3" Cat-Back Custom Exhaust System

[JamJay]

Hello all.

I have a friend who has opened up his own garage recently and is very much focussed on customs. He has just completed as V8 engine transplant into a VW Polo Coupe but anyway, that's besides the point .

He has offered me a full Cat-Back system for my LCR for £200, custom made of course and he can do 3".

My questions...

1. Will installing a system this large have any gains over 2.5" or 2.75"?

2. Will it mate up with the OEM Cat at this point until I get a 3" Sports-Cat & DP?

3. Will it have a negative effects, such as less back pressure than a system using smaller pipework?

 

[Gubien]

As I've read in here, the restriction is at the DP and CAT, not the actually mid and backbox..

I guess you just will get more "boominess"...

 

[Willie]

I felt an instant difference with my CAT back fitted.
Only issue to watch out for is if it's his first one for a Leon then it could be boomy at 70-80MPH which is VERY annoying on the motorway and no excuse to travel and 80MPH+, lol

 

[turbin]

I ended up doing 3" DP and 120cell cat. stock 2.5" pipes back to a turbo muffler and an oval 6x4 inch tip. Not boomy just ripping good laughs !

 

[DPJ]

1. Will installing a system this large have any gains over 2.5" or 2.75"?

 

[JamJay]

Thanks for the replies

I'll head on over there in a few weeks and have a chat with him.

 

[S3 Nattie]

I got a quote a few days ago from a very respectable exhaust company by me for a turbo back 3" system with decat. £600 which I thought was alright. He said it wouldn't be drowning and will give good performance gains, which it would because its a less restricted bigger diameter system.

 

[Willie]

I got a quote a few days ago from a very respectable exhaust company by me for a turbo back 3" system with decat. £600 which I thought was alright. He said it wouldn't be drowning and will give good performance gains, which it would because its a less restricted bigger diameter system.

and that was who?

 

[S3 Nattie]

The place is called Pro speed exhaust in Cardiff.

 

[Willie]

The place is called Pro speed exhaust in Cardiff.

Thats a very good price if it's a stainless steel system, with a decent tail pipe, 200 CELL CAT and Lambda probe wells.
How much do you know about the exhaust?

 

[S3 Nattie]

It will be with a de cat running lambda probes so hopefully shouldnt get any lights on the dash. The tail pipes are the same as standard but bigger diameter. The de cat will be in the same places as my cat with the flanges I think as I said I want it so I can easily change them around MOT time.

 

[JamJay]

Just to add to this, what are peoples opinions of custom systems? Are they any better or worse than Blueflame of Milltek in terms of performance? I know on the Jap scene, most systems are extensively dyno tested to get the best gains but I have never seen such reports with Milltek for example which makes me think they're going to be no different to going custom.