A1 block? I thought you had your heart set on an A4.
1. Why did it need a line bore? Spin a bearing?
2. What cylinder bore size?
3. How much was it decked over stock?
If they decked it by an significant amount you'll want to recalculate you displacement before deciding on what pistons you want. 12:1 cr and nitrous will not be good, even with race gas. I'd think that it would be wisest to start at 11:1 cr or lower, run the nitrous for a season, see how it holds up, and then mill the head a bit to get more compression.
Also from what I've been hearing and seeing in dynos it is better to use smaller domed pistons+ milling than to use just huge domed pistons. Supposesly the flame front isn't able to exert as much downward force on a domed piston as it can on a flat piston.
Originally posted by laughin2.2 A1 block? I thought you had your heart set on an A4.
1. Why did it need a line bore? Spin a bearing?
2. What cylinder bore size?
3. How much was it decked over stock?
If they decked it by an significant amount you'll want to recalculate you displacement before deciding on what pistons you want. 12:1 cr and nitrous will not be good, even with race gas. I'd think that it would be wisest to start at 11:1 cr or lower, run the nitrous for a season, see how it holds up, and then mill the head a bit to get more compression.
Also from what I've been hearing and seeing in dynos it is better to use smaller domed pistons+ milling than to use just huge domed pistons. Supposesly the flame front isn't able to exert as much downward force on a domed piston as it can on a flat piston.
example: v=force vector
domed ...... flat
v ...... v
..... / _____
..../
Yes, spun a bearing then it was built. I am aiming for 11:1 so if it comes out 11.2:1 its cool. We'll have to measure it to see. I was set on the A4 block because its cheaper to resleeve. I still have some time before I have to choose pistons. Stock bore size. Other than the price of resleeving, there is no benefit to the A4 block except a little heat displacement. I will never need the added crank strength. The crank has been worked already.....I may just have it balanced.
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