the extra casting cost is nil I suspect. .
like barely, barely more expensive to cast it with ribs or fins than
without.
and besides,
as I said, it adds stiffness and strength.
it's an almost free improvement.
there is no reason not to have fins on an aluminum sump, generally speaking.
( though diesel vanagon does not )

Scott

----- Original Message -----
From: "Alistair Bell" <albell@SHAW.CA>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, July 21, 2011 7:35 AM
Subject: Re: Watching Oil Temp (long, as usual)

I have no idea, but I'd guess adding fins must make some useful difference
else it would not be worth the casting costs.

alistair

On 2011-07-20, at 11:29 PM, Scott Daniel - Turbovans wrote:

> sorry..
> I didn't make it clear that is just a wild guestimate.
>
> what is your hunch on it ?
>
>
> ----- Original Message ----- From: "Alistair Bell" <albell@SHAW.CA>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Wednesday, July 20, 2011 3:58 PM
> Subject: Re: Watching Oil Temp (long, as usual)
>
>
> how the heck did you come up with that value?
>
> is this based on any measurement?
>
> what is the increased surface area provided by the fins? if you know that
> then you can start using numbers, otherwise its all hooey Scott.
>
> alistair
>
>
> On 2011-07-20, at 3:04 PM, Scott Daniel - Turbovans wrote:
>
>> Like if there were no ribs..
>> just smooth aluminum ...about a 1 and 1/2 percent difference..
>> on other words, not much.
>