News

355 Exhaust Questions/Opinions

Discussion in '348/355' started by bcar1, Jul 7, 2019.

  1. bcar1

    bcar1 Karting
    Silver Subscribed

    Aug 2, 2017
    51
    NYC/NJ
    Full Name:
    Bob
    I had some time before the 4th so finally decided to install the larini secondary cat bypass i bought last year. I mistakenly thought this was a simple process- remove airboxes/heat shield/bypass valve then remove and replace secondary cat. I did not realize the primary cats also had to come out- so got stuck into some more work than expected.

    Anyway, now that i have the entire exhaust system apart I figure I might as well replace some of the hardware which is pretty beat up. I am definitely buying new gaskets & diverter bolts- Does anyway have any opinion of the Hill engineering vs OEM? (https://www.hillengineering.co.uk/exhaust-parts/bolt-kits/ebc-355-m5-2) Also considering buying both parts for the rear clamps (https://www.hillengineering.co.uk/exhaust-parts/exhaust-clamps-flanges/ec-355-exhaust-clamp-set & https://www.hillengineering.co.uk/exhaust-parts/exhaust-clamps-flanges/157417) I never even heard of these until I went to look at parts on eurospares. If anyone has any opinions would love to hear, namely is this a waste of $ for an equally functional part that no one can see, or a true upgrade.

    Finally, Im contemplating installing the primary cat by-pass pipes I bought since I have to remove the hyperflows that are currently on the car to get access to the secondary cat. I have heard varying reports of success with fabspeed 90 mini-cats (https://www.fabspeed.com/universal-90-degree-o2-spacers-with-catalytic-converters-pair/)- my car is a 5.2 and i would really love to avoid CELs anyone have any thoughts before i take the plunge?

    Image Unavailable, Please Login Image Unavailable, Please Login
     
  2. bcar1

    bcar1 Karting
    Silver Subscribed

    Aug 2, 2017
    51
    NYC/NJ
    Full Name:
    Bob
    I went ahead and bought all the hill replacement parts see below for photo comparisons. No surprise, but the quality difference vs OE is pretty substantial. The new oem replacement gaskets were also much needed despite being much thicker & lighter than the ones on the car. One issue with the hill bolts for anyone looking is they only sell the diverter bolts, not the header-cat bolts which i did not realize. I ended up using the hill engineering springs/spacers/washers with the original bolts that i cleaned up. Will post photos of the finished install when its all together.

    Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
     
  3. chrisj951

    chrisj951 Karting
    Silver Subscribed

    Feb 18, 2015
    118
    Metro Atlanta
    If you run primary cat delete pipes on a 5.2 you run the risk of a CEL. Plus the fumes would be more pronounced. When I did my major on my 2.7 I put Tubi headers and cat delete pipes and after driving it twice, I swapped the pipes and put my fabspeed cats back on.


    Sent from my iPhone using FerrariChat
     
  4. bcar1

    bcar1 Karting
    Silver Subscribed

    Aug 2, 2017
    51
    NYC/NJ
    Full Name:
    Bob
    I thought I read somewhere the 5.2 fumes weren’t as bad- fully aware that I may be making the switch back. Hoping the fabspeed minicats solve the cel issue assuming I can handle the smell!
     
  5. F355Bob

    F355Bob Formula 3
    Silver Subscribed

    2.7 run richer so 5.2 smell maybe not as bad. Is your upper bypass pipe collapsed to clear the frame. It looks like it in the picture
     
  6. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    2,560
    Sydney
    Full Name:
    Ian Riddell
    Same here with my 5.2. My eyes were watering. I fitted Larini hi flow cats. It's a good compromise between sound and smell and I've had no SD/CEL since I fitted them. It stopped the neighbours grumbling, too.
     
  7. bcar1

    bcar1 Karting
    Silver Subscribed

    Aug 2, 2017
    51
    NYC/NJ
    Full Name:
    Bob
    Yes it came that way from larini, it barely clears. The fabspeed has a similar design I think.
     
  8. INTMD8

    INTMD8 F1 Veteran
    Silver Subscribed Owner

    Jun 10, 2007
    5,193
    Lake Villa IL
    Full Name:
    James Moran
    I suppose mine is the exception

    :)
     
  9. F355Bob

    F355Bob Formula 3
    Silver Subscribed


    My early 95, built in 94, was very rich below 3500rpm. Another local guy had a 95, 4 serial numbers away from mine and he constantly fouled plugs. I had a ton of fuel removed with the piggy back computer tune and throttle response drastically improved below 3500. Tech at Lake Forest Sports Cars, the Chicago dealer, said the 95's fouled plugs when they started them and moved them around the shop and shut them off without getting out of the warm up stage. Yours might be the exception which is lucky for you
     
  10. INTMD8

    INTMD8 F1 Veteran
    Silver Subscribed Owner

    Jun 10, 2007
    5,193
    Lake Villa IL
    Full Name:
    James Moran
    Yes, odd. Mine is October 94 production. Also used to own a 99 GTS. Both were nearly the exact same air/fuel ratios monitored with a wideband (and actually if anything a bit lean down low only going slightly rich at high rpm)
     
  11. F355Bob

    F355Bob Formula 3
    Silver Subscribed

    I had test pipes and the exhaust smell was so bad could not drive with the windows down. Took them off and put on Hyperfow cats. Mine is a July 94 build.
     
  12. thurman_merman

    Silver Subscribed

    Jul 26, 2017
    25
    Austin, TX
    I personally don't know why anyone would want to bypass working catalytic converters on a 355, especially with a catless secondary pipe. The cats cut down on fumes and sound at low speed operation and they are bypassed by design when you get on the throttle. If you want a loud idle get a bypass remote and change it with the push of a button. Just my opinion.

    In my experience the catted O2 extensions helped to eliminate my cel because my fabspeed cats were setting off inefficiency codes. I didn't want to spend big money to replace them so I took a gamble on the extensions. I have read a lot of posts saying they won't stop a cel with test pipes and only a few saying they will. When I bought them the fabspeed rep warned me that they aren't going stop a cel with test pipes before I told him I still had cats on the car.
     
  13. ttforcefed

    ttforcefed F1 World Champ
    Rossa Subscribed

    Aug 22, 2002
    10,928
    the cats on the f355 create alot of heat and accelerate the failure of the exhaust manifolds/headers. i love the smell my 95 makes with test pipes - are u kidding me? to die for.
     
  14. drbob101

    drbob101 F1 Rookie
    Silver Subscribed Owner

    Nov 26, 2012
    3,656
    Tinton Falls, NJ
    Full Name:
    Bob Ferraris
    There are some who have test pipes and mini cats with no issues. Skipp can comment here as I believe he does.

    Google Big Daddy mini cats
     
  15. bcar1

    bcar1 Karting
    Silver Subscribed

    Aug 2, 2017
    51
    NYC/NJ
    Full Name:
    Bob
    I suspect you’re right- my thought was more because the cats had to be removed to instal the secondary cat- I might as well try it. Will report back.
     
  16. Drock28

    Drock28 Formula 3

    Jan 13, 2013
    1,316
    Montreal
    Full Name:
    Tony
    1997 5.2 completely decat. Fabspeed headers, Fabspeed test pipes, Nouvalari ypipe, Nouvalari exhaust. with mini-cat spacers on the test pipes. No CEL.
     
  17. chrisj951

    chrisj951 Karting
    Silver Subscribed

    Feb 18, 2015
    118
    Metro Atlanta
    Where does one find mini-cat spacers?
     
  18. Drock28

    Drock28 Formula 3

    Jan 13, 2013
    1,316
    Montreal
    Full Name:
    Tony
    the ones i’m using are fabspeed.
     
  19. bcar1

    bcar1 Karting
    Silver Subscribed

    Aug 2, 2017
    51
    NYC/NJ
    Full Name:
    Bob
    I also got the fabspeed ones- incredibly well made. Will post photos once up and running.
     
  20. bcar1

    bcar1 Karting
    Silver Subscribed

    Aug 2, 2017
    51
    NYC/NJ
    Full Name:
    Bob
    Image Unavailable, Please Login Everything back together. Waiting on some replacement bolts & bits from eurospares/Ricambi before I completely finish & test drive. You can see the cat extenders in this photo (they’re pretty big) I also attached a close up below- the clearance is a bit tight but everything fit. Initial reaction is the fumes are not noticeably worse, but will really need to run it before I comment.
    Image Unavailable, Please Login
    Close up of fabspeed mini-cat w/ right angle.
     

Share This Page