Those who have replaced a faulty (for whatever reason) OE controlled waste gate with the spring, well, they think they died and gone to Heaven. They'd be equally impressed if they corrected the fault in the vac system.
However, far less moving parts with a spring, no more worry about vac pump, solenoid, etc. failing, though they are removing the factory protection the (yes, somewhat complicated, and somewhat conservative system) provides. Protection is still there, via defuel tier 2 protection actually with a fooler if the PCM is not aware of tru boost pressure there is little difference in running a TM as far as de-boost goes, both defuel on mega high boost or high IAT in some ways a fooler might be worse as PCM will never see the mega high boost depending how much fooling one has dialed in
The OE system generally provides trouble free service for ~150,000 miles, but YMMV...
I recall early on gmctd had a concern about wastegate component wear with the spring, as it is constantly flapping to relieve boost, that's the chatter you may hear buzzing under hood, he stuck with the boost fooled, vac actuated system... That is not way I remember it, I'll call later tonight to reconfirm
We're starting to see a few examples of that now on these forums, though very few, so probably not of great concern. I've seen more worn WGs over the years of being on the forums with vac controlled systems than any with a TM, what is not being captured in your assertion is how many TMs were installed after the fact of a bad vac system that may have had wear prior to the TM being installed? And an incorrect assumption made that really is a coincidence to the timing of the TM install
When the 6.5 first hit the road, those using for towing were quickly looking for more boost than GM programmed, and a boost fooler was invented over at the Page, John Kennedy sells a variable plug and play version, which works fine to this day.
Agreed I had one of those and ran it for years until I reflashed and I no longer needed it.
A fooler is a good stop-gap to aid in better performance from stock but a reflash is the cure and if folks gripe about the cost of a TM see what Kennedy's fooler costs for $5 worth of electronics and $10 worth of connectors for plug & play I'm not knocking his fooler at all free market sytem one can charge what they want for their widget, but when I got it I was disappointed to see what it was vs. what I paid for it
The pre-94 6.5 turbo diesel had a similar arrangement to the Heath spring, except was dampened so as to not chatter. Not exactly similar yes but that spring was for boost regulation at same wussiliy boost curves as what GM provided with the PWM boost control, the TM does a far better job on those as well, now one can modify a early style to work like a TM and be as well served with that as a TM, you just need boost monitoring capability to set it properly FYI Kennedy at one time sold TMs from Heath I don't know if he still does so it was a viable solution for him as well at one time
A spring is a good solution for those without the wherewithal to diagnose and maintain a GM designed digitally controlled waste gate.
Only my observations, but I'm sticking with my vac system, quite happy with it, and so far it seems have competent enough to maintain it.
