So my buddy has a 6.9 idi that he has just installed a r&d idi turbo kit on. He has also put in a crank girdle and head studs as well as stage one injectors and a new injection pump (I forget which one). What we are wondering is how much boost should we put in there? The truck is a daily driven trail rig so we need to keep it as reliable as possible.
6.9 idi turbo
- Thread starter BlueHound
- Start date
If you want it to be as reliable as possible then put as little boost into it as possible, the 6.9 head bolt size is very small and even with head studs many have had headgasket failures past 20 psi.
pelky350
Full Access Member
If he had the money for a r and d kit and rebuilding a engine he should have used a 7.3.. 20psi is probably what would be considered reliable with studs on a 6.9. If he's running a large pump, large turbo and those injectors im curious as to how much those heads are gonna hold on too. Yes on a 6.9 cylinder walls are thicker but blowing up cylinder walls isn't a think happening to the 7.3. Cavitation seems to be a thing but not As common as some belive. Sounds like the limiting factor here is gonna be the head gaskets
15-16 should be fine. For your 7.3 if you have to over bore it a lot I would sleeve it, but it’s not a nessasity for the engine to live. If you head stud it then it will hold the gaskets for more boost than you will ever make with a rotory injection pump
