[Tigers] engine ancillaries

[Stephen Waybright]

If Car Craft ran the same compression in both engines, there should be no HP difference between the iron and alum heads... but the thing is, if all else is identicle, you can run higher compression with alum heads before the engine starts pinging because they dissipate heat faster. That's where the extra HP comes from running Alum heads.

--- On Fri, 6/13/08, Sandy Ganz <sganz at pacbell.net> wrote:

> From: Sandy Ganz <sganz at pacbell.net>
> Subject: Re: [Tigers] engine ancillaries
> To: "tigers at autox.team.net" <tigers at autox.team.net>
> Date: Friday, June 13, 2008, 2:19 PM
> That is exactly the discussion I'm looking for! I did
> poke around on the web
> and found a car craft article debunking the HP loss/gain in
> aluminum vs iron
> head in some ways, with dyno data and while interesting not
> totally
> conclusive, but seems to cover a good amount of the common
> cases run into in
> warmed over motors. The summary was they picked up 2 sets
> of heads from Dart
> Machine who makes an almost identical aluminum and iron
> head for the SBC. They
> flowed before testing and the iron head and aluminum were
> very close in all
> numbers. The numbers on the dyno were almost not measurably
> different, they
> also messed with timing and no difference where motors with
> either head
> type would detonate. Some other stuff too. I think the
> compression for the
> test was in the mid 10's so while I might not consider
> it high, others might.
> Long and short was HP was no different according to dyno
> data. It did not
> address any cooling system issues which would be more what
> this thread was
> about.