If I'm not mistaken, you'll get a few more HP with the cold sump?
That's what we're led to believe. Does anyone have numbers, back to back on the same engine?
My first -7 have a Superior with the cold sump and my second -7 has the std Lyc with hot sump. To me, the Superior is more willing to run smooth at LOP (I lean until the LAST cyl reaches -50*F) on all powersettings. (up to 75% that is) The Lyc must be adjusted alittle richer to run smooth.
I don't doubt the observation, but there's not much logic tying it to the induction system choice. Consider...
Lyc and Superior are two different cylinder head castings; minor port details can make a significant difference.
The induction is air distribution only. Fuel is added at the ports, so fuel distribution is unaffected by an induction change, unlike a carb application where we really
need some manifold design work. Any difference in air distribution can be matched with an injector nozzle restrictor change....classic tuning for LOP operation.
It's called a "cold air sump". How much colder is the air it delivers? At 2700 RPM, each cylinder's intake runner is passing 2.3 cubic feet of air
per second.
Let's say oil in the standard sump is about 200F. We assume the Lyc induction plenum is about the same because of conducted heat energy. Although the Superior cold air induction is outside the sump, it is bolted to the bottom, which would also conduct some heat to the plenum.
The plenum is only part of the plumbing. With
either system (Lyc or "cold air"), the induction tubes from plenum to cylinder head are exposed to the hot downflow from cylinder head cooling. I've measured as high as 240F at the baffle tie, hotter than the sump temperature, and the induction tubes appear to have much more surface area than the plenum. Obviously there's nothing cold about the tubes on either system. Not that it necessarily makes a lot of difference; the "cold air" plenum is bathed in the same hot air, again, air that is warmer than the oil.
Not saying it's a bad deal. It works fine, and it does save three lbs. I'm just hesitant to believe it delivers lower induction air temperature. Anybody have a
measurement?