The great big MK6 Golf 118TSI tuning thread

**Lucas_R** · 14-09-2016, 05:52 AM

Ive never personally seen the cats on a 1.4 twincharge engine, but have many times on Mk5 Golf GTI, Mk6 Golf GTI and Mk6 Golf R (which all appear identical) and can tell you they are a brick wall (very dense and restrictive).

On the GTI and R the downpipes actually have 2 cats - one right up near the turbo (which can be DIY removed easily in about 5 mins to reduce restriction and increase airflow) and a secondary cat down under the car. This secondary cat could be easily cut out and a new hi flowing cat welded in its place.

Surely something along these lines can be done on the 1.4 twin charge?

Pics for inspiration (my Mk6 Golf GTI)

**Lucas_R** · 14-09-2016, 06:05 AM

Some pics here of the 1.4 twin charge setup: Downpipe Ø63mm VW GOLF VI 1.4 TSI TWINCHARGE (160 Hp)

Doesn't look like there is as much room as on the GTI but with some imagination, and someone willing to take the risk and spend a little money im sure you can sort something out.

Pipe diameter looks ok, could possibly be 1/2 inch bigger, but its not too small that its being a major restriction.....but that big ugly cat on the other hand.....

**Rawcpoppa** · 14-09-2016, 06:19 AM

A guy on vortex took out the down pipe and chiseled it out. It was for a beetle in Europe that used the twincharger. The pics from that thread died I believe.

Will look thru hard drive to see if I saved anything about it. The procedure didn't seem unreasonable.

**ope126** · 14-09-2016, 07:14 AM

Originally Posted by Lucas_R

Some pics here of the 1.4 twin charge setup: Downpipe Ø63mm VW GOLF VI 1.4 TSI TWINCHARGE (160 Hp)

Doesn't look like there is as much room as on the GTI but with some imagination, and someone willing to take the risk and spend a little money im sure you can sort something out.

Pipe diameter looks ok, could possibly be 1/2 inch bigger, but its not too small that its being a major restriction.....but that big ugly cat on the other hand.....

Brondex Downpipes look really well made. I can see that there is a 63mm and 70mm option available.
Would you need a tune with this also (does it throw codes etc.), or would it be ok to "hook up" to the rest of the "standard" exhaust system?

One thing that has me confused though (as per the website), "The imitator of oxygen sensor will possibly be needed"...

**Rawcpoppa** · 14-09-2016, 07:17 AM

It will throw a code if you remove the catalyst or if you choose a catalyst that doesn't perform as the oem one does.

The o2 sensor after the cat will sense more environmentally unfriendly emissions and the car will throw a code.

The imitator o2 sensor fools the car into thinking things are ok. Another option is to flash the ecu and tell the car to ignore the error.

**rygreen93** · 14-09-2016, 08:42 AM

Originally Posted by Lucas_R

Some pics here of the 1.4 twin charge setup: Downpipe Ø63mm VW GOLF VI 1.4 TSI TWINCHARGE (160 Hp)

Doesn't look like there is as much room as on the GTI but with some imagination, and someone willing to take the risk and spend a little money im sure you can sort something out.

Pipe diameter looks ok, could possibly be 1/2 inch bigger, but its not too small that its being a major restriction.....but that big ugly cat on the other hand.....

From those pictures do you reckon that looks like the stock pipe is around 2.5inch or smaller? Just trying to figure out the best option as I don't want to spend a massive amount of money on the DP if it's not going to yield a huge difference compare to just putting a hi flow in.

Also if I use a hi flow cat I can keep the stock heat shield.

Cost of a full DP installed will be about $900 + cost to heat shield it + $200 for stage 2 tune.

Cost for hi flow only $250 installed + $200 for stage 2 tune. Massive difference in $$$ there.

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**Mk R** · 14-09-2016, 09:00 AM

Originally Posted by rygreen93

Hey Mk R. Why didn't you get me one? I'm still looking

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Heheh, there was only one but i've always got an eye out!

**Mk R** · 14-09-2016, 09:13 AM

From memory the stock downpipe is 2.25" and looks a bit bigger than that with all the heat shielding on it.

Two things i'd be wary of with the stock solution:

1. You'll be left with a franken car when you come to sell it.
2. You won't get the full benefit of the cooler exhaust temps at stage 2 with a pipe thats 0.25" smaller diameter. I've no idea what the difference would be but i'm guessing it was enough for the 2.5" exhaust to be developed.

I saw this used stock downpipe on ebay if you're interested. VW Golf MK6 Catalytic Convertor 1 4 Cavd 02 09 04 13 P N 1K0131701EE | eBay

Overpriced but it's another alternative.

Have you considered asking an exhaust shop what fabrication of a custom pipe would be? Might not be very much...

**Mk R** · 14-09-2016, 09:24 AM

Also keep in mind that you need to step down from the 2.5" downpipe to the 2.25" exhaust. If you use the Brondex pipe that will happen immediately after the downpipe, which is a crowded spot, whereas a custom job might do it after the suspension kink and get you better flow.