355 Exhaust valve. | FerrariChat
Buy

355 Exhaust valve.

Discussion in '348/355' started by DMOORE, May 23, 2006.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. DMOORE

    DMOORE Formula 3

    Aug 23, 2005
    1,720
    San Diego
    Full Name:
    Darrell
    #1 DMOORE, May 23, 2006
    OK. So I have been reading through some of the threads on exhausts for the 355. Some people have mentioned wiring the exhaust valve open. So the other night I was a bit bored and gave it a try. All I can say is I wish I had done this 6 years ago. The car sounds FANTASTIC. It sounds as good as any aftermarket exhaust I have heard. Also. I've noticed a BIG plus. The car REVs much quicker from low rpms, (1500-4000) than it did with the valve normally closed. It makes me think that Ferrari put the valve in for noise cancellation only and not for needed backpressure. I was very pleasantly suprised that a bit of saftey wire made such a difference.

    Darrell.
     
  2. Llenroc

    Llenroc F1 Veteran
    Rossa Subscribed

    Jun 9, 2004
    5,493
    Colorado
    Full Name:
    Vern
    #2 Llenroc, May 23, 2006
    I have a story for you guys on doing this. Not that this could happen on a road car because of the muffler still being in place and adding enough back presure but, on my 355C when I first got it home the CELs were coming on at low RPMs and then going off after you were above 3000 RPM. After reading the codes on the ECUs and it telling me that I was having 02 sensor errors. What the problem was is that the upper exhuast, the one that would have the bypass in it, flows better than lower side when you remove the bypass, (the CH cars don't have the bypass valve at all or the upper cats) the lower one has the cats plumbed into it, the upper exhaust flows so well that it causes a vacuum/reverse flow thru the lower exhaust sucking fresh air thru the cats in reverse so that the 02s were one not getting warm but didnt have any exhaust to read but, after 3000 or so there was enough exhaust presure to cancel the reverse flow and allow hot enough exhaust to pass over the 02 sensors and turn off the CELs. I have since fixed my problem. Anyway my point is if the your CELs come and they read an 02 error code then you might be having the same reverse flow problem. anyway just a pointer if you guys that do open your bypass and have your lights come on. Regards, Vern
     
  3. rketex7

    rketex7 Formula Junior

    Jan 8, 2004
    511
    Midwest
    Full Name:
    K.C.Y.
    #3 rketex7, May 23, 2006
    Hope your MY97 check engine light and slow down light like MY99. It takes at least 3 start ups and stops before the lights come on. However, I have spoken to other MY95 (OBD 1) which do not have any problem with the valve wired open. Good luck.
     

Share This Page