Powerflow experience, anyone?

[Pbruce]

It looks like I might have an opportunity to pick up a FWF engine package from a Cessna 177 Cardinal. This one is a parallel-valve 0-360. It is equipped with a powerflow exhaust system. I’ve always been a fan of powerflow. If it could be used on my Patrol, I would do so. I know the end of the pipe would reside outside the cowl, which is fine with me. I’m wondering if all the other tubes and bends would fit under the cowl though. If anyone knows anything about this matter, I’m soliciting opinion and info.

Also available is the Cardinal 3-blade McAuley prop, which in its current form is too heavy. However, if it was equipped with Whirlwind (or other) carbon blades, I wonder if it would be suitable. Again, any informed opinion or info will be gratefully received.

The only other negative is the single drive magneto. Obviously they work well, but I prefer dual so I would have to live with it or trade out the back of the engine, or install dual electronic ignition (most likely option)

thanks

[rv8bldr]

I had that single drive mag in my RV-8 (IO-360-A3B6D). I flew it for 13 years and 600 hours and never had an issue. The new owners are still flying it. I don't know if I got a good one or what, but it always seemed to worked great.

YMMV of course...

Mark

[rodsmith]

Not a big deal to find a different accessory case. I consider the single (dual) mag as adding another level of risk. My Maule M5 had one and I didn't have an issue in 500 hours, but my mechanic knew of two other Maules that went down in Alaska due to them failing. I still find it surprising that the FAA ever allowed them.

[whee]

My sister just bought a 150hp Cardinal so we have been looking at the Powerflow for hard evidence it actually works. A few Cardinal guys have done sufficiently accurate testing that I’m convinced it works. The key data point for me was a solid increase in climb rate. But I doubt the Cardinal Powerflow will fit inside the Patrol cowl. It hangs down a bit.

Whirlwind can reblade your Mac hub. I can’t remember the cost but it was very reasonable. I don’t remember the weight of their blades but I recall it being such that their 3 blade was comparable to a metal 2 blade.

With there being affordable electronic ignition systems available the dual mag would be no factor for me. I’d remove the mag and install electronic ignition.

[Ray Strickland]

Removed mag. Installed dual Lightspeed. Still have dual mag on the shelf if anyone wants it.

[Gary Wallace]

Im sure the exhaust will NOT fit under the cowl. I got an O360 from a Cardinal, single mag mount as well ..the original exaust was with it and not even close to fitting in the cowl. I scrapped it.. i am assumjng the power dlow is the same dimensions a s the stock exhaust. From what i remember it was...as far as the mag, i am now going with electronic ignition for the top plugs and sticking with the mag for the bottom. Likely going to remove the dual mag, and put the drive gear etc on a single mag that will fit on the accessory case. I went eith the vetterman exhaust. Great piece of work. Fit like a glove

[Pbruce]

Thanks Gary. I talked to powerflow. They couldn’t say, of course, but they are sending me some drawings. He did say you could re-weld the tubes in different orientations, at the cost of some efficiency. I was studying their pictures and it looked like the Husky exhaust system from Powerflow was almost the same as the cardinal O-360 system. I reasoned that a Husky system had good odds of fitting on the Patrol. The more I look at it though, I’m starting to think that the exhaust tubes drop too far down and out as they come off the port. I will keep looking at it as long as this engine is a possibility, but it is a pretty long shot.

Which heater options did you select from Vetterman, Gary? And how did you configure your induction system? And if I may, what designator is your engine? There are many re-powered 180 hp Cardinals as well as factory models. Did you keep the prop?

[Ray Strickland]

I used Vetterman’s integrated muffler/heat muff. Good heat.

[nborer]

I can’t help with the Bearhawk installation question, but I can report on our experience with a Powerflow exhaust. Our club has a DA40 that we bought used with the Powerflow exhaust already installed. We don’t have a “before” comparison, but can say we consistently beat the book numbers in cruise. Our CHTs always seem a bit high, but I don’t know if that’s the exhaust or something else. We end up in cruise climb at 24 squared and a little faster to keep temps down and still get acceptable climb rates. It seems to be the real deal if it’ll fit.

[JimParker256]

When I had my Grumman Traveler, I investigated the PowerFlow question quite a bit, as I was looking for better climb performance. Every empirical before/after test I saw showed faster climb and marginally faster cruise, at the expense of a slight increase in fuel burn. (Makes sense that the identical engine would use more fuel to produce more power.) The key is that it improved the exhaust enough that the engine could produce that extra power. I would also add that at least a few of the folks who went to PowerFlow exhausts needed to enrich their carb's mixture settings just a bit to help keep CHTs down in prolonged max-power climbs.

For "full disclosure", I wound up NOT purchasing the PowerFlow, because it turned out that my O-320 engine was already set up with everything except the new pistons and rings that was needed to apply the high-compression piston STC to increase from 150 to 160 (nominally 157.5 for certification purposes). That upgrade got me the improved climb I was looking for, and also dropped the fuel consumption slightly at "book" speeds. Or I could use book power settings, and cruise almost 5 knots faster than book. Win/win.

If you decide to go the PowerFlow route, be sure that you understand the requirement to lubricate the joints in that exhaust system every annual. Many people overlook it, and wind up having problems with their exhaust systems. It's not a big deal to do it, just another item on the annual checklist. (It's part of the ICA, but many just ignore it - to their wallet's peril.)

[Pbruce]

Good info Jim. Thanks. Powerflow sent me drawings of the Husky system and of the Cardinal. I reasoned that odds were high for a good fit if the Cardinal system was contained within similar dimensions to the Husky, and if it fits a Husky, it probably will fit the Patrol. Unfortunately, I don’t think it will work. The Husky system starts tapering inward, away from the full 31” width about 5 inches below the exhaust port. With the Cardinal it’s more like 12” of drop before they bend in. Seems like the outer forward corners will encroach on the cowling. Oh well. I think I can get the engine with or without. I’ll probably go with Vetterman, since I’m not really much of a mechanic. Bolt-on, made-to-fit stuff is better for one such as me.

[Gary Wallace]

Pbruce....i went with vetterman crossover exhaust with the dual heat muffs. Again...fit like a glove inside the cowl with good clearance. The powerflow will not work for u im sure...if its the same as the cardinal O360 original, muffler up front a bit beneath engine. Not near enough room even if u were to shorten up all tubes a bit im sure. My engine is O360A1F6D. It was originally on a cardinal, then stc to a aeronca sedan with the same exhaust. Had a seaplane borer prop on it, fixed pitch, which i sold and now have a hartzell HC-c2yr-1bf 8275-2. 80 inch prop

[Gary Wallace]

I expect yours will also be the O360A1F6D

[zkelley2]

Most of the certified aftermarket exhausts just get close to giving you rated horsepower. Factory exhausts are so ill thought out and restrictive they make your engine produce less than the engine manufacturer rates them for. Lycoming for example rates their engines using fairly short straight pipes. No muffler, no heat shroud, etc.

You shouldn't expect much of anything in cruise speed from HP. A knot maybe. Speed is about drag. Takeoff distance and climb is about HP. For example, if you cruise in a patrol at 130kts all out on 180hp, to get 135kts you need 21 more HP. And at our ~.5lb/hr/hp at full throttle that's 2gph more for 5kts.

Last year whirlwind re bladed my McCaulley for $1650 per blade and overhauled the hub for $1020.

[Pbruce]

Good info on exhaust in general. Yes, you are quite right about the futility of chasing speed with HP alone. . I actually wasn’t trying to chase speed, or even horsepower for climb (Vetterman will probably scavenge equally well and will fit, for certain). Just wanted to take advantage of a quality exhaust system for cheap. I’m all but certain it’s not going to work though, after hearing back from this group and carefully perusing the drawings.

Thanks for the Whirlwind pricing info, Z. The original 2-blade prop looks good to go as is, but it’s only 76” diameter and weighs about 59lbs with blades. Overhaul status is TBD. Putting modern carbon blades on while overhauling the prop will cost about $254 per pound of weight saved. Of course anything you touch on the power plant will be costly. No wonder fixed pitch props are popular!

[jaredyates]

A little off topic, but be advised that terminology with the prop folks is very nuanced. If you say "overhaul" they have a particular set of steps to follow that includes grinding material off of the blades whether they need it or not. They can inspect and repair the prop, including new seals and paint, and it will look and fly perfectly but still extend the life of the prop vs an overhaul.

[whee]

Jared’s comment on prop overhaul is right on. I’d suggest an IRAN. 180hp Maules came with 76” props which I think at just too small for that type of plane but they do work.

I’ve been studying tuned exhausts and intakes like crazy. I’d have to agree with zkelly on the Powerflow being more about eliminating the restrictive factory exhaust rather than actually tuning the exhaust. I’ve ran the numbers every which way and talked to performance exhaust guys and I can’t get tube lengths that are even close to those of the Powerflow. IDK if Vetterman exhaust is tuned but it’s certainly better than most factory systems. Exhaust scavenging takes very specific primary tube lengths that vary with camshaft profile, engine RPM, valve size, cylinder bore size, etc.

[jaredyates]

I'm running a 76" prop that came off of a 180hp Husky, because it was a good price. The other thing about the 76 is that on a 4-cylinder engine you are supposed to run a harmonic balancer for anything bigger than 76, whatever that is worth. We did an article about how theoretically the 80" prop should be different based on Lowry's calcluations (https://bearhawk.tips/1647) but have not done much real testing.

[Pbruce]

Interesting. Are you running a 76” on your 4-place Jared? And by harmonic balancer, are you talking about a counterweighted crank? This engine does have 6 lbs of counterweights on it. (O-360-A1F6D) I thought that was a negative attribute since I’m trying to keep the weight down but perhaps it’s good? I think Whirlwind says counterweights are not needed on an O-360 up to 8.5:1 compression which this is. Above that compression or on the 0-375 they seem to require the counterweights. Aerosport Power told me directly that as long tas you stay below 195 hp you don’t need the counterweights. A local engine builder told me that it will eliminate the restriction for transient operation around 2300 rpm, but I haven’t seen that documented anywhere.

I appreciate opinions I’m seeing here from Z and Whee regarding exhaust: PF and Vetterman, et al are working successfully at mitigating the poor performance of stock muffler systems, but are probably not yet achieving large tuning benefits due to the practical limits of size and cost which the market (me) demands. Still, what a great situation we are in with experimental, that we can use this cool stuff which is custom made for us at a fraction of factory cost.

This discussion has been very helpful in my assessment of this engine (still looking good) prop (ditto) and exhaust (probably not). Thanks everyone! What is an IRAN, by the way?

[gregc]

IRAN - inspection and repair as necessary