Spot the difference with the pictures :dunno:

 

I know I know... One is bigger than all the others...

 

should be up now, though i took my time spotting the difference in your avatar

 

Don't the bodies dictate the first stage opening? Think etv went into some length about this in the 300dti thread.

 

Ah thats good to know mate, i thought for some reason the 'build up' in the nozzle would contribute to the pressure. but probably got confused about the first second stages.

Should have them together later on in the weekend, then its just deciding whether to get them pop tested as some say you dont need to and some say you do.

 

pop testing is one of those things that will ensure it'll run nicely, and your engine will love you long time for it.

I've looked into building my own pop tester rig - and soon went off the idea, after seeing the damage a singular stray "spurt" can do, at 100Bar.....

Necrosis of the flesh.... usually resulting in amputation being the ONLY "fix"


Send them off to a deisel specialists, usually costs £10-£20 each from what I've heard

 

Yeah I've seen that pic before, not pretty. Will get them pop tested then, only thing my local can only do the first stage though I hear that you can usually get away with it.

 

So you are building some 'hydrids' with SDI nozzles on the bodies (and the higher 1st stage pop pressure) from the ZR/25 injectors.

I think you will notice a good few benefits over a pure SDI injector, less smoke and more mpg hopefully.

Good luck with it. There is always the remap option to add more power if you require.

Will be interesting to see the pop pressures of these, and whether swapping the nozzles causes them to vary a lot, i.e. whether dismantling and swapping bits over causes one injector to pop at quite a different pressure to another.

If the pop pressures need adjustment, I would go with 210 bar for the 1st stage pressure, and if possible, the standard figure for the 2nd stage (I think it's 280bar, both SDI and ZR/25 are the same though). This should keep timing closer to the the factory figure. I think this will help with mpg, compared to the SDI pop pressures - my theory is that the slight pop pressure difference on the 1st stage of the SDis causes the pump ECU to retard the timing slightly, which is why people complain of mpg loss when driven the same as pre-SDi injectors.

 

Thanks for the input tim, yeah I hope quite a few troubles with the sdi's will go away when using the standard bodies. If anything the higher pop pressure should help with atomisation and will keep the smoke down quite a bit. your input on the timing should help too as the 'bang/cycle' should be shaped better?

I'm hoping to get away with a remap, as long as she does not smoke and I get decent performance I will be happy (new nozzles alone on sdi's would help I'm sure)

Most places seem to think if you set the first stage right you should not have any worries with the second as long as youve not messed with them, so I should be golden.

 

Sounds like you have a good idea of where you want to end up with tuning your ZR. I hope it all goes to plan and you end up with more smiles per mile!

 

This setup works a treat have been there and you get just about the same bhp once it is mapped but lots less smoke and no judder glad to see someone else doing this setup really dont know why it has not caught on to more people but still.

 

probably because on paper it shouldn't make a lot of difference tbh

if the second break pressure is left alone then the main injection shouldn't be altered much at all

 

Mine with these hybrids some time ago with only remap and straight though it was hitting 154 bhp with very little smoke and no judder.
So these do work i was just thinking would changing the nozzles alone mean the break pressures would be altered as i dont do this work my self i just get specialist to do it for me and they calibrate them etc but we might be able to just change the nozzles.

 

To answer your question, yes it would.

As for whether it works or not, I can only shrug. I've a feeling its one of those things where you get a different answer for every one who has tried it.

From a theoretical point of view though, it should not make a (noticable) difference really. It's just altering the pilot (not main) injection, and only by a tiny amount. Going from used nozzles to new nozzles of the same type i'd imagine would make a bigger difference but that's just imho.

 

Dont know, will see during the week. I'm fairly certain the extra pressure will give a slightly better mix of fuel which I hope will mean less smoke - more mpg. But new nozzles can do that anyway, so its an unknown really.

All things being equal, changing nozzles are closer to stock than sdi's maybe thats less heartache for the ecu ect? The ecu can change the timing but is that bang on, or some sort of 'default it'll do' redundency setting which isnt quite as good as 'bang on' in the first place? (i gather the ecu can tell the opening pop due to the wire?)

If all else fails I will be happy that I wont have worn nozzles on my injectors, which is a bonus whatever happens.

 

How much were the nozzles lovewise?And where did you get em?

 

My advice

Give to a diesel specialist with written instructions to set the primary injection pressure to 210 bar +5 / -0.

They will shim and pop test and repeat until they get the pressures you are after.

If you have no cash then simply fit and try them and then get them re-calibrated after if they aren't up to scratch.

 

Well I fitted them myself due to enthusiasm, they work fine. At least the car goes with no untoward noises and stuff. There is less smoke than the sdi's and the power delivery is a lot smoother. Seems to be more spirited at higher revs - maybe less clag means more burnt fuel/power? The car seems to be happier all round.

Still got some judder though, but it is a LOT smoother, even with the EGR enabled. All in all its a good mod, though i'm kind of missing the clag and 'dollop' power the sdi's give.

 

Did you fit these to 25 injector bodies or 200 ones?

If they are the 200 ones then you've simply fitted a new nozzle so you should get a little less smoke but no big changes.

If you have fitted them to the 25 type injectors then you also have the benefit of retaining the stock timing too (probably a minor effect but it will be there).

 

I put them on 210 bodies, and they run great. With it running right, do you think Ive gotten away with not having them balanced?

 

so they are 25 bodies with sdi nozzles?

 

Yep which is the same as a di injector set to 210 bar opening pressure as I suggested.

So yes you may well get away with not having them balanced. My diesel place only used to charge a couple of quid to test an injector so if they were mine I'd have had them tested to be sure, but chances are you'll have got away with it. Problem is you'll never know for sure!

 

Indeed, i know a place I can send them to for 5 quid an injector so I think ill get them tested to make sure.

Maybe I'm easily confused, but with the 25 bodies being used I'm closer to stock timing. But if the ecu detects the pilot injection, wont it compensate itself? thats what the wire is for?

 

Yes it'll compensate however it gets a bit complicated because the ECU only knows the pilot injection start point, not the main injection event. Becuase it is expecting this at 210bar because it opens at 200 bar (it doesn't know the pressure), the main injection event is shifted slightly in time. So if you want stock timing you should set the break pressure to 210 bar on the 25/45 etc. It is only a minor issue but if you want it perfect then that is the best bet to start with.