Turbos and superchargers...

["Storhok, Eric (E.M.)" <estorhok@domain.elided>]

Interesting debate concerning turbos and superchargers, especially the "which comes on faster" arguments.  I think for a typical installation, a blower would be far easier to get the flow you really need.

Yes, you can go with umpteen different variable vane geometry turbos, but how are you going to set it up to control it?  Its not trivial...  On the other hand, I've seen some really cool ways to do it a better way.  Coming to a turbo near you in about 5 or so years (don't ask- I can't tell you).

But for the average installer, the blower will be easier.  Consider- for a turbo you need a bracket and a VERY custom exhaust manifold.  On our Challenge Spider (see http://photos.groups.yahoo.com/group/alfa2002k/lst) we got really lucky- we found one that we could adapt.  You could be lucky and find a very talented exhaust fabricator who could fit one, but you are still not out of the woods- don't forget to plumb for oil, water, and some type of heat management.  The last thing is very important- our turbo Spider doesn't cool very well as we've managed to block one of the main air paths with a very hot piece of metal.  And you still need a bracket to support it, but that can be rather trivial.

For a blower, quite a few fabricators are capable of making a bracket to hold a blower.  And the pulley system- the quality of this depends on how much air you are planning to move- quite a few OEM systems which are warranted out to 50k miles use normal multi groove belts, not drive belts.

The intercooling can be debatable.  For much over 7psi, something is needed, but under that, I'm not that sure.  If you only drop the compression to 8.5:1, you need it, but 8:1, eh- gray area where you may be able to live without it.  If you use the boost very little time, you could also do water injection.  See http://www.dawesdevices.com/water.html for a DYI project.

Controller?  As we have found out, you can get away with a VERY simple control system, but they can be tricky to tune, and we have tools that are worth more than the car...  Most of Jim Steck's projects use Electromotive, and while not perfect, they work pretty darn well.  I would like to try the one Zamani recommends- sounds interesting.

If we do manage to find that ideal GTV for a $200x challenge, it will be with a blower, not a turbo.  And water injection.  Very simple, less things to go wrong and to plumb.

Eric Storhok
Core Emissions and Fuel Economy Team
Advanced Powertrain Engineering
(313)33x75011
MD 35, FPC-B
Ford Motor Company
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