Thanks for the info! Its just an idea for now, but yes, I was thinking about
a low boost turbo only. My engine (P76 V8) is pretty low reving, with
maximum power produced at about 4500rpm, so I'm keen to produce useable
boost in this rev range.
I believe that with an asymmetrically turbocharged engine a wastegate is not
required. Is this true, and does anyone know why?
-----Original Message-----
From: Randell Jesup [mailto:rjesup@wgate.com]
Sent: Tuesday, 15 December 1998 13:44
To: Simon Sparrow
Cc: buick-rover-v8@autox.team.net
Subject: Re: Values of 215 & 4-speed?
Simon Sparrow <Simon.Sparrow@wang.co.nz> writes:
>Anyone got any information on the turbochanged engine? I'm interested in
the
>concept of running just one turbo from one bank of a V8. Saab do the same
>with their new V6. Anyone know what the pros and cons are?
Well, the optimum camshaft profile on each bank will be different,
at least on the exhaust, I'd think. Turbos like cams with less overlap,
for example. Though the difference may not be large enough to really
matter for a low-boost turbo, say 5-7 psi with say 8:1 or maybe 9:1
compression. If you're being serious, and running say 8-15+ psi of boost,
then finding a camshaft profile might be interesting. Probably selecting a
general turbo grind will do ok, though. Also, you might want to have dual
exhausts with no crossover pipe, though again this may not be very
important so long as it's a good high-flow exhaust (you'll be pumping more
(or much more) air than a normally aspirated version).
Buick 300 heads would probably be a good choice - bigger ports and
chambers. If you get serious, don't forget to plumb for an intercooler -
they make a big difference in getting high cylinder pressures without
eating pistons. If you're pushing the preignition limits, other important
things: strong pistons with strong lands/rings and maybe ceramic coatings;
a saddle or crossbolting for the main bearing caps (you're putting a lot
more power through the crank/block); a good fuel pump/filter (going lean
will kill a hot engine Really Fast), cool air intake, oil cooler and fully
functional (perhaps uprated) cooling system. A mixture meter (O2 sensor
and LED) might be useful, especially if you go EFI. (Personally, I'd
prefer an aftermarket port-EFI system in a hot turbo engine with a knock
sensor (and I'd want an O2 sensor as well just to be sure I don't lean
out), but that's just me.) Also good silicone HT wires; turbos and their
hot plumbing tend to cook wires even if they don't touch.
Just some off-the-cuff rambling...
--
Randell Jesup, Worldgate Communications, ex-Scala, ex-Amiga OS team ('88-94)
rjesup@wgate.com
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