Got a gague, tried it out - couldnt' get any more than 14psi on my 1.9 aaz. Is that normal? I kept unscrewing the wastegate but didn't go any higher.
I've got a Rover 220D conical boost pin in there, but the stock spring. I was worrying about wasting fuel due to the LDA going all the way down too quickly, but I notice that boost climbs up to max levels REALLY quickly, like less than a second when I put my foot down. So surely I can only be wasting a tiny drop of fuel by having the stock spring?
I was considering stretching the spring out - making it longer would effectively increase the preload on the spring, and hence be like having a stiffer spring. Anyone know what the dimensions of the spring are when it's in the pump? Like, how long it is at no boost and full?
did you raise the spring seat any?That will increase tension.
Shims? I don't know what it looks like but shims always increase tension on springs
Well yeah, I could try the shims. I didn't look to see if there was an adjustable spring seat...
The thing is, I don't know how much to adjust it. I could pull the pump, sit it on a bench and examine how much boost gives how much fuelling but that's a right pain
The stock AAZ spring is worthless to meter fuel as a function of boost. Somewhere on the forum, I posted the results of some tests. The AAZ spring was bottomed out by 4 psi or so, the MUCH stronger Cummins spring I put in wasn't bottomed until 11-12 psi. You can't shim the AAZ spring enough to be effective as even fully compressed, it is only 1/3 as strong as the proper spring.
I think what I did for my test was have the pin in place, but the cover off, and with the pump on a scale, I measured the force needed to bottom it out, then figured the area of the diaphragm to find what PSI I would need.
you have prob posted it but what if you used the 1.6 TD pin and spring?
like i used that combo in my aaz and if does seem that fuel comes on too quick for it to build boost to burn it, you say a cummings spring when is that close to the 1.6?
can you shim the 1.6 sping in the aaz pump?
it is only 1/3 as strong as the proper spring.
So I roughly want a spring of the same dimensions but 3 times the rate? Ok, gotcha
The question is, how will I know if the LDA is working as it should? It'll just mean a bit less fuel used, won't it? Maybe a little less smoke when I hit the pedal, although I don't really see that anyway...