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Old 04-25-2020, 07:45 AM
v8volvo v8volvo is offline
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Join Date: Jun 2009
Location: Montana, USA
Vehicle: '86 745, '83 764
Posts: 1,618
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Based on what you have said, it sounds like the difference between the DW and DV is the same as what we would think of as the D24 and D24T, but expressed in VW engine codes rather than Volvo codes. In that case the only difference is likely the "pop" pressure calibration of the injectors -- 130 bar for the naturally aspirated D24/DW and 155 bar for the D24T/DV.

The higher pressure turbo spec injectors will run just fine in the non-turbo motors. The extra injection pressure is mainly needed in order to overcome the higher initial combustion chamber pressure in the cylinders of the turbo engines when the turbo is delivering full boost pressure. The higher injection pressure is not necessary in the non-turbo motors, but it certainly will not damage anything at all, and most likely will make no noticeable difference of any kind.

Buying the Bosch reconditioned injectors sounds like it was a good move. I have installed a few sets of those with good results. Bosch seems to do a reasonable job with quality control on them, at least that was the case as of my last encounter. I used to sometimes test batches of their recon injectors before installation using a cheap DIY-grade pop tester and most of the injectors out of Bosch boxes were right on, a few a little high or low, but they were probably at least as good as many fuel injection shops might produce. In theory a set redone by a really good independent fuel injection specialist might be best of all, if done very carefully by someone with a lot of experience and attention to detail and plenty of time available to spend on them, but as you point out, it could just as easily be hit or miss with that, if working with a shop you don't already know well and have confidence in.

The only small but noteworthy implication of running the higher pop pressure turbo spec injectors is that the actual in-cylinder "start of injection" (SOI) timing will be retarded slightly, versus where it would be with the same set of injectors at a lower pop pressure. This is because it will take maybe another degree (or perhaps a fraction of a degree, who knows) of rotation of the fuel injection pump, and the engine, in order for the pump plunger to build enough pressure to pop the injector open and begin injection. So, in theory, you might find with the new injectors that cold weather starting and power and fuel economy see a small negative effect. If you do find that, you could advance the injection pump timing very slightly. You have been through that process now so you know it's not too difficult once you have the hang of it!

However, you may also find there is no noticeable difference. This effect of injector opening pressure on in-cylinder timing is real, but it would take a lot of complex engineering calculations to know exactly how significant it is, and it may be that it's miniscule at the pressure difference you have here, or if measurable it may still be well within the acceptable range. If you are happy with the way the engine starts and runs, and with the mileage, then there's no reason to worry about it. Just raising it since you were wondering what *possible* effects might be seen from the turbo injectors in the non-turbo engine.

Nice photos of your van, and nice work getting it up to shape for use. Hope you will get some good use of it this summer now that you have it running well! Those are neat vehicles, too bad we didn't have them here. You might have already mentioned this somewhere, but do you know the history of the last timing belt and water pump change? If not that is something you may want to consider doing before putting on too many miles.
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86 745 D24T/ZF 345k lifted 2.5"
83 764 D24T/M46 155k
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