I think I posted this up before, but here goes again.
If you are serious about twin turbocharging an engine, it doesn't have to
be ultra-complex, but to get maximum preformance it will get very pricey.
-Rebuild the motor to handle the increased cylinder pressures (this has
already been said, but just reinforcing it). It's also a good time to put in
roller rockers, a better set of cams, maybe switch to a set of overhead cam,
32 valve heads. Who knows what that monster could do if you can find a set
for the 318/360.
-Get a set of "shorty" headers so that they terminate close in to the engine
and give you space to mount each turbo.
-Get a heavy duty oil cooler (this is oft over-looked) as the turbo gets so
hot it can turn oil pumping through it into varnish faster than fast,
synthetics are a must for turbo-engines unless you like flirting with a dead
turbo before 100K miles.
-Use Variable Vane or Variable Geometry turbos. These are worth their weight
in gold. They are faster at spin up than a standard turbo, provide boost
according to demand more quickly than a regular turbo, and don't require ANY
wastegate system. If then you are in an over boost situation, the vanes close
down and don't put out as much pressure to compensate. It's a simple yet more
efficient solution. Allied Signal produces a Variable Geometry turbo (in
small and large sizes, I'd recommend 2 small ones rather than 2 big ones:
those are for Tractors/Rigs).
-Intercooler is a must, air intercoolers are maintenance free so look into a
huge one, but they also have liquid cooled intercoolers and they can work even
better since you can mount the exchanger in a "thinner" area, air ones are
rather "thick". I'd mount a big 'air' one behind a chin skirt so it didn't
interfere with the heat exhange system though the radiator.
-If you can afford it, a custom programmable engine computer is the best thing
for turbos, but if not, you'll have to find a way to rig the sensors on the
new system and make up for the higher air flow. I understand many a garage
turbo tech has their own way of tackling this.
I researched this, and had two different racing motor builders (they built
oval racers) recommend these things to me if I were "crazy" enough to try twin
turboing a V8. A blower is far simpler, but in raw power to the engine with
little being sapped from the engine, a turbo is hard to beat. It's *almost*
free energy (if you don't count actual cash!). I was looking at a price tag
of over 7K for the whole system and told myself I was nuts to even contemplate
it.
Shaun H.
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