i have a GSR motor, its all torn apart right now waiting for pistons
i want to run NA for a while before i put a turbo on just to work out all the problems i may run into
but when i turbo it, i might want to run high boost so im gonna order forged pistons
the stock compression is 10:1
but i should drop the compression for the turbo application?

so im wonderin should i get lower compression pistons now so i dont have to rip it all apart again for the turbo

what do you guys recommend

 

9:1 and you'll have plenty of room to make power with boost

 

You will need low compression when you boost anyways...

 

with 9:1 will is still run good without boost though?

 

I'm not to sure about this and I'm interested in the same thing. I'm planning on possibly doing the same sort of process (N/A to boost). I'm jus sittin here thinking and all I can come up with is that it wouldn't be as great as if you had a higher compression. To me the boost provides more power and wouldn't need that much compression (possibly blow motor) while with N/A you aren't providing that "quick burst". I'm jus goin on how my dad's Saab 93 Turbo went though and this is just a theory. As it says to the left of this, I truely am a n00b.

 

well the lower the compression the higher boost you can run when it is boosted...the stock 9.2:1 will do fine for some boost but its not good for the double digit boosts...
i have three ls motors so im driving one motor while building another...seemed easier that way.

 

not quite.

the real weak point in boosting B series motors is not the compression itself but the ringlands. 9.2:1 is a fine compression ratio to gain high levels of boost but stronger pistons are needed. when it comes to the DOHC VTEC motors they tend to have quite a bit higher compression compared to its non vtec counterparts. Bringing down the compression is a great thing for boost BUT id bet if the ringlands were stronger than theyd be able to handle more power even with stock compression.

9:1 will be fine without a turbo. youd be much happier with boost but it shouldnt be unbearable.

but to answer your question yes while the block is torn apart invest in atleast a piston/rod combo as well as some ARP headstuds and rod bolts along with OEM or ACL main and crank bearings. IF you have the money than sleeving isnt a bad idea either but if thats too pricey than stock gsr sleeves are pretty strong. trust me if you dont do some internal work while the block is apart youre going to be stuck with doing ~300whp maybe a bit more and maybe a bit less and who knows how long that will last.

 

it will run just fine.. exactly like it should.. its just gonna be rediculously slow until u boost it.. definitly go for the Low compression pistons. 9:1 is perfect. so in recap

1. Yes, buy the low compression pistons now while its torn apart
2. yes, u can break your engine in on them its just going to be REALLY slow until boost