larger nozzle on stock boost

[K7ERG]

I am planning on changing the diesel nozzle to larger one soon. Stock are 0.216 going to 0.232. Being new to diesel tuning I am wondering if it will be ok to run with these for a bit before altering boost etc. I found a guide about installing and recommends the engine should be cold. Which rules out travelling to my nearest rolling road.

Any suggestion?

[byd1380]

Not sure which ones you're putting in, I ran the ones from the 151bhp Transporter with no issues, I also rang a set of .232 Bosio ones in my 110tdi, can get a bit lumpy on idle, just adjusted injection quantity with vagcom.

Ivan

[prj]

Installing larger nozzles is pretty much like installing bigger injectors.
It'll run rich. The engine you have does not have any kind of O2 sensor, which could provide closed loop fueling, so it'll just keep running rich.

Without a remap, and at the same boost level you will:
* Significantly increase EGT, which can lead to engine failure.
* Have horrible fuel economy.

Even if you just increase boost, you'd still be injecting too much all the time. The only time it would be remotely alright, would be when it's on full boost.
Doing it correctly requires recalibration of the pump voltage map, or recalculation of IQ using the newer nozzles and readjusting every other map in the ECU that has to do with determining IQ plus SOI.

[AndyP]

Not sure which ones you're putting in, I ran the ones from the 151bhp Transporter with no issues, I also rang a set of .232 Bosio ones in my 110tdi, can get a bit lumpy on idle, just adjusted injection quantity with vagcom.

Ivan

Are these the nozzles you used?

http://www.ebay.co.uk/itm/Transporte...item3f15c9afed

These are a direct replacement on an AEL to give a better spray pattern and better MPG right?

[spink]

sorry mispost

[K7ERG]

Bosio pp502s will be going in shortly.

[AndyP]

I went for Bosio's in the end, too many Bosch copies around for my liking. I went for PP520's from Kerma, great price and arrived in a couple of days.

Not fitted them yet, but post up again when you've done yours and let me know how it went.

[byd1380]

I had a A6 Tdi Quattro (C4), I fitted the Bosch ones from a 151bhp transporter, it did help a bit, I then sold the car and bought a tdi 110bhp Seat Ibiza, I then fitted the Bosch ones to it, but needed more power, I bought PP502's and they gave a good increase over the Bosch ones, so much so I needed a new clutch. Good luck and keep us posted.

[K7ERG]

Will do mate

[5cylinderman]

In my opinion using larger nozzles will not make you run "richer".
The injection pump decides the fuel quantity injected, not your bigger injectors. Your choice of Bosio size is a good one. Injectors just atomise the diesel that the pump sends to them.
What will happen is that with larger nozzles the fuel will be injected slightly faster so if your timing is not adjusted to perfection you will put a larger load on your pistons and rods (faster rate of injection could inherently "advance" injection timing).
The later Transporters (151 bhp smaller diameter but 5 hole type?) used different nozzles but the their pumps were designed to use higher pressures. Stay away from those on your motor.
Before you raise your boost I would suggest that you carefully check your dynamic timing. You may need to adjust your fuel quantity to give a smooth idle.
I would suggest removing injectors while the engine is hot insofar as I have removed countless dozens of them successfully over the years without issue.
Be very careful that the seat in the head is spotless before refitting and use new copper washers every time. Use a small amount of engine oil on the bolt threads and under the convex clamp bolt washer. Torque 'em down with a decent torque wrench too.

[K7ERG]

Cheers for the info.

[prj]

In my opinion using larger nozzles will not make you run "richer".
The injection pump decides the fuel quantity injected, not your bigger injectors. Your choice of Bosio size is a good one. Injectors just atomise the diesel that the pump sends to them.
What will happen is that with larger nozzles the fuel will be injected slightly faster so if your timing is not adjusted to perfection you will put a larger load on your pistons and rods (faster rate of injection could inherently "advance" injection timing).
The later Transporters (151 bhp smaller diameter but 5 hole type?) used different nozzles but the their pumps were designed to use higher pressures. Stay away from those on your motor.
Before you raise your boost I would suggest that you carefully check your dynamic timing. You may need to adjust your fuel quantity to give a smooth idle.
I would suggest removing injectors while the engine is hot insofar as I have removed countless dozens of them successfully over the years without issue.
Be very careful that the seat in the head is spotless before refitting and use new copper washers every time. Use a small amount of engine oil on the bolt threads and under the convex clamp bolt washer. Torque 'em down with a decent torque wrench too.

Yes, thinking about it, you are right.
Timing needs a remap, since SOI will be completely out though, and you'll hit PCP before TDC.
I was thinking of a common rail system I think, where larger injectors will inject more.

This is a mechanical system.

[K7ERG]

If pump is able to supply the fuel to the larger nozzles will it not achieve more power without remap with slight increase in boost like 0.4 bar. I already have a chip in there which is working good on my setup. It was showing when on the rolling road it was running a bit lean and was needing fuel. But since then changed the fuel filter and it was clogged. Engine pulls well as it is.

If the pump needs altered can this not be altered via vagcom.

[prj]

The reason for fitting larger nozzles on a mechanical system is not to get more fuel.
It is to lower EGT's by being able to inject the same amount of fuel in a shorter duration.

But you need to recalibrate SOI completely, best done on a dyno. You will be putting a lot of stress on the engine if PCP occurs before TDC!

Forget VAG-COM, you need to remap the ECU.
And you will actually get LESS power if you don't recalibrate SOI.

P.S.
I have a tip. First think of what you want to achieve.
Then think what the limitations are.
Every change has to be done with an understanding of WHY you are doing it. Whether it is a mechanical change or a software change.

Also, fitting off the shelf "chips" when you have changed components around is a horrible idea. The ECU has to be remapped live according to the setup fitted.

[K7ERG]

One problem I have is no one likes mapping these engines or I can't find anyone. What is require to live map this ecu?