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Rear Exhaust and IVA
Johnmor - 29/9/20 at 02:10 PM


I have completed my rear exhaust and it now terminates at the rear of the car under the back pannel

I suppose my question is "will this pas the IVA test" and will they apply the 2.5mm radius to either the exhaust outlets and the corner edge of the base of the fibreglass rear pannel.

I read that anything below floor line is not tested but its how they define the floorline that i suppose matters

Ive tried several times to post a pic but just get syntax errors and although ive managed before im just getting frustrated as ive been at it for 15 mins, its only 250 Kb but to no avail

I have a pic in the archive but it doesent show the pannel so not as clear and not even sure if this will appear

[img] Description

gremlin1234 - 29/9/20 at 03:14 PM

weirdly the thumbnail doesn't show up, but if you move your mouse over it you can see the expanded image
having tested several photo sites, I suggest you upload it via
and copy their bb full link into your message

nick205 - 29/9/20 at 03:51 PM

Can't answer you're IVA question, but I'll throw another question in.

Do the ends of the exhaust clear the rear panel - i.e. will the boot area fill with exhaust fumes?

Johnmor - 29/9/20 at 04:22 PM


lol, Yes they do stick out beyond the rear pannel by about 60mm, ive tried to add some pics

this makes me think they maybe subject to test , although my first Viento passed SVA first time in 2006, however things have changed a little since then and i know its a tougher job to pass now

nick205 - 30/9/20 at 07:19 AM

The clearance out the back overcomes the exhaust gas in the boot area question, thanks.

IVA testing I still can't answer I'm afraid.

Mr Whippy - 30/9/20 at 11:53 AM

I don't think you have that right. Reading the manual it seems to say that the exhaust if it protrudes is also included in the projections evaluation. The inner pipe part of your exhaust doesn't look like it would pass the 100mm sphere test, the rest of the exhaust looks ok for the 2.5mm radius. One fix would be to recess the inner pipe further back into the tailpipe. May sound daft but I bought a 100mm plastic ball from Firetoys to check the car myself only cost 10 and it's a lot cheaper than failing the test...

[Edited on 30/9/20 by Mr Whippy]

Johnmor - 30/9/20 at 12:31 PM


I thanks for the feedback,

I tend to agree that it will be assessed, your correct, I made a 2.5 radius guage and the outer sectionon of the exhaust seems ok, but the inner, although a soft edge is about a 2mm radius so will probably fail, I may look at possibly fitting a softer edged piece of pipe over the inner outlet.

Its ironic as these are Suzuki GSXR tail pipes and would normally fit around 500mm above ground fully exposed for all to bang into, however I have a set of GSXR race cans that have a softer edged outlet but typicaly may not pass the noise test,

I could add some baffle material to the race cans to see if I can reduce the noise a bit,

It's a pity cause these are stamped with the db noise level and that they are exhaust for road use

Cheers for the thoughts


CosKev3 - 30/9/20 at 01:15 PM

What engine is in it?

You might find the bike cans restrict the power?

My m8 had one kicking about in his shed and liked the tailpipe, so he fitted it to a 1.9 derv golf and it restricted the power a lot!

Johnmor - 30/9/20 at 02:21 PM

Possibly may restrict things a little, but they seem ok, it's really just to get through IVA, it's a rover 3.5 v8 , I intend to swap for race cans , which are basically straight through after test, should also consider this is the only silencer on the system. Bearing in mind the GSXR 1300 had around 170hp and a 10000 red line! I used a similar system on my Alfa v6 Viento, sounded fantastic didn't seem to affect the performance too much, in addition fitting race cans is a 5min job once the system is made up, and cheap!!