Has anybody ever done this? Has anybody calculated the static cr? I'm looking at options right now. I have an agg bottom end, pb head (this will be ported), Kent gs3h cam, R1 throttle bodies, speeduino ecu and probably a 4-1 exhaust. (I am doing ea Motorsport engineering degree so I will calculate what I need here and go forward) the engine is only for track use really in my MK2 Scirocco. I'm looking at positives and negatives for skimming the head Vs abf pistons Vs aftermarket pistons. Obviously if I can save money where it doesn't need spending then I'm all up for that . Thanks for any info.
Don't ABF pistons have valve reliefs for the inlets, and a lack of a suitable (for 8v) combustion chamber?
It's true that there is a valve relief, however with the increased duration of my cam (285 degree) the effective dynamic compression ratio will be reduced requiring me to increase it via one of the methods mentioned above. A set of used abf pistons is far cheaper than a set of mahles etc..
If I'm missing something please let me know. I'm still learning. But I have read from a very reputable source that flat top pistons are the way to go for the best squish etc.... Material can always be removed from the head to compensate I suppose
I used AGG pistons in my 2.0 mk2 build, in the AGG block. But machined some material off the top of the pistons, and the same then off the top of the block. Even the higher comp pistons from Wiseco, Wossner etc still look like Oem in style, so that would suggest that head needs a combustion chamber in the piston crown. Otherwise you'd have diesel like compression, or need to really remove a lot from the head. I think.
What cr have you gone for? What's the rest of the spec? I have bought some abf rods and pistons now. They can always be machined down if need be. They were cheap enough.
Oh nothing wild, 11.5 or so iirc, it's a while ago. It's a road car, TSR Digifant head I tweaked, 3 angle seats and back cut valves, TSR 4 branch, panel filter, slightly higher fuel pressure. Seat of the pants, it's not that much faster than when it was a fairly standard 1.8, but I did change to a mk4 O2j when I fitted the engine. I have it running on an Omex 600 now, with Alpha N. Hopefully ready for dyno tuning when the virus craziness settles down.
