Quad Conversion - Project Write up
Posted: Tue Apr 21, 2009 9:27 pm
I’ve had several requests to pull together a brief write up of the project to convert to a Quad system, so here we go:
My intention was to continue to develop the Zed inline with my overall theme, not replicate an ///M but bring the rear in line with the rest of the car. I set some overall criteria:
• The exhaust had to be fully functional and not dummy pipes, or a cheaper ‘T’ off the back box. Noise levels to be acceptable, net weight the same and no drop in performance (nor gains sought)
• Luggage space had to be maintained.
• I had sourced a pair of brand new M boxes (thank you Ebay £21 Vs £850) so wanted to go with them if possible.
• Controlled costs as this was experimental.
• It had to say ‘OEM’ or at least BMW could have done that.
The movement of parts
A lot of space had to be cleared to get the RHS box in as it’s a space already full of components. (Hence the reason why on the ///M BMW just lobbed the battery on a tray in the boot and hid it under carpet)
Battery had to be removed, box narrowed by 20cm heat welded back together and new Hawker battery fitted. New earth lead fitted.
The boot floor was plated, sprayed and sealed in. Great job by MRH Autos on the plate and spray work
Starter and other cables rerouted and all returned to normal in the interior, so retaining my luggage space and keeping all the OEM battery disconnects, crash sensors, etc.
The charcoal fume breather was removed (later found to be required only for OEM emission tests, but may later slot it back in between the rear boxes)
The Carbon Diffuser
Inspired by the latest race derived look appearing on many high end cars I wanted a CF diffuser on the back, but it was only available in single outlet and for the facelift as an OEM part.
The inspiration seen on several cars like these:
I also wanted to keep the OEM lights too, so switching to a later bumper cover would have meant bodywork around the lights, something to be avoided.
Lots of cutting, teasing, customising and moulding of a second exit and a prefacelift quad CF diffuser was born out of the OEM CF facelift version, that fitted the bumper and accommodated the proposed new pipes.
The new outlet moulded in:
Glossed, cut down from it's assymetric shape and finished aside minor trimmong once in place.
Not a good look though, to have been driving around for a week though with only LHS exhausts….
The new pipework
All that really remained was to couple the new boxes to the existing system. This was entrusted the MIJ who did a great job of fashioning stainless pipes, mounting everything and threading the new RHS pipework as a mirror of the LHS. The guys even flanged their pipes so the back boxes are correctly bolt mated on and we fitted an OEM ///M heat shield above the new box and various undertrays were modified. At a later stage it will be possible to bypass the main cats if required, but this was skipped for now due to unknown noise levels and sound of the system.
The Result
Well I’ll let the photos speak for themselves, but I love it. It has a very OEM look to it, obviously is fully functional and has a glorious sound that is not at all loud. My criteria were fully met too.
We’ve got 1,000 miles on it and all I needed to do was cut a little CF off the diffuser as the exhaust stretches by 10mm when hot and was touching the diffuser and the diffuser needed adjustment to sit square.
Thanks to all those who chipped in comments, kept me ‘true’ on design ideas and provided a sounding board.
Of course I'd not do it again and as the Iphone ads. say have shortened and missed some steps in what was an interesting little project
My intention was to continue to develop the Zed inline with my overall theme, not replicate an ///M but bring the rear in line with the rest of the car. I set some overall criteria:
• The exhaust had to be fully functional and not dummy pipes, or a cheaper ‘T’ off the back box. Noise levels to be acceptable, net weight the same and no drop in performance (nor gains sought)
• Luggage space had to be maintained.
• I had sourced a pair of brand new M boxes (thank you Ebay £21 Vs £850) so wanted to go with them if possible.
• Controlled costs as this was experimental.
• It had to say ‘OEM’ or at least BMW could have done that.
The movement of parts
A lot of space had to be cleared to get the RHS box in as it’s a space already full of components. (Hence the reason why on the ///M BMW just lobbed the battery on a tray in the boot and hid it under carpet)
Battery had to be removed, box narrowed by 20cm heat welded back together and new Hawker battery fitted. New earth lead fitted.
The boot floor was plated, sprayed and sealed in. Great job by MRH Autos on the plate and spray work
Starter and other cables rerouted and all returned to normal in the interior, so retaining my luggage space and keeping all the OEM battery disconnects, crash sensors, etc.
The charcoal fume breather was removed (later found to be required only for OEM emission tests, but may later slot it back in between the rear boxes)
The Carbon Diffuser
Inspired by the latest race derived look appearing on many high end cars I wanted a CF diffuser on the back, but it was only available in single outlet and for the facelift as an OEM part.
The inspiration seen on several cars like these:
I also wanted to keep the OEM lights too, so switching to a later bumper cover would have meant bodywork around the lights, something to be avoided.
Lots of cutting, teasing, customising and moulding of a second exit and a prefacelift quad CF diffuser was born out of the OEM CF facelift version, that fitted the bumper and accommodated the proposed new pipes.
The new outlet moulded in:
Glossed, cut down from it's assymetric shape and finished aside minor trimmong once in place.
Not a good look though, to have been driving around for a week though with only LHS exhausts….
The new pipework
All that really remained was to couple the new boxes to the existing system. This was entrusted the MIJ who did a great job of fashioning stainless pipes, mounting everything and threading the new RHS pipework as a mirror of the LHS. The guys even flanged their pipes so the back boxes are correctly bolt mated on and we fitted an OEM ///M heat shield above the new box and various undertrays were modified. At a later stage it will be possible to bypass the main cats if required, but this was skipped for now due to unknown noise levels and sound of the system.
The Result
Well I’ll let the photos speak for themselves, but I love it. It has a very OEM look to it, obviously is fully functional and has a glorious sound that is not at all loud. My criteria were fully met too.
We’ve got 1,000 miles on it and all I needed to do was cut a little CF off the diffuser as the exhaust stretches by 10mm when hot and was touching the diffuser and the diffuser needed adjustment to sit square.
Thanks to all those who chipped in comments, kept me ‘true’ on design ideas and provided a sounding board.
Of course I'd not do it again and as the Iphone ads. say have shortened and missed some steps in what was an interesting little project
