Outer Limits 4x4 Board

Hi Bob,
The custom kit would undoubtetdly give better performance as long as you aren't too concerned about price! I would suggest that the custom kit would be quite a bit more expensive than the off-the-shelf kits.

The major difference between a kit and a custom job would be the manifold - typically these are cast iron, and are hardly tuned to perfection - they are just aimed at getting the exhuast gases into the turbine housing by whatever means possible. Tuned, matched length exhaust headers in a custom mandrel manifold would give you that slightly better performance. As would a mandrel bent exhaust matched to the turbine housing. The turbine housing itself should be sized to match the engine also - these factors will improve the spool up time of the turbine by increasing flow and reducing back pressure.

Once again, it really comes down to how much you want to spend and what sort of power gains you are looking for - regardless of boost, spool up times etc, they are just an afterthought.

For example, there are a few companies around who use standard Garrett turbochargers (one that springs to mind is developed around the T-27 core) with custom ordered housings / wheels - if you are happy with the performance gains of these relatively standard units, then it may be worth asking if they could special-order a GT27/28R frame with their housings and wheels, from there you could have the custom manifolds and pipework bent up to suit.

This involves:
- making / sourcing a custom exhaust manifold
- making / sourcing a custom aircleaner assembly (pressurizable / sealed)
- the compressor side suction and discharge pipes
- turbine dump housing and pipe
- pressurised oil & water lines
- adapters to suit engine block and turbocharger for oil & water
- sump modification for oil return
and optionally:
- intercooler installation
- oil cooler installation

If you are after more than the standard power gains (around 130FWHP peak +/-), then additional pump work and cooling become necessary, including fitment of an intercooler, and possibly oil cooler also. Achieving the goal of faster spool up and wider operating ranges also become slightly more challenging as the compressor map becomes tighter when selecting a t/c.

It is not too much of a problem to work out the best match turbo to your particular application - the key is *where* you want the compressors most efficient operating range to be (in terms of engine RPM / load)

Considering that the TD42's peak torque output is at 2000-2200rpm, I would suggest that this would be where you would want your efficiency to be. In calculating the compressor size, you would then need to consider where the effective stall limit is, and ensure this is below your required boost rpm start.

claim very high figures, t his might not be a good thing in the long run.....

In terms of longevity, I am aware of one particular TD42 running 24psi of boost, with LPG injection, dynoed at around 220RWKW, maximum pump advance, a LOT of fuel, no intercooler, no oil cooler.

It has done around 220,000km with this setup (from new) and is just starting to show signs of wear, but still running well.

But ... agreed ... any power increase resulting from an increasing the Mean Effective Cylinder Pressure is bound to have consequences in terms of engine longevity, and the driveline longevity will be affected also.

Hey spannercrab, the man wants a turbo, NOT a custom race car.....
Trust me BOB when I say that the race car option is asking for trouble.
Call your local 4x4 joint and ask about a DTS turbo kit, you can install this type of kit in your own garage with no hastles.
The kit comes with everything, from the turbo & manifold, all oil lines & water hoses/fittings and it comes with instructions, And the kit is made in australia by aussies.
The boost facter is up to you, all you need to do is TWEEK that magic screw that turns the fuel up, more fuel means more boost.
For figures sake, you should get around 12psi by the time 2200rpm comes.
If you need more info Try PGS 4WD Accessories in victoria 03 5975 2642

Plenty of good turbo kits around embryo - I'm just pointing out that it's all horses for courses and largely depends on the spare cash you have lying around ... one can make an awesome setup and go the whole hog, if money and motivation allows - or can just throw a standard kit on.

Nobody can answer the question "which turbo" or "which kit" - only the driver or owner of the vehicle depending on the resultant behaviour of the vehicle they are looking for.

If buying to a budget, then a kit is going to be the best bet (or possibly a 2n'd hand custom job) - if affordable, then a custom matched kit / manifold etc, if money is no object, then the sky is the limit!

I can categorically say that a BB turbo will perform better than a bush type, and a mandrel bent & matched header will perform better than a cast iron job, and an intercooled setup will be better than a non-intercooled setup - but does the price outweigh the performance gains? That depends on the customer ...

Any kit salesman worth their salt will tell you that their kit is particularly suited to an application or budget - if someone tries to tell you that theirs is the "perfect" kit that provides full boost from idle through 4500rpm, then they are leading you up the garden path.