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Head differences


N9TE

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Hey,

I was dropping my turbo gas head off at my shop and they asked me if anyone was looking for a diesel head they had done for a well known independent Peugeot shop that stiffed them. These guys are very well known and do great work so the head is probably 100%.

Is there any difference between the XD2S and XD3T heads?

If so, how to distinguish between them?

Or are there more than 2 kinds of diesel heads.

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Pretty sure XD2S (2.3L) an XD3T (2.5L) were the same, but if it's an older diesel (XD90 2.1L) then I think they're different. That's just based on info absorbed off Peugeot-L though. Brian Holm or Rob Coutier would know for sure.

*Edit - I do know that the water pumps are different between the XD2S and the XD3T however...

Did they say how much they wanted? I might be interested if it's the XD3T head. That way I could build up the top end as unit with the egr-less manifolds so I can figure out an intercooler solution off the car. Leaning towards FMIC now with no mods to the intake - just need to ensure room is left for re-installing AC later on if so. Doing a top mount like the XD3TE is a lot of work to make it work with the non-intercooled intake I have.

Rabin

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The XD2S and XD3T heads are distinctly different. For one thing, the external casting looks different. The XD3T head came in two versions (both different from the XD2S). One of the XD3T iterations had exposed ribbing in the casting connecting the head bolt holes, in sort of an alternating V pattern.

Beyond that, the prechambers are different--the XD3T being larger.

The XD3T has larger exhaust valves

I believe the cooling jacket around the water pump cutout is different as well.

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I was under the impression the head gaskets were the same for the XD2S and XD3T (maybe they still are?) so guessed they were the same casting. Thanks very much for clarifying Joe!

Koll - I can try to get some close up pics of the XD3T head in my car for reference - see if it has that pattern Joe mentioned between the head bolts, or any other distinguishing features for visual confirmation.

Rabin

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I haven't seen a naked XD head in a while, and seeing the port side makes me think what it would take to give it 8 proper ports. Clearly the coolant runs close to the surface as the heater core outlet is there as well as a few small freeze plugs. But I wonder if some careful cutting and re-welding new material is possible. Surely the cost to do that as well as fab new exhaust and intake manifolds would be prohibitive, but still...

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  • 3 weeks later...

I was going over some crazy ideas in my head and came up with a weird proposal. I think the hot ticket for XD performance using stock parts would be an XD2S short block, XD3T cam, and XD3T head. Combine that with a VNT turbocharger with a high maximum boost pressure, a highly customized injection pump, and I think you could get a lot of power very reliably.

- XD3T cam has higher lift

- XD3T head has larger exhaust valves

- XD3T swirl chambers are larger which would mean a lower compression ratio on the XD2S--better for high boost

- XD2S has a short stroke which means lower pistons speeds and therefore less bore wear and better tolerance to high revs

- XD2S reciprocating assembly is lighter--crank has 4 counterweights unlike the 3T which has/needs 8. XD2S pistons are lighter as well.

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I was going over some crazy ideas in my head and came up with a weird proposal. I think the hot ticket for XD performance using stock parts would be an XD2S short block, XD3T cam, and XD3T head. Combine that with a VNT turbocharger with a high maximum boost pressure, a highly customized injection pump, and I think you could get a lot of power very reliably.

- XD3T cam has higher lift

- XD3T head has larger exhaust valves

- XD3T swirl chambers are larger which would mean a lower compression ratio on the XD2S--better for high boost

- XD2S has a short stroke which means lower pistons speeds and therefore less bore wear and better tolerance to high revs

- XD2S reciprocating assembly is lighter--crank has 4 counterweights unlike the 3T which has/needs 8. XD2S pistons are lighter as well.

For peak or ultimate power I think you're bang on with that combo. Many VW IDI enthusiasts picked the 1.6 TD engine to chase the really big power numbers as well - some of them pushing 6500 rpm and big boost!

I know of only a couple guys that have pushed the XD performance in Finland - but nothing like the VW guys have done. Same with MB diesels - there are some CRAZY builds out there, but again nobody really embraced Peugeot IDI modifications so I'm curious how they will do.

I suspect they have TONS of untapped potential and I'm VERY curious to see what gains my TD project realizes with the upgrades I've got planned.

Rabin

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