I've been learning about LS motors for the past few years, but when i got into the blower world, I'm suddenly finding that FI setups like certain types of cam profiles, pistons, piston rings etc.

I've managed to get my 97 LS1 running smoothly for now making healthy power for it's age, but looking into the future, I'd like to learn what to look for. How much $$ is required for various power/boost levels. What heads, pistons, connecting rods etc are better for blown cars that N/A cars don't necessarily need.

Any helpful reading material is welcome.

 

Your question is extremely vague. I would recommend that you read every build thread that you can find on here. Learn from others mistakes and until you know what you are doing, try copying something that works. It just seeps in over time but stay away from all the "theory" threads and stick to the real world stuff. Opinions are like ********, everyone has one and most are full of ****. Quantifiable results are what you want to base decisions on.

 

This is true. I'm basically looking for answers to questions like:

- Why are certain piston better for FI applications than NA?
- What is a "Blower cam" or "Turbo cam" and how does it differ from NA
- What are the preferred GM head castings for low compression?
- What kind of piston rings work best on FI motors and why?
- What parts need to be upgraded on a say an 800hp motor that don't need to be addressed on a 600 hp similar motor.

The problem with build threads is that they usually consist of a lot of brand names, part numbers and drooling. I'm not at the level where i can understand and appreciate an FI build thread. I'm looking for the science behind what works....and what doesn't work so well.

 

1. Lots of different reasons. Piston material, compression height, ring stack, dome strength, weight and yielded compression ratio. All the same factors taken in to account when designing great N/A pistons apply here, but most times the application is opposite. FI pistons are under extreme duress, and the importance of all these factors is magnified, x10.

2. Different Camshaft profiles. NA motors use inertia tuning for increased cylinder fill and scavenging. Boosted motors tend to require profiles that prevent charge dillution,a nd maximize energy of the exhaust cycle. Turbo and Blower cams here different in that regard. Nothing is universal however, every Cam vendor tends to have their own theories based on their testing. Your best bet is to talk to a couple of vendors based on what your plans are. There are several well known Blower grinds from vendors. I got mine from Cam Motion, based on the fact that lots of guys that were doing things on the bleeding edge used and recommended them. That was several years ago though, technology always changes.

3. Depends. You talking Cathedral port? Probably 317 truck heads. Best intake port and large chamber yield a lower CR. Best by GM, probably, probably something from the LS9-LSA familly or something from GMPP.

4. Depends. Some rings are better than others for forced induction, but all have trade offs. Most high end, all out builds run stainless rings, at the expense of Cylinder bore wear. I believe some where that I read that Plasma coated rings don't fare to well. Whatever you do, you want to keep oil out of the combustion chamber to prevent detonation, So going with a super low-drag oil ring setup may not be the best way to fly with FI.

5. Depends what you start with. If you start with say an LQ4 or LQ9 truck engine, I would swap out the pistons and rods, before I got to 600 HP, and that would take you past 800 pretty easy. Also Good Head and Main studs, and valves and springs area must as well, and rocker arm fulcrums should be changed.
I would change all those before I got close to 600, and that will more than likely carry you well past 800.

 

I would also add that depending on whether you are doing a Supercharger, or Turbo, You might have to change the crank out after getting close to 800, not because the crank will break, more so the fact that the stock cranks don't have a keyway and key for the dampener to index to, which is what the drive pulley for the blower attaches to. You can pin them (which I have done), but if I had to do it all over again, I would have opted for a real crank like a Callies, and a dampener that supports the proper key. Turbo, I wouldn't sweat it, several folks are making over 1k HP on a stock crank.