Increasing injector break pressures

[Dan!]

Just an idea I had while fiddling at work the other day and after thinking about getting Lucas injectors to just break higher, instead of buying bosch injectors..

Theory - You could easily increase the break pressures of bosch injectors by shimming the internal spring, literally by adding like 0.1mm to the spring preload you would gain about 10bar. But would it be of any advantage?

If they broke later then the injection timing would be more retarded (which could be solved by advancing the pump slightly on the slots or even by a tooth on the cambelt if it was that drastic, which I doubt.) But would you get more fuel in at the higher pressure or would the injection period be shorter because of the later pressure breaking? Not something im sure anybody could certainly answer, but me and Dave have just had a chat about it and it might be worth a try at least....


Genuine thoughts/opinions welcome....

[londondan86]

Sounds pretty good idea! Surely the smaller injection window would be minimal, and if your shoveing more fuel in anyway in that window it should make more power.

Not sure how far you could go without completely messing with the advance but a bit of trial and error for someone with the time would be worth a shot surely.

[Dan!]

Well the theory is there, sort of And I would say upping them from 175 to maybe 190bar would be the first step of testing, seeing as people can run a bosch pump on lucas injectors (at ~135bar?) withh not too many advance problems...

Anyway, 306oc tells me that Ruan is viewing this thread, so hopefully my idea will be reviewed soon

[Ruan]

Just to let you know, 275hp has been made on a 1.6TD with 135bar injectors...

Nozzles/break pressure really doesn't make any difference with indirect injection, a long injection keeps the the burn happening throughout the cylinder stroke. This is IDIs main advantage over DI... Because the burn happens in the precup, it can easily keep going long after TDC.

[darrenjlobb]

Unless you have made a pop tester then dont even try to do this at home, adding shims by measurement will have different effects on the injectors as no two springs react the same....bosch injectors cost pennys anyways so little point trying...

[Dan!]

The IDI thing was Dave's main point, not sure how much of an effect break pressures would have with the swirl chamber in the middle.

Darren, I can use the bench tester for pumps/injectors at work so I could calibrate them all before testing no problem.

Thanks for the posts though guys

[Jtrigga]

Just drill the end of the nozzle

[Dave]

Just drill the end of the nozzle

Now this is what im talkin about!!! XUD full of win...!!!