Hey Gouldy,
Personally speaking i think the X type oil burner needs a v6 d unit but the s type 2.7 dont fit the x type but i would probley go the for the rechipping of the car you have, Jag have pretty much done the 2.2 engine alot of upgrading anyway and the question is down to bucks per gain, i think the upgrage you are thinking of doing warrents a closer look ( gain per buck), but chip it first and see how you like that.
Just my opinion but then my wife has a good tug at my purse strings

 

is this jag a diesel turbo?
ive never messed with the diesels before but by adding a boost controller you can get a little more power, and adding a slightly bigger turbo helps too. those are usually just bolt on parts...a biger intercooler wont give you more power unless you are flying down the track, they need a lot of airflow and then you have to get into cutting holes in the bumper.

 

Several advantages from bigger intercoolers; less pressure drop, more flow, and of course bigger surface area to improve heat dissipation. The reduction in pressure drop also improves the cooling effect (due to less friction. As friction generates heat, which reduces the efficiency of the cooler).

 

Bigger intercoolers may be fine for petrol cars but can sap power on diesels due to heat soak as they are on boost more of the time from lower revs and throughout more of the available rev range
Read on......

"Diesels


Turbo diesel road cars are on boost far more than an equivalent petrol engine car. In fact, because the off-boost airflow of a diesel doesn’t vary with load, there’s potentially enough exhaust flow to keep a turbo boosting even when the driver has their foot off the accelerator on the over-run! And a diesel turbo that runs 2 or 3 psi boost in normal highway cruise is common.
There are two reasons for this differing behaviour – a diesel doesn’t use a throttle and so the airflow generated by the turbo is not artificially reduced; and because diesels are intrinsically less powerful for their capacity than petrol engines, to make up for that power deficit, the turbo is usually sized to work harder more of the time.
In addition to being on boost a far higher proportion of driving time, diesels generally use higher boost figures than petrol engine cars. And irrespective of whether the car is under load or not, the air temperature exiting the turbo depends on how much it has been compressed, that is, its boost pressure. Higher equals hotter.
This combination of factors – higher boost used more often – results in different intercooler demands. In short, a diesel intercooler has to work far more at ‘real time’ removal of heat rather than acting as a heatsink.

So what implications does this have?

• Heat Soak

In a diesel, heat soak becomes a huge problem. Take an intercooler that’s mounted under the bonnet, as many factory diesel intercoolers are. The car is driven and then parked. The underbonnet environment then gets hot – much hotter than when the car was running and there was airflow through the engine bay, and (separately) through the intercooler. In fact, on a hot day, it’s not hard for a heat-soaked intercooler to be at 70 degrees C.

The car is started and driven off. Because it’s a diesel, straightaway it’s likely to be on boost – and plenty of it. So air is exiting the turbo at (say) 100 degrees C and then passing through an intercooler that’s at (say) 70 degrees C. As can be seen by the relativity of these figures, the intercooler will still drop the temp of the induction air, but only by a small amount. The result is hot induction air entering the engine, resulting in poorer power, fuel economy and throttle response.

• Heat Sinking Capability and Underbonnet Intercoolers

Now here’s where it starts getting really interesting. In most cars, an intercooler with a high heat sink capability is a good thing – it allows the intercooler to knock off the temp spikes caused by short-term high boost events. But if the heat-soaked intercooler has a high heat-sink capability, it will stay hot for longer.
So for example, an underbonnet water/air design, which has a high thermal mass (water has a very high ability to absorb heat, or to put this another way, stay hot once it is hot!) will have poor effectiveness as an intercooler for quite some time after a hot car has been re-started.

That’s just the same as for a water/air intercooler under the bonnet of a petrol turbo car. Measured intake air temps on a factory water/air intercooled Subaru Liberty RS shows that intake air temps remain high for some time after a hot car has been restarted. But in the petrol turbo car, boost is used less and is lower in level, so allowing time for the water/air heatsink to drop in temp after driving off.
Real Time Heat Removal

Because boost is used far more often in a diesel, the intercooler has to be designed to be effective at real-time heat transfer to the atmosphere, rather than storing the big spikes for later, slower dissipation. This means the intercooler efficiency must be higher – much higher than in a petrol turbo car. And because a turbo diesel can generate high boost pressures at low road speeds, forced air cooling (eg by fans) is needed far more often than it is in a petrol engine car.

• Pressure Drop

At a given boost pressure, a diesel has equal airflow at one-tenth full load, half full load, and full load. In other words, diesel airflows are on average considerably higher than are experienced in a petrol engine car of the same capacity. This has major implications for intercooler sizing. If the intercooler causes a pressure drop (ie has a flow restriction), not only will top-end power suffer but, through the increased pumping losses, cruise fuel economy may also be affected.

Water and Diesels

Because of their small cylinder clearance volumes (ie high compression ratios), diesels are very susceptible to engine damage if they ingest water. This has implications for water/air intercooler designs – any internal water leak could quickly prove catastrophic.
Sunmmary



So where does all this lead us for diesels?

• An underbonnet intercooler should not have a high heat-sink capability. That is, its thermal mass should be low. This has significance for water/air systems that place a large volume of water (eg 1 or 2 litres) in the heat exchanger. It also implies that air/air intercoolers should be physically light.

• Water/air systems can benefit from a large volume of stored water, if that water is stored in location that does not heat soak when the car is stopped.

• In addition to having low thermal mass, underbonnet intercoolers should have forced air fan cooling to enable very quick temperature reduction after restarting a hot car. This is also advantageous in low speed / high load conditions.

• Intercoolers should be sized and designed to allow large amounts of heat to be removed real-time. For example, air/air cores (and for water/air system, the water radiator) should be located so that lots of outside airflow passes through them. In other words, the old plonking-of-a-big-core-in-front-of-the-radiator without paying any attention to actual flows (ie difference in ambient pressures before/after the core) may not be very successful. (Many high performance petrol engine cars get away with this approach because a 10 second burst of boost might have 120 seconds to get rid of the absorbed heat...)

• Intercoolers should have a very high internal airflow capacity. For example, for the same intercooler size, an air/air intercooler with a small number of long tubes will have a greater flow restriction than an intercooler with a large number of shorter tubes.

Conclusion

It’s easy to look just at the power figure of a turbo diesel and assume that little intercooling capacity is needed. In fact, view the intercoolers of some factory turbo diesels and you could certainly think that! However, because more boost is used much more often, intercooling a diesel turbo requires much better design than an equivalently sized petrol turbo engine."