The engine actually runs on less fuel than you would call a carbie leak. Thats the whole thing - go start you engine you have running and look directly down the carbie and make note of how much fuel is actually being used.
An engine can be tuned to run pig rich enough to make everything black. When the engine was detonating did you turn it off and never run it there after? You have an engine that runs rich most of the time and under boost detonates. Its not like you have an engine that runs lean all the time and at service time you can check the plugs.

I am not saying fuel leaking is your only demon. Ignition timing could of been crap. Intake temps could of been crap.
But dont think the leaking fuel is nothing.
Fuel evaporates in hot environments.

i see where ur coming from but the mixture was never lean the spark plugs were never white or even close to brown, the exhaust is so badly blackened with soot, and the amount of fuel coming out was about a drop or so after driving for an hour or two, the fuel only just ran down the fuel bowl onto the carby body so was #### all fuel. im not saying it wasnt that it was running lean but surely if it was, the plugs would show a sign..... ohh well at least one thing came out of it, next time i know to not drive it when its out of tune like this time, i am going in search of a dyno tuner, ive heard mick's motorsport at milperra can dyno dellorto's, he has australia's fastest n/a gemini it runs webers so i think ill give him a call.

Maybe because fuel blew out the carbies and it ran lean and detonated. Detonation is actually happening and doing damage even before it can be heard. If you can hear it, its already doing its work.

Most people beginning to experiment with blowthrough, always seem to overlook the fuel leaking from their carbie.
Its the most important thing. Think about how much fuel you saw leaking and then think about how much fuel a carbie actually supplies to an engine.
A really lean mixture still burns. It actually burns hotter than a stoich mixture. Being hotter it makes the engine produce more power and appear to be running excellent.
Lean mixtures turn spark plugs white. For something to heat up and turn white, it is really past hot and beginning to burn. Now think about the rest of the combustion chamber.

Dont over look your leaking carbies.

hey guys another a15 turbo update, i pulled my motor apart tonight and it all looked perfect, bearings had not a score, they hardly looked used, the bores were the same, as for the crank bearing surfaces. i then got to the pistons, and i pulled em all and looked at no3 and it looked like it had a crack i wiped it clean and then took the rings out, whilst doing this i knocked out two broken ring lands...... i wonder what caused it ?? i got the engine hot at one stage, (no coolant) but i ran it after that and it held 135 psi across all four a few days after running hot.. maybe the slight amount of detonation i had is wat killed it??? ohh well looks like off to jeffs for another piston at least, and new rings bearing and gaskets. this time im gonna save up heaps of extra to get it done properly, ie tune, exhaust, engineering and that.

maybe your right if it was leaking into pushrod hole could it be down on comp? it wasthe third cylinder.

Look on the positive side. The head gasket could be leaking into the push rod holes.
Either that or it could be a broken ring land. Did the machinest give your bores a bit of extra clearance to allow for your pistons to grow a bit more due to your running boost?
Which cylinder was down?

the engine was run in with stock carby and extractors for over 400 k's only then did i put the turbine on, anyways it was only 7psi i think this time around it was the tune that was to blame. i comp tested it this arvo and one cyl is down at about 80-90psi the restare hovering around 130 maybe have a set of cracked ring or a broken piston.... hmm wateva it is looks like im going to have to have a look inside. more updates next week maybe.

Damn that sucks big time.
You did say the carbies were leaking under boost.
My bets on the rings.
I wouldnt have even been running boost until the rings had a chance to bed in.

Most likely rings. You woudnt think it would be a piston this early in the peace. Was the motor run in properly. Thats the biggest question. A few pound of boost shouldnt hurt it this early if it was a fresh rebuild unless high boosting on a not run in motor.

ok guys now for the bad news.....
looks like my engine is now phucked, i just took it apart and put stock carby back on and started it up runs fine but blows ####loads of fumes out the breathers, and if u have the motor running and take of the oil cap it blows off as though the block is all pressurized, it even blew my breather hoses off the inlet manifold, ohh well looks like its back to jeffs for more parts. anyone suggest problems? im thinking either rings or pistons are like swiss cheese???