I think it's all about controlling air flow control, channeling as much air
as you can through the radiator core. After, of course, making sure the
radiator is not clogged internally or externally.
As Fergus points out, a puller has to be better, given the same size, than a
pusher for no other reason than the fan itself obstructs some air flow
through the rad. Then again even a puller needs to be sealed to the back of
the core in some fashion so that the fan pulls air strictly through the
radiator. I had a '92 Skylark on which the fan/shroud had about a 1 inch gap
between the core and the shroud/fan carrier. You could feel air being pulled
into the fan through that gap, however because of the way the fan assembly
was designed you couldn't use anything to seal the gap. I put a second 9
inch Hayden in front of the rad to get the temp under control in the Texas
summer heat. A real POS, IMHO. The Skylark, not the fan.
Bob's idea of going with the biggest fan that'll fit tight to the radiator
makes sense. I may look at fabricating some baffles to go in front of the
rad between the grill and the rad support to "funnel" as much air through
the core as I can and I may go with an electric fan if I can get the old
viscous coupler off the water pump without messing up the shaft or the pump
bearings. At some point in the past someone JB welded the coupler and used
large sheet metal screws to lock things together. I'd rather not replace the
water pump right now unless I have to.
One nice plus of the VW Rabbit radiator (12.5 x 21, $110 at Jegs) swap
popular in the 510s is the dual fan/shroud assembly ($180 at Jegs) that's
made specifically for the unit. The shroud totally covers the back side of
the radiator so every square inch of radiator core surface is utilized. I'll
have to measure to see if it'll fit the roadster, although haven't some
folks used the Honda Del Sol radiator/fan assembly for the SR swaps?
FWIW,
Ron
> Bob Mann
> I have a 9" SPAL puller on there now, thermostatically triggered at 190
> degrees.
>
> Over the summer I found it to be less airflow and slower to cool down
> than ideal.
>
> I have a 14" SPAL puller teed up to install over the winter.
>
> BTW, a 14" SPAL does fit inside the stock shroud -- if you want to leave
> it on.
>> Fergus O'Farrell
>> I know I have read somewhere, that pushers are at least 20% LESS efficient,
>> and I believe that is because at highway speeds, when fan is not on, you now
>> have blocked some of the cooling flow. Yes, you remove the shroud, as
>> clearance is tight, and from what I have saved of people's installs the 14"
>> diameter fan was what was chosen. I suppose if you wanted to improve you
>> could re-fab a shroud, I am sure some have some opinions, it'd probably be a
>> good idea with our SoCal heat and traffic. Fergus O
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