max PSI without having to stud heads?

[505powerstroke]

today i got bored and swapped my kem 345 tune for an h&s "hot" tune and althought they are comporable in power, the boost levels are night and day, the 345 maxes out about 38 psi and the hot tunes pushes 46psi, that got me to wondering at what point ill start to lift a head or blow a headgasket? i assume one tune relies on boost to make power and the other must use injector timing? i assume?

[clutchdabomb22]

i would also like to know what one is safer and better for my engine without head studs!?

[08twinturbo]

Don't know if this helps, but I hear a lot less injection rattle with the 345 than my spartan 310. It's so quiet it reminds me of a gas engine. From what I have been told it uses less injection timing than other high HP tunes.

[08stroker250]

The 345 tune only makes 38 psi of boost? Never would have thought that.

I can hit 48-50 psi with our 310 tune. I'm not recommending it, but I do have stock head bolts. No gasket failure yet. Boost isn't so much the problem when it comes to blowing head gaskets though. Boost pressure is going to increase back pressure, which can cause the heads to lift....but high back pressure is putting you at a greater risk of floating valves and causing valve to piston contact.

If I am not mistaken, high cylinder pressure is the main cause of blown head gaskets. I could be way off on that though....

[505powerstroke]

so now im confused, others who are running the 345 tune are saying that they are running 46psi on the kem 345 tune, and they also say that their idle rpm is around the stock 750ish, when my truck idles at 950rpm with the 345 tune

[08stroker250]

What is idle rail pressure with the 345 tune?

950 RPM is high, unless it's cold weather high idle. Do the RPM's drop if you tap the brake or throttle?

[505powerstroke]

no they dont drop, the cold weather idle it around 1100, then if i tap it, it will drop to around 900-950. its always done this, i thought it was normal . i have an email in to mike so lets see what he says, the max boost must be a fluke as well...