Hey @RossoRocket, that's an interesting project, fitting a proper QV back box onto your Veloce instead of just wrestling with aftermarket tips. Have you had a chance to get under the car and compare the hanger locations on the Veloce to where they are on the QV box? Adding a few photos of the underside might help the community chime in on how to best tackle the pipework

 

Hi,

An update to the above. The QV exhaust has been bought and the original removed.

First things to note.

Rear Bumper removal is a must for access and ease of removal and re-instillation.

A ramp to lift the car up is also a huge plus.

The QV back box and Veloce Back Box are exactly the same dimensions, they also share the exact same hanger placements and mounting points on the box itself. This means that from a fitting perspective, they are interchangeable. The single inlet on the left of the back box when viewed from the rear of the car perfectly aligns with the left most pipe going into the QV back box. So if you wanted you could blank the right off and just marry the left one up, but as we don't know what wizardry is going on in there, we want to maintain both inlets for a smooth flow and hopefully sound.

The Pipes feeding into the QV box and the Veloce box are also the same Diameter and area all Mild Steel and not Stainless from factory, this is easier for the welding guy to work with.

The original Veloce pipe work has a flat spot along about 12 inches (30 cm ish) of the top of the pipe to allow it to fit next to the bracing and rear diff sections. We need to maintain this so all pipework will be done Aft of this section. This actually makes aligning the whole thing pretty easy on the exhaust Jig as it basically acts as a 'this way up' reference point.

The Black pre-diffuser (no idea what it is called but it protects the back box from the road and probably has some slight aero affect.) will need to be "adjusted" to allow for the pipework but nothing that a careful hand and a few power tools can't fix.

This is all pretty positive so far.

The exhaust guy is happy that he can Y pipe the QV box into the existing Veloce Pipe for a clean install and maintenance of flow.

Next up is installing an exhaust valve control box and pipework in the boot and then routing the vacuum line to the vacuum valves on the QV box pipes to allow for control of these. These kits can be had on Ebay for around £60. I will update as I do this but initial inspection of the boot and floor lining suggests that placement of the control box should be easy enough with the foam under the boot floor to deaden the sound of the small pump drawing a vacuum and the battery right there to tap into. I can't yet see a hole in the boot floor though so I may end up making one and then securing the pipe with a waterproof gromet into the hole before routing it to the valves.

Hope that others are interested in this little project as so far it appears to be very possible and actually very cost effective. If it works and sounds good/ok then it is basically a valved, OEM quality, handsome looking (tips i mean) exhaust system for around £400.

See images of the QV exhaust and the OEM on the car and off. You may also note the ugly "Quad" tips that sparked me to undertake this whole project as they look very wrong on the car.

I'm away for the next few days as the exhaust shop works on things so an update should follow on Sunday (21/09/25) with more detail on the Valve kit and re-install.

Happy travels all

 

Hello All!

I have news!

The muffler / Back Box has returned from the weld shop, all welded up and looking good.

The valve control kit arrived minus a pump so that is on order.

It has all been installed!

What I learned;

The exhaust fits seamlessly, all hangers align easily and it was basically a bolt up job.

There is a way to route the vacuum line for the valves from the boot to each side of the exhaust.

The valves when not under vacuum are open by default.

It sounds AWESOME!!!
See videos for proof, one is a cold start the other once warm.
It burbles, it softly pops, it actually sounds somewhat like a QV?

Next up is to complete the valve control kit and install that in the car, then it will be done!

Pictures are showing the alignment of the hangers, the vacuum line in blue, the whole affect and the videos of the sound!

Cold Start

Running Warm

More to come once I complete the valve kit and reinstall of the resprayed bumper.

 

The images

 

last two

 

That does sound pretty good! Interested to hear some clips while driving, in and out of the cabin if possible!

 

Will do. I sat in it for a bit while the assembly paste cured as it was running, it was not loud in there but I will get some proper clips next week.

 

Hope you get the valves working as well, would like to hear how it sounds closed.

 

Dumb question, but "back box" == muffler?
If so, that is some new to me British car lingo. Or, is it a term made up for this thread?

 

haha yeah back box is Britain speak for a muffler as it is the box...at the back
I've changed the name to aid in identification of the thread as most Brits will understand what a Muffler is.