Well it looks like I am going to go ahead and get the rusty LQ4 I described in another thread. I have a couple questions about gaskets. I would like to use my 2.5 TSP heads that I have now. I would also like to boost the snot out of it (well like 17 PSI or so). I will be going the turbo route. My concerns are with my heads having about 60cc chambers, and I want the CR to be boost friendly. From everything I have gathered, the stock specs are:
4.000" bore
3.622" stroke
6.098" rod length
1.338" comp. ht. pin location
-6.7cc dish piston
71.06cc chamber
0.051" gasket thickness 4.010" bore
9.24" block deck height

So half of the stroke =1.811
plus the rod length =6.098
plus the compression height = 1.338
_______________________________
would put me at 9.247
minus deck height -9.240
would put me out of the hole .007


If I ran the stock gasket thickeness(.051 compressed), my calculations would put me at 10.5:1 CR. I would think that would be too high for that much boost. Maybe not. I did find some gaskets that are .086 thick compressed with a bore of 4.030, and that would put my CR at 9.68:1 (If I am calculating right). or if I could find a .070 gasket, that should put me right around 10:1. What CR would everyone suggest? I will more than likely be running water meth with the new setup too.

 

well my 243s heads are milled .030 on my LQ4 and I'm right a 11.1 with stock MLS .051 gaskets according to ADVANCED INDUCTIONS so yeah def not boost friendly

 

How much boost??? Probably stay around 10:1

 

I was hoping to push it around 17.

 

I dunno if I'd run stock piston that high. If you upgrade the slugs, you can run whatever compression you want.

 

Yeah, that is another option too. I'm gonna pull the long block apart, and check the cylinders. If the cylinders need to be bored, I will get new forged pistons. If the cylinders and pistons are good, I will get thicker gaskets. Well at least that's the plan at this point.

 

17 is gonna need a real good tune to keep stock pistons together... If its good and clean get forged .005 over and hone it to match.

 

^^^^This

 

We have several options to chose from at .005" over, as far as dish is concerned to get you closer to your desired compression ratio...