Boost drop after timing?

[rlyons]

I advanced my timing this morning and seem to have lost a little boost pressure. I was getting 32 psi max and now have about 28 max? It seems to sound a lot smoother and smoke is down a little,power is good but a little less boost. Is this normal?

 

[RustyJC]

By advancing the timing, the injection and combustion event begins earlier in terms of crankshaft rotation. Therefore, it finishes earlier as well. This means that the piston has moved farther downward since completion of the combustion event (thus extracting more energy) before the exhaust valve opens. The end result is that more energy from the combustion event is extracted in the cylinder (more power), and less energy is available in the exhaust manifold to drive the turbocharger. Therefore, a slight decrease in boost pressure would be expected.



Rusty

 

[rlyons]

Thanks Rusty, I sort of thought that way as like I said it seems to have more power so I guess all is good.

Roy

 

[Mel Fuelling]

Advancing my pump timing dropped my boost a little below 2k, but seems to make it pull better above 2k. Hopefully, this change will be easier on drivetrain parts. This is seat of pants impression, not documented.

Mel

 

[rlyons]

Just came back from a long drive in mine and it does run smoother and sounds a little less noisey, it did a lot of hammering on full throttle before, it does seem to have a little more power at higher RPMs but it did lose a little power at lower RPMs. I do think that it will make things last a little longer though as it has a more even tone throughout the RPM range now if that makes any sense. Before the pump really was noisey at high RPMs. I also backed my star wheel out to 3 1/4 turns from the bottom to slow the low RPM pulling smoke a little. I had way too much when pulling my fifthwheel. I can live with a little less low end power to get the other benefits I think.