MadaboutKitcars

The exhaust on the car is a tad noisy when all 4 holes are open so we've been running around with one hole on each side plugged. We've been looking for a more elegant solution that would allow us to choose the volume.


The starting point, Vauxhall Omega V6 2.5 throttle body, nice and cheap on ebay for £5 !


After chopping the throttle body in half with a hack saw and removing excess bits with an angle grinder it was time to turn it down on the lathe.


This is how it will work in the exhaust.


Here's one half down and the other half still with the rest of the metal on it.


Now both are cut out on the lathe.


Test fit with valves closed.


Valve open!


Hole drilled through exhaust tip, throttle body metal fitted in.

Cool, that would be good for trackdays where the noise level is limited too

I've seen this on the MG-ZR 160 backbox too, worked well there too, although how are you going to open and close it? mechanically variable or via vacuum level from the engine?

Not figured out that bit yet the idea is that the valve opens at a certain RPM maybe 3.5k, possible combined with a reading from the AFM so it does it under load and not while cruising.

I've got a spare vacuum based one from a BMW back box so if I can get a second one and some way to electronically shut off the vacuum I'll be sorted

the ZR used a vacuum operated switch in the engine bay to a servo/solenoid on the exhaust housing

I'll check out that system thanks