Just so you know, as soon as you bring product from across the puddle, you get 20% VAT. You need mention that.
As for how these nozzles are produced, we have over 10 years in our "ma and pa" shop, not only calibrating, but we have developed methods that are unique. We have taken several supposedly 'set' injectors and turned them from fuel-sucking pigs to great performance/ economy nozzles. Paul, the OP and I have a history and know each other. Trust also counts for a lot.
As for the 'do it yourselfer', we have seen over the years how it's done. Several have taken forays into trying to set them up with varying results. One particular vendor's nozzles, we watched for a full year's events and once a month, they melted the pistons out of an engine... no joke. Eric Antos was the first in a string of them. those are supposedly 'calibrated'. The vendor always says 'it's the installers/ owner's fault...' whomever, but not him.
Those who I have set their nozzles know the difference in getting 28 mpg, turned into 44 mpg, by properly setting injectors. And here's the real trick...that was done by using the existing injectors... Some will not even look at injectors that aren't 'there own', but replace them. In a Mr. Verhey's case, although he requested they be replaced, we told him we would check them and it turned out, we repaired them... yes, 'repaired' the nozzles.
Now, as for volume, we are not capable of producing a large volume of product, and that is not my purpose. I'd rather get them right, one set at a time.
As for the Bosch shops, last I knew, the rules were to test the first stage. If the injector failed, replace the injector. Our local Bosch dealer refers VW's to me. They would rather work on a Caterpillar or Freightliner, etc., where they get the big bucks.
The rest of the story is, setting pressures is not job finished. We have seen all about that. We have developed a method of testing and setting the VOLUME of both stages. It's a little more work, but the results speak for themselves. If you don't get the flow volume correct, your injectors will vary, one from another. Excess fuel means excess heat. If one injector blows too much fuel, and we have seen a lot of that... the EGT may say it's a little warm, but the one cylinder may be screaming 'Melt Down'.
'You get what you pay for.' It's still mostly true. Sometimes, you pay too much and still don't get the value, but get hammered.
One last thing... this has to do with upgrading PD injectors. We are not going to invest the $75,000 in equipment to get them done correctly. We have enough to do. But even more than that, we really don't like upgrading when it's not necessary. For example, when we tune a PD engine, we do not change the injectors, 'just because' you want another 30-40 hp. We see what the injectors will do. We have PLENTY of engines increased from 100 to 150 hp (or more) with the same injectors that came in the vehicle. The rule is simple. Try what you got before you waste $1000 for nozzles that belch black smoke and are too big.
The PD injectors' duty cycle for the second stage is calibrated in milliseconds that the solenoid operates. Increasing the duration is the tuners map to figure out. There is usually enough volume in the injector to fuel quite an additional volume. So, as long as the driver chips in the ECU are not overworked, the fueling can be raised in the stock injectors, usually to the point the customer is happy and they kept a $grand$ in their pocket. If the chipset is driven to it's safe limit and there is not enough fuel, that is reason for moving up in injector size. But without trying the originals out, you will not know. Bluntly, what have you got to lose? Answer: $1000. There is a recent customer; a Mr. d'Allesio whom we told that. He wished he'd talked to us before he made the purchase. But there is no going back. His previous nozzles are in the trash. Hopefully, we can get his Malone tuner to pull the excess smoke out.
