Boost Compensator.
Posted: Sun Aug 31, 2008 10:09 pm
Just throwing my 2 cent's in, as this might help someone someday.
Lost power and turbo was extremly slow to spool up on td42. On drive to bush it was fine on the highway back, I noticed the lack of power and the turbo not spooling up to 10 psi within about .5-1.5 sec, which i normally run. It would just increase in boost as the revs climbed, which felt like the same power as a N/A td42. 5th gear foot flat to the floor I could only get 5psi and 2200rpm max.
Anyways I thought I must have split a line to the boost compensator as it felt like it wasn't schedualling more fuel for increase in boost. I couldn't find any problems with the lines, so I cracked off the top of the compensator, and at the same time found that the adjustment allen-key screw and locknut were loose. Inside the compensator diaphram housing this screw conects to a rubber circle about the same size as a 10 cent coin, on which the bottom "flat" surface is tapered (it has a low point and at 180 degrees offset is the highest point). At its highest point it pushes down on a ball relief valve in the center of the compensator diaphram and at its lowest point the ball remains untouched. With the ball fully down all your boost is bled off through this valve and it neutralises presure over the diaphram and will not increase fuel with boost, in the lowest position you have full compenstaion and power.
I though I'd post this as my adjustment screw had vibrated to the position of max relief. Also might be worth checking for curiosity's sake, because the difference between the min and max settings is huge.
Lost power and turbo was extremly slow to spool up on td42. On drive to bush it was fine on the highway back, I noticed the lack of power and the turbo not spooling up to 10 psi within about .5-1.5 sec, which i normally run. It would just increase in boost as the revs climbed, which felt like the same power as a N/A td42. 5th gear foot flat to the floor I could only get 5psi and 2200rpm max.
Anyways I thought I must have split a line to the boost compensator as it felt like it wasn't schedualling more fuel for increase in boost. I couldn't find any problems with the lines, so I cracked off the top of the compensator, and at the same time found that the adjustment allen-key screw and locknut were loose. Inside the compensator diaphram housing this screw conects to a rubber circle about the same size as a 10 cent coin, on which the bottom "flat" surface is tapered (it has a low point and at 180 degrees offset is the highest point). At its highest point it pushes down on a ball relief valve in the center of the compensator diaphram and at its lowest point the ball remains untouched. With the ball fully down all your boost is bled off through this valve and it neutralises presure over the diaphram and will not increase fuel with boost, in the lowest position you have full compenstaion and power.
I though I'd post this as my adjustment screw had vibrated to the position of max relief. Also might be worth checking for curiosity's sake, because the difference between the min and max settings is huge.
