Wednesday, 9 March 2011

F355: Oh oh...

After reading a post on Ferrarichat or ClubScuderia about slight blows in the F355 exhaust system making a huge difference to the "boominess" of the exhaust note I checked mine and noticed a blow coming from the bypass valve. (The bypass valve is closed under a certain rev range for noise regulations and opens up above this range to really make the system howl.)

I decided to change the gaskets on the bypass valve. A quick check on Eurospares: £51 each! For a metal ring. I phoned a few places but nobody could supply them. I had nearly given up when I emailed Capristo. They have their own ones for 12 Euros each! Excellent. So I emailed back two order two up and asked  to advise on payment. Two days later 2 gaskets show up in the post! Capristo never took any money off me, thumbs up to them! I also ordered a new bolt kit from Superformance.co.uk. Ended up being around £30 for a couple of nuts and bolts, 2 springs and spacers.

I removed the bypass valve, to get at it you need  to remove the airboxes, MAF sensor and exhaust heat sheild. The old gasket rings were very flat and caked into the valve, I did however, manage to pry them free and position the new capristo gaskets, refitted the gasket with the bolt kit. Reassembled the car and fired it up! Still blowing!

I took it all to bits again and applied a little bit of exhaust paste around  the gaskets and refitted everything. The blow appears to be gone but now the car is idling too low around 750rpm and runs really badly up until about 2000/3000rpm.

When I initially fitted Nouvalari the car did run slightly oddly at first but turning the battery off and letting the ECU relearn did the trick. I will give this a try at the weekend along with hooking up an OBD 2 reader to see if I've done something to the MAF sensor!


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