Author Topic: Why the same injector for both turbo and N/A  (Read 3916 times)

October 15, 2005, 10:02:22 am

Peter

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Why the same injector for both turbo and N/A
« on: October 15, 2005, 10:02:22 am »
why has bosch and vw gone to useing the same injector for both the turbo and N/A motors for my 86 jetta turbo...the older turbo injectors with 155 bar also have a different nozzle then the ones you buy at 135 bar...is it possible that changing the nozzle time opening you can also drop the bar rating and create a more universal type of injector that fits both types of diesels

Reply #1October 15, 2005, 10:05:59 am

vwmike

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Why the same injector for both turbo and N/A
« Reply #1 on: October 15, 2005, 10:05:59 am »
I don't think they've changed the opening pressure, merely superceeded the original nozzles used with one comparable nozzle.

Reply #2October 16, 2005, 11:04:43 am

Peter

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Why the same injector for both turbo and N/A
« Reply #2 on: October 16, 2005, 11:04:43 am »
I guess I am seeking to know what changes have been made or lost if that is the case by going to an injector made for both turbo/NA, when at one time they specifically had an injector for each application....
Quote from: "vwmike"
I don't think they've changed the opening pressure, merely superceeded the original nozzles used with one comparable nozzle.

Reply #3October 16, 2005, 11:52:45 am

Master ACiD

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Why the same injector for both turbo and N/A
« Reply #3 on: October 16, 2005, 11:52:45 am »
turbo and n/a nozzles and injectors should be the same, atleast thats what my bosch certified injector rebuild guy says. he told me the only difference on the american 1.6 n/a and td were the breaking pressure. the nozzles and holders  are all identical.

Reply #4October 17, 2005, 10:55:22 am

Peter

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Why the same injector for both turbo and N/A
« Reply #4 on: October 17, 2005, 10:55:22 am »
I understand the nozzles and holders are the same and also the breaking pressure is different, at least so it was in the past...which brings me to my original question,..Why does bosch or vw have the same injector and braking pressure for both the N/A,Turbo 86 jetta....
Quote from: "Master ACiD"
turbo and n/a nozzles and injectors should be the same, atleast thats what my bosch certified injector rebuild guy says. he told me the only difference on the american 1.6 n/a and td were the breaking pressure. the nozzles and holders  are all identical.

Reply #5October 17, 2005, 11:44:41 am

fspGTD

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Why the same injector for both turbo and N/A
« Reply #5 on: October 17, 2005, 11:44:41 am »
In 86, along with the introduction of the hydraulic lifter motor, VW changed the part number of the injector nozzle on their 1.6l diesels.  The newer 1.6 nozzle has 13% less lift, so is likely to be more restrictive than the older nozzle for solid lifter motors.  My best guess as to why they switched to a more restrictive injector is that it perhaps spreads the burn time until later in the stroke, thus lowering peak combustion chamber temperatures and NOX emissions.

As others have said, although the NA and turbo diesels use the same nozzle part number (comparing solid lifter NA versus solid lifter TD, or hydraulic lifter NA versus hydraulic lifter TD), the breaking pressures of the same nozzle are set up differently depending on whether it is going into an NA motor or a TD motor.
Jake Russell
'81 VW Rabbit GTD Autocrosser 1.6lTD, SCCA FSP Class
Dieselicious Turbocharger Upgrade/Rebuild Kits

Reply #6October 17, 2005, 12:37:01 pm

vwmike

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Why the same injector for both turbo and N/A
« Reply #6 on: October 17, 2005, 12:37:01 pm »
Increasing the pop pressure is going to reduce fueling a bit across the board....so if power is a concern I would doubt this would be the way you want to go. For economy though, I'm sure it will work well.

Reply #7October 17, 2005, 04:10:05 pm

vwmike

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Why the same injector for both turbo and N/A
« Reply #7 on: October 17, 2005, 04:10:05 pm »
I'm not about to go and reduce the pop-pressure on my car. I think there is an acceptable working range although in my experience the higher pop pressures seem to result in a tighter cone shape out of the nozzle. This may or may not be a good thing. VW probably increased the pop pressure to help improve atomization under the higher cylinder pressure associated with the turbo engine. Like anything else, this is probably more for emissions than anything.