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IVA Gas Analyser
GrahamC - 18/1/21 at 05:04 PM

Just going through my final steps for IVA prep and had the car mapped last week.

I got caught off guard when the chap was testing the emissions as he said the probe did not go very far into the exhaust. I had never considered this.

In my efforts to cut costs I had used a really stubby great looking (and crucially free) motorcycle silencer on my car engine build. It is also happily IVA noise friendly.

However, it is full of baffles and the gas analyser would only go into it by 19cm, the whole thing is only 40cm long.

The IVA manual states:
"Gas analyser probe
It is important to ensure that the gas analyser probe is inserted as fully as possible into the exhaust tail-pipe and is secure
"

The chap managed to do emissions but pointed out that he was getting a high oxygen reading probably as the probe wasn't very far up the pipe, so to speak.

Does anyone have a view of what an IVA gas analyser looks like or how far it needs to be inserted for them to be happy?


Mr Whippy - 18/1/21 at 05:52 PM

quote:
Originally posted by GrahamC

Does anyone have a view of what an IVA gas analyser looks like or how far it needs to be inserted for them to be happy?


Their never happy unless the probe inserted real deep...


coyoteboy - 18/1/21 at 06:05 PM

I'm not going to be any help as I've never seen it, but I wouldn't think you'd need to be more than 3 diameters up there, unless it's a really windy day.


02GF74 - 18/1/21 at 07:23 PM

quote:
Originally posted by Mr Whippy
quote:
Originally posted by GrahamC

Does anyone have a view of what an IVA gas analyser looks like or how far it needs to be inserted for them to be happy?


Their never happy unless the probe inserted real deep...


I'm afraid I totally disagree.


ttalps2000 - 19/1/21 at 08:54 AM

It is the same as any MOT gas analyzer


Mike S - 19/1/21 at 10:18 AM

Why not make up a temporary extension to the exhaust that is a push fit into the outlet?

It would only need to be 6" to 8" long or so, to accomodate the probe. Would need to be a reasonable fit in the exhaust though.

Take it with you in your pocket for testing and MOT time (probably not your trouser pocket as they may get the wrong idea)

Mike


TimC - 19/1/21 at 10:38 PM

Blimey, I’d never considered this - I’ve a slice of cat in the end of the silencer tail-pipe from when I was taking it racing and that seems to be the only way to meet the regs without melting cats. I’ll get a length of silicone hose to go over the end for the emissions test.


Irony - 19/1/21 at 11:00 PM

I had sound mufflers in my exhausts right in the tips for IVA. There was barely any room at all. I never considered this an issue and the IVA tester didn't mention it. He even let me hammer one of the mufflers back in when on the speedo test the car coughed one out and it pinged across the tarmac.

I was so nervous at my IVA (I don't think I slept). When he was driving it on the rollers at above 90mph it 'coughed' the muffler out. When a V8 (even a Rover V8) coughs a muffler out at 90mph it doesn't just drop on the floor. It flew across the test centre and clonked the opposite wall. It was at that point I nearly laid an egg.


TimC - 20/1/21 at 09:38 AM

Haha.

They take it to 90mph on the rollers?

They’d better be short - or they ain’t fitting in mine. I did read somewhere that the punter is staying in the car during COVID-IVA.