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im trying to plan my boost build on a y8. ive done the compression calculation online using a few different sites. I keep coming up with 9:1 compression and im trying to figure out a way to bump it to 10:1. any info would be appreciated.

plans so far

d16y8 block:
vitara 76mm pistons
custom length rods FJ or scat with arp's
acl race bearings

y8 head:
full port and polish
supertech or ferrea valve train
delta 272 cam or maybe a bisi
head gasket?

fuel:
750cc injectors, don't know what brand yet
I haven't even started looking at fuel pumps yet

turbo:
godspeed or i'll piece my own together

tune:
Neptune
 

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My civic
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Mil deck of block and head, run smaller head gasket.

OR,

SEARCH!
 

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Compression will help spool time. Youll also make more power at the same boost level. 10:1 isn't even really high anymore on forged internals. I would be careful going to high on cast pistons. Higher compression means lower knock threshold. I've seen a coupke of 13:1 + turbo setup. One cheap way is you could go to flat faced valves. It'll bump it .3-.5.
 

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ej8
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Compression will help spool time. Youll also make more power at the same boost level. 10:1 isn't even really high anymore on forged internals. I would be careful going to high on cast pistons. Higher compression means lower knock threshold. I've seen a coupke of 13:1 + turbo setup. One cheap way is you could go to flat faced valves. It'll bump it .3-.5.
Understandable, but I see no point in bumping it just a small amount when you can just up the psi some and be done with it.
But I guess each to there own.
 

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Shouldn't higher compression technically hurt spool?

Heat & exhaust gasses spool the turbo-with higher compression you'd have less exhaust gas, and since the mixture did more work, it's temp would be lower?

My last build was 10:1, but I never got to run it. :(
 

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ej8
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Shouldn't higher compression technically hurt spool?

Heat & exhaust gasses spool the turbo-with higher compression you'd have less exhaust gas, and since the mixture did more work, it's temp would be lower?

My last build was 10:1, but I never got to run it. :(

The bump in compression means a bump in fuel, air and power.
So it will push out more exhaust which will spool the turbo faster.

Lower comp wont push out as much air so they spool slower but you can run more boost pressure.
 

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Still think its less. More work done in the engine leaves less for the turbo.

Although the higher compression engine will have more torque and accelerate faster, off boost, getting you into boost sooner, which means time wise, turbo spools faster
 
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