Intercoolers..

[Jonathan R. Lusky]

Craig Pugsley writes:
> 
> A few questions about intercoolers on turbo engines.
> 
> i/  What is better at removing heat from the intake air:
>     Air-Air or Air-Water?

Depends on the application.  For the same surface area, air-air
will be more effective, assuming you are cooling to ambient air.
But you can't always fit a huge air-air where it needs to be AND
get adequate airflow.

> ii/ Where do Air-Water intercoolers get the water supply from?
>     The engine cooling system or a totally seperate system

Totally seperate.  On mine I had on radiator mounted inside the
front bumper, and another mounted on the trailer hitch receiver
(this was on a truck), with two electric pumps and 50ft of hose.
Took about two hours to bleed the system.

>     (I was thinking of putting a container in the boot/trunk
>     and filling it with ice water to feed the intercooler).

Yes, you can do that, and it works *VERY* well.  Gale Banks has
done it quite a few times at Bonneville, even on normally aspirated
vehicles!  He uses a large icechest full of ice and water.

> iii/If you were to run fuel injection with LPG, would the
>     cooling effect from the LPG expanding as it comes out of
>     the injector be sufficient to not require an intercooler?

I am too lazy to dig out my old thermos book and calculate exact
numbers, but I don't think it would be that significant.

> The application is to turbocharge a 13B rotary in a Mazda
> 1300 (~=R100). The main problem is space constraints (ie an
> air-air intercooler would be difficult to fit).
 
Air-icewater sounds good to me :)

-- 
Jonathan R. Lusky                        lusky at knuth.mtsu.edu
http://www.mtsu.edu/~lusky/                 (615) 726-8700
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68 Camaro Convertible - 350 / TH350  \_/ 80 Toyota Celica - 20R / 5spd