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Reply to "Need input from IM owners"

You’re right about the external cooler being a band aid, but for the wrong reasons.

Yes, VW designers gave us an adequate cooling system - For a 1600cc type 1 engine, and even that was aided in the final years with increased air into the engine from enlarged external grills.  Even the later 356 moved to twice as much air into the engine compartment, when they moved from the 1500 normal engine to the 1600 Super.  The cooling system for the 2liter (I’m assuming you mean the type 4, here) was (a.) vastly different from the type 1 and (b.) moves a helluva lot more air than the type 1 did.   Same can be said for the pancake type 3 and 4.  

All that aside, it was only 2/3’rds of the equation.  The other 1/3 was how they designed the car around the cooling system and turned that into an advantage.   Our Speedsters do not have that advantage.  As far as getting more cooling air into the engine, they are marginal at best and several ideas that we thought had promise to improve that situation (fans or ducting blowing into the compartment, for instance ) proved less than beneficial due to low pressure areas where we didn’t expect them (yes, someone has tested for this all over/under the car).   Just look at the orange VW sedan in the article you referenced:  Just the air grill to the engine compartment up over the lid has twice the air flow area of our single little grill.  No wonder a lot of us have opened up a hole in the firewall right in front of the fan inlet.

So, we’re starting with one hand tied behind our backs with a marginal car design and, through trial and error, some of us have developed several things that we, as a group, have seen work and incorporated in our cars, too, always with success.  Propping open the engine cover on highways, adding a fan assisted external oil cooler, having all of the engine heat shields in place, running a 1971 or later fan shroud and a larger internal oil cooler, running lighter viscosity oil; These things have been proven to reduce oil temps by 5° - 15° with no other changes to the surrounding car (We’re still talking just Speedsters, here).  Relying on the tried and true German cooling system design, with a sub-optimal car cooling design surrounding it and hoping that it will be alright has never worked for us.

Listen to us.  We have lots of people and over 20 years of messing and curing Speedster Overheating behind us.  And we haven’t had anyone seizing up over abnormally high head temps, yet.  If anything, we have people Who are running 4-cyl CHT gauges reporting lower head temps than most of us expected.  Our experience is also that most Spyder owners are running most of the same cooling tricks as the Speedster Group with very similar success.

Last edited by Gordon Nichols
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