XUD7, XUD9 and upgrade conrods

[assembled]

Hello, fellow XUD tinkerers!

I found that XUD7 and XUD9 motors had at least 3 different conrod part numbers:

XUD9 1.9D 0603 77
XUD7TE 1.8TD 0603 45
XUD7 1.7D 0603 77
XUD9SD 0603 77
XUD9TE 0603 90

So, atmospheric and Suction diesel (low pressure turbodiesel) shared the same conrods, 1.8TD and 1.9TD had their own.
Does anyone know differences between these three?
Also, what is the benefit of using HDi conrods? In XUD7TE? XUD9TE? Quote below explains XUD9 having a weak sport. What about XUD7?

Something I found on another topic:

ALL XUD9 and DW10 conrods are "forged"... They just have a weakness seemingly around the little end area - if you look at the wrist of a XUD9 vs a HDi conrod, you'll see that it actually goes smaller underneath the pin on an XUD9, whereas a HDi is almost straight downwards, there's just a lot more meat there...

Shame they still snap lol... The cranks and rods are forged, the pistons, however are not...

[bashbarnard]

All the part numbers if you order them go to the last most recent number. Superseded. If you order a xud9 rod youll get one for a 16v 2.0hdi. As theyre just a newer stronger version.
Generally speaking the newer the rod the stronger the rod.


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[assembled]

Thanks for your reply. Your point regarding part number is very interesting. I have never heard about this before. Did a search for 0603 in Citroen catalogue. They use these digits for conrods ranging from 1.1l XY "suitcase" engine to DW12 2.2l and V6 3l ES9 engine. They all at least have different big end journal size and the last one is kit of 6, instead of kit of 4. What am I misunderstanding? It seems that Citroen (and I guess PSA in general) use 0603 xx for all or at least a lot of their conrods.

[welshpug]

you need to use the full part number.

[Ruan]

You'll find that the PSA part number is totally useless, as from memory they now specify the same part number as DW10BTED4 conrods all the way back to the XUD9TE and tell you to use different bearings (AFAIK DW10TDs were the change over point for the later sputter bearings with tabs reversed). As far as PSA is concerned, they're not a different part, rather an updated design of the same part since the conrods all fit, you just have to use a different big end bearing type past a certain RPO. They updated the design as they were finding that failures were happening, probably down to changes in material quality and the original FEA calculations weren't holding up, so they beefed them up where they deemed appropriate. There was no need to change the part number since it's technically all the same part - why would they want older, weaker conrods to be purchased.

I've noticed even between early '99 DW10TDs from 306s and later '05 DW10TDs out of 206s, even with identical part numbers, the conrods are much bigger in the later '05 engines.