Wortec Woes

[Reltub]

Been to Oulton Park today to have a noise test done and its failed. It needs to be 105db, reading was 114db. I've a switchable Wortec with cats and headers and it was set on quiet (I checked the valves were fully shut before the test) I'm after a solution, thinking maybe fit a standard cat back. I'm sure I read somewhere that the Wortec was track day friendly. Any experience that can be shared would be appreciated.

BTY its a VXR8

Edited by Reltub on Tuesday 12th May 12:50

[KMud]

Do those exhaust bung things work?

[Wyld Stallyn]

Reltub said:

Been to Oulton Park today to have a noise test done and its failed. It needs to be 105db, reading was 114db. I've a switchable Wortec with cats and headers and it was set on quiet (I checked the valves were fully shut before the test) I'm after a solution, thinking maybe fit a standard cat back. I'm sure I read somewhere that the Wortec was track day friendly. Any experience that can be shared would be appreciated.

When Did you get the switcheable system...? There was a bad batch where the butterflies weren't toleranced close enough and let the flavour flood out.

My Wortec registered 108.9dB at Thunder Road set on Loud with headers and a cam got a switcheable after that.

[ArnieVXR]

Try sticking a tenner to your back bumper next time. Apparently that works too

[jonnM]

114db on the quiet setting!

I think with headers fitted your only option will be standard back boxes. Even then you may struggle to get under 105.

[Wyld Stallyn]

ArnieVXR said:

Try sticking a tenner to your back bumper next time. Apparently that works too

Having worked with Sound and Acoustics for many years now I can categorically say that that would definitely alter the readings

Two Fivers would have the edge for Lowering Resonance

[Reltub]

Wyld Stallyn said:

When Did you get the switcheable system...? There was a bad batch where the butterflies weren't toleranced close enough and let the flavour flood out.

My Wortec registered 108.9dB at Thunder Road set on Loud with headers and a cam got a switcheable after that.

Had the valves fitted about 3 months ago. It had the loud plates in when I bought the car.

With a Maplin db tester I got 105db, that's why I thought I best check with them before booking a day.

The guy was not happy today when I arrived, think he was planning to have a bad day. I don't know if that makes any difference, but I have been on a few track days and I'm sure there have been race cars which sound louder than the R8.

[Wyld Stallyn]

Reltub said:

Wyld Stallyn said:

When Did you get the switcheable system...? There was a bad batch where the butterflies weren't toleranced close enough and let the flavour flood out.

My Wortec registered 108.9dB at Thunder Road set on Loud with headers and a cam got a switcheable after that.

Had the valves fitted about 3 months ago. It had the loud plates in when I bought the car.

With a Maplin db tester I got 105db, that's why I thought I best check with them before booking a day.

The guy was not happy today when I arrived, think he was planning to have a bad day. I don't know if that makes any difference, but I have been on a few track days and I'm sure there have been race cars which sound louder than the R8.

What's the dB difference between Loud and Quiet?

[MyM8V8]

Did he offer up his recent calibration certificate for the noise level. Or is your Maplin unit out?

[Reltub]

Does any one know if the standard exhaust and the Wortec can be mixed and matched.

I like the fiver/tenner idea but don't want to risk £200+ for them to turn me away.

[Wyld Stallyn]

MyM8V8 said:

Did he offer up his recent calibration certificate for the noise level. Or is your Maplin unit out?

Depends how you and he measured them...

You can get wildly different readings depending upon distance and angle.

dB are measured on a Logarithmic scale 3dB more doubles the volume 3dB more Doubles again etc etc

however if you double the distance you measure at you halve the volume.

A new dB meter should be at least in the ball park tho.

[Reltub]

I think the norm is 45 degrees, 1m from the exhaust in an open area. Which is what he did and I did with the Maplin. Ill do a few more tests myself with both settings.

[Wyld Stallyn]

Reltub said:

I think the norm is 45 degrees, 1m from the exhaust in an open area. Which is what he did and I did with the Maplin. Ill do a few more tests myself with both settings.

That sounds just about right

What RPM did he ask you for..?

Keep us posted...

[JohnnieVXR]

Tried stuffing wire wool down the silencer? It's what the racing boys alledgely do at Donno if they fail their noise test on Race day.

[ARAF]

IIRC, the Wortec has sleeve joints, and the standard exhaust is butt joints with gaskets. Probably easier for you to get some quiet cores made for the exhaust ends. 5 minutes with an allen key to install or remove all 4, and the small additional holes in the sides of the exhaust tips will hardly notice.

[Granby]

Wyld Stallyn said:

Reltub said:

I think the norm is 45 degrees, 1m from the exhaust in an open area. Which is what he did and I did with the Maplin. Ill do a few more tests myself with both settings.

That sounds just about right

What RPM did he ask you for..?

Keep us posted...

Also how did you get to the rpm, I was told a trick by a noise tester to very slowly build up the rpm, sounds silly but it did work for a friend who failed his noise test first time

[Reltub]

ARAF said:

IIRC, the Wortec has sleeve joints, and the standard exhaust is butt joints with gaskets. Probably easier for you to get some quiet cores made for the exhaust ends. 5 minutes with an allen key to install or remove all 4, and the small additional holes in the sides of the exhaust tips will hardly notice.

I'll look at this I think, thanks.

I tried controlling the revs up and then down, but don't know if it was smooth enough. I think the overrun made the reading so high although the tester said it was 114db before I shut off.

[bigunit00]

http://www.decibeldevil.co.uk/

[VinceM]

bigunit00 said:

http://www.decibeldevil.co.uk/

Does this actually work?

[ARAF]

VinceM said:

bigunit00 said:

http://www.decibeldevil.co.uk/

Does this actually work?

Similar products work on motorcycles, and frankly anything shoved down the end of the exhaust will quieten it. 20 odd years ago, people used to shove wire wool in the exit pipe, and then lock-wire across the end of the exhaust to hold it in place.