Nozzle and injector questions

[MikkiJayne]

Hi everyone,

Well despite mucho searching and reading and more searching I'm no clearer on which nozzles are which, and what they all do  :?

I believe my AHU has .184 as standard? Is that a single hole measured in mm or many holes? My injectors are so sooted up its impossible to tell.

I'm looking at .216s - are they equivalent to PP520s?
I believe there is also a .232? Is that equivalent to PP764? Can they be used without a bigger turbo (until I get one!)?

What (if any) are the differences between VW nozzles and the Bosio that Kerma sell, other than the huge price difference? Is there any power difference?

My injectors are 150,000 miles old. Will they be ok with new nozzles or should I really be replacing them? Can they be stripped and cleaned?

Sorry if this is all written somewhere else - I can't find it if it is, and I've read all the FAQs and TDIclub, etc.

Thanks  

[jtanguay]

clean up your injectors and just install the new nozzles.  remember KEEP THE INJECTORS CLEAN!!! any bit of dirt in there can totally screw you over.

you might want to get the injectors pop tested, but for the most part they should be ok.

for my tdi i'm probably going with some .216's.  how much power do you want? are you going VNT-20?

[lord_verminaard]

From what I know, the PP or "power plus" nozzles have proprietary design changes over the OEM design.  I read somewhere that a PP nozzle tested against an OEM nozzle of the same size will produce more power, less smoke and more fuel economy.  The measurement is of a single hole.  Pretty much any injector (within reason!) can be used with any turbo, and I feel it's better to err on the side of too big than too small.    It just depends on how much smoke you can live with.  Back when the TDI-club faq was written, nobody was using R520 injectors because everyone was using stock turbos and was afraid it would burn a hole in a piston.  Now, with proper tuning, R520s can be used with stock turbos and they run well.  (turbo is of course the limiting point, and EGT's would be higher than you'd probably want)

.216's would work well and be cheap for a stock turbo, Kerma's "Sprint 764" are an OEM design .216, which is basically like a factory nozzle from a 5-cylinder TDI.  They will work well with stock turbo and tune.  The PP520's are the powerplus design and make the most hp and torque with zero smoke in stock tune and turbo.  Which is why they are $100 more.  

Your stock nozzles are probably ok- the only real way to tell is to get them cleaned and pop-tested.  That will check the spray pattern for problems, set all the breaking pressures to the factory spec and they should be as good as new.

Good luck, hope that helped.

Brendan

[MikkiJayne]

Yes thats very helpful  

I spoke to a local diesel specialist about pop testing the injectors, which is only £3 each, but when I mentioned new nozzles he got a bit less keen. He is suggesting that as stock they will be single stage, but if I change the nozzles they will be two stage  :?  This seems a bit odd, but he has never heard of people changing nozzles before so was a bit wary.

Would the requirements of the pop test be the same with larger nozzles as stock?

One problem I have is that I had to use a home-made slide hammer to get the injectors out of the head, and in doing so got a fair bit of dust and crud down the top of them. I stripped one of the injectors and now have a nice little pile of shims and springs. I'm thinking blow them through with an air line, rinse everything in thinners, and put them back together?

Thanks!

[hillfolk'r]

when i bonught my kerma race 520's,the instructions said to only  disassemble them far enough to install the new nozzles,and do one at a time
yea you usually need a slide hammer if they get stuck
one thing that helps for next time is to coat the outside of the injector body with antisieze
yea you do drop crud in when you remove them,its enevitable
yea try and blow the cyls out with a small air line,or crank it over with no injectors installed
ive got a pop tester,and i checked them before+after
they were ok before,nice and even(i forgot the exact numbers),if maybe in the middle to low side of the spec
after the new nozzle install,they all increased to the high side of the spec(probably about 150 psi more),and stayed even
about 85% of the time if you just replace a set of nozzles that ran ok,and you dont find any broken or damaged parts on disassembly,they will be just fine
if you want,id have them tested afterwards just for kicks