Grumman Tiger power flow exhaust experience

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Radpilot

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Radpilot
I posted to dedicated Grumman website but no response:

I have a 2004 AG5B Grumman tiger, 180 HP lycoming. Flew today in 97 degree weather at sea level way underweight and my climb performance was poor...I'm gonna say 500 fpm. Maxed at 2100 rpm leaned on initial takeoff roll, 2350 on initial climb in pattern.

I have been strongly considering the powerflow stc prior to today. A mechanic I use, also a powerflow dealer, said it wasn't worth it. Others I read on internet swear by it. I would like opinions from anyone who has it installed in a 180hp, ag5b tiger, not a cheetah or traveler. Worth it? What did you see in performance... takeoff climb, ceiling? Did you need to adjust prop pitch after? Is overheating a problem? Is it more noisy? And lastly, if you are in the Northeast or near it, could I possibly fly it with you to see for myself? I'm not too worried about any fuel savings with this...I want to feel safer on climb on hot days and high da. Also, if any of you use 1/3 flaps to improve climb, please let me know your exact procedures....speed at rotate, flaps in through full takeoff roll out or just partial? when do you remove flaps in climb, etc.

Many thanks for your time with thoughts and opinions!
 
I was fighting a hot cylinder(s) issue on my Cherokee and Powerflow came up as a possible solution, so I called them. I can only say that their support (for a non-customer) is outstanding. Their technical guy worked with me for several weeks having me collect data to get better insight into the problem. They said, that while their product would lower cylinder temperatures, they weren't comfortable making that recommendation until we understood the problem better (I had been chasing it with my A&P for a year). I would highly recommend you give them a call. They are very knowledgeable and probably one of the most ethical companies I have ever dealt with.
 
Radpilot said:
I have a 2004 AG5B Grumman tiger, 180 HP lycoming. Flew today in 97 degree weather at sea level way underweight and my climb performance was poor...I'm gonna say 500 fpm. Maxed at 2100 rpm leaned on initial takeoff roll, 2350 on initial climb in pattern.
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I've only flown AA5B's and not AG5B's but those numbers sound off. It seems to me that the only way a Powerflow is going to help is if your stock exhaust system is plugged.
 
Definitely worth a call to the Powerflow people, they do have excellent customer service! Do have a Powerflow exhaust on a Cherokee 140 (O-320). Very satisfied! From the view of quality of materials and safety, a big improvement. Did see an increase in climb - not so much for cruise. It will make a difference in sound, the Powerflow has a "throatier" pitch. Can't say there was much difference in fuel burn, maybe a tad less.

As mentioned above, depends on the stock exhaust you have. Powerflow systems don't always result in improvement. I needed a few new exhaust parts anyway, so it was a no-brainer to go that route. More than happy to show you the set-up, I'm based in Quakertown PA (UKT).
 
probably you have considered/done already;
-What do the performance charts say to expect?
-is the tach mechanical? (a digital one would be more believable)
and then, is it making rated rpm?
-timing right on the money?
-last compression test results, how long ago?
-how do the plugs look?
-leaned correctly? What is climb fuel flow?
-prop pitch?
 
Radpilot said:
I posted to dedicated Grumman website but no response:

I have a 2004 AG5B Grumman tiger, 180 HP lycoming. Flew today in 97 degree weather at sea level way underweight and my climb performance was poor...I'm gonna say 500 fpm. Maxed at 2100 rpm leaned on initial takeoff roll, 2350 on initial climb in pattern.

I have been strongly considering the powerflow stc prior to today. A mechanic I use, also a powerflow dealer, said it wasn't worth it. Others I read on internet swear by it. I would like opinions from anyone who has it installed in a 180hp, ag5b tiger, not a cheetah or traveler. Worth it? What did you see in performance... takeoff climb, ceiling? Did you need to adjust prop pitch after? Is overheating a problem? Is it more noisy? And lastly, if you are in the Northeast or near it, could I possibly fly it with you to see for myself? I'm not too worried about any fuel savings with this...I want to feel safer on climb on hot days and high da. Also, if any of you use 1/3 flaps to improve climb, please let me know your exact procedures....speed at rotate, flaps in through full takeoff roll out or just partial? when do you remove flaps in climb, etc.

Many thanks for your time with thoughts and opinions!
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Its been quite a while since I was flying a tiger, but those numbers make me think you are NOT making full power at full throttle. I'd be looking at plugs/compression/fuel flow/airflow. Something is not right.

Powerflow should help a LITTLE bit with its tuned exhaust, and eventually pay for itself over hundreds of hours... but it will not fix an engine that is not able to develop full power.
 
Thanks for your thoughts as they were helpful in leading me to have the plane thoroughly checked. Here is an update. I tested static rpm (leaned on hot day) and it was 2150, below lower limit (2175). I had mechanic look into it. Engine is 1100 smoh. Compressions were excellent (79, 79 , 70, 74). Oil and filter were clean, still awaiting full analysis. The spark plugs were normal wear and tear worn and i was advised to change them so they were replaced. That brought static rpm up to 2250, in normal limits. I was a little surprised no mention was made of the plugs at annual/prebuy 6 months and 35 hrs flight time earlier by a different a&p. They also found a crack and a little movement in this honeycomb like plate inside the exhaust muffler that may have altered flow of exhaust gases and increased back pressure of the engine. When the exhaust was replaced, static rpm remained at 2250, midway between the low and high limits. With all deemed in good order flew today at oat of 86 and da of 1600 and performance definitely felt improved.
 
Radpilot said:
Thanks for your thoughts as they were helpful in leading me to have the plane thoroughly checked. Here is an update. I tested static rpm (leaned on hot day) and it was 2150, below lower limit (2175). I had mechanic look into it. Engine is 1100 smoh. Compressions were excellent (79, 79 , 70, 74). Oil and filter were clean, still awaiting full analysis. The spark plugs were normal wear and tear worn and i was advised to change them so they were replaced. That brought static rpm up to 2250, in normal limits. I was a little surprised no mention was made of the plugs at annual/prebuy 6 months and 35 hrs flight time earlier by a different a&p. They also found a crack and a little movement in this honeycomb like plate inside the exhaust muffler that may have altered flow of exhaust gases and increased back pressure of the engine. When the exhaust was replaced, static rpm remained at 2250, midway between the low and high limits. With all deemed in good order flew today at oat of 86 and da of 1600 and performance definitely felt improved.
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That is all good. How much time on the mags?
 
Everything I've read and personal experience with a couple of O-360's (C177 & C172/180hp) and a couple of O-320's have lead me to the following beliefs:
1. The Power Flow system is really great for o-320's with stock exhaust systems. Noticeable and documentable performance gains.
2. When installed on a O-360, not so much. no documentable performance gains.
3. If you are looking at replacing an exhaust system because of age/rot/whatever. The power flow might make sense.

My dad had a Cardinal with a good engine monitor. He ran tests before and after, no improvement, But it did sound different. I could tell it was him coming in before I could see him.
 
You will see a bigger difference with a re-pitched propeller than the exhaust.
 
Grum.Man said:
You will see a bigger difference with a re-pitched propeller than the exhaust.
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What is your opinion of the best pitch for the AG-5B prop for a combo of cruise speed and climb performance for the occasional take off at a 2300 ft field on a hot day? I've heard 62. Is 63 really that different?
 
Radpilot said:
What is your opinion of the best pitch for the AG-5B prop for a combo of cruise speed and climb performance for the occasional take off at a 2300 ft field on a hot day? I've heard 62. Is 63 really that different?
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I hope it's clear on both ends unless you are flying solo. But yes 62 is good. You will gain 100rpm static which is probably 10 or more hp.
 
Me thinks you got other issues other than a power flow exhaust.
 
Grum.Man said:
I hope it's clear on both ends unless you are flying solo. But yes 62 is good. You will gain 100rpm static which is probably 10 or more hp.
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It seems you are very knowledgeable with regard to the Tigers. How much speed loss would you encounter in cruise at 75% power with a 62 vs. a 63 (my understanding being that 65 is best cruise and 61 is best climb)? I'm actually pretty surprised going from 63 to 62 would have that much effect. What do you estimate such a prop re-pitching would cost, including removal, re-pitch and re-install?

Yes, would only use a runway that short if very clear on both ends-- the one I was referring to had flat farmland on both ends as far as the eye could see.
 
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