DIY swapping altitude compensator for boost compensator Bosch VE

[Captaincademan]

Hi 3DB,

thanks for a bloody good reply. As you might have noticed from my initial post I am going to do this properly, a complete install from compensator to gauges. I want it to last and work seamlessly.

i have a spare vehicle so I can afford to have the cruiser off the road for a couple of weeks while I do it myself. I am now confident enough to do the compensator myself, it can't be that hard to do with the right parts and lots of care.

Once the gauges are fitted and it as all back together, I think I will just turn the fuel up on low boost to start with to get my 4 or 5 psi at around 2000 rpm then dial up the top end take the max boost to under 9 at say 3200 which is where I normally change up. I am not sure if this will work as planned but I think that's what I would like to achieve.

I have also read that 500 - 600 is a safe max temp too but I thought this was measured post turbo for some reason. I reckon it would be a lot cooler after the turbo due to the energy use to turn the turbine, so it does make sense to measure it pre turbo.

Modern exhaust kits kits come with a threaded point in the dump pipe, so I think I'll just fill that with a bolt. I have never tapped a thread into cast iron, so I will be interested to see how that goes

I expect there will will be losses in the gauges so I need to buy decent gauges that are calibrated well so the numbers are real and not just relative.

Input as as always is greatly appreciated

[3DB]

I tapped my EGT probe port into the cast iron turbo exhaust housing and it wasn't fun. It worked though but only just as the cast kept crumbling. I was too lazy to do it in the manifold and there was a perfect spot where the EGR would go if I had one. My Merc has its probe pre turbo and I feel this makes the most sense as it is the bore you are worried about rather than the turbo. Aluminium pistons expand faster than the steel bore taking the ring space and scoring the bore. As you say, lots of heat loss through the turbo so you are never really sure what combustion temps might be measuring post turbo. I guess if you lagged the exhaust and used a turbo blanket it might be closer?

[Ratau]

I'm busy doing the same modification on my Patrol 4.2 diesel that was NA and had a altitude compensator on. I fitted a turbo, inter cooler and 3 inch exhaust.


I swapped all the necessary parts from the altitude compensator top to the boost compensator top.


I installed it and turned the main fuel screw till the engine started and idle normal at 600 Rpm. I found there is no throttle response at all. I took the top of to check the if governor spring was hooked. It was and put the top back on, still no response.


Then put the altitude top back on and it work perfectly. Do I need to do more mods on the boost compensator or do I need to change some more fuel settings?