I think I reached the promised land. 200 cell cats are on and the car is loud as hell, screams like a baritone banshee and has bucket loads of aggression. Given how I mainly just whallop the car around fast roads, I wanted this kind of soundtrack.

With great help from lots of people here and the wonderful Andy @ Zorstec in Shipley, Yorkshire (nothing shameless about plugging good industry guys!), I managed to get a sound worthy of the car.

After going the Gundo route (which many are clearly happy with), I just felt I wanted more. I also felt that for some reason my car, being an early 3.6, didn't actually sound naturally as good as the 3.8. I know some feel the 3.8 is a step backwards sonically, but for me it has more natural "zing" than the standard Carrera (or at least in my case). Anyway..

So mine was a car that had previously been Gundo'd then un-Gundo'd (the pipes had been sealed) and then RE-Gundo'd by myself, so this is a car with a genuinely eccentric history! But I looked around for the best overall value aftermarket muffler option. I'm not an Akrapovic spend 3 grand on it type.

Eventually I plumped for the Dansk Super Sound. What I can gather / feel from these boxes is that they've essentially emptied the boxes of much of the OE baffling but they have made them resonate somehow. There's a definite growl / whistling rumble as you go beyond 4k. They aren't simply empty token boxes to fill the space that just create volume. It's a really addictive noise once it's settled in.

Then I added a BMC air filter, which definitely adds some induction depth to the sound. It's more aggressive at WOT

Volume at thus stage is what I'd call "sporty+" - it sounds tuned, but if you've owned TVRs in the past, you kinda lust after that a more "gates of hell" soundtrack 😬

So then came the cats. As I became increasingly irritated chasing around purpose built cats (various places sold out or were just charging crazy money esp when adding labour fitting etc), so as usual, I did things my own unique / bananas way...

2 x Magnaflow 200 cell universal cats bought for £140 (bargain?)

..straight off to Andy for his expert surgical enhancements AKA slicing up original cat pipe, taking out original (enormous!) 1920s Steampunk-style 600 cell (I think?) OE cats and welding in of new ones.

We made the cut AFTER the pre-cat O2 sensors (as they looked pretty seized in) and decided to simply snip away the post-cat sensors. Yes, I'm currently running a CEL, but I've been told this can be removed by way of a remap / ECU tamper

All in all, cost wise was better overall than buying the best value 200 cell pipes I know of, and heck, when is car experimentation not fun?? 😂

The noise is BIG. It now barks like a V12 Ferrari. In other words it makes the 6 cylinders sound double. And whereas before, it appears the cats were baffling a lot of the high rev tones, this all feel completely freed up. It wails. It really wails.

As for performance.. I have a torque loss at around 2-3.5k / 4k revs. Without doubt. So it looks like this isn't just an X-Pipe thing. Clearly, those big OE cats create back pressure.

However, I'm hopeful that a quick stage 2 flash should remedy this at the very least, if not actually making the car quicker and peppier than it was. My car has felt quick in recent weeks, so I'd be happy just getting that pre 4k peppiness back. Let's hope the remap does this.

Overall, if you want a significant volume increase (remember I have very liberal back boxes, too) then bloody well get it done! 😈

Great read Basalt_Yellow_997, I am sure the remap will put anything back you lost, I had big bore 200 cell xpipe and can't say I feel any loss at all only gains all through the low mid range, but we may drive differently and as such have a different feel . the sports boxes and cats do make the car faster than stock , I would love to hear a vid of yours if you can I know it doesn't translate perfectly but I would get the idea. I though you description of the pre cat sound and the post cat sound was spot on and very similar to my findings. and the induction kit ,bmc filter and resonator cap do make a nice sound to add to the overall . :thumb: :grin:

This thread is useless without a YouTube clip... :grin:

Phil 997 said:

Great read Basalt_Yellow_997, I am sure the remap will put anything back you lost, I had big bore 200 cell xpipe and can't say I feel any loss at all only gains all through the low mid range, but we may drive differently and as such have a different feel . the sports boxes and cats do make the car faster than stock , I would love to hear a vid of yours if you can I know it doesn't translate perfectly but I would get the idea. I though you description of the pre cat sound and the post cat sound was spot on and very similar to my findings. and the induction kit ,bmc filter and resonator cap do make a nice sound to add to the overall . :thumb: :grin:

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Hi Phil

Thanks for your advice along the way!

The torque loss now feel a little less noticeable. The ecu has relearnt. The pull after 4k is ridiculous now though. It's worth the sacrifice!

We discussed that "exotic" European car sound (we meant Italian cars really) and it does feel like I have that timbre now. It's still gruff at low revs but there's a really trumpety shrill top end now that's just delicious. I will be getting through more petrol for sure.. 🙄

Loko said:

This thread is useless without a YouTube clip... :grin:

Click to expand...

Ha indeed. I'll have to get my buddy on fly-by cameraman duties.. 😆

Basalt_Yellow_997 said:

Phil 997 said:

Great read Basalt_Yellow_997, I am sure the remap will put anything back you lost, I had big bore 200 cell xpipe and can't say I feel any loss at all only gains all through the low mid range, but we may drive differently and as such have a different feel . the sports boxes and cats do make the car faster than stock , I would love to hear a vid of yours if you can I know it doesn't translate perfectly but I would get the idea. I though you description of the pre cat sound and the post cat sound was spot on and very similar to my findings. and the induction kit ,bmc filter and resonator cap do make a nice sound to add to the overall . :thumb: :grin:

Click to expand...

Hi Phil

Thanks for your advice along the way!



The torque loss now feel a little less noticeable. The ecu has relearnt. The pull after 4k is ridiculous now though. It's worth the sacrifice!

We discussed that "exotic" European car sound (we meant Italian cars really) and it does feel like I have that timbre now. It's still gruff at low revs but there's a really trumpety shrill top end now that's just delicious. I will be getting through more petrol for sure.. 🙄

Click to expand...

:floor: I am glad you finally got the sound you were looking for. as its a very personal thing and getting it just right for your ear takes thought.
re the fuel that's for sure my ave. is about 17.5 mpg but as you say worth to get the sound you want .
It would be good if you could get your mate on a vid driveby at 4k rpm and 6k rpm lol :thumb: :grin:

Pic showing install. Think this was before final welding / clamps went on

You see the bar with the two bolts in I had to remove that as it was redundant anyway as I had xpipes, the cats were touching it under load and vibrating, so if you find as it settles you get the same look there first unless you have now clamped to it . :thumb: :grin:

Phil 997 said:

You see the bar with the two bolts in I had to remove that as it was redundant anyway as I had xpipes, the cats were touching it under load and vibrating, so if you find as it settles you get the same look there first unless you have now clamped to it . :thumb: :grin:

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Interesting thanks for that!

I guess I may have detected a bit more noise that could be down to vibration. I'll check the clearance after I've washed her!

My car legit.. LEGIT sounds like a 458!!!!!!!!!!!

I am in frikkin dreamland. 🙈

(and more to the point, it still looks like / drives like a 911)

Basalt_Yellow_997 said:

My car legit.. LEGIT sounds like a 458!!!!!!!!!!!

I am in frikkin dreamland. 🙈

(and more to the point, it still looks like / drives like a 911)

Click to expand...

I so want to hear a soundbyte :thumb: :thumb: :grin:

You muse post a video now :floor: :?: