turbo 5.9 magnum budget build suggestions

Hey all, I don't post over here much (although I'm sure some other Dakota R/T guys will recognize my name) but I think this is probably one of the better places to ask a few engine related questions due to the abundance of turbocharged small blocks. First off, here's my current setup (I've already ruined one stock bottom end):

-58mm throttle body
-4bbl m1 intake port matched
-mopar 2.02 r/t heads flow 260-270cfm from .500-.600
-harland sharp rocker arms, smith bros pushrods, hughes 1110 springs, custom bullet cam 226/226 .544/.544 112*lsa

Essentially I have a pretty stout top end and my tune is rock solid (11.7 afr across the board) but on pump gas (92 octane) with 26* timing at 10psi I think my pistons/rings didn't want to cooperate any longer. My intake temps are about 140* without an intercooler although I will have a meth kit within a couple of weeks and now my timing is at 20* which should be plenty safe especially once I'm spraying meth (I hope). I'll find out next week what went wrong with my pistons but it for sure didn't hold compression. There aren't any holes in the pistons but I think the rings and ring lands let go.

I'm wondering how many of you guys have used Probe pistons and if you had any luck with them? Without wanting to spend 1000 dollars on a set of custom JE's I think the Probes are probably my best bet unless there are any other off the shelf forged pistons that might be worthwhile (if so please let me know what you'd recommend as I'm open to suggestions). Unfortunately the Probe's are only available in 4.030+ so I'll have to get the cylinders bored which is going to add to my total costs.

What rings would you suggest for this? The most boost I'll probably ever see is about 15psi, IF I even go that high with it (which would only be at the track for a pass or two). Most likely 10-12 tops though. I'm using felpro head gaskets so I don't want to push the limits of those either (I have head studs holding the heads down though).

Will the Probe pistons (or others if there are other decent options available) work with stock reconditioned rods? I feel like a set of recon rods with ARP bolts should hold up just fine for what I want to do. I don't want to go crazy with boost or power, maybe about 500whp or so give or take some. I can't go that high with my current fuel system but if I had a stouter engine I may consider upgrading my fuel system. I don't think my combo with 12psi would break 500whp though, definitely not more than about 550whp (which would make me very happy to see).

I'll probably use the stock crank and main caps, although I'd be using main studs. If for some reason you would advise against this let me know. Billet caps just seem like a lot of money and for as often as I'll actually crank up the boost I don't think I'll need that much security. (this is a street driven vehicle that might see a few dozen passes at a track each year). I have a 6psi spring in the wastegate at all times and a dual stage controller that will get me up to a max of 12psi that will mostly be used at the track or on the dyno, or if I come across something interesting on the street that wants to race which doesn't happen often. I'm not much of a street racer I just like to have a good time while I'm driving and 6psi definitely does it for me. I like to make it home in one piece so there's really no need to drive around at 10+ psi all the time.

Aside from that I'll invest in a better oil pump and pan. K1 has a crank with a 3.79" stroke that sounds pretty interesting but I feel like the money needed to make that setup work would be out of my price range anyway. Otherwise I don't want a stroker crank, I'd like to keep it a 360.

Essentially I'd like to keep the costs down as much as possible but I need something that is going to last longer than a stock bottom end which seems to be my weak point right now. I feel like anyone that boosts a stock bottom end is on borrowed time, period. I've never known a stock bottom end to last very long once it experiences boost. After going through one I know this second one is only going to last so long so I'm wanting to rebuild my old one as quickly as possible but I'd like for it to actually last a while once it is together. I think the pistons/rings are really the weakest links and for the turbo I'd like to upgrade the oil pan/pump while I'm at it. So without spending 5 grand on an all out forged beast what are your opinions on this idea? Am I wasting my time trying to save money or can I get by with a budget build that only needs to handle 6psi/425whp every day and occasionally visiting the track for some 10+ psi 500ish whp passes while staying in one piece and allowing me to make it home afterward? Thanks for your input.

sounds like a cool build. while i dont have any first hand experience with turbos, i did sell a magnum 318 to member of forabodiesonly.com

he has a k-car that runs 10's (check on u tube!) on the turbo 4cyl and said he wanted to build a turbo magnum 318.

anyways, i will try to dig up his contact info, but you might want to try posting there in the tech section to get a hold of him.

I'm not an expert, but as a "rule of thumb" stock cast pistons are limited to around 5 lbs boost if the tune is perfect. If you were up around 7-10 that's too much. Also, 11.7 AFR is pretty rich... but may not be rich enough under full boost. The meth injection will help there. Hopefully you can also tune to get higher AFR under low load/cruising to improve efficiency and reduce engine wear.

For 7-10 lb, I'd suggest a shelf stock forged piston minimum in the compression ratio of your choice with ring gaps set for boost (wider).

Quote:

---

I'm not an expert, but as a "rule of thumb" stock cast pistons are limited to around 5 lbs boost if the tune is perfect.

---

That would depend on the piston of course.

I'm told the 5.7 hemi pistons are not much good beyond 5-7 psi without breaking due to the thin ring packs but other pistons will take as much as 30.

All depends on the engine, lots of Dakota guys running 10 psi+ on stock slugs.