View Full Version : best pre turbo mixture

14-08-2015, 09:45 PM
good evening.

after reading the commends of this man I started driving pre turbo injection in the firs place.

Pre-compressor injection offers a host of benefits. In a nutshell, injecting water (and ideally a few other miscible fluids of high specific heat capacity) pushes the compression from adiabatic to near isothermal. This is way more efficient (up to 30%).

Yes atomisation is critical, but the technology is there.

problem 1 is that water on its own, whilst having a very high latent heat of vapourisation, doesn't have that good a saturation partial pressure. You can only put so much in before the air is at 100%RH. Above this the water will not cool the air until you compress it in the engine. However, if you add a second fluid, say methanol, Dalton proved with his law of partial pressures that the methanol doesn't know that the air is saturated with water vapour and goes on to vapourise as well. Add a 3rd, such as acetone (all available chemicals) and you get a 3rd tranch of cooling.

The net result is that you may be able to cool the air to slightly below ambient with the right mix. So your compressor becomes more efficient, you can throw away the intercooler, increasing your flow, and in some cases significantly improve the flow from turbo to inlet.

Its good, very very good.


I'm building a duel stage turbo set up.
between the first en second stage there is no room for a intercooler and I like the results of my WMI with pre turbo injection so far.

I want a second WMI system on board eats with a different mixture.
one for pre turbo injection and one for post intercooler injection.

but what would be the best pre turbo mixture to start with ?
I would like to come to near isothermal compression as close as possible.

I think:
-isopropyl alcohol.
-demineralised water.

would be the best to start with.
what proportions would work best ?

16-08-2015, 09:42 AM
i like reading old treads on this forum.
to bad there so little activity these days.

no one ????

Flr Power
17-08-2015, 01:25 AM
Sure, it will make it more efficient.
Practical an easy maintenance, may be not so much.

17-08-2015, 11:48 AM
tnx for responding.
any idea for the mixture ?

25-08-2015, 12:22 AM
I have had some great results on the 70 % M1 to 30% distilled water sprayed pre-turbo.

27-08-2015, 02:18 PM
O.K. I'll start with that.
ever tried acetone or isopropyl alcohol ?