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What nozzle type should I get?

Before that can be answered, please take some time to understand some facts. The OM615-617 and OM60X are in-direct injection engines. The fuel is sent by the injection pump to the injectors, which then spray it into a pre-combustion chamber. Check out this illustration from dieselhub.com

Nozzle-options-Google-Docs

This is different from direct injection where the fuel is sprayed directly into the cylinder. 

Because these are IDI engines, the nozzle type does not influence as much as it does in a direct injection engine, where a certain nozzle will determine flow. In these engines the injection pump does that, not the nozzle. Simply put, the nozzle spec does not matter a whole lot.

Because these are IDI engines, the nozzle type does not influence as much as it does in a direct injection engine, where a certain nozzle will determine flow. In these engines the injection pump does that, not the nozzle. Simply put, the nozzle spec does not matter a whole lot.

Here are the stock nozzles for each engine:

OM615-617: DN O SD 261 

OM602/603: DN O SD 265 

OM605/606: DN O SD 310

Note: Mercedes originally used 240 on the 615-617 but replaced it with 261. Likewise, the 602-603 started with 265, but Mercedes switched to 314 later. If you have a Bosch shop rebuild 602/603 injectors now, they’ll use 314. Speaking of 314, check this out:

image

Notice the needle diameter of the 314 as it is about 1mm wider. Does this mean it will flow more? Technically no, because the injection pump determines fuel. But it does mean that it can flow more fuel, more easily. I put one 265 and one 314 nozzle injector on the pop tester. I popped each one 150 times. They both delivered EXACTLY the same amount of fuel. With that being said, if you are going for the most power/fuel possible on your super-turbo build, you can’t go wrong with the 314.

I’ve gotten feedback that the 265 nozzle seems more “eager, snappy and aggressive”.

Dieselmeken uses stock 310 nozzles on their OM606 super-turbo builds. 

This is why it's hard to give recommendations.

What nozzle brand?

If it were up to us, we would only use Bosch. We have used thousands of Bosch nozzles. They have been great and our customers have been happy.

Unfortunately there are a few comments out there that Bosch nozzles are made in China now, so they’re no good. First off, Bosch nozzles are not made in China, they’re made in India. And even if they were, do you know where most Holset turbos are made? iPhones? In China. Bosch continues to make quality products, regardless of where they are made.  A company's quality control matters way more than where it makes its products.

Regardless, we’ve always offered at least two brands for our injectors. Monark used to be revered as the best, but they merged with another company in recent years and their quality has gone down drastically. Bosio is pretty much extinct. 

We used to really like Firad out of Italy. After a couple hundred Firad nozzles, we got an order where the majority of the nozzles were faulty. We contacted Firad. They informed us they were aware of the issue and for us to send them back to have them repaired. The majority of the nozzles in our next order were also flawed. We documented the fault and provided video evidence. We sent them back and were refunded, but Firad claims they tested our nozzles and couldn't find any faults. No thanks. 

We then switched to DTP (Diesel Truck Parts out of Germany). Same story. First couple orders are great. After a while we are sent faulty nozzles. We contact them and are told to send them back. We did so, yet they deny any faults. 

We are now working with Seven Diesel out of Italy. They have been really good. We are hoping to not repeat this story.

All this time, we haven’t had any issues with Bosch, which is why we would prefer to just use Bosch. Either way, don’t be afraid of purchasing any of our injectors with any of the above mentioned brands. We only use a nozzle if it’s passed our tests and we are confident in it. We warrant and guarantee our injectors regardless.

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