Have a set of Bozios being pop tested and installed..any input to improve performance??

Injector Pop test@135bar
Injection Pump Timing Advanced@27degBTDC

It will regain any performance lost due to injector wear but you won't gain anything over stock.

Any recommendations on timing advance?

26-28 is a good range.

Thanks forced..always coming through..care to expand on the science behind it to make the thread worthwhile??:D

Advancing the timing makes the expansion pressure peak closer to when the piston starts moving down, which increases torque, and allows the gasses to expand longer, which increases efficiency.

If you go too far it starts expanding before TDC and the piston has to try and compress the already expanding gasses, which will stress the headgasket and hurt power output. That will sound like shaking a bucket of nails when you accelerate and the engine will be hard to start.

MB had to meet emissions at the time and retarding the timing lowers combustion temp and NOx production.

If you go too far it starts expanding before TDC and the piston has to try and compress the already expanding gasses, which will stress the headgasket and hurt power output. That will sound like shaking a bucket of nails when you accelerate and the engine will be hard to start.



If you have done this...........at what point (BTDC) did you notice those sounds? Did you ever have it at 30°?

I got up to 28* and it was harder to cold start so I backed down to 26.

When I had the cut delivery valves installed, the engine would bog down and rattle like hell if I floored it below 2000rpm. They may have just been quenching the flame with too much fuel but I know altering the delivery valves also alters the injection timing because of how it changes fuel flow. How much, we don't know yet.

I got up to 28* and it was harder to cold start so I backed down to 26.

When I had the cut delivery valves installed, the engine would bog down and rattle like hell if I floored it below 2000rpm. They may have just been quenching the flame with too much fuel but I know altering the delivery valves also alters the injection timing because of how it changes fuel flow. How much, we don't know yet.

Interesting that 4° over stock will already affect the cold start. I have to bump up the SD and see how it does.

You really cannot have "too much fuel" unless it's putting out significant black smoke...........which you might have without the ALDA. In that situation, it can certainly bog down if the fuel is excessive.

Those valves certainly affect the timing..........possibly more than you can realize. I don't see any good way of determining this value, however, other than a lot of testing with greater "retarded" timing settings until the engine performs in similar manner to stock.

outstanding.:thumbsup: any gains in adjusting pop pressures?

My injectors are set at 150bar (instead of 135), I lost a little off-idle torque but I gained some top end power and 2mpg. I also use different nozzles and 2-stage injectors so the pressure change alone is only part of my gain.

Link to my thread. (http://www.superturbodiesel.com/std/viewtopic.php?f=9&t=5)

You really cannot have "too much fuel" unless it's putting out significant black smoke...........which you might have without the ALDA. In that situation, it can certainly bog down if the fuel is excessive.


Yep, not kidding about that. I test drove a 6.5TD Suburban yesterday that the turbo had something stuck in it (didn't buy it!). But man hit the accelerator and it'd smoke like crazy and actually go slower than with less throttle. Probably putting out the fire with too much fuel at that point. It literally looked like a tire burning worth of smoke coming out the tailpipe at anything higher than idle!