More Horsepower

[rwtucker]

Several DAN discussions focus on efficiency (e.g., injectors optimized to run well LOP). How many DA40 owners running the IO-360M1A are experimenting with the other side of the equation?

At my airport, several IO-360 owners have made modifications that extract as much as 250 hp from normally aspirated engines. Anyone here experimented with larger injectors, high compression heads, porting and polishing, electronic ignitions, and ???? If so, what kind of results are you getting?

[Antoine]

Several DAN discussions focus on efficiency (e.g., injectors optimized to run well LOP). How many DA40 owners running the IO-360M1A are experimenting with the other side of the equation?

At my airport, several IO-360 owners have made modifications that extract as much as 250 hp from normally aspirated engines. Anyone here experimented with larger injectors, high compression heads, porting and polishing,, and ???? If so, what kind of results are you getting?

Robert, I am afraid most of the stuff you mention would only be possible on an experimental. I have considered a few "invisible" mods, but I think no shop does them in Europe.

The only exception I am aware of is the ignition. It is funny you mention electronic ignition, as I have ( for the third time now) re-read all 3 CAFE analysis reports that ElectroAir post on their web site, hoping to find something to make me change my understanding - to no avail...
See for yourself...

[rwtucker]

Antoine, I was not aware of the specific restrictions in Europe. I wonder if you have the latitude to do such things as re-drill injectors or replace "used" injectors with a size or two up? Also, I would not think that blueprinting (porting, polishing) would not be considered an engine modification. It is really just finishing the job the factory engineered . . . but I could be way off. In terms of benefit, high compression heads would probably deliver the greatest increase in HP (15-20%), followed by tuned exhaust (8-10%), then all the other refinements. I haven't made the move to electronic ignitions yet but my friends who build RVs (Experimental) love them and report noticeably greater climb and cruise (maybe 3-5% more horsepower at high RPM). A side benefit is easier starting. In the US, current STCs permit replacing only one Mag even though one electronic ignition has a built in Mag as a fail-safe. It will take time for the rules to catch up.

[Antoine]

Antoine, I was not aware of the specific restrictions in Europe. I wonder if you have the latitude to do such things as re-drill injectors or replace "used" injectors with a size or two up? Also, I would not think that blueprinting (porting, polishing) would not be considered an engine modification. It is really just finishing the job the factory engineered . . . but I could be way off. In terms of benefit, high compression heads would probably deliver the greatest increase in HP (15-20%), followed by tuned exhaust (8-10%), then all the other refinements. I haven't made the move to electronic ignitions yet but my friends who build RVs (Experimental) love them and report noticeably greater climb and cruise (maybe 3-5% more horsepower at high RPM). A side benefit is easier starting. In the US, current STCs permit replacing only one Mag even though one electronic ignition has a built in Mag as a fail-safe. It will take time for the rules to catch up.

Do you know how much gain the polishing and porting can bring?
as to EI, it is just that ElectroAir do a terrific job of killing their own offering....
They really, badly need some factual information to replace the disastrous CAFE findings... I think the CAFE test plane had hot rod magnetos to start with, and the gain from EI would be greater on a more normal plane

[Tommy]

Antoine, I was not aware of the specific restrictions in Europe. I wonder if you have the latitude to do such things as re-drill injectors or replace "used" injectors with a size or two up? Also, I would not think that blueprinting (porting, polishing) would not be considered an engine modification. It is really just finishing the job the factory engineered . . . but I could be way off. In terms of benefit, high compression heads would probably deliver the greatest increase in HP (15-20%), followed by tuned exhaust (8-10%), then all the other refinements. I haven't made the move to electronic ignitions yet but my friends who build RVs (Experimental) love them and report noticeably greater climb and cruise (maybe 3-5% more horsepower at high RPM). A side benefit is easier starting. In the US, current STCs permit replacing only one Mag even though one electronic ignition has a built in Mag as a fail-safe. It will take time for the rules to catch up.

First of all, I seriously question horse power gains that are being claimed. In my opinion based on my experience they appear to be extremely optimistic if not down right impossible. Also, based on my experience, if you do realize those kinds of horse power gains, get ready to start seeing all kinds of things (like rods) flying through your crank case including cracked cylinders, cases and other assorted catastrophic failures. Not really a bad thing when it happens on the ground in a race car or dragster, not a good thing to happen in the air. Anything that increases stress on the power plant is not a good thing. Just my opinion of course.

[rwtucker]

First of all, I seriously question horse power gains that are being claimed. In my opinion based on my experience they appear to be extremely optimistic if not down right impossible. Also, based on my experience, if you do realize those kinds of horse power gains, get ready to start seeing all kinds of things (like rods) flying through your crank case including cracked cylinders, cases and other assorted catastrophic failures.

Tommy, There is nothing magic about the factory HP of the M1A and if you look at the Lycoming manual, you will see several normally aspirated 200 HP factory configurations as well as two turbocharged version.

In the case of the work at my home base, these guys are serious mechanics who bench their work on dynos. Beyond that, I have visited two specialty shops: one in California and another in Washington. I'm sure there are many more shops but none that I am aware of that specialize or have even done a lot of work on Diamonds. For the guys around here who build RVs and other experimentals, achieving bench demonstrated 225-250 HP at T/O RPM is not a stretch at all.

As far as rods flying through your crank, other things being equal, higher compression ratios do increase the chance of failure at articulation points, but the picture is vastly more complicated than your opinion recognizes. If you really believe what you say, you might want to take a look at the internal pressures and T/O MP of a P-51 (we have a few of them around here and one of the later models is rated for approximately three atmospheres). Ask yourself how they hold all the parts together with no undue incidence of flying rods or barrels, and all with 1940's technology. Amazing!

In my opinion, you have a greater chance of losing a barrel on an IO-360 by taking off with your oil at 85 degrees than you do managing high compression heads intelligently. One DA40 at Boeing Field did just that. It was stock.

[Tommy]

All I know, is what I know and what I know is what you are suggesting will definitely increase performance, but at a cost. That cost (as I have experienced) will be reduced durability and reliability, something I'm not willing to compromise in an airplane. I strive for performance just as anyone else would. I'm just not willing to go down the path you are suggesting. This has been my experience and I trust my instincts over any facts anyone else may present. I've been down that road. My instincts have been right more often than facts presented to me by others.
I assume you are going to go ahead with the performance enhancements you have suggested. As you have mentioned, pretty much any decent machine shop can perform the mods and tweaks you are eluding to. Honestly, porting and polishing can pretty much be done by anyone in their basement or garage. I'd like to know how it really works out from strictly a performance perspective.

[Steve]

First of all, I seriously question horse power gains that are being claimed. In my opinion based on my experience they appear to be extremely optimistic if not down right impossible. Also, based on my experience, if you do realize those kinds of horse power gains, get ready to start seeing all kinds of things (like rods) flying through your crank case including cracked cylinders, cases and other assorted catastrophic failures.

Tommy, There is nothing magic about the factory HP of the M1A and if you look at the Lycoming manual, you will see several normally aspirated 200 HP factory configurations as well as two turbocharged version.

In the case of the work at my home base, these guys are serious mechanics who bench their work on dynos. Beyond that, I have visited two specialty shops: one in California and another in Washington. I'm sure there are many more shops but none that I am aware of that specialize or have even done a lot of work on Diamonds. For the guys around here who build RVs and other experimentals, achieving bench demonstrated 225-250 HP at T/O RPM is not a stretch at all.

As far as rods flying through your crank, other things being equal, higher compression ratios do increase the chance of failure at articulation points, but the picture is vastly more complicated than your opinion recognizes. If you really believe what you say, you might want to take a look at the internal pressures and T/O MP of a P-51 (we have a few of them around here and one of the later models is rated for approximately three atmospheres). Ask yourself how they hold all the parts together with no undue incidence of flying rods or barrels, and all with 1940's technology. Amazing!

But the average MTBF in those engines was approximately 100-200 hours. Tons of maintenance done for each flight hour. They were really at the limit of engineering and materials science. Far more than 200 HP, but you have to put a lot more horsepower out for a small increase in speed.

Steve

[Antoine]

This is a timelesss topic- I would boil it down to:

- a certified plane (and especially a DA40) is a rigid engineering picture and every aspect of its not so ambitious performance is thoroughly tested to be safe and accordingly certified
- there are many ways to exceed the above performance level, but very few if any would maintain the certification although some make perfect sense.

As far as I'm concerned, I'd be willing to look at porting/polishing, which as said by the OP is not much more than finishing the factory work, but I would not run the risk of replacing pistons.

The experimental world is fascinating, and I would have taken the plunge long ago. Now listen to this sad news:

Here in Europe, Experimental means you have to renew the permit to fly EVERY YEAR, for EVERY COUNTRY you intend to visit. And forget about IFR or even night VFR...

Lucky americans..

[rwtucker]

Antoine,

I agree with your summary. At the end of the day, these are just engines. They are conceived within and conform to the principles of physics.

Increases in HP do not necessarily represent tradeoffs in structural reliability as Tommy suggests. Some changes, fail-safe electronic ignitions for example, increase HP and reliability, including structural reliability due to more complete combustion. The same is true for blueprinting, porting, polishing, balancing, etc. These changes result in increased HP and a smoother, longer running engine that achieves higher TBOs. This philosophy is behind the P-Ponk modifications made by the company in Washington state where pistons are balanced to within a few grams (unfortunately, they do not modify IO-360s).

The IO-360 engines placed in our DA-40s are mass produced to commercial standards. Compared to current capabilities, they are relatively crude engines. No two run the same because they do not balance parts all that closely and they do not optimize the paths by which fuel and gasses flow. This is one reason why the tuned exhausts add approximately 10% HP (largely at the resonant RPM).

I'm investigating your question about porting and polishing, etc. I will let you know what kinds of HP increases the experts say you can expect. It is all new to me. One thing I do know is that an engine modified in this way sounds and runs like a completely different engine. The smoothness is amazing. I thought the DA-40 was relatively smooth until I flew behind these power plants. It is kind of like the difference between riding in a Ford and a Rolls Royce.