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  1. #1

    ultra 250 supercharger question

    my ultra 250 supercharger boost only goes up to 10 on the dash is there somthing wrong with the supercharger or do they not go up to 15 unless they are upgraded


  2. #2
    The maximum boost on stock 250 is about 11.5 psi on a good day. It can be any one of the following issues that can cause the low boost.
    > fouled plugs
    > slipping/worn out belt
    > fallen air intake boot
    > oil contaminated ic
    > damaged/peeled off rotor coating
    > lack of compression
    > etc.
    Do a search on this forum for any of the above issues and you will find more detail. That's your hw.

  3. #3
    UltraKvz's Avatar
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    Quote Originally Posted by meangreenman View Post
    The maximum boost on stock 250 is about 11.5 psi on a good day. It can be any one of the following issues that can cause the low boost.
    > fouled plugs
    > slipping/worn out belt
    > fallen air intake boot
    > oil contaminated ic
    > damaged/peeled off rotor coating
    > lack of compression
    > etc.
    Do a search on this forum for any of the above issues and you will find more detail. That's your hw.
    Hi MGM. I read somewere that a pully kit that produces extra boost can damage an unmodified engine beceause of more compression on the pistons over time. My question is this: If you put a good blow-off valve at the back of the IC, tune it to blow off at precisely 11.5 psi, will it not give the ski more consistant boost in diffrent RAD's without the damage? At high altitude I'm struggling to get more than 10.5psi. At sea-level it's not a problem. Or should I just have diffrent pithced impellers for diffrent condisions?

  4. #4

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    Quote Originally Posted by meangreenman View Post
    The maximum boost on stock 250 is about 11.5 psi on a good day. It can be any one of the following issues that can cause the low boost.
    > fouled plugs
    > slipping/worn out belt
    > fallen air intake boot
    > oil contaminated ic
    > damaged/peeled off rotor coating
    > lack of compression
    > etc.
    Do a search on this forum for any of the above issues and you will find more detail. That's your hw.
    Hey.. meangreenman.. was reading about the fallen air intake boot... does this make a difference.. I just found the boot out of the air box.. ?

  5. #5
    MADRUI madrui's Avatar
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    yes it makes.take it off.i have mine off since new.

  6. #6
    Quote Originally Posted by UltraKvz View Post
    My question is this: If you put a good blow-off valve at the back of the IC, tune it to blow off at precisely 11.5 psi, will it not give the ski more consistant boost in diffrent RAD's without the damage? At high altitude I'm struggling to get more than 10.5psi. At sea-level it's not a problem. Or should I just have diffrent pithced impellers for diffrent condisions?
    > Not only higher boost can crack the pistons, it can also melt/peel off the supercharger coating on the rotors due to the increase in the compressed air temperature. That's more likely than anything. The S/C gets really hot even with the OEM pulley if engine is run at WOT for a prolonged time. Can't even touch with your hand and I'm guessing it's at >200F.
    > I say try a lower pitched impeller

    ---------- Post added at 01:23 PM ---------- Previous post was at 01:21 PM ----------

    Quote Originally Posted by KawaHead View Post
    I just found the boot out of the air box.. ?
    Supposedly it is supposed to increase the speed of intake air by its design. Hence, it's called "velocity stack" in auto industry. Put it back and THIS time use super-glue.

  7. #7
    Quote Originally Posted by madrui View Post
    yes it makes.take it off.i have mine off since new.
    thanks for the help i will research

    ---------- Post added at 06:34 PM ---------- Previous post was at 06:33 PM ----------

    thanks for the help i will do my research

  8. #8
    nicjak's Avatar
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    wheres the switch to turn the s/c on and off lmao, i saw an ebay add the other day and a guy was selling his ultra, he said it come with a learner key to turn the s/c off some people have no idea and watch too much tv

  9. #9
    Quote Originally Posted by UltraKvz View Post
    ...If you put a good blow-off valve at the back of the IC, tune it to blow off at precisely 11.5 psi...
    UltraKVZ, sounds like you have another project! Back in 07 and 08, I remember that testing of stock BOV revealed surprising failure rate (premature release) causing loss of boost, prompting some to block off. The one time I handled my 07 BOV I dropped and cracked it. $325+ klutz move. Heck, you may come back and report the thing was originally used on a Husqvarna chain saw. I remember someone else asked about the on/off supercharger switch a while back and NJ said the same thing--been watching too many Mad Max movies!

  10. #10
    Take the time to smile sirbreaksalot's Avatar
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    Quote Originally Posted by UltraKvz View Post
    Hi MGM. I read somewere that a pully kit that produces extra boost can damage an unmodified engine beceause of more compression on the pistons over time. My question is this: If you put a good blow-off valve at the back of the IC, tune it to blow off at precisely 11.5 psi, will it not give the ski more consistant boost in diffrent RAD's without the damage? At high altitude I'm struggling to get more than 10.5psi. At sea-level it's not a problem. Or should I just have diffrent pithced impellers for diffrent condisions?
    waste of time putting a pulley on and then bleeding boost of just to maintain 11.5

    Reason's
    1. the extra rotor speed of the blower will increase charged air temperature and only make problem worse
    2. can increase the potential for supercharger failure. ( they are fragile enough as they are STOCK )

    But saying that my 07 250 has done 85hr on 1-1 with Zero damage to coatings on the rotors........But the odds are against you once you wind these chargers up !!!

    The only safe way to run at altitude is repitching.

    Waz

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