1hd-t 1hd-ft

[83bj60]

I prefer the HZ one the higher compression and I all ready have it.

Hmmm... You can certainly improve the compression quite a bit on a 1HD simply by selecting a thinner head gasket or possibly shaving the head a bit (don't know if it's possible with this engine though).

The thing that I would worry about with this project is the precups. I remember the precups in the old 3Bs would frequently crack under high engine loads/temps and could fall into the cylinders. Now I don't know in fact how many suffered this fate, but that would really bother me doing this to an indirectlty injected diesel.

 

[BlackSmoker]

How do the precups fall into the cylinder? Are they not on the deck surface?

 

[83bj60]

Well the precup itself doesn't fall in, but it cracks then parts of it can fall into the cylinder and score it very badly.

There was a post a long time ago on the DTLC about this.

 

[Tapage]

I'm still thinking about smaller AR in the turbine side .. the back pressure can raise easy your EGT and head temps .. not to mention at the top end rev of the engine .. when you pass over 3500 rpm ..

 

[Dougal]

I'm still thinking about smaller AR in the turbine side .. the back pressure can raise easy your EGT and head temps .. not to mention at the top end rev of the engine .. when you pass over 3500 rpm ..

If you run more boost and a smaller A/R turbine then the cooling from the extra airflow reduces the exhaust temps.

Run a backpressure gauge if you're concerned. I have and the results were very interesting.

*edit*
Full T25 Specs.

TH 1456J
14411-96f11 - Nissan Part #
455767-0003 - Garrett Part #
51.3mm/40mm cold, 60 trim 0.48 A/R cold
53mm/42mm hot, 63 trim, 0.49 A/R hot
hot turbine 22mm long

Effective area hot side = 323mm^2
= 0.5 in^2
*/edit*

 

[Tapage]

Those are pretty close A/R numbers of my K26.8 turbo ..

Actually in my aplication I'm pretty concern about the backpressure and don't having right now any EGT issue .. but I swap the exhaust manufold gasket with the 12H-T version ( metal ones ) coz the factory 2H exhaust gasket ( asbestos ) just fail after some km ..

 

[Dougal]

Those are pretty close A/R numbers of my K26.8 turbo ..

Actually in my aplication I'm pretty concern about the backpressure and don't having right now any EGT issue .. but I swap the exhaust manufold gasket with the 12H-T version ( metal ones ) coz the factory 2H exhaust gasket ( asbestos ) just fail after some km ..

Is your K26 based on a T3 with the 60mm exhaust wheel? This T25 with 0.48 A/R spools at a similar rpm to another T3 copy (my IHI RHB6) with a 60mm exhaust wheel and 0.42 A/R.

With a bigger wheel, you need a smaller A/R to get the same gas speed at the tips.

It's the expansion and contraction that kills the fibrous gaskets. My engine has stainless gaskets, one is original (21 years).

 

[Tapage]

Is your K26 based on a T3 with the 60mm exhaust wheel?

I'm not sure if it's based or not .. but it's pretty close ( the numbers )

This T25 with 0.48 A/R spools at a similar rpm to another T3 copy (my IHI RHB6) with a 60mm exhaust wheel and 0.42 A/R.

It's the expansion and contraction that kills the fibrous gaskets. My engine has stainless gaskets, one is original (21 years).

I change those gaskets from 6 month ago .. or something like .. not problems reported yet .. this same turbo K26.6 and K26.8 are the turbo that use the Porsche 944 Turbo Intercooled ( 2.5 engine ) that make 250 HP ..

 

[mikeblack]

Scrap Emission controls

Hi HDJ105,
Could you explain exactly what has to be done to mount a 1HD-ft in my HZJ105?
Should I change the con rod bearings?
Thanks