ok heres the deal. i plan on sleeving a gsr block, and boosting the **** out of it. My question is this: What would be the ideal bore and why? And why would i choose a gsr crank over an LS crank, or vice versa? Aftermarket crank is not really in the plans here. Any input appreciated.

 

well in regards to bore, with turbos; the smaller the bore the better, maybe a little worse performance but for the piece of mind of not cracking a sleeve, in my opinion its worth it...

 

like i said, the block will be sleeved, we wont be working with the stock sleeves here.

 

well yeah, but it would suck to have to big of a bore, have something scratch up your sleeve and then have to get it resleeved because you chose to big of a bore in the first place...

 

mosty of the bigger bore builds i am seeing seem to make a good amount more power than the smaller bored builds. My question is around what would be an ideal bore for a gsr or ls crank and 15+ pounds of boost as far as reliability and maximum power goes?

 

am i asking a stupid question here? does anyone have an opinion?

 

I went with 83mm which is almost a 1.9L. This way I had plenty of room to bore for the worse case scenario. Earl@laskey racing was telling me that you wouldn't want to go any more past 84.5mm if boosting. So I have plenty of error room. I also had the gsr or ls crank issue since the original I sent had bearings spun and was damaged. I scraped it for another gsr crank since the block was gsr. Yea the ls gives you longer stroke and little more displacement but some will argue it reduces durability/reliability if u plan to rev 9000+.

Either crank will work but I didn't think the extra stroke was worth it imo. Search some more on the topic and you will see both sides of things.

 

If you going to get this motor sleeved and built, it won't really matter what bore stroke you go with because 1.8 or 2.0 will work and the GSR or LS crank will work, it just depends on your goals. Sounds like you running a crap load of boost anyways, so just keep it simple.