Large bore or stick to standard?

[alex160]

Ordering a decat this month but do I go for a Hoffman decat which is standard diameter or a milltek large bore diameter? Which will give better gains? My golf is a 130 which has been remapped and egr removed, thanks

[Hoggy]

I would go big bore but what is the rest of your system? Standard or bigger bore?

[alex160]

Well I would probs get a custom made system cat back and get it as a 3 inch system, I have been told that I need to get a system that keeps good back pressure though as the tdi engine don't like not having any back pressure :a

[Hoggy]

If your going custom then go for the big bore decat.

A decent backbox will give you enough back pressure

[tdi_blu]

My CAT was cut off along with the back box it's a straight pipe all the way think its 2.5 inch bore makes a great sound.What difference does the performance CAT make over just cutting it off?

[Rhyso]

I had the Milltek on mine mated to the original system for a bit until I went for a full stainless system

On mine the decat freed up a few extra lbs ft and a couple of bhp across the range.

There are some graphs in my old project page showing the difference before and after 

[tdi_blu]

Mines s/s would the de-cat on mine do the same as performance cat?

[Rhyso]

Mines s/s would the de-cat on mine do the same as performance cat?

Performance cat is a waste of time on a derv. They dont need the cat to pass the MOT 

I didnt think a performance cat was even available anyway 

[tdi_blu]

Got ya that's all I was getting at so really with the derv your better off just having it cut off what I've done thxs for the reply 

[gt130dave]

HOW MUCH WOULD A FULL 3IN STAINLESS EXHAUST COST APPROX 130TDI