hows 290rwkw for under 2 grand sound

Hi Guys,

I have done alot of work with turbos, and have owned my current Subaru liberty RS turbo since early 96. As I work in engine management, I have worked on many cars, and tuned many cars.

There is alot of crap in this industry, and also alot of good parts.

High intake temps in themselves do no damage to an engine. I am aware of many cars that have run high boost levels with no intercooler. Also be aware that turbo outlet temps are relative to the turbo being used (compressor map), and the boost level. Because the T makes its power from using a fairly good turbo, with high capacity and relatively low boost, turbo outlet temps are going to be much lower than cars with smaller capacities running at higher boosts. However, the flow is higher, so there will be higher quantities of air that is not as hot to cool. For a street car or drag car, you can get away with smaller intercoolers, as you are never on it enough to get the intercooler very hot. In a race application or any with length periods of high throttle openings, the story is different.

Back to my initial topic. An engine will happily take 100C intake temps, but the thing that will cause engine damage is:

* Detonation

* Too much power for the internals

It is possible to tune a car with good head design and good fuel (98) to take 100C intake temps with no detonation, but it is obviously easier to do it with lower intake temps. If an engine is not detonating, than the intake temp has little effect on engine reliability, and has more effect on engine power. For a start, you have to tune around detonation which generally means pulling out power. Also, the air mass is lower, so you cannot produce as much power from lower air mass flow.

Unfortunately one thing that is often overlooked is that the cooler the intake air (at a constant boost level), the higher the peak combustion pressure (there is more air and conmustion products in the same space), the higher the peak combustion temperature (more pressure = more temperature), and the more power (heat is energy afterall). So making your intake temps low may prevent pinging, but at the end of the day, the forces on the engine internals (rods, pistons etc.) for an engine that is not detonating are related to the power output, and not the higher temps.

Anyway, the point I am trying to make is that good intercoolers, exhaust etc. have obvious value, and will certainly produce more power, but it is certainly possible to produce a highly reliable car without these as long as you tune to avoid detonation. You will obviously not make as much power as with the right mechanical mods, but at the end of the day, it is detonation that kills these things, so reliability should be judged by the tuners ability to avoid detonation rather than the size of the intercooler and exhaust.

-- Adrian