<VV> turbo non boost

[djtcz at comcast.net]

It was my experience a turbo exhaust must be so tight that an idling engine can be stopped by clamping a folded shop rag tightly over the exhaust outlet with my hand flat.  I think I read that somewhere and found it to be true.  It only really matters between engine and turbo, but it's hard to pressure test anything but the whole system.
--
Dan Timberlake


-------------- Original message -------------- 

Date: Tue, 29 May 2007 16:32:19 -0400
From: "Robert Hawley" <iamrgh at charter.net>
Subject: <VV> Spyder Turbo/Carb mismatch issue?
To: "virtualvairs \(posts\)" <virtualvairs at corvair.org>
Message-ID: <002201c7a230$765ec240$ff9a5947 at DGYY2L61>
Content-Type: text/plain;	charset="iso-8859-1"

Howdy All,  I noted recently a discussion about Turbo ID's and using the correct 
exhaust housing with the EM turbo: the gist of which was that if you have 
1965-66 housing, your EM (small) turbo will probably produce little if any 
boost.  After having the exhaust housing and exhaust pipe on my 1963 Spyder 
replaced with a donut style to better seal to the turbo exhaust outlet, I began 
to have lack of boost issues. A compromise resulted when my original YH carb (Main body # 0-1580) 
was replaced by a LM YH as Ken Hand couldn't get the car to run properly and 
provide boost. 



Boost is meager to say the least (2-3 #) and after looking at the exhaust 
housing on my turbo I realized that it could be the LM style as it starts out at 
the turbine fan at 2 1/16  inches and flares out to 2 ½ inches where the donut 
seal area starts.  Does this make it a 1965-66 exhaust housing?.  My Turbo is 
part #3840830 (1964 turbo).  The YH carb tag part # is 3692S-SA (believed to be 
the correct tag) which should indicate a main body # 0-1580 (1964 but with a 
75-1629 metering rod), but the YH main body number now running on the car is 
#0-1750 (1965).  



Something has obvious been changed along the way and I am wondering if the 
possible mismatch of components is causing the boost problem?  The exhaust is 
tight and was fully repaired and sealed last year by Ken Hand and the car has 
less than 26K original miles so compression is excellent.  The car starts (and restarts) from cold or hot without fail and 
runs smoothly, but has little boost.  



Is there a unique 1964 only style of turbo exhaust housing that has a small 
opening like the 1962-63 turbo housing and incorporates the donut (instead of 
flat) style seal? Is anybody willing to trade components or suggest the right 
combo to make things work?  (The current exhaust housing and exhaust down pipe 
are both Jet Hot coated in chrome and in excellent condition) Any enlightenment/ 
recommendations will be appreciated - perplexed in Kalamazoo.  Bob Hawley