S3 good 159 now
around 260hp V good
Join Date: Jan 2008
Location: United Kingdom
Attention, 2.2 quick hesitation cure. YES IT WORKS.
My son (filby boy) after a year of 2.2 Brera car hesitation problems and a full specialist service which made no difference, considered fitting an exhaust system at a cost of nearly £800 to solve the problem. I said it can’t be that bad and took it for a drive, it was appalling, (especially after my 159, 2.4) so I said I would have a look.
I am an engineer by profession and a few years ago had to design a marine exhaust system to solve back pressure problems on 710 hp diesel engine installations.
Without going into boring details I looked at the air flow through the cats and first box including exhaust diameter and they were ok. I then looked at the baffle arrangements in the back box on each side and concluded there were too many U turns to allow the gasses to free flow when a sudden rapid increase in exhaust volume/flow was required. This would choke the engine until the faster flow was established around the baffles.
I concluded that a 14mm diameter hole through the side of the final baffle each side would be large enough to allow excess exhaust pressure to spill flow and reduce back pressure. I then drilled a 14mm hole inside both back boxes as shown.
The results were amazing. It is a different car, smooth acceleration, no jerking or coughing. You can pull away slowly or roar away with confidence and gear changes are now smooth. I cannot describe how different the car now drives and it was such an easy cure with only a slight noise increase at tick over.
This cannot be done on a 159 because of the exhaust shape.
If you don’t believe it, I am happy to show the difference if you are in the Yarmouth area.
In the pictures below I have sprayed silver paint in the exhaust to show up the hole which you would not normally see.
Last edited by Filbyman; 30-09-14 at 19:58.