<VV> 145 Turbo

[Charles Sadek]

I agree with Kevin!

-----Original Message-----
From: VirtualVairs [mailto:virtualvairs-bounces at corvair.org] On Behalf Of
kevin nash via VirtualVairs


I have a 63 Spyder with the orig 145CI motor that I'm rebuilding but
everyone i communicate with try to talk me into converting to a 164ci
instead, Why..?

Thoughts on staying or converting

Thx Flat6fan

--
Isn?t it funny how day by day nothing changes, but when you look back
everything is different?
C.S. Lewis


Here's some reasons why you might leave your stroke alone and get "Torque"
some other way.
The stuff that has to be changed when going to the longer stroke: Late
pistons, late cam, late crank
 and HB and some work clearancing the short stroke case for the longer
stroke crank. Not as easy as it sounds! Also, a major reason for the lack of
torque that all corvair turbo's have (late or early) is timing and
compression ratio. You can easily jump the compression on your stock heads,
with a better cam you can and should bump it more and if your heads have
been worked on (better squish, turbulence and flow) you can go higher still.
My heads are 8:1, and with the cam that is in it now, (along with some other
changes) I kind of which I had bumped the cr up to 8.2 or perhaps a bit
more. The stock distributor timing for Corvair turbo's leaves a LOT to be
desired... it is way too
conservative, and is really only kinda sorta close to right just before
going into boost. The lack of vacuum advance and rpm advance until way too
high of an rpm causes the engine to be way down on both torque and power,
until the late advance hits and by then you've already lost the race!
My ignition timing is programmable and the easy way to explain it is its
like having a 140 distributor with a different vacuum advance curve with
boost retard. I've had an opportunity to drive a stock Late vs my little
short stroke engine with more compression, timing and air flow mods
and I can tell you it is NOT down on torque enough to feel. When I hit the
throttle, it feels way more healthy than the stock late car. As it should
with more compression ratio, higher flowing heads better timing and a bit
more than double the stock peak boost. Yup, 18 to 19 in second gear!
   Another reason to keep your short stroke crank, is that the late ones
have been known to break, I haven't heard of a early spyder crank breaking
yet!
One last thing, if you do want more torque via displacement, larger bores
work extremely well with the short stroke crank.
Kevin Nash
63 Turbo port injected daily driver,
baddest cooling fan on the planet!

 



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