supercharger loosing performance

Discussion in 'New Owner Questions' started by 427cobra, Sep 27, 2011.

  1. 427cobra

    427cobra Enthusiast

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    I am new here so hello to all....I have a 99 RT/10 with a paxton s/c that was installed several yrs and around 4000 miles ago. It has worked flawlessly and very impressively..that is until the first drive of the year this spring. When it was adequately warmed up I got into it and it performed as usual by roasting the tires thru 1st gear. As the morning wore on, each time I nailed it the performance diminished to the point that by the 5th time it wouldn't even chirp the tires and felt like it had no more than 350 or 400 hp. I took it to the shop that installed the blower ( who I trust very much) and they have not been able to diagnose the problem..in fact when the car was at the shop, we took it around the same block 5 times in a row (did this several times over a week or so) and it keeps loosing pwr. They have changed plugs, O2 sensors, checked fuel pressure, checked the boost which is the same when its working as it is when it looses pwr..around 5-6 lbs. A call to Paxton has been of no help other than they suggest sending them the ecm for them to check out but they say that is never the problem. I thought I'd see if any forum members have any ideas before I start sending parts away. Thanks in advance
     
  2. plumcrazy

    plumcrazy Viper Owner

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    call doug levin and ask him about it. 954-434-9356 he will help ya out. tell him i sent ya
     
  3. AbsolutHank

    AbsolutHank Viper Owner

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    What about catalytic convertors getting plugged?
     
  4. mbccenter

    mbccenter Viper Owner

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    Belt slipping?
     
  5. Martin

    Martin Enthusiast

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    I'm guessing you checked all the obvious things like clogged air filter, loose serpentine belt, and don't have any bad noises coming out of the blower (bearings going out).

    Have you run it on a dyno while hooked up to a data acquisition device? If it's doing funny things, the best thing to do is run it back to back on the dyno until you can reproduce the problem - and look at all the data the PCM is putting out. That at least will give you enough info to pinpoint the obvious.

    If you don't want to spend all day on the dyno, you can get an OBDII bluetooth adapter, and link the adapter to your Droid device (or a laptop) and collect data. Big things to look at are O2 sensor readings in and out of the cats, A/F ratio (if you can), intake air temp, MAP readings, timing, calculated load, and fuel pressure (if you can).
     
  6. Red Snake

    Red Snake Viper Owner

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    Strap it to a dyno and monitor boost, AF & fuel pressure. You should get some indicators on the culprit.
     
  7. bluesrt

    bluesrt Viper Owner

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    did you check fuel pressure under a load while driveing,does the fuel pressure drop when you punch it while in park? a good fuel pump will rise when you punch it, the guage will spike a smidge
     
  8. Doug Supercharged Vipers

    Doug Supercharged Vipers Enthusiast

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    You can call me if you prefer .... I'll be happy to help :drive:

    Thanks Phil!

    Doug Levin

    954-434-9356
     
  9. TowDawg

    TowDawg Viper Owner

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    This may sound odd, but your clutch could be slipping as well. Not so much that it's readily noticeable (like rpm's really climbing with no acceleration), but just enough to make it feel like you're losing power. It would also go along with the fact that it seems to get worse each time.

    I had no idea my clutch wasn't getting a full grip, but I replaced it while I had the car apart for some other things anyway. After putting in a brand new clutch, it felt like I picked up 75+ hp!
     
  10. 427cobra

    427cobra Enthusiast

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    Thanks for all the advice guys !!I will start working down the list!
     
  11. Red Snake

    Red Snake Viper Owner

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    Make this call before you spend a bunch of time working on this. DL probably knows more about the Paxton set up than anyone else on this board. ;)
     
  12. plumcrazy

    plumcrazy Viper Owner

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    i taught doug everything he knows :)
     
  13. ViperGeorge

    ViperGeorge Enthusiast

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    Ok, I had the same problem on my Paxton supercharged 06. Changed cats, changed crank sensor, O2 sensors, cam sensors, rebuilt engine, (yea I know), sent blower to Doug Levin for a rebuild including the bypass valve. I had boost gauge and wide band O2 sensors, Intake air charge, fuel pressure gauge, etc. Turned out it was the split second box that comes with the Paxton. Sent it to Doug Levin and he immediately diagnosed the problem, the box was dead. It controls timing and the aux. fuel pumps. Replaced it and the car runs like a raped ape again. Doug can walk you through some diagnostics on the blower over the phone but my money is on the split second box.
     

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