dazdavies

iTrader: (22)

Not necassarily if its only occasionally.

Paben

iTrader: (5)

I understand that but if it happens at all why would it only happen occasionally?

dazdavies

iTrader: (22)

Could only be at certain throttle events and at a certain point in the map, who knows.

The valve impressions are taken with the advance set at it's most. The engine will certainly have not been spending alot of time at 100%. That tune was for run in only don't forget. The second tune went on to do 643hp at the wheels 16 drag runs in the 11's, 1 in the 10's and 8000 kms.

Also it's fairly loud at 100% it could easily have been masked.
There is literally no other explanation for this happening other than that and its pretty hard to refute.

Paben

iTrader: (5)

It certainly sounds like the most likely cause, but worrying for those building their own engines that such a thing could happen to one so carefully constructed.

dazdavies

iTrader: (22)

I think it's more to do with overly aggressive original tune.

But it's also a lesson to measure PTV clearance on AVCS engines which I will be doing from now on.

Steve Whitehorn

iTrader: (13)

Thanks for posting your findings Daz