Has anyone checked the actual compression ratio of their LB-9 or L-98? The stock ratio is suppossed to be 9.5 to 1 but my L-98 only checked out at 9 to 1 and my LB-9 checked at 8.9 to 1. Did anyone else get number similar to mine?

 

ARE motors (Augustino Racing Engines) Tend to have the opposite problem

CC them out, and you discover your "11:1" 383 was really a 13:1 detonation Machine.

 

I have an info sheet in front of me that says the LG4 has 9.5:1 and the LB9 and the L98 have 9.3:1 from the factory. Not sure why there would be a difference

 

Happens a lot on stock engines and gm crate engines. Factory tolerances and such. That's why machine shops make so much money verifying deck heights and cc'ing chambers on performance rebuilds.

 

How did you determine those compression ratios?

 

I determined the ratio's by cc'ing all of the engine components and then doing the math. I am sure I did the job correctly.

 

was each cylinder consistent with the others? rhuarc30 is right factory is all assy line products so they go on what they figured from the engines that they built for the prototypes and such anything else has a tolerance of probabaly +-.5 :1 from the advertised. and once again thats why machine shops are so pricey

 

Thats a huge difference IMO.

What sorta numbers did you come up with? Maybe from that we can pinpoint where the discrepancy is.