Fitting De-Cat on 944S2??

[nick3814]

As I'd mentioned elsewhere on here I'm in the process of changing my exhaust and jacked it up today to have a look at whats involved. I'm fitting a polished stainless back box and have a stainless Janspeed De-cat pipe to fit also. The end of the De-cat has a split end and a U clamp fitted to obviously slide onto the original pipe and I thought the Cat thats on now would be fitted like that but its not! Its one contiuous section up towards the engine so it needs cutting [&:] Has anyone else tackled this? Any advice on how best to measure it before cuttig and how best to cut it would be appreciated []

Also the exhaust pipe that goes towards the engine manifold has a sensor fitted, can this just be ignored or will it need removing? Curiously its before the cat so must get its readings from the gases before they pass through the cat!!

Thanks

 

[Diver944]

The sensor is the Lamda Oxygen sensor so that the ECU can adjust the fuel mixture and protect the cat from damage. It's fine just to leave it in place when the cat is removed.

You need to allow a couple of inches of original pipe to fit inside the Janspeed de-cat so that the U-clamp has somethig solid to get a seal against. Measure twice cut once is the old adage

 

[Diver944]

Here's a very uninspiring pic of the straight pipe I had fitted in place of my S2 cat this week. You can see the flare at the front of the pipe where it sleeves over the original pipe immediately behind the support bracet

 

[nick3814]

Cheers Paul. Your right about the photo, very uninspiring!!!!! Where is it LOL [][]

In your experience will the gasket/ring between the joint of the back box and cat definately be salvageable when I take them apart, it will be sods law that I take the lot off and find its no good [&:]

 

[Neil Haughey]

Can't see why not, mine was. I had maniflo do it many years ago now and what they did was cut the end of the cat section then reuse it to weld the straight SS pipe into. I watched the guy do it all and the entire operation couldn't have taken more then 1/2 an hr including all fitting.

 

[Diver944]

Ooops - just testing [] Here it is taken from the passenger side, front of the car is to the left

Yes I reused my gasket on both cars when changing the rear box

 

[pauly]

Paul, where did you source the pipe from ?, I wouldn't mind removing the first silencer box on my turbo.

 

[Fen]

You are actually supposed to jumper a couple of pins in the ECU when you fit a decat to an S2. I don't think it makes a lot of difference (based on most people not knowing / bothering to do it) but Porsche have a part for the purpose. That would make the sensor redundant and if you prefer you could put a blank in there instead.

The ring gaskets are frighteningly expensive for what they are, but there isn't much can go wrong with them so they go again, and again, and again if necessary.

 

[Diver944]

ORIGINAL: pauly

Paul, where did you source the pipe from ?, I wouldn't mind removing the first silencer box on my turbo.

I used a local place in Northampton called Bodymek who I had heard good reports about building their own stainless exhaust systems. They charged me £15 for a metre of 66mm stainless tube and 2 hours labour to cut, weld and fit it.

I was going to do it myself using stainless tubing from Jetex but realised it would have taken me much longer pfaffing around under the car in cold weather and end up costing me more through lost time at work:

http://www.jetex.co.uk/website/custom_parts.php?mat=Stainless&dia=2.5+inch

 

[nick3814]

Paul I would imagine yours must be quite loud now if you have taken out a whole silencer, is that the case?

 

[Diver944]

Actually no, and I was really worried about that as I don't like loud exhausts and was prepared to take it back and get a silencer if it was

It is definatley a bit rortier once you are over 3500rpm or are giving it full throttle and I noticed it as soon as I left the garage. However it's my wifes car and she drives it every day and I purposely did it while she was away on a course on Wednesday and didn't tell her. She only noticed yesterday and casually commented that she thinks the split in the cat must be getting a bit bigger and we ought to get that straight pipe fitted soon []

 

[pauly]

ORIGINAL: Diver944

ORIGINAL: pauly

Paul, where did you source the pipe from ?, I wouldn't mind removing the first silencer box on my turbo.

I used a local place in Northampton called Bodymek who I had heard good reports about building their own stainless exhaust systems. They charged me £15 for a metre of 66mm stainless tube and 2 hours labour to cut, weld and fit it.

I was going to do it myself using stainless tubing from Jetex but realised it would have taken me much longer pfaffing around under the car in cold weather and end up costing me more through lost time at work:

http://www.jetex.co.uk/website/custom_parts.php?mat=Stainless&dia=2.5+inch

Thanks for the link, I suppose a piece swaged both ends would be the easiest option, have you done something similar on your turbo ?.

 

[nick3814]

ORIGINAL: Diver944

However it's my wifes car and she drives it every day and I purposely did it while she was away on a course on Wednesday and didn't tell her. She only noticed yesterday and casually commented that she thinks the split in the cat must be getting a bit bigger and we ought to get that straight pipe fitted soon []

I like your style [][][]

 

[Diver944]

ORIGINAL: pauly

have you done something similar on your turbo ?.

Yes, virtually identical. Jon Mitchell had it done when my car was back there for the engines post run in service. It made a very noticeable improvement to the spool up time for the turbo. It's still quieter than the S2 because the turbo itself mutes some of the noise.

 

[pauly]

ORIGINAL: Diver944

ORIGINAL: pauly

have you done something similar on your turbo ?.

Yes, virtually identical. Jon Mitchell had it done when my car was back there for the engines post run in service. It made a very noticeable improvement to the spool up time for the turbo. It's still quieter than the S2 because the turbo itself mutes some of the noise.

Good, that's another easy mod to carry out when it warms up outside.

 

[nick3814]

Well I cracked on with it this afternoon and four hours later its all done []

Janspeed De-cat pipe and Dansk rear box

I'm really pleased with the result it looks mint. I took it for a run and once it had settled and warmed through it sounds really nice, not boy racerish/Saxo etc just a nice burble on tick over and a bit more bass with a rasp over 3500rpm []

Thanks for all the advice lads []

 

[Diver944]

Well done Nick [] Glad that it went straightforward and you are happy with the sound. What did you use to cut the old cat out, and could you do it with the front pipe still attached to the car?

Noticed any performance increase?

 

[nick3814]

Ended up cutting through the cat pipe with a cutting disc whilst still on the car, typical german engineering, that original pipe is soooo thick! Had to borrow a friends 9" cutter to get the top of the pipe but not a bad job at all, once the end was dressed up the new de-cat slipped on really well, good tight fit, just had to knock it along and secure with the U clamp and the Dansk system fitted a treat. Sound is almost standard really, on tick over its a little bassier and once you get upto around 4000rpm its got a bit of a rasp but not obtrusive which is what I was after really. As far as performance goes I would swear it was quicker!! But then isn't that often the case [] but definately more responsive without a doubt.

I tell you what mind its worth doing just for the weight..... The new system must be half the weight of what I've taken off, easily []