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308 loading up in corners

Discussion in 'Technical Q&A' started by jw6513, Jan 29, 2004.

  1. jw6513

    jw6513 Karting

    Nov 24, 2003
    50
    Arizona
    Full Name:
    Jim Whitney
    I have a 78' 308 - (stock engine with webers). The engine runs very close to perfectly in a straight line, however I've always had the problem with it flooding or loading up in relatively tight corners. I've had a couple of knowledgable Ferrari mechanics tell me that it is normal for the 308 as the carburators were designed to be in line and are transverse in the 308. I've been told that fuel sloshes from the bowl and temporarily chokes the carbs. Has anyone had any success in eliminating or significantly dimimishing this condition. Thanks, Jim
     
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  3. jmillard308

    jmillard308 F1 Veteran
    Silver Subscribed Owner

    May 29, 2003
    5,964
    Perth West Oz
    Full Name:
    John Millard
  4. Mike328

    Mike328 F1 Rookie
    Rossa Subscribed

    Oct 19, 2002
    2,655
    Boulder, CO
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    Mike
    You're not alone in your problem.

    I'm not positive, but I thought that I read somewhere that DCNFs were in fact designed for a TRANSVERSE application, like ours.

    I think I found the link:
    http://www.mirafiori.com/faq/content/idf.html

    Now, it's on the web, and it's somebody stating a fact without referencing their source, but it's at least an indication.

    I, too, as well as others, have a problem with fuel starvation/hesitation/cutoff in corners, and not necessarily at high speeds.

    Have a read at this entire thread in the FerrariChat archives:
    http://www.ferrarichat.com/discus/messages/256120/262013.html?1055302715

    Does this sound like your problem?

    Setting float heights a bit higher, and/or using concave floats in the carbs, is one HYPOTHESIS geared towards fixing the problem (the idea being that more fuel is in the float bowls), but I've seen no hard data to support this.

    I was successful in getting this problem to go away for a few months when my mechanic did some carb work, but it came back eventually.

    The one reference I ever found to the problem was in Pad Braden's "Weber Carburetors" book in reference to the Progression Circuit (Pg. 39):

    The progression circuit has the most profound effect on driveability, and is the circuit most used in everyday driving. It's the circuit that allows the carburetor to maintain the same mixture strength as it makes the transition between the idle and main circuits. Engines that stumble as they pull away from a stop or turn a corner slowly probably have a progression circuit needing attention.

    Lots of carb folks have this problem. It's my #1 peeve with the car. It doesn't show up in any car reviews of the 308's era, leading me to believe that either 1. The problem wasn't present when the carbs were new, or 2. This was a common carb problem and as such was overlooked, either for its commonality or because the 308 was a "sports car" and they may not have focused on out of town driving.

    Would be interested in hearing any other folks' thoughts. In fact, I'm going to start a poll.

    --Mike
     
  5. jw6513

    jw6513 Karting

    Nov 24, 2003
    50
    Arizona
    Full Name:
    Jim Whitney
    Thanks for the input guys. I checked the threads, but it doesn't sound as if anyone has really figured it out. I've checked the float levels and they are all on spec. I also had Bob Wallace (Ferrari Engine rebuilder extraordinare) go through my carbs. He believes the carbs are in excellent shape and set properly. I have no hesitation in a straight line or during high speed sweepers....only slow speed tight corners.....feels like it just runs out of fuel for a second. I'll give it some more thought. Thanks again.
     
  6. Mike328

    Mike328 F1 Rookie
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    Oct 19, 2002
    2,655
    Boulder, CO
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    Mike
    Just for reference, your symptoms are exactly my symptoms. I think the F community will eventually solve this one! We'll see how the carb rebuild did for me (will know in a few days).

    --Mike
     
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