Gibbo

Hi there


I've been reading and searching these forums for sometime now.


My car is a 997.1 C2S from what I've been reading these cars seem to benefit most from 200 cel CATS giving good improvements of circa 20BHP, would others agree with this here?

My questions are:-

1. Is it a simple case of removing the original CATS and bolting high-flow ones in place making it a simple bolt-on mod?
2. Is it just basic tools and approx 1hr job?
3. Whats best highflow CATS to get and where from or is anyone selling any used ones?


Oh if it makes any difference my car does has PSE.

Skibum

Agreed.

1. Yes
2. 1 hour if you have done it before. Removing the O2 sensors can be a bit of a pain. I'd allow 3 or 4 hours.
3. Not sure about BEST.. Look at Fabspeed and AWE.

KeninBlaine

I've done about 4 installs/de-installs. It makes it much easier if you remove the rear bumper, which adds maybe 20 minutes but saves many headaches. I remove the air box too so I can create some slack in the O2 sensor wires. But yes, it is a simple bolt on replacement that just needs a little patience. I loved the high flow cats, especially the sound. Good luck.

Skibum

After doing it the "hard" way.... if it's only 20 minutes to remove and reinstall the rear bumper, I think I would opt to do it that way should I do it again.

utkinpol

be aware that some sport cats may cause CELs to appear as post-cats O2 sensors are getting exposed to hotter gas than before. usual solution is to flash ECU to suppress those CELs - or you can use extension tubes in-between O2 sensors and cats like you would do with cat bypass pipes.

Cats are easy to unbolt - it takes much longer to take off mufflers as you would need to unbolt 3 horizontal bolts that hold whole bracket in place in which Porsche inserted that vertical bolt on which mufflers sit with head up so you cannot extract it. it would worth time to unscrew those brackets and reverse that bolt upside down to make furute possible muffer removal a 10min job.

be careful with amount of force you apply to bolts on headers-cats connection, actually, to nuts. When I did this job on my car that had 40K miles I snapped off 2 bolts out of 3 on each side. It is not a big deal as those bolt are pressed in and can be replaced but it is still a PITA. soak those nuts really well before you start undoing them.

some people suggest taking off rear bumper for this job - i did not do that. just take off airbox and disconnect O2 sensor wires from the top connectors and drop wires down - it will make life much simpler. I doubt you will be able to unscrew O2 sensors while cats are in the car.

I use fabspeed, AWE etc are probably all same good just make sure they are reasonably new and do not buy used ones.

Skibum

utkinpol-

Did you have an issue with your CEL using the Fabspeed cats?
How long after installation if you did?

Thanks

KeninBlaine

I had no codes using the second generation AWE cats (where the sensor ports were re-designed to prevent the CEL problem). The AWE cats I had (2 different used sets for my last 2 cars) had no studs like the factory cats so I used SS bolts/nuts. Studs would make it easier to mate the flanges.
Since the rear bumper comes off so easily, I think it is worth removing just to give yourself more working room.

utkinpol

Nope, I did not, and I did not flash my car right away, for about of a week I drove with fabspeed x-pipe on stock ECU. But I saw somebody on forums complaining about such CELs in both cases of AWE and Fabspeed. Go figure...
Most people do not get that so I think it has to be related to something else perhaps.

Of how long it took - I did it myself so I had no time limit. Took about of 4.5 hours I think with going in and out of a garage. Most of time was spent to try to undo O2 sensors from below - it did not work out, then I spent plenty of time figuring out what and how to undo bolts to take muffler brackets off as for some reason i was looking for vertical bolts and did not realise those were horizontal ones, then I found workshop manual on my computer , then trip to autozone to get proper wrench adapter, etc. then I tried to get to spark plugs and failed as my hands could not fit there. So you get the idea.

Skibum

lol.. thanks.

Did you do the requisite "Knuckle buster" while your hands were up there? I know I did.
Yeah the O2 sensors were really the hardest part from the bottom up.
The folks at Fabspeed did say to at the very least break them loose before you remove the old cats from the car.
(I knew about the can bracket bolts as I had done the Borla's 2 weeks earlier.)

utkinpol

to undo left O2 sensor wire connector was for some reason quite difficult, I think I broke of a little part of that plastic lock. IMHO Porsche did not think it wil be a reusable part. right one did not pose any issues.

it also took long time to manage how to put back muffler pipes clamps with no leaks. that is actually a damn critical thing to do, I noticed that engine runs unstable at low rpms if you get any leaks in that connection.
IMHO those clamps also were not meant to be reused, plus all bolts I had access to (homedepot, autozone, local store) are modern Chinese crap that gets twisted and torn apart after you apply more than 20lb/ft of torque to them.

appdevman

Hi all
thanks for all the info.

I have:
2006 Carrera S 3.8L TipTronic - Coupe

I want to do exhaust work and do an ECU flash to make it a more bitchen car.

Currently I do not do track racing, this is my daily driver in southern california.

When the track comes to Carson in 2015 things might change.

I guess I want to put on X51 headers, AWE 200cpi cats, and either the Tubi or AWE cat-back exhaust (oh decisions!).

Then do the GIAC ecu flash and cold-air intake.

1. Is this WAY too much for a daily driver? Dumb, maybe? If its way too much, should I just do cats and disregard the cat-back and headers work?
2. If I do work like this, will I be able to pass DMV-required smog tests on the car, if they come up?

I want to mod the car and make it more bitchen, but I dont want to fail smog tests if they come up!

Thanks guys!
Cheers

KeninBlaine

My understanding is that you could fail the smog check if you have high flow cats.

FWIW, I doubt you will get any measurable power gain with all the changes you mention. It will sound better, and I expect your imagination will tell you it has more power, but I doubt it will translate into much of a performance gain overall.

Personally, I would save your money and enjoy your car as is, unless you REALLY want the deeper and louder exhaust note. I installed the X51 headers, PSE mufflers, and 200 cell cats on my last car, but left my current car alone. I enjoy it just as much as the previous one.

Skibum

My personal opinion is that the addition of cats and cans is worthwhile for performance as well as sound. (On my 2005 anyway)
I am totally happy I made the changes. No CEL.

solidst8

Turning 6 years old soon, my car (997.1S with AWE HJS cats, X51 headers, no other mods) got its first smog check in CA last week. I passed, but just barely. The HC emissions were right at the limit, CO and NO emissions were very low however. I did make an effort to get the cats nice and toasty just before I got tested, the cats work better when they are hot. If I got in there cold, I'm sure I would've failed.

MagnusB

@solidst8, Were the X51 headers worth it?