bjherron

Long story, working on a 09 CTS-V and need to replace the heads. While I'm at it, I'd like to find the best bang for the buck upgrade.

So far, it seems like the GM LS3 ported heads might be it:

http://www.lsxtv.com/news/new-produc...ormance-parts/

http://www.summitracing.com/parts/nal-88958758

anyone using these heads on an LSA? Is is a direct bolt-up? Anything else I'd need (new pushrods, etc)?

Do I need a new cam? Is there a bolt-in one I should do while I have it apart?

Thanks
Brian

Sssnake

I know a few people have gone this route but I have yet to hear concrete results. I was under the impression that the LSA head used a better casting process that made them stronger. I did not see that mentioned in head you mentioned. Also, most of the gain in flow (from going to LS3s vs LSAs) seems to be associated with the removal of the swirl wing in the intake port. While I believe this does increase flow what effect does removing the swirl wing have on timing? I thought it provided a more consistent fuel air mixture to minimize pre combustion of the charge. If you gain more flow but loose timing do you really gain hp?

I can say this, I went to the LSA heads and an EForce blower on my LS2 and can now run MORE timing than I could with the 243s and no blower. I did not expect this. The increase in timing also yields more hp (over the reduced timing in the SCd engine). Are the swirl wings in the LSA intake port the reason? Who knows, there were waaaay to many things that changed in my build for this to be anywhere near conclusive but it does provide you with a data point.

pannetron

Good response! Most people don't seem to realize that at 14 PSI boost the air is twice as dense as a naturally aspirated engine breathes. So each CFM of air carries twice the oxygen. On a blown engine, it's not just about big CFM flow numbers.

NAVYBLUE210

Check out the build section in CTSV Owners Web Site.
I would have the Stock Heads ported as they have denser
Aluminum and thicker decks I think. Another alternative
Would be the TFS LS3 Heads which offer great flow from only
255CC INTAKE PORT and much better exhaust flow then either
Stock, ported or the GM CNC ported LS3 Heads along with a
Thicker Deck.
That means You can run a much smaller cam and get the same results.
Check out Tony Mamo @ MMS he has a CTSV with a baby cam
Making ~ 700 RWHP with ported stockers. He is a vendor here
and also posts on the other site, I think you can find his full
Combo over there.

NAVYBLUE210

Actually that would be 14.7 PSI @ the same Temperature, Elevation
& Density
Would be 2X the Air molecules, O2 included, in the same volume.

More efficient heads swallow air better with less restriction (reading
Less Boost) and less heating, as well making more power with the same
Volume CFM, and can take more timing and are less sensitive to
Detonation.

pannetron

Yes, agreed, more airflow is better! But don't discount the critical importance of swirl in that incoming airflow. With enough swirl you can run more timing advance that yields a more efficient burn. My point is that airflow doesn't tell the whole story.