Alright, so, I've been pretty quiet on the forum since I had my final exams, and then went to Fraser, but I've done a fair bit of thinking over the past few weeks and need some opinions. I know that SD33T's are notorious for cracking heads when pushing more power than stock, however I don't know the threshold where is a 'safe' amount of extra power. I had the thought the other day that surely they only crack heads when the extra power comes from adding extra fuel and boost into the engine (correct me if I'm wrong), so doing performance upgrades like a free flowing exhaust/turbo elbow delete, intercooler, and in my case plumbing up the snorkel so it's sucking cooler air in the first place, won't affect the engine's durability as it does not put more stress on the engine, in fact it may put less stress on as it is able to do it's primary job of spinning the crankshaft with less restriction. So I have a couple of questions:
-Is my theory of non fuel/boost-related upgrades reducing likelyhood of head cracking correct?
-What actually causes the head to crack? (I have an egt gauge and always make sure to keep egt's below 475*C post turbo)
-How much extra fuel and boost is agreed to be absolutely safe to put into the engine without worry of cracking the head? If any.
-How much of a difference does removing the horribly restrictive 90* elbow after the turbo make? I've had a bit of a look around on the binder-planet forum at some of the guys in the USA with SD-powered International Scouts, and a few people there seem to have had good results by removing it.
-How easy is it to remove the elbow, and does it tie into anything else such as the wastegate which complicates the removal? Or is it a simple unbolt 3 bolts and bolt new exhaust onto turbo?
-And just for speculation how well would a dawes-valve powered GT2052v VNT Garrett turbo from a ZD30 work on the sd? Dad (@trev zd30) will be replacing his soon, and I'm in need of a new turbo anyway (my turbo seals are pretty leaky), so we figure that if we could make it bolt on it could work well as it is plenty capable of producing the 7-10psi of boost that the SD33T runs from factory (7psi with muffler, 10 without from my experience). Would it be easy enough to adapt to the SD mounts?
Big post I know, but I figured it's probably better to make one thread with a few burning questions than many threads of one question each. Thanks everyone.
-Is my theory of non fuel/boost-related upgrades reducing likelyhood of head cracking correct?
-What actually causes the head to crack? (I have an egt gauge and always make sure to keep egt's below 475*C post turbo)
-How much extra fuel and boost is agreed to be absolutely safe to put into the engine without worry of cracking the head? If any.
-How much of a difference does removing the horribly restrictive 90* elbow after the turbo make? I've had a bit of a look around on the binder-planet forum at some of the guys in the USA with SD-powered International Scouts, and a few people there seem to have had good results by removing it.
-How easy is it to remove the elbow, and does it tie into anything else such as the wastegate which complicates the removal? Or is it a simple unbolt 3 bolts and bolt new exhaust onto turbo?
-And just for speculation how well would a dawes-valve powered GT2052v VNT Garrett turbo from a ZD30 work on the sd? Dad (@trev zd30) will be replacing his soon, and I'm in need of a new turbo anyway (my turbo seals are pretty leaky), so we figure that if we could make it bolt on it could work well as it is plenty capable of producing the 7-10psi of boost that the SD33T runs from factory (7psi with muffler, 10 without from my experience). Would it be easy enough to adapt to the SD mounts?
Big post I know, but I figured it's probably better to make one thread with a few burning questions than many threads of one question each. Thanks everyone.