Is this normal kad300

jon and michie

jon and michie

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Hi - I have noticed on start up that air is blowin out of the side of the the small box after the air filter housing and sounds rough after a while I then hear a click and it stops blowing and the engine sounds normal???
I will post pics of the "box" later.
Jon
 
When your KAD300 is cold, the supercharger runs in neutral. This kicks out once the engine reaches a certain temp (40 degrees I think someone mentioned previously?) - This is normal.

What is not normal is 'air blowing out of the small box' - Sounds like a leak? On a KAD32 I had years ago, a jubilee clip needed tightening up on a flexible house - sounded like a fog horn! 2 min fix, thankfully.
 
Thank you alt for your reply I will take a look on Friday.
I also noticed the rpm was only going 2900rpm.
I had the elbow off and the turbo runs freely
Jon
 
Part 11 the air induction manifold has a non return valve come flap that engages only when the super charger kicks in. If you are reving above the Sc range and come down into sc range you should hear an audible "whumpff" as it engages. Make sure all seals are airtight in the induction manifold system as above. Test with a length of tissue or ribbon.

PentaParts zoom
 
Thanks Bruce - yes that is the correct part no 11.
I will check on friday hopefully.
is the none return valve electronically controlled ?
Jon
 
Thanks FARSCO - so basically the air flow pressure when the supercharger kicks in then forces the flap/valve in the closed position.
Jon
 
Right finally got back to the boat and that the torx screws in the one way valve housing were slightly loose which I tightened up, also found that the small rubber pipe between the cast turbo inlet and the plastic valve housing wasn't fully sealed.
All above corrected however there doesn't appear to be any leaks but on start up (cold) I have noticed that the the engine although ticks over ok its sounds Alt put it "like a fog horn" and rubber hose that connects the the cast inlet to plastic valve housing expands as if it is over pressurised and the air box inlet is sucking air immensely once the super charger kicks in (assuming initial warming up) the hose feels normal airbox eases off and the engine sounds fine.
Is this normal for the rubber hose to expand like this?
Many thanks for your help so far
Jon
 
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Like a balloon? Oh yes. I look at mine and think Jesus Christ it's gonna blow while prodding in gingerly from a safe distance. The hotter they get the more they expand too.
 
Thanks Bruce - hopefully take her out for a run later and report any findings hopefully all good.
It is a bit poor on volvo's part they could of made the plastic part longer so that less of the rubber hose is exposed to all that air pressure also having the cast iron with that tight kinked bend doesn't help with the air flow in my opinion.
Jon
 
Remember it's an evolution. From the KAD42 there are 3 of those rubber sleeves. One on the supercharger to the aluminium pipe which amplified the now infamous SC whine. From the ali pipe to the Y and from the Y to the turbo inlet manifold. For a short period with KAD43 they had a rubber hose all the way from the SC to the Y in an effort to silence the whine before they added the muffler. So all things considered you have the best of the evolution. As for the bend, yes I guess it would pose a restriction but to be fair the total volume of the inner diameter tubing prior to the turbo is significantly greater than the exhaust ID once blown so I'm sure it balances out. Remember the SC boost is at ~1 bar all the way to the intake valves so the rubber sleeves expanding is more to this than caused by a restriction at the U
 
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