Exhaust doesn't extend past sill

Isaac_Blanc · 2025-07-25 19:00:30

The exhaust on my van does not extend beyond the vehicle sill. This strikes me as odd. The exhaust has always stuck out on vehicles I've owned previously. I had thought this was a safety requirement, so that exhaust fumes would not collect underneath the vehicle and potentially seep into the cab. The van is Euro 6 compliant, so has an AdBlue aftertreatment system. The standard also requires lower CO emissions, but are they really so low as to risk breathing them?

I ask because I am going to cut a hole (~30mm) in the floor of the van to install a gas dropout vent. I am wary that exhaust fumes may drift into the cab through this hole. Thoughts? Also asked on Reddit.

Last edited by Isaac_Blanc (2025-07-25 19:00:48)

kenbw2 · 2025-07-26 01:05:50

I know when I've driven with my rear doors open to carry a load I can smell my exhaust as I'm driving, although my exhaust is particularly pungent

That said, I wouldn't worry about a 3cm hole. Out of the factory our Mk1s have a large pressure vent hole on the rear corner (opposite side to the exhaust)

The exhaust also doesn't extend out past the bumper

Isaac_Blanc · 2025-07-29 08:05:22

That's interesting to know that the Mk1s have a hole in the floor & an exhaust that doesn't extend beyond the sill. That's not what I would have thought, but its an encouraging sign for my dropout vent. Cheers!

Last edited by Isaac_Blanc (2025-07-29 08:05:47)

OAT · 2025-07-29 23:18:52

You could use one of those short chrome extensions.
Or even find a bit of scrap that fits near enough.

Last edited by OAT (2025-07-29 23:20:38)

kenbw2 · 2025-07-30 01:29:21

OAT wrote:

You could use one of those short chrome extensions.

Bloody hell I know Mk3s are modern but I didn't know you could install these in them

https://chromewebstore.google.com/category/extensions

Isaac_Blanc · 2025-07-31 23:38:29

OAT wrote:

You could use one of those short chrome extensions.

I'm reluctant to make the exhaust longer for fear of messing up potential wave tuning in the exhaust and therefore reducing efficiency. I may be massively overthinking though.

kenbw2 wrote:

I didn't know you could install these in them

Hahahaha

OAT · 2025-08-01 08:16:42

Isaac_Blanc wrote:

OAT wrote:
You could use one of those short chrome extensions.
I'm reluctant to make the exhaust longer for fear of messing up potential wave tuning in the exhaust and therefore reducing efficiency. I may be massively overthinking though.

To be safe then, an oversize one shouldn't impact pressure but still deflect?

I have done it with older vehicles no problem but share your lack of confidence with the sensitivity of more modern stuff. So long as there is no damage done though and a performance issue was the only drawback, you could soon remove it.
Also, if oversized, it should direct without affecting pressure?

kenbw2 wrote:

Bloody hell I know Mk3s are modern but I didn't know you could install these in them
https://chromewebstore.google.com/category/extensions

Only you could make that joke Ken. Had me going though.
Thinking, "It's only three self tappers!"

OAT · 2025-08-01 08:19:53

OAT wrote:

Isaac_Blanc wrote:
OAT wrote:
You could use one of those short chrome extensions.
I'm reluctant to make the exhaust longer for fear of messing up potential wave tuning in the exhaust and therefore reducing efficiency. I may be massively overthinking though.
To be safe then, an oversize one shouldn't impact pressure but still deflect?
I have done it with older vehicles no problem but share your lack of confidence with the sensitivity of more modern stuff. So long as there is no damage done though and a performance issue was the only drawback, you could soon remove it.
kenbw2 wrote:
Bloody hell I know Mk3s are modern but I didn't know you could install these in them
https://chromewebstore.google.com/category/extensions
Only you could make that joke Ken. Had me going though.
Thinking, "It's only three self tappers!"

Isaac_Blanc · 2025-08-11 19:41:05

That's a good point that I could just remove any exhaust extension if it affected engine performance. (Un)fortunately, I completely forgot about this and have been staying in the van for the past week with (touch wood) no exaust-induced poisoning, in spite of the small hole I have in the floor. In conclusion, I think its fine, even without the exhaust extension. Thanks for all the replies!

Last edited by Isaac_Blanc (2025-08-11 19:41:31)

kenbw2 · 2025-08-11 21:16:01

I reckon there's nothing to worry about. Compared to our Mk1s your exhaust fumes consist of rainbows and butterflies anyway haha

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#1 2025-07-25 19:00:30

Exhaust doesn't extend past sill

#2 2025-07-26 01:05:50

Re: Exhaust doesn't extend past sill

#3 2025-07-29 08:05:22

Re: Exhaust doesn't extend past sill

#4 2025-07-29 23:18:52

Re: Exhaust doesn't extend past sill

#5 2025-07-30 01:29:21

Re: Exhaust doesn't extend past sill

#6 2025-07-31 23:38:29

Re: Exhaust doesn't extend past sill

#7 2025-08-01 08:16:42

Re: Exhaust doesn't extend past sill

#8 2025-08-01 08:19:53

Re: Exhaust doesn't extend past sill

#9 2025-08-11 19:41:05

Re: Exhaust doesn't extend past sill

#10 2025-08-11 21:16:01

Re: Exhaust doesn't extend past sill

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