Thread: diesel into P38

As far as I am aware my engine is at stock power levels, so 135 bhp (99kw) and 375N/m @ 1400rpm, I am under the impression that 175bhp is fairly easy and safe, also seen some 200 bhp claims but I would rather believe the lower figures, doesn't seem excessive compared with a 300tdi that had some attention.

I actually have a bigger intercooler in the shed, just waiting for the time to do the job.

Originally Posted by finallyrangie

As far as I am aware my engine is at stock power levels, so 135 bhp (99kw) and 375N/m @ 1400rpm, I am under the impression that 175bhp is fairly easy and safe, also seen some 200 bhp claims but I would rather believe the lower figures, doesn't seem excessive compared with a 300tdi that had some attention.

I actually have a bigger intercooler in the shed, just waiting for the time to do the job.

To hit 200hp in a 300tdi you'll need to pull 355Nm at 4000rpm. That will require almost 25psi boost at 21lb/min. That's beyond the map of a stock 300tdi turbo. It would need the 56mm compressor from the 2.8 to acheive that.

Your 2.8 because it's longer stroke hits and leaves peak power earlier. Stock it's 3,800rpm and it delivers 250Nm at that rpm. Power is torque x rpm.
To deliver 200hp at 3,800 rpm you need to deliver 372Nm there. This would need about 25psi boost and 24lb/min airflow.

And then we get to really test the reliability.

Lara in Belgium is running 38psi into his TD5. That's a true 180kw at 4000rpm.

Originally Posted by Dougal

To hit 200hp in a 300tdi you'll need to pull 355Nm at 4000rpm. That will require almost 25psi boost at 21lb/min. That's beyond the map of a stock 300tdi turbo. It would need the 56mm compressor from the 2.8 to acheive that.

Your 2.8 because it's longer stroke hits and leaves peak power earlier. Stock it's 3,800rpm and it delivers 250Nm at that rpm. Power is torque x rpm.
To deliver 200hp at 3,800 rpm you need to deliver 372Nm there. This would need about 25psi boost and 24lb/min airflow.

And then we get to really test the reliability.

Lara in Belgium is running 38psi into his TD5. That's a true 180kw at 4000rpm.

That's why I thought 200 bhp was whistling in the wind, not quite as technically as you, it just seemed an unreasonably claim, 175 I am more willing to accept.

When I do the disco I'm only planning a small tweak, I am more worried about the gearbox than the engine in that, if the P38a project gets a tgv the gearbox can take more, and being that bit bigger and heavier will need a bit more shove, I understand it will never keep up with the 4 litre standard engine but it should be enough that it's not a slug

With regard to 'turning up the taps', I think it's fair to say that if you go far enough you can break anything, it's about being sensible and realistic, if you need that much power the engine blows up, you need a bigger one!

Originally Posted by Dougal

You've misread that entirely.

The concerns I have about the 2.8 are structural for those intending to turn the screws. I've only raised the ZD30 for comparison.

Look at main bearing size.
300tdi is 63.5mm 300TDI Torque Settings and Engine Spec - Land Rover Zone
2.8 is likely the same.
The TD5 has similar bearing diameter, but because it's 5 smaller cylinders, the stress and crank deflection is less for the same torque.
Zd30 is 70mm.
Toyota 3B is 70mm, albeit with a higher compression ratio the guy I know running 20psi boost (approx 400Nm) has just broken his crank.



Your 2.8 is at stock power levels?

A smaller journal diameter means less parasitic drag so possibly less wear too, (yes, yes, it all depends on journal finish, bearings, loads, oil flows/volumes, etc) and journal diameter is but one determinant of overall crank strength.
The 2.8 isn't a truck engine, it's a light duty diesel but a successful one that copped plenty of abuse in South America in a ute application and appears to have a reputation for reliability, unlike the other Tdi based engine used there in the Merc Sprinter, the 2.5l Maxion.
Apparently it was a pile of faeces.

A stock 2.8 is more powerful than a stock TD5 too.

Yes, the TD5 has more potential and the basic block design appears better (head bolts run through to the crankcase rather than just into the deck, etc.) but there are plenty of Tdi's running 18-20psi with the fuel turned up to the max yet only late '98 Tdi's do cranks (faulty bearings) and I'm pretty sure the HS2.8TGV runs something like 22+psi stock.

Tgv runs 1.2 bar (17.5 psi ish) as standard but they have a laminated stainless head gasket standard as well and are reportedly good for 25 psi with no problems.

Hi there

I do not visit here often and just found this thread.
I fitted a Nissan QD32ETi engine in my 1998 P38 and am very happy with the results.
Still some minor issues with the 4HP-24 change points to be sorted. Minor mod to the left engine mount on the chassis, and that was it. It took me 2 years of measuring engines and comparing with the RR suspension to find a suitably powerful engine that will just "slip" in. City cycle fuel consumption is now less than 50% than with the 4.6. It's a pleasure to drive not worrying about fuel consumption any more.

JP

How does the QD handle towing large loads or steep hills?

Having only 330Nm and 110kW would certainly make a noticeable difference to drive ability?

Cheers
Keithy

Originally Posted by JPC

Hi there

I do not visit here often and just found this thread.
I fitted a Nissan QD32ETi engine in my 1998 P38 and am very happy with the results.
Still some minor issues with the 4HP-24 change points to be sorted. Minor mod to the left engine mount on the chassis, and that was it. It took me 2 years of measuring engines and comparing with the RR suspension to find a suitably powerful engine that will just "slip" in. City cycle fuel consumption is now less than 50% than with the 4.6. It's a pleasure to drive not worrying about fuel consumption any more.

JP

ETi was electronic injection. Have you kept that or converted it to a mechanical injector pump?