Hi Ben
Mostly I'm saying that just because the factory number is 165 hp is no
reason to believe that the commercial stock 2.5 conversions are in fact
achieving that. I have heard a lot of claims and technical obfuscation
though. I guess I got the impression you might be expecting to get even
more than 165 hp.
There are a few people that have worked with both engines and that I
respect that have said that the 2.5 does not respond near as much to
things like cam grinds as the 2.2. In one case the fellow talked about
the bore to stroke ratio as being a significant factor between the two
engines. I believe a cam grind, to extend the rpm that the torque peak
occurs at, is by far the biggest mod that you can really do as these
are not like the old EA81 where there are many things that each add a
bit of power. There are believable third party dyno numbers for the 2.2
that are consistent with the factory numbers stock and that show a 25 hp
increase to 160 hp with a cam grind. While I'd definately use a 2.5 if
doing it again, I would realistically not count on more than about 150
hp from the stock normally aspirated engine with modified intake and
exhaust. With expertise and dyno testing you could probably/assuredly do
better but I have seen no convincing evidence of that achievement so
far. Nor would I expect an extra 25 hp from cam grinds like in the 2.2.
By all accounts the 2.5 is an excellant 0-320 alternative but it is
already a highly tuned engine with little to be gained by mods from what
I understand.
OTOH if you are burning and carrying less fuel and perhaps have a lower
drag cooling system, it may be as good as having some extra power ;)
Ken
bransom@dcsol.com wrote:
Ken,
Like any engine's max rated HP, that number is rarely reached in real
life.
Do you know of any tricks in getting more HP that work on a 2.2 and
not on a
2.5? All of the power enhancements I've read about seem to apply
similarly
to the two engines, with equal believability or skepticism. Or, maybe
you're
just saying an EJ25 isn't really going to deliver more power than a
Lyc 0320?
-Ben
8/28/2004 6:28 AM,
KLEHMAN@ALBEDO.NET wrote to REBEL-BUILDERS:
Ben
I would guess that it could be done but probably not without custom
exhaust and intake.
FWIW I consider the 2.5 TOPPED at 165 hp normally aspirated in stock
internal condition. The claim that the stock engine makes 165 because
the computer says 100% load is bogus. Fundamentally all the later oem
computer knows is rpm and manifold pressure so it reports 100% if those
parameters are met regardless of actual mass flow or power. Once you
change the exhaust or (especially) the intake that may or may not
correspond to 165 hp. The computer has no way of reading actual power.
Fuel flow is meaningless because the oxygen sensor is full scale rich
and ignored at aircraft power settings. Unlike the 2.2, the 2.5 is not
an easy engine to coax more power out of as the factory has done their
homework.
Ken
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