<VV> LM turbos and no lower shrouds

J R Read hmlinc at sbcglobal.net
Sun Oct 23 20:33:41 EDT 2011

I put the shrouds on (been off 15 years) this past spring.  This is a 140 
and I'm not afraid to use the skinny pedal and open up the secondaries.

While I had partial heat without the shrouds, I now have very good heat 
whenever I want it and defrosters on cool - damp mornings.  I hardly ever 
need to turn the heater fan on (except for defrost situations - rare) and 
engine warm-ups are much quicker as well.  Head temp typically stays just 
below 300 at highway cruise and practically never gets above 325 - even on 
long up hill runs (we do have SOME hills in IL).

What was the cost in terms of head temp?  Around 15 degrees warmer and well 
in the safe range.

Later, JR

PS - I was previously a proponent of shrouds off, but I no longer think that 

----- Original Message ----- 
From: <jvhroberts at aol.com>
To: <flash at vicsmba.com>; <virtualvairs at corvair.org>
Sent: Sunday, October 23, 2011 5:30 AM
Subject: Re: <VV> LM turbos and no lower shrouds

> Um, the stock system is not all that and a bag o' chips. Sorry. For those 
> of us who have turbo cars, etc., the cooling is utterly inadequate. 
> Removing the shrouds produces a noticeable drop in CHT and oil 
> temperature.
> Even on a non turbo car, if driven spiritedly, the cooling system runs out 
> of breath.
> So, there is, in fact a better system out there. GM simply failed to 
> install it!!
> John Roberts
> -----Original Message-----
> From: Eric S. Eberhard <flash at vicsmba.com>
> To: virtualvairs <virtualvairs at corvair.org>
> Sent: Sun, Oct 23, 2011 2:30 am
> Subject: <VV> LM turbos and no lower shrouds
> I am always puzzled by this discussion which comes up every so
> often.  The car was designed well from the factory.  If you have
> everything correct -- all the shrouds as well as seals and so forth,
> there is no better system.  I am in AZ, totally bone-stock, at
> altitude (3500-8000 feet), summer temps of 110 ... and I NEVER have
> even gotten remotely close to overheating.  Our speed limit is 75 and
> I can go up a 6% grade at 80, no over heating.  From my 3500 to 7500
> feet happens in 6 miles, no overheat even at 80.

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