turbo SBC's... was RE: Thanks for the EFI! (off topic)

Bruce nacelp at bright.net
Tue Dec 11 05:20:57 GMT 2001


From: "Andris Skulte" <skulte at skulte.com>
Subject: turbo SBC's... was RE: Thanks for the EFI! (off topic)
> > I'd be interested in what you are doing with your engine. Any details?
> So far the plan is to build a bulletproof 350ish engine. It'll be from
> either a Dart or Bowtie block, 6.125" rods, 3.48 stroke ex-NASCAR crank
> possibly (or Cola or Callies, some sub $1k crank), 4.000 bore, heads with
> around 210cc intake runners (AFR, Canfield, Victor Jr's), 8.5:1
compression
> and cam specs based partially on the current engines backpressure vs boost
> characteristics (measured when I strap this tired mule to the dyno - will
be
> fairly mild with duration), and some custom JE/Venolia/KB pistons.
> My reasoning is to make a reliable, build it once road racing/street fun
> engine. I still am considering a 377, but I like the detonation resistance
a
> smaller bore gives you. The question of the hour is whether I'll make more
> power unshrouding the valves with the larger bore and less boost. I'm
> planning on going to about .035 quench, but some folks more experienced
than
> I claim that a quench that tight really disturbs the flame front travel at
> TDC. To knock down compression, I plan on mirroring the combustion chamber
> shape in the piston, since this should give you the fastest burn time.
Some
> words of wisdom from the previously mentioned turbo folks suggest going
with
> a plain 'ole open bowl piston, but again I'm having a hard time convincing
> myself that that's the way to go, when the collective theory based
knowledge
> usually says to go with a tight quench and small dish.
> Any thoughts or comments before I'm committed to building it? Thanks!
> Andris Skulte
> Z28tt-89 IROC T56 DFI Twin Turbo
> http://www.skulte.com

Small as possible chambers
Dished pistons
9:1 CR
20 cubes is worth going for
Barrier coat the chambers (after smoothing them), but you have to run WI to
keep the carbon to a min..

Having power pre boost is a good goal.
Little extra compression and bigger motor are great.

Might consider off set wrist pins.
Bruce

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