: I'm not sure how close the Desktop Dyno results
: are to real slant sixes, but some of the
: results implied building a killer turbo
: slant six is less difficult than I thought.
: Does anyone know how well it works with
: /6's, or have detailed flowbench data for
: modified slant six heads?
:
: The combo I used starts with a small turbo (not
: having a turbo map for the Itsibishi turbo
: from a 2.5 that I've got, I went with a
: Rajay 300 limited to 8 psi of boost) that'll
: deliver full boost at very low RPM - around
: 3,500 in this case. It also had a 30
: efficient intercooler. I described the head
: as a "pocket ported wedge with large
: valves" using the Mopar Performance
: valves. Other than that, this engine was
: described as bone stock with the '71-'77
: camshaft. I could refine this even more if I
: had a turbo map for the Chrysler 2.5's.
:
: I was floored at the results from this
: seemingly simple setup. The computer
: predicted nearly 400 lb-ft of torque at
: 3,500 RPM, and a hair over 300 hp. It sounds
: like I could merely bolt a ported head and
: turbo setup onto one of those parts store
: rebuild short-blocks discussed earlier, get
: the tuning straighened out, and get ready to
: waste V8's. Or waste a lot of 7 1/4"
: axles.
:
: How realistic is this estimate likely to prove?

:
: I hadn't realized how close a turbo setup could
: get to the limits of breaking something with
: so little boost and a small turbo. I'd
: expected it might at least need a better
: cam. Getting that much power can be a mixed
: blessing. Looks like my next mod may either
: be a bottom end rebuild or a stouter rear
: axle, and hopefully neither one will break
: before then.

: How realistic is this estimate likely to prove?

: Using the formula in a turbo book I have you
: get the following estimate from 10psi, 225
: ci and the lowest efficency turbo example
: they show(52%).
:
: .052 X 225 X 24.7 = 289hp

:
: *************************************************
: Hey, Tom......does that formula also apply to
: superchargers?
:
: Roger

: No the formula refers only to turbo
: applications./---/ Since they actually rob hp
: to make more hp the formula would have to
: reflect this.

: No the formula refers only to turbo
: applications. Maybe someone else can shed
: some light on superchargers. Since they
: actually rob hp to make more hp the formula
: would have to reflect this.

: I ran across an old study from the '30s by the
: federal government (by the predecessor of
: NASA) that showed there was no differance
: between exhaust driven versus belt driven
: superchargers when producing increased power
: with aircraft engines.

: The drag race pros use superchargers, but
: turbos dominate in F1, Indy, endurance
: racing, and most other forms of racing where
: they are allowed. I think this is because
: drag racers are only concerned about max
: power and do it as simply as possible. The
: big sledge approach. Other racers are more
: concerned with fuel economy and longevity.

: Actually, there's a simpler reason why many pro
: drag racers use superchargers. The powers
: that be have banned turbos from many drag
: racing classes, and only allow Roots style
: blowers. And in some cases where they do
: allow turbos, they hit them with weight or
: displacement penalties compared to
: superchargers. Sometimes that still doesn't
: stop them from being competative, though.

: What I'm curious about is the comparison of the
: torque/horsepower curve across the rpm band
: for both forced induction methods. Daily
: drivers look for results at the mid to lower
: end and therefore might lean towards SC,
: others are looking for results at WOT where
: turbos should perform better. I think that
: intended usage probably dicates avenue
: chosen.

: For a daily driver, I would go with a Turbo
: setup, and try to keep the spool as high as
: I could... say around 3500.