[MugenPoweredLude]

does it matter what block you use for boosting??? advantages/disadvantages of using a JDM block over a USDM?
my guess is no

 

[schwett]

just the block or the whole motor? the block is the same, there are differences in the pistons and maybe the head chamber configuration. the JDM motor has a bit higher compression, which in theory makes it harder to keep your motor detonation free. you would need a bit more fuel and bit less timing.

on the other hand, if it's all tuned properly and has a good fuel/timing setup, the JDM motor might make more power. even though the JDM motors are rated for LESS power than the USDM motors, they seem to make a little more.

 

[MugenPoweredLude]

just the block, i guess it really dont matter if you sleeve it and put some 8.5:1 or 9.0:1 pistons in there

 

[h22 bb6]

When you bump the compression down, say on a normal USDM motor, if you wanted to go like 9 psi, what should you drop down to to be safe? 10:1? 9.5:1?

 

[schwett]

10.0:1 is the stock CR on a USDM H22. 9.5:1 is hardly worth the trouble. 9.0:1 will allow you to run quite a bit more timing and boost.

on the other hand, you can certainly run 9psi at 10.0:1 CR. people run that much boost and more on engines with a stock 11.0:1 CR. it's just a question of the tolerances, the conservatism of the tuning, and having the RIGHT system for controlling timing and fuel.

from what other members here have said, below 9.0:1 the lude gets a bit sluggish off boost. my JRSC lude at 9.5:1 still felt strong off boost, so your mileage may vary.

 

[MugenPoweredLude]

so its better to go with 9.0:1....interesting