strange faillure after boost surge

[Dirtrag2]

I had just finished installing a k14 in my aaz 'cus the t3 had an oil return leak and when I went for a road test all was fine, 15 psi boost spike then it settled at 13psi on acceleration. I then bled off the wastegate a bit and then boom    a huge surge, it instantaniously buried the needle on my 35 psi gauge at wot in 1st, followed by a loud noise from out the back ( exhaust ), sounded like the turbo blew and chunks came out the back!!

I let off the fuel put the clutch in and pulled off to the side, the engine was running horribly, like a gasser running on 3 cyl so i shut her down.  everything under the hood was fine ie no holes in the intake and turbo turned freely so after checking the road for "turbo chunks" I started her back up.  a lot of white smoke 

shut her down again let it rest a minute then gave it a final try before giving up... she ran like a top. I droped the wastegate bleed a bit, now spikes at 20 and hangs at 15, drove 35 km home and all seems ok.

my friend said it sounded like a semi on Jake Brakes... what is the chance that a valve stuck due to overboost, or could i have done bad damage that will haunt me later?

[rabbitman]

I wonder if the high drive pressure held the exhaust valves opened? The jake brake part made me think of that.

The only problem with that theory is that is should've ran fine as soon as the boost went back down. If the exhaust valves hung open the fuel wouldn't have burned but instead gone into the exhaust system possibly coming out as white smoke .

Did you notice a power loseas it did it?

Your probably lucky the turbo didn't go boom

[Dirtrag2]

Did you notice a power loseas it did it?

Your probably lucky the turbo didn't go boom

power was prety much non existent, so much so that i feared a blown hg.

really strange thing is that it didnt run well untill it sat for a couple of minutes.

oh and on a side note, is the k14 supposed to be loud?  I can really hear it wizz conpared to the t3

[blackdogvan]

Could this have been a stuck injector issue?

[Dirtrag2]

that could make sense that after sitting the fouled injector lost built up pressure and " reset " itself but if it was injector failure, how would that make the huge jake brake noise??

[rabbitman]

that could make sense that after sitting the fouled injector lost built up pressure and " reset " itself but if it was injector failure, how would that make the huge jake brake noise??

Jake brakes work by building cylinder pressure and right before firing the exhaust valve opens and dumps the pressure.

I'd say your exhaust valves hung opened (making it gutless) even though that doesn't explain why it ran good after sitting a bit.

A k14 making 35+ is gonna take some serious drive pressure.

[Dirtrag2]

I dunno what to think of it... I was keeping an eye on the boost gauge 'cus this was the first run on boost with an unknown turbo ( i just put it in ) in 1st at wot it pegged 35+, made that loud "farting" noise and i let off the fuel.

it seems to run fine, i put over 200km on it since and no probs so if there is dammage i will see it when i open up the engin for upgrades later this winter... otherwise it will forever remain a mystery