Opinion of what she is worth

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Peter Connan
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Re: Opinion of what she is worth

Post by Peter Connan » 13 Sep 2017 06:02

I think you are not comparing apples with apples. You are comparing high-pressure turbo-charging with low-pressure supercharging. Also, I think some of the ifo you quote is a little out of date.

The need (or not) to change engine internals is purely a factor of the inlet pressure (actually of the BMEP, but in the same engine, that is directly related to the inlet pressure and temperature), and has nothing to do with how that pressure is generated.

Thus, if you limit the boost to the same 0.3 bar that the supercharger generates, then the standard engine internals are fine.

I agree that a turbo probably requires more control, but that is simply because it can generate far higher pressures than the supercharger. Choosing a smaller turbo will reduce those issues, and spool up faster, thus reducing the lag you are concerned about.

Furthemore, there have for many years been systems designed to protect turbos against the removal of oil pressure while the turbo is still spinning.

I firmly believe it is possible to do everything you want to achieve with a turbo, and more to boot, and I am also sure that virtually every single OEM that was using superchargers before have moved to turbo now. But, there probably isn't a local fully-developed turbo conversion which carries a full engine replacement type warranty.
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Peter Connan
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Re: Opinion of what she is worth

Post by Peter Connan » 13 Sep 2017 10:58

Sorry, i do want to add one more comment:

It seems to me that what you are looking for is almost exactly what Michael's TDI's deliver.

Perhaps you should just take a spin in Michael's car before you spend any cash...
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Mystical_Beast
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Re: Opinion of what she is worth

Post by Mystical_Beast » 13 Sep 2017 13:40

Peter its great having your technical knowledge shared here on the forum.
It forces me to think more clearly about the implications, options and gives a better understanding of the technical workings of the two systems
And so I understand that 0.3 bar forced induction is whatever it is regardless of the means used creating it.
The argument however is which will be deemed more reliable and overall better performance range.

Patrol Turbo Conversion are awesome, I just don’t know who could do it successfully and back it up with warranty, for this reason I am inclined to go Super Charged.

For those that love the Turbo route I leave you this

https://www.youtube.com/watch?v=exAW8kr646E

https://www.youtube.com/watch?v=dGFh3ucxyJI

https://www.youtube.com/watch?v=ZwylKztd7jE

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Peter Connan
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Full Name: Peter Connan
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Re: Opinion of what she is worth

Post by Peter Connan » 13 Sep 2017 17:52

Julian, this post is not intended to influence your decision, as I think your mind is made up, and I suspect you are correct in your main concern that there is nobody locally who has a fully-developed turbo solution which comes with the type of warranty you are looking for. This is by way of being a bit of a ramble.

Once again, I would not do either of these modifications to my own Patrol. I still believe that, if you want a race car, buy a race car, and secondly, in an overland vehicle, reliability is the primary concern. And as far as I am concerned, the moment you put a different computer in it than what it came out the factory with, that's out the window.
But anyway...

I believe a supercharger plays to the strengths of a diesel engine. Low-down torque, not top-end power. Looking at the torque curves posted earlier, this is true of this particular supercharger conversion. I believe (but have no proof to back it up) that this supercharger's capacity is not high enough to create the same pressures at higher RPM that it does in the mid range. And using a bigger one will lose you a lot of the bottom-end advantages.

I therefore believe that you can make substantially more power AT THE SAME MAXIMUM BOOST with a well-thought-out turbo conversion.
I further believe that, by using modern technology, you could do a turbo conversion that will blow that supercharger out of the water right through the rev range. And I suspect it could still be done cheaper than the supercharger, but it will cost a lot to develop. Since most of the cost in a turbo conversion is not in the turbo itself but in the plumbing and so forth, twin turbos (small and large) will not add that much to the cost of such a conversion.

And finally, there are a variety of anti-lag systems available nowadays, that could literally create boost at zero RPM. Difficult to control, I grant you, but there it is. I just think the turbocharger has so much more potential...
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