Cast Piston Boost Limit?

[Bad Vibe]

Is there a limit that we can go on cast pistons with boost? I am using a stock 89 2.5 TI bottom end with a TII head. I am going to replace my turbo and waste gate accuator. Turbo has seal leaking and accuator spring is bad. I was runnig 14 PSI for about a day till my spring went. I can get about 10 PSI till the accuator gets hot then I only get around 5 PSI. My daytona is fully set up as a 2.5 TII and runs great other then the boost problem.

Also does anyone know what the stock boost for a 89 TII was?

[Mr P-body]

If you don't have a intercooler, bigger fuel pump ,adjustible regulator I would trust it to about 12 psi with the correct timming.
I have run two types 1) speed pro and 2) sealed power both in 2.5l 110 race fuel and about 13 to 14 intl timing with 18 psi no intercooler stock fuel system.

1) speed-pro held up for about 3 weeks with moly coated skirts and ceramic tops. It then generated hot spots on the front and rear thrust sides and melted the back half of the piston away.

2) I then went to sealed power wich has more material around the top ring land and pin bore. I ported the pistons to relieve all the sharp edges around the valve reliefs and ring land and coated it with same material. I then went a few steps farther by intercooling , fuel cell , mallory pump , fabtech ajst fpr , ported head , ported exh manifold, and intake. I then ran around 12 deg intl timing with 20 psi and the weak point was the # 3 rod bolt.

Point : Cast pistons will hold up with proper prep work and right tune-up. Just remember the thing that kills pistons is heat and detonation so if you remove those two things from the equation you will be fine.

[Bad Vibe]

Ok. I think I will be ok. I have 20+ injectors, adj fuel reg, air fuel guage, exhuast temp guage, and an innercooler. I was told I could go to around 17lbs of boost, but I only want 14lbs. I just want to be safe on my build. Thank you.

[TheRock]

See this thread: Cast pistons + Boost

Cast pistons will take plenty of power, but you HAVE to have a good Intercooler (multi-core or Spearco) and plenty of fuel, and preferably no calibrations with lots of timing...

[DblTrbl]

The limit for cast pistons is very high as long as you don't detonate. This means that you must have enough fuel, a cool charge and expecially octane. I've had stock Mahle 2.5 pistons over 28PSI and drive it daily at 25PSI.

Here's some useful information about pushing your pistons:
http://www.omniturbo.com/Mopar%20Pag...ust%20read.htm

[omnivore]

Dean Stille was using them at 25+ psi, +40's, Spearco cooler, S60 turbo, 11.7's at 117 if I remember right.....I don't think you can put a boost limit on the pstons pre se, rather the point is not to ping it...if you are pinging it, you could break it at 15 psi, and if you aren't, you can get away with 25 psi.....get gauges , lots of fuel,and watch what you are doing, use good gas and a good intercooler.