<VV> 145 Turbo
wrokit at hotmail.com
Sat Jun 1 15:48:53 EDT 2019
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
Thoughts on staying or converting
Isn?t it funny how day by day nothing changes, but when you look back everything is different?
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.
63 Turbo port injected daily driver,
baddest cooling fan on the planet!
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