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512tr alternator belt keeps coming off

Discussion in 'Technical Q&A' started by 512tr, Apr 30, 2004.

  1. 512tr

    512tr Formula Junior

    Feb 6, 2004
    336
    montreal
    Full Name:
    tony
    Just installed a TAP computer chip, revs are bumped up by 400 rpm's,k&N FILTERS and tubi exhaust withouts cats were already on the car. The difference is very impressive. Only one problem, with the higher revs the alternator belt came off twice while testing the car. It got late and left the car at the garage. Any comments, tips, advise on how to reslove this problem. I'd like to go see the technician and have some advise for him to make it easier on him and my pockets.

    Thanks,

    Tony
     
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  3. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,358
    NY
    Tony don't quite understand you problem. Why would a few hundred rpm's make a difference. If your belt stayed on in the past at 7-8k rpms why would this make a difference.
     
  4. 512tr

    512tr Formula Junior

    Feb 6, 2004
    336
    montreal
    Full Name:
    tony
    That's what the technician can't quite figure out. I'm just wondering maybe it could be the bearing but we didn't have time to look at it any further, it got late. I posted this thread just to see what kind of feedback I'd get.
     
  5. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    19,283
    Texas
    Full Name:
    Steve Magnusson
    Is it a V-belt or a flat "Poly-V" belt?

    This is kind of a tough area for a manufacturer -- at idle, you need to spin the alternator fast enough so that it charges well, but at the same time, if the linear belt speed or alt. bearing RPM get too high at redline these can be problems (so there's ususally not much upper-end margin to begin with).

    You've certainly got the right approach to first make sure that the stock arrangement is mechanically healthy (if the alt. bearings feel good you still might want to confirm low pulley runouts and good alignment), but if the problem persists you could try things like:

    1. a slightly larger alternator pulley,
    2. a slightly shorter belt (to reduce the span and raise the natural frequency of the "span flapping" mode -- but this requires even better alignment between the driving and driven pulleys since they're closer together).
    3. improving the existing bracketry to reduce "cocking" (if any) of the alternator body (and hence the pulley) under the belt load.
    4. If you really get desperate you might be able to add some fixed nearby UHMW plastic guides that don't normally touch the belt, but would limit the belt span excursions under extreme conditions.

    Just some random thoughts. An interesting problem -- let us know how it works out.
     
  6. james patterson

    james patterson Formula Junior
    Professional Ferrari Technician

    Dec 8, 2003
    417
    Dallas Texas
    Full Name:
    James Patterson
    Tony - This is a common problem on the turbo TR's we do with the flat rib belt like on your car. If you get the belt very-very tight it normally stays on pretty well. If that does not work machine a guide plate, just as Steve suggested, for the front side of the alternator pulley. The guide plate has always solved the problem for us.

    Good luck,
    James Patterson
    Norwood Performance
     
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  8. 512Professore

    512Professore Karting

    Feb 3, 2004
    145
    USA, GA.
    Full Name:
    Brian Strasburg
    Luckily, I haven't had that problem with mine, but a 512M that I know well had that problem as well, but only became a problem after a ECU chip change with the corresponding rev limit increase. I agree with the comments from Norwood. Getting the belt very tight solved the problem for this particular 512M. OF course, the space in which you/mechanic have to work and apply the appropriate leverage makes the task rather frustrating and can generate a few 4 letter words.

    Also, the Ferrari anciliary electricals, such as the alternator are pretty much near the limit at 7,200rpm. I would like to see one of our Fchat sponsors develop an underdrive pulley set for the 512, perhaps EVOSPORT, as I have one of their underdrive pulley sets installed on the M3, and it works very, very well.

    So, you really like the Tap chips, and can notice a significant improvement ??? Excellent !!! What part of the rev range do you see/feel the biggest improvement ??? Now, you need a good set of spark plugs to augment the car's current setup.

    Keep the Rubber side down.....
     
  9. 512tr

    512tr Formula Junior

    Feb 6, 2004
    336
    montreal
    Full Name:
    tony

    The difference is truely remarkable. The car just breathes alot better. I'M not not sure about the rev range because I only tried the car once, but I'd say at 2500 rpm it just opens up and gets to 7200 rpm in a flash.If this works out, I think it's gotta be the most inexpensive way to get the extra HP. I can't believe that Ferrari would leave that extra power on the table.
     
  10. 512Professore

    512Professore Karting

    Feb 3, 2004
    145
    USA, GA.
    Full Name:
    Brian Strasburg
    Believe It !!! The flat-12 engine has been around for a long time with many years of development, making it a very SWEET engine.

    From experience and talking with other knowledgable people, I have concluded that there is about 100bhp sitting on the table with this engine as it left the factory. With your car being set-up very similar to mine, with no cats, a Tubi and K&N's, your chips just makes all these things work together. IIRC, Tap advertises that they don't modify the fuel/ignition curve until 2,500rpm, so your seat-of-the-pants test drive basically confirms. With mine, the engine seems to explode with power at 4,200rpm, and continues all the way to red line. The engine sounds are worth it alone !!!!

    Have Fun....
     
  11. 512tr

    512tr Formula Junior

    Feb 6, 2004
    336
    montreal
    Full Name:
    tony
    Have you upgarded your chips ?
     
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  13. 512Professore

    512Professore Karting

    Feb 3, 2004
    145
    USA, GA.
    Full Name:
    Brian Strasburg
    Yeah, the chips(EPROMS) were upgraded several years ago. Initially, from the seat of pants, I thought the change/improvement was somewhat subtle. The butt dyno(at least mine) has a hard time discerning the extra power, but I soon realized, since the car's chassis delivers the power so smoothly and quickly, that WOW, things in the engine bay are not what they used to be !!!! Since the new chips were installed(myself), it has provided the opportunity to continue with other mods that makes sense, some of them subtle, but the engine receives the mods well, and they are additive in nature. No, haven't done an actual dyno run on the car, but I would expect some very nice numbers, as the car currently out-runs 550's, and just about anything else.
     
  14. 512tr

    512tr Formula Junior

    Feb 6, 2004
    336
    montreal
    Full Name:
    tony
    I'd like to thank everyone for their responses and suggestions via your replies and PM'S. The problem seems to be solved, a new alternator belt with the correct tension seems to have done the job. Ivor at TAP1 was very helpful and reassuring. His 1st suggestion like many others, was to make sure that the pullies were properly aligned. Usually the case when there is an out of car engine service which was done last year. Ed (technician) was confident that this was not the case. 2nd suggestion was to make sure that the belt was properly tightened but not overtightened. What we think caused the belts to snap off, is that the first one might have been loose to begin with and the 2nd belt snapped maybe due to age, it was taken from my tool kit which is 11 years old.

    I test drove the car today with Ed at Auto Bugatti and let me repeat what I've said before, I can not believe the extra power that it has now. I think the three changes (tubi, k&n filters and TAP1 chips) work great together. It has alot more tire spin in 1st gear, something I need to get adjusted to while launching (hehe) and rpm'***** the redline much sooner.

    Looking back at last Friday night when I posted this thread, I must have been in panick mode wondering, why this problem? what did I get myself into? (even though Ed reassued me that I would have the car back as soon as they would receive a set of new belts) and dissapointed because I wouldn't be able to take the car home for the weekend All in all, I am very happy with the changes on the car, not that I wasn't happy before, but the car needed a little more power to keep in pace with the newer cars.

    Thanks again everyone.

    Tony
     
  15. Steve

    Steve Formula Junior

    Nov 1, 2003
    901
    Seattle, WA
    Full Name:
    Steve Jenkins
    Glad to see you found the problem.

    I've done the TAP Chip, Tubi exhaust, K&N, and the Tubi cat bypass tubes (still passes emissions, tho). The bypass tubes were the best upgrade I did. The sound difference is AMAZING.

    One thing I've noticed, however, is that my HP curve is flat from about 6000 to 7200 after installing the chip:

    http://ferrari.stevejenkins.com/downloads/512dyno.jpg

    I would have thought it would peak rather than plateau. Anyone else seen this in their chipped 512TR?
     

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