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Discussion Starter · #1 ·
I’m looking to turbocharge my truck project. I’m cool with packaging, piping, etc., my concerns are the engine. Most builders I know say that an N/A 4-bolt main big block can handle about 750 – 800hp reliably. Then I see guys with hairdryers making huge power with stock or nearly stock components, even in production smallblocks. 900 - 1100hp seem to be common, even in production big blocks.

What gives? What can I do to a production Gen 6 to help it live? I already have a good forged stroker crank and good set of rods along with some good forged pistons (all new) and a block that will clean up nicely at .030 over. I plan to stud the bottom end and have it align honed, can run studs on the top as well if needed, Cometic gaskets are definitely in the budget. I’m not looking to generate more than 15lbs of boost max, probably more like 10.
I guess the question that keeps me scratching my head is how folks can get huge power numbers on an engine that I would have thought would blow up long before it got anywhere near it’s N/A redline.
I’ve found plenty of sites that have info on turbos, plumbing, injection, etc., but there’s not hardly any info regarding bottom end building tricks.
Any help would be appreciated!
 

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Gary,

It all depends on how each component is manufactured and how well it was assembled will determine how long it will last. We have all seen 900hp motors that run and shouldn't and my 350hp 385 wipe out a thrust bearing in 20 minutes!!! lol Somethings just defy explanation!!!
From everything I have read it seems you are on the right track, have you tried LS1tech web site? I have heard it is a great site for LSX information. Good luck with your build and keep us posted!!
One thing I have learned in my life is, if we are pushing something hard enough we will eventually find it's weakest link!!! Hopefully it's much later then sooner!!!
 

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For the little amount of boost you say your going to use you'll be ok. Now when you want more boost you'll be on the edge of what that block will handle,it's cheaper to step up now to a better block then later.
 

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What, you think 1,000 fwhp out of a late model 1pc rear seal roller block is crazy? It may seem that way but you have to look at why a turbo engine makes more power. It is not because the intial explosion is bigger but rather that the duration of increase pressure of the combustion stroke lasts longer. It is in this added duration that the turbo engine creates more power.

It's not really the amount of tq that hurts a block, a combimation of tq and rpm. If you can limit rpm you can increase tq.

I'd do a partial fill on the block and let it cure for 30 days. Install and torque as many components as you can while your filling and curing. When I fill my blocks I torque the opposing head on, all the mains, the engine mounts the bellhousing bolts, waterpump, timing cover, and the 4 front bolts. Sometimes i even bolt the oil pan on. Once i'm done pouring one bank I torque that head on then let it sit for a day. Remove the other heads and pour again, retorquing that head after the pour.

I have my blocks bored and honed with a torque plate and with as much bolted to it as my guy will put up with.


Just remember, 14.7 psi of boost essentially doubles your base horsepower. So your 400hp big block quickly is making 800. Also remeber that boost is a disease, you say 10-15, and end up at 25. I'm ready to feed mine 30-32 this year, i started by saying 15 ish a few years ago...



Pistons and piston to wall clearance are a little different with boost. Your going to want to move the top ring down and your going to a a couple thou to the piston to wall. Also top ring gap increases, and i'm a beleiver in running the 2nd ring gap a few thou larger to help stabilize the top ring. Other then that, everything to do for an N/a engine will help with a boosted engine.
 

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What Calc said.
 

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Discussion Starter · #6 ·
What, you think 1,000 fwhp out of a late model 1pc rear seal roller block is crazy? It may seem that way but you have to look at why a turbo engine makes more power. It is not because the intial explosion is bigger but rather that the duration of increase pressure of the combustion stroke lasts longer. It is in this added duration that the turbo engine creates more power.
As opposed to nitrous which does make a much more powerful combustion event?

I can handle the lower rpm's, that's one of the reasons I'm looking at using a hairdryer.

Thanks for the info!
 
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