Milltek X-Pipe Cat Back Exhaust

[djone101]

I'm confused. How does this tie in with SteveP's post at the top? Not overly concerned though.

:shrug:

Steve has measured static sound levels. This is what they do at track days and IVA inspections. It's a simple repeatable method.

However European regulations mandate a "drive-by" sound level. This is measured on a certified surface. The vehicle is driven through a test area with microphones on either side. You enter the test area at a specific speed and accelerate at wide open throttle until you leave the test. It's quite a short test but has to be done at the right temperature, wind speed, etc. This test measures all of the sound created by the vehicle including tyre noise, intake noise, exhaust noise, shell noise, transmission noise, etc. It's virtually impossible to isolate the exhaust noise from this overall sound level. There is not always a direct correlation between drive by levels and static measurements but when the exhaust is the dominant sound then that is what you would expect.

The above test is only run as part of the whole vehicle type approval process and doesn't apply to any aftermarket products.

I had to go through all of this when we (Roush/Ford) got the Ford GT approved for sale in Germany to meet TuV requirements and we ended up having to add a pneumatic system with valves, controller, air pump etc and a unique muffler to get the cars through the test.

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[slowhand99]

Anybody noticed that your sound level is on the V5 for the vehicle (section U on the second page). Mine states 87 dB @ 3750 rpm and 75 dBA 'drive by'.

The figures for my Mondeo (diesel, sorry) are 71 dBA @2625 rpm with 71 dBA 'drive by'.

Are these the figures that would be applied at MOT (assuming sound levels were measured at MOT)?

 

[Jimboy2]

Sounds levels aren't measured at MOT. But I guess if they were then they would go by those.

 

[SteveP]

Steve has measured static sound levels. This is what they do at track days and IVA inspections. It's a simple repeatable method.

However European regulations mandate a "drive-by" sound level. This is measured on a certified surface. The vehicle is driven through a test area with microphones on either side. You enter the test area at a specific speed and accelerate at wide open throttle until you leave the test. It's quite a short test but has to be done at the right temperature, wind speed, etc. This test measures all of the sound created by the vehicle including tyre noise, intake noise, exhaust noise, shell noise, transmission noise, etc. It's virtually impossible to isolate the exhaust noise from this overall sound level. There is not always a direct correlation between drive by levels and static measurements but when the exhaust is the dominant sound then that is what you would expect.

The above test is only run as part of the whole vehicle type approval process and doesn't apply to any aftermarket products.

I had to go through all of this when we (Roush/Ford) got the Ford GT approved for sale in Germany to meet TuV requirements and we ended up having to add a pneumatic system with valves, controller, air pump etc and a unique muffler to get the cars through the test.

We also test drive by as this is required for exhaust ECE / TUV approval

 

[SteveS]

Thanks!

 

[stiggy]

For anyone interested in fitting the quad tip, I have a brand new Roush rear valance for it for sale in the classifieds.

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