Turbos are alot kinder on drivetrain components
Tommo- how many miles have you put on your current set-up? Very impressed by the £/bhp - just wondering at what true price this comes?
I put 6k miles on the 1.3 Spi at 1.2 bar. It was fine when I stripped it down for inspection, there wasnt one det mark in the pistons or the head. Exhaust valves looked fine etc. If it wasnt for the fact that I stripped a thread in the block when I fitted the wrong head bolts by accident, then I would probably still be using it now.
As for the 1.4 ive only done about 1k miles on it although pretty much all of those have been giving it absolute death setting it up. I dont really see why the life of it should be all that compromised. I made a mistake with the dizzy and inadvertantly ran 42 degrees max advance on the 1.4 engine, and whilst racing my mates scooby I got a good few seconds of machine gun style detonation (exact same type of det that broke the ring lands on my mates accralite pistoned mini). I crapped myself but it still runs fine, it had little bobbles of ally stuck to the plugs after but even the head gasket has been fine ever since. It would be interesting to get the head off to see what damage that actually caused.
I had reservations about running the 7mm valves that my ABD had but so far they have been fine, obviously if I was to spend money on a decent set of pistons I would go for the 8mm sodium filled ones because for the cost its not worth the risk, but such is the beauty of genuine scrap yard parts.
The only other reservation I had was the ring gaps. Having machined 2.4mm off the piston top I was concerned that the top rings may get a bit too hot and nip up. But I decided against opening the ring gap up in the interest of experementation. So far they have been totally fine but the rings are the original VW ones which have done over 100k miles, so will be a bit worn. Either way there is still 5.5mm from the top of the piston to the top of the top ring gap, which is the same as a 200sx. And as the combustion chamber is in the piston I should think this will keep ring temps down.
What max ignition advance do you run on full boost do you run yoof? Mine is set at 18 degrees but I suspect that I could get a fair bit more on there, I know that a lot of high power metro turbos run upto 24 degrees, but aparrently they have a very good combustion chamber. I didnt have time before the rolling road to try advancing it, plus im getting ever more consious that spending all night doing 130mph up and down the motorway between services is not going to do my liscence any favours at some point. I dont really want to run any more boost because the chances of me finding another turbo for £20 are slim so I want to make this one last.
I suppose the chinese £11 big end bearings that I fitted wont last as long as VW ones would, but again, all in the interest of science.