Im building my first single turbo system for my 350 goodwrench truck replacement engine with a stock CR of 8:5:1 but with my vortec heads its prob at 9 or high 8's in CR. i had this engine completely taken apart and cleaned with replacing all the bad parts from getting scratched,etc. The owner i bought the engine from ran N20 and apparently didnt know what they were doing because it left some internal damage. But after the rebuild its back to new, my question is will this engine hold up to a max of 8psi sometimes and a daily of 5-6 psi? My mods are xe-262h cam with lifters and the 062 vortec heads, everything else is stock. Heres the engine http://www.jegs.com/i/GM+Performance...67353/10002/-1

 

Yes. A naturally aspirated engine can withstand an incredible amount of pressure during quench, but at the same time a boosted engine can succumb to detonation at a mere fraction of that naturally aspirated max pressure. Additional pressure during quench doesn't destroy engines, detonation does due to an improper tune, or sudden loss of fuel...

 

yep 8psi should be fine and I'd actually expect it to take 12psi or more with a good tune. I've seen 12psi on stock L98s and no problems, just need to make sure the tune is good. Start conservative, low timing, rich fuel mix and colder plugs and work your way up.

 

Thanks, for plugs would these be good? I need shorty style due to clearance issues. http://www.jegs.com/i/Accel+Spark+Pl...74S-4/10002/-1

 

Those will work fine, just gap them correctly for boost...

 

The plugs are pregapped at .035". What should they be gapped at for boost? Or is every plug different?

 

At a max boost pressure of 8-psi, I would gap them at around .025-028...

 

Depends on the ignition system. I'd like to see a non projected tip plug. Those appear to be such plug. I gapped my at .030" or so and havent blown out spark up to 18 psi from what I could tell. Worked great at 14-15 thats for sure.

 

I'm really curious about the tight plug gaps that people are recommending here all the time. A tighter gap makes for an easier to light, more reliable spark, but a larger gap results in a larger flame kernel which should result in a faster, more complete burn. I've owned 80's factory turbo cars with stock ignition systems that had plug gaps in the mid .03x" range, and if an 80's distributor ignition can fire that gap I don't see why the aftermarket setups that most of us run couldn't. My brother's SBF powered supercharged car runs .040" with >10lbs boost

 

Your mileage may vary. 0.030-0.032 works well for me. Possible larger gap will work fine but i never tried it

 

thinking about supercharging same engine..getting ZZ4 aluminum heads, not sure what cam yet..anything i should know?