MPI Supercharger Pulley Failure

christopher · Mar 25, 2012

Got my sled all put back together and took off into the mountains of british Columbia this morning. The idler arm let loose on my MPI Supercharger and that was the end of the ride for nytrocity. I am just DOOMED. Don't know how but the main nut that holds the idler pulley was siting in the bottom of the side cover with the idler pulley wedged at 45 degrees behind the oil tank. Nearly sliced the drive belt in half right down the middle.

If it hadn't been for the fact that I had an overheat warning and was trying to chase down a coolant leak I wouldn't have found the supercharger problem, and we have NO clue at all why she overheated this morning.

I guess it was just my turn to ride the backup sled for this trip. Maybe next time will be better!

Sent from my Apple iPhone 4S using the AVOW TapaTalk app.

94fordguy · Mar 25, 2012

Bummer.... Sounds like you got some wrenching to do when you get back

:beer;

mountainhorse · Mar 26, 2012

Hey.. you are in BC... AND you have a Backup sled... You live a blessed (not doomed) life!!

Iceman56 · Mar 26, 2012

I feel your pain I've been on a backup sled almost the whole season. Mine wont build over 10psi boost this whole season no matter what we try. Really takes the fun out of it when you drive 10 to 15 hours to ride it:face-icon-small-dis

RACINSTATION · Mar 26, 2012

Not that it matters now, but you HAVE to check pullys and tensioner tension EVERY ride on the superchargers.

TheBreeze · Mar 26, 2012

Mod sleds sure have a way of building mental toughness! And backup sleds are key.

If anything, you learned something.

Blk88GT · Mar 26, 2012

You have a backup sled, no big deal. Enjoy!

BOOSTD · Mar 26, 2012

Sounds like the idler but was never tightened. It is a lock style nut so if it was tightened upon assembly I don't know how it would have come loose after that. Like stated above, it's a good idea to check the pullys at least every ride if not every other. Of all the ones I have built I've never had one come off but a couple customers have after their build.

Also the two most common places for leaks on a supercharger are either from where you install the water pipe on the head where the sensor is now located or the plug that you pound into the thermostat. This would be the first places I would look on any super. Hope this.

kinger9 · Mar 26, 2012

RACINSTATION said:
Not that it matters now, but you HAVE to check pullys and tensioner tension EVERY ride on the superchargers.

Yikes I haven't checked mine in 4 years. I think the cause is still TBD. You shouldn't have to babysit a belt like that. I dont check my pulleys on a car and they use the same process since MPI builds supers for cars.

I'm not saying dont give it a once over but have you tried to check the belt that drives the SC from the jackshaft? You know the one buried under the intercooler, battery (apex) , charge tube, etc ya its fricken BURIED in there.

Good luck Christopher, you did a TON of mods at once. Hard to do it all perfect the first time.

WakeGD · Mar 26, 2012

I just got done replacing several bearings on my kit. The Apex's are a little different, but my idler bearing was shot (in addition to the jackshaft bearing that exploded).

So frustrating when they don't run! Stock sucks.

christopher · Mar 26, 2012

Making the first leg of a long drive back to Idaho falls today.

We DID check and torque the nut that failed before we left on this trip. With the heim joint failure on day two that got me less than 8 hours of use before failure from the last time we checked it.

Really do not understand this failure yet. Will have to wait till I get he and get the oil tank off of it so we can see it more clearly.

Sent from my Apple iPhone 4S using the AVOW TapaTalk app.

BigFish BC · Mar 26, 2012

christopher said:
Making the first leg of a long drive back to Idaho falls today.

We DID check and torque the nut that failed before we left on this trip. With the heim joint failure on day two that got me less than 8 hours of use before failure from the last time we checked it.

Really do not understand this failure yet. Will have to wait till I get he and get the oil tank off of it so we can see it more clearly.

Sent from my Apple iPhone 4S using the AVOW TapaTalk app.

i seem to remember a few other theads about this same the pulley coming off not sure how they stoped it. but remember guys having to tighten on the mountain to keep them on

m8magicandmystery · Mar 27, 2012

hope ya still had a great time...!!!!!!

Turbo11T · Mar 27, 2012

Should have gone with the turbo. Not so much mechanical moving parts to fail.

08nytromtxa · Mar 27, 2012

Turbo11T said:
Should have gone with the turbo. Not so much mechanical moving parts to fail.

x2 i think i can remember a thread he started and most said go with a turbo!

christopher · Mar 27, 2012

Couple of snap shots from the mountain when the pulley failed.

TNytro162 · Apr 4, 2012

New summer project ,,,,,MCX turbo for ya christopher.:face-icon-small-sho You gave the S/C a chance...

judger101 · Apr 4, 2012

i think you need to change your status. i dont think you are currently: loving your MPI supercharger.... :face-icon-small-con

paulharris · Apr 4, 2012

judger101 said:
i think you need to change your status. i dont think you are currently: loving your MPI supercharger.... :face-icon-small-con

LOL!!

wilmot · Apr 6, 2012

I had the same problem. After my first ride i was running my sled and checking it over and found the lock nut by the chain case. I added a little lock-tight and re-installed. So far so good. I like the MPI S/C but I need more POWER. Im trying to decide what turbo to install on my 2011 nytro. Not sure the 180-200hp is enough for me.

MPI Supercharger Pulley Failure

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