Fwd: <VV> LM carbs

[HallGrenn at aol.com]

In a message dated 5/2/2006 8:54:57 AM Eastern Daylight Time, NicolCS at aol.com 
writes:

> My personal theory is that this additional heat in a smog engine 
> is due to burning fuel in the exhaust manifold (where it's all converted to 
> heat, none to power) and reduced ignition advance in midrange RPMs (which 
> also 
> heats up the exhaust).
> 
> Craig N.
> 

I agree with Craig's comments.  I have very little experience tuning Corvair 
engines for performance--just what I read in the books.  But I have spent a 
lot of time rebuilding my carbs and carbs for friends' Corvairs and tuning them 
to Chevy standards.  The SMOG engines were designed to meet emissions 
standards in addition to all the things earlier carbs had to do.  All SMOG cars I have 
rebuilt have had larger jetts (almost always 52's) than other, earlier carbs. 
 The engines do run hotter, but not distructively so (one of my SMOG engines 
was just shy of 200K when something broke inside and the other one was over 
140K when it blew a cylinder gasket).  As Craig said, I think the extra heat 
comes from the hotter exhaust manifold due to air injection.  The extra load of 
the SMOG (A.I.R) pump also contributes--and lowers performance due to drag.  
But they will still run the socks off most anything around town.

Bob Hall
Group Corvair