*Chasing opinions/experiences* - Those with downpipes (smell)

[idek]

Hi all,

I wanted to chase some opinions on this:

So ever since I've had my High Flow 200CELL Downpipe installed (custom) on my 6R, it's been bothering me with the smell.

I primarily notice it when i Cold start & Stop at the lights with windows cracked down (mainly hints, but not drastic).

Now I keep the car in a 2-car space garage and with cold starts - the car basically fills the entire garage with the petrol-like/fume/exhaust smell - you'd 100% notice it walking around unless you're deliberately covering your mouth/nose. (garage door opened always). Once or two there's actually been little to no cold start smell, but 90% of time; you notice it.

Now i've seen various opinions online - some say they smell 'nothing' but some also say they smell very little. So i'm not really sure and this isn't a popular 'issue' from what I see either.

As a result, the cold starts annoy me especially when I walk around/to the car whilst it's warming up/idle. Or even when other people are in proximity to the car.

This could be normal as it's fewer cats then factory or it just being me, but as a solution I was also considering swapping to some branded downpipes (if they'd be more effective in this smell aspect) to tone it down, so thought i'd get opinions on what everyone's opinion/personal experiences are.

Cheers in advance

[Lucas_R]

Sounds more like you have an exhaust leak somewhere too be honest. Ive had 2x Mk6 Golfs (GTI and R) and now a MK7 GTI and all have had aftermarket downpipes with 200cel cats and I have never noticed the exhaust fume smell to be any different to when the car was standard.

The only time I have noticed a bit of a stronger smell is when I have 10-15L of E85 in the fuel tank - that smells a bit different.

Things to check:

1) Do you have a genuine VW gasket where the turbo and downpipe mate together? If the exhaust shop used gasket sealant instead or a cheap aftermarket gasket then this is likely to be an area where you would have a leak.

This is the type of gasket it should be: 1K0253115AB - K03 Turbocharger Exhaust Gasket - Audi 8P/8J & VW MK5/MK6 (K03)
– VAGPARTS Australia

This is a garbage quality gasket: 3" Turbo GASKET FOR 2.0T Decat Fits VW Golf GTi Jetta Audi A3 06+ | eBay

2) Underneath the cabin (literally right underneath where you sit when driving the car) is where the downpipe and catback section of the exhaust mate up. They use a sleeve clamp like this (link below). These clamps do rust and sometimes seize up when trying to remove them, so its possible it was damaged when the exhaust shop fiddled with it. Worth checking if its leaking. Also you can use an exhaust grade silicone sealant on these sleeve clamps if they are leaking a bit.

Genuine Volkswagen Audi - 1K0253141P - Exhaust Sleeve With Dual Clamps - Priced Each (1K0 253 141 P)

[idek]

I have no clue about the gaskets they used. Will try to check on the things mentioned.

I'm suprised to hear that you notice no difference with stock - this is what I definitely would've wanted mine to be like, but wasn't sure if achievable. Does this include no hints of fumes at all? Even cold (which would be the worst/most presence for me) and may I also ask which brands you've used.

I've heard cat placement could also be a factor in this - mine is placed as the pipe bends straight not right up after the turbo.

[Sharkie]

Are you running a tune on the car? And if so, did you update it after changing the cat?

If you are changing the flow of the exhaust fumes (high flow cat flows better) the car will adjust the fueling unless the tune is modified to allow for better flow.

Also, did the position of the O2 sensor change?

[idek]

Yeah it is tuned - was done after downpipe installed and hasn't been altered since. From what i remember it's been the same in terms of smell even when I was stock with just DP.

I'm not sure about the sensor position vs stock, but it's where the high flow cat sits as I mentioned which is after where the pipe becomes straight, near the transmission.

[Lucas_R]

I have no clue about the gaskets they used. Will try to check on the things mentioned.

I'm surprised to hear that you notice no difference with stock - this is what I definitely would've wanted mine to be like, but wasn't sure if achievable. Does this include no hints of fumes at all? Even cold (which would be the worst/most presence for me) and may I also ask which brands you've used.

I've heard cat placement could also be a factor in this - mine is placed as the pipe bends straight not right up after the turbo.

There is certainly some more noise with the aftermarket downpipe, but no difference in smell that I can notice. For a short period of time a few years ago I had no catalytic converters on my Lexus IS-F V8 and it was horrible - the smell and strength of the fumes was gross. I just had to wait a few weeks for my exhaust shop to order in the hi flow cats I wanted which were on back order at the time.

I always start my car in the garage (smallish 1 car garage) and let it idle for 20-30 seconds before I reverse out. And yes of course there are exhaust fumes in the air but nothing different to when the car was standard.

As for downpipes I have had - although I doubt it makes any/much difference as they all had 200 cel cats in them. On my Mk6 R I had a Scorpion, then a 42 Draft Designs, and finally a SPM downpipe.

On my Mk6 GTi I had a EuroJet downpipe.

And on my Mk7 GTI i have an Integrated Engineering downpipe.

Curious as to why you decided to go for a custom made downpipe when there are so many well made options available off the shelf for the Mk6 Golf R?