Best way to Prep Stock 5.9 Magnum For Boost?

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Piston Speed

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Howdy everyone,

I bought a complete 5.9 Magnum with around 90k miles on it for my '72 Demon after reading up Magnumswap.com.

My plan was initially to build it up into a hot 400 horsepower engine with new heads, cam, carb, headers and intake; basically similar to the 390hp 360 Magnum crate engine Mopar used to sell.

Since then, however, I decided I'm going to install a single turbo to the engine with low to moderate boost to get to around 550 or so horsepower and similar torque.

My question is this: do I need new heads for the engine now that I'm going with the turbo, assuming the heads I got now are good to go and not too cracked? I'll still go with the cam, carb and intake although I assume I'll need an intake that will fit Magnum heads.

Thanks!
 
Might be able to get away with a stock steel crank, h beams rods, forged pistons, carb set up for blow through and a cam designed for turbos, should be able to make that with a cummins turbo easy to come by via junk yards. Stud the heads and mains
 
Thanks for the responses. No, it's not running right now; doing body work on the car.

My plan is to keep the shortblock stock without tearing it open. I've read about guys on the Dakota forums doing just that with great results.
 
Clean up the bowls and open the pushrod pinch area if your going to use the magnum heads. Mine bowls had 90* walls where the seats are pressed in.
 
I built a stock mag 318 with a 62-1 turbo. Tuning it now but I studded the rods and kept the stock bore, pistons, and crank. Ditched the stock heads for replacement EQ heads and used arp bolts. I ended up with about 9:1 compression, pistons were down pretty low. I don't think a cummins turbo would work well, a diesel runs out of steam pretty quick so the turbine and compressor are pretty small compared to a gas engine. I'm high altitude so iron heads and a smaller turbo were ok with me. If you have the money, get aluminum heads and keep the compression as low as possible and keep it rich
 
There are guys on the b body forums and else where running cummins turbos making close to 1000hp with a pair, the housings aren't that small, they look the same size as the 70mm turbos for my dart. The boost on my 6.7L comes in around 2 500rpm and pulls till close to redline, but then with a controller you can get more boost out of a stock diesel turbo turning well over 30psi on a stock turbo.

If you don't want to tear that far into it, atleast stud the heads and mains, it would be better insurance to also have the rods bolts upgraded if you want to reach 500hp
 
Uh, I ain't no expert now, but from what I can read on a map an HX30 seems to be about right on a slant built for it. Maybe you should specify what you mean by 'Cummins turbo' seeing how they make everything from 4 popper bread truck engines to 10 liter road tractor engines...

Oh, and just because it acts one way on a diesel doesn't mean that's how the turbo will act on everything...
 
He's most likely referring to the Cummins isb 5.9l turbo. It is a common engine in dodge pick ups. The more recent dodges run 6.7l isb engines with vgt's (variable geometry turbo). on a side note Cummins does not build a 10 liter truck engine. The common truck engine is the isx 15l and the less common isx 12l.
 
The OP said he decided on a single turbo, not twins. Remember, he has a stock bottom end so making 1000hp is just not realistic by adding two diesel turbos. His goal could be attained easily with a single turbo by reading maps and plotting his airflow on the chart and selecting one that way, or call a manufacture and ask for help in the proper selection. I would say a 550 hp on a stock short block is pushing the limits of its structural integrity. With that goal you may want to tune it down or add forged internals. But it has been done.
 
Yes I was talking about the cummins 5.9L motor, i just brought up the twin to show what can be done with them, even a single one would get him to that level, but since he wants to stay stock with out getting into the motor and 2 ants 500he, i agree he's pushing the limit of a complete stock motor with out a few upgrades to the bottom end.
 
Thanks for the replies; sorry it took me a while to respond again.

I was under the impression that a stock 5.9 shortblock could take 10psi boost since the guys over on the Dakota forums run that without problems. I wouldn't go over that myself; probably slightly less.

I'm thinking about the eBay GT45 since it has good reviews on the turbo forum.
 
10 lbs is not far from reach and a 360 could most likely handle it if you have the rotating assembly magnafluxed for defects. Tuning is critical here, it must never run lean and cooling the intake charge is necessary
 
Keep the boost low and do not let it detonate.
Buy a good air/fuel gauge, fuel pressure gauge, boost referenced fuel pump and boost retard controller.
Keep in mind the magnums have hyper pistons in them, they won't live long detonating.
Stock mag, 450 hp is more realistic for longevity.
 
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