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Avstar Or Airflow Performance

decathlon737

Well Known Member
Benefactor
Trying to get my Lycoming order ready and need some advice, I have the option of Avstar or Airflow performance fuel injection. Jeffery Shans at Lycoming says I would have to modify cowl for Airflow performance, I really don't want the complications of return lines to the fuel tank, can someone weigh in as to modifications to cowl? Pro's and con's of either fuel system?
I'm familiar with my last Bendix system but no experience with either of my options. They are both forward facing, so what cowl mods need to be done?
Thanks in advance.
 
Trying to get my Lycoming order ready and need some advice, I have the option of Avstar or Airflow performance fuel injection. Jeffery Shans at Lycoming says I would have to modify cowl for Airflow performance, I really don't want the complications of return lines to the fuel tank, can someone weigh in as to modifications to cowl? Pro's and con's of either fuel system?
I'm familiar with my last Bendix system but no experience with either of my options. They are both forward facing, so what cowl mods need to be done?
Thanks in advance.

The AFP FM-200 is longer and has no entry flange. The AFP FM-150 has the same footprint as the Avstar or a Bendix RSA-5, including mount flanges. I seem to recall some builders were having a linkage issue with the FM150. Ask Don Rivera about it.

The FM-150 has a disk mixture valve (low leakage) thus doesn't need a purge valve, thus has no need for a return line.

I'd like to add that I think you're smart, and a chick magnet, and a truly great aeroplane builder ;)
 
I have the FM-150 and no cowl modification was required, only a bit of modification to the snorkel, nothing too fancy or difficult. And of course as Dan mentioned, no fuel returns are required.

I hope this helps.
 
Well maybe a chick magnet! So you would recommend AFP FM-150 and deal with linkage problems over the Avstar?

Well, it comes with pick-up-the-phone service from Don.

I'm not saying there is anything wrong with Avstar, and of course it's only my opinion, and my opinion is no more valid than any other person's opinion, and I hope you won't be upset because I've offered it ;)
 
For some Dan, your opinion may not be much, but knowing you for as long as I have, your opinion means everything to me.:)
 
I am not sure what type of support you would get from the Avstar folks, but I can tell you that Don is awesome with customer support. Every single time I have interfaced with him I have learned a lot. I recently purchased an FM-150 to replace my FM-100. Hope to install that soon.
 
Just chose the AFP-150 over the SilverHawk for my new IO-370.
Ran the FM-200 on my previous engine for 10 years with 0 issues.
The team at AFP rocks.
 
Totally worthless advice, but I have the 150 on my 390 that hasn't flown yet... but is sure is pretty!
 
I've never heard of anyone who has ever been disappointed by Don's customer service and tremendous depth of knowledge.
 
Parts

Its may not be a big deal, but consider parts availability and overhaul cost.
Overhaul servo every 12 yrs
Overhaul Flow Divider 8 yrs

Where can you get parts for Airflow Performance (other than Airflow Performance)?

Parts for the Avstar and Precision Airmotive units are available from multiple sources since these units are installed on certified aircraft.
 
Parts for the Avstar and Precision Airmotive units are available from multiple sources since these units are installed on certified aircraft.

Right. And companies that supply parts for certified aircraft NEVER go out of business. :eek:
 
Its may not be a big deal, but consider parts availability and overhaul cost.
Overhaul servo every 12 yrs
Overhaul Flow Divider 8 yrs

Where can you get parts for Airflow Performance (other than Airflow Performance)?

Parts for the Avstar and Precision Airmotive units are available from multiple sources since these units are installed on certified aircraft.


It's a fair point. I don't know if Don designed around standard replacement components, like servo diaphragms, and I wouldn't expect him to tell me. Pretty sure you could substitute any brand of flow divider.

Anyway, it doesn't bother anyone making avionics purchases.
 
Right. And companies that supply parts for certified aircraft NEVER go out of business. :eek:

You are CORRECT airguy, most companies go out of business... specifically why its important to have a good source for spare parts.

The repair parts for Precision/Bendix/Avstar are available from multiple sources, and are manufactured by multiple companies. For instance, you can get rebuild kits for old Bendix FI units from different manufacturers and different vendors. AFP parts only come from AFP.


It's a fair point. I don't know if Don designed around standard replacement components, like servo diaphragms, and I wouldn't expect him to tell me. Pretty sure you could substitute any brand of flow divider. Anyway, it doesn't bother anyone making avionics purchases.

The Airflow Performance units do not use the same parts as standard components... I did ask when deciding which unit to purchase. Yes, you can use a Bendix/Avstar/Precision flow divider with an AFP FI unit (and vice versa).
Its easy to swap one brand of mechanical FI out for another (like avionics)... so no matter what brand you choose it will be ok and no big deal to switch when its time for overhaul.

I believe AFP is the best new mechanical FI unit for the money and has the best support, but advantages to the Bendix/Avstar/Precision models are a network of rebuild parts suppliers and A&P's out in the field that are familiar with the units.
 
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Just an opinion

You sign up for obsolescence the moment you buy something. A big lesson learned from 50 years in manufacturing and automation is the response " we don't make that model or support parts, but we do have the new Whizzee model you can upgrade to".
That said, what is the probability you will keep the plane or outlive the FI system? It is hard to refute Don has carried mechanical FI forward more than any other source.
If you are NOT committed to a dinosaur, use an SDS FI system, that solution will be around until EAB is nuclear ;)
 
Be fair. IIRC Bendix/Avstar/Precision have gone thru changes of ownership.
AFP does not necessarily end with Don. When he is done, someone else will probably pick up the company and maybe even grow it.
I have FM-150, it works great. My son has Bendix, it works great, but cost of service is much higher.
If you already have one, I'd probably stick with it. But I didn't, so I went with Don and it's been all Sunshine so far, plus it cost less.
 
AFPs service is outstanding.. When you call you get the 'man' or the other 'man'
(no offense Colleen!) You'll talk to the guys that designed it and built it.
Doesnt get any better than that.

Tom
 
All I can say is 100% of the AVSTAR FCU's I have seen get taken off and put on the fuel flow bench and get corrected to the tune of 12-15% more flow.

Just an observation.

Buy the Precision if you are not going with Airflow.
 
I've got an AvStar fuel servo, and it's been working flawlessly for 315 hours. I did some GAMI testing and determined that cylinder EGTs were peaking so close together it wasn't worth changing injector nozzles.
 
Avstar/Precision/Bendix

Van built the cowling and plenum to fit the Lycoming Bendix throttle body mounted on the forward facing sump. (Lycoming I0360A1B6) If you use the other system you will be in for a major change of your cowling, and a complete re-make of the plenum. Why would you do that?

If you like building more than flying, contact Rob Reese at 52F. He installed Airflow performance and developed a mold for the modification required to the cowling. That will save you redoing the months of work Rob did.

The other reason I hear for Airflow performance is the ability to recirculate cool fuel prior to a hot starting is a big plus...... Non sense! It is easy to start a hot, fuel injected, Lycoming without the extra cost and complication. I've been hot starting the Doll for nearing 19 years now. It's easy. Do yourself a big favor and use the Avstar/Bendix system. Don't butcher you nice new cowling, and save months of extra work.

If Airflow performance has a model with the same footprint as the Avstar/Bendix unit, then maybe that model would work as well. Don't forget that Van makes a bell crank unit that bolts to the sump for the Avstar/Bendix style throttle body. It reverses the travel to the mixture lever on the throttle body keeping the mixture control cable away from the exhaust.
 
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The other reason I hear for Airflow performance is the ability to recirculate cool fuel prior to a hot starting is a big plus...... Non sense! It is easy to start a hot, fuel injected, Lycoming without the extra cost and complication.

On 100LL, sure, I did that quite a bit on my RV and on the 172 with the same engine, and you're right.

Now try it with 91E10 on a hot day, and get back to me. The AFP purge valve I installed on my Bendix system makes it just like a cold-start now.

Quite a few folks are running nonstandard fuels these days, just sayin'...
 
I bought a new IO-360M1B from Van with the Avatar horizontal induction setup. There were zero complications using Vans cowlings and FWF kit. Everything fit as advertised-very simple installation. No fuel return line required, made fuel system install a snap. Hot starts have never been a problem if they are performed properly.
 
I bought a new IO-360M1B from Van with the Avatar horizontal induction setup. There were zero complications using Vans cowlings and FWF kit. Everything fit as advertised-very simple installation. No fuel return line required, made fuel system install a snap. Hot starts have never been a problem if they are performed properly.

I agree. If the engine is properly set up with a healthy ignition system then it is almost always pilot technique that makes starting a hot fuel injected Lycoming easy or difficult. Since the Wright brothers, pilots have been taught by pilots. If the instructor has poor technique and teaches it to his students, that poor technique is pasted down over and over again. Like the old saying says: You can always tell a pilot, you just can't tell him very much!

Sadly, hot starting is easy and requires the pilot to do next to nothing to be successful.
 
Just for the sake of data, and you must have a pretty accurate fuel flow calibration before submitting results. I would be keen to see the following for all those with AVSTAR fuel control units (540, 360 & 320 engines).

Takeoff and going through 300 feet or so (stable data) log the following;

MAP, RPM, Fuel Flow, your HP rating.

:)
 
All I can say is 100% of the AVSTAR FCU's I have seen get taken off and put on the fuel flow bench and get corrected to the tune of 12-15% more flow.

Just an observation.

Buy the Precision if you are not going with Airflow.

Corrected, as in outside the specification, or corrected as not rich enough to meet your recommendation?
 
I know I had at least 3 customers that were suffering from low fuel flow resulting in overheating (plugs also showed evidence of overheating).
Don't recall if they were Silver Hawk of Avstar units on the 360.
 
Avstar or Bendix style fuel control

I have had great performance and zero issues with my Avstar fuel servo @600hours.

In addition it works well with the Vans cables and linkages, with just a minor mod to the Vans snorkel, and easy to adjust idle and idle mixture, and goes well with my keep it simple stupid and light motto with no extra widgets to install. There is a method for hot engine starting that will be needed.

I'm sure the AFP is a great product as well, but I'm just sharing my experience the Bendix/Avstar style of fuel controls.
 
Corrected, as in outside the specification, or corrected as not rich enough to meet your recommendation?

Not my recommendations, thanks for asking :rolleyes:

Not meeting Lycoming spec, not meeting the two best engine shops in Australia's expectations and the Lycoming reps expectations.....and a combination of all of the above.

One needed about 15-20% more flow to reach the top end of the range. Having said that the specification is very wide. The old timers will tell you they need to flow at the top end. Lycoming's man based in NZ confirmed a BSFC at full rich should be 0.58 or close to it.

This has been going on for several years and others here on VAF have found the same.
 
I found this post a bit confusing.
If I understand correctly the Avstar requires little to no cowl modification and not return lines? Would this be correct for a RV-14?

I would be curious to know what Bill the original poster decided on.
 
AFP 150

Went with the AFP, haven't flown yet so can't report performance, very minor snorkel mod to make fit, looks top notch and the gold anodizing sure is pretty.
The modification is easy peasy compared to the canopy.
YMMV
 
I purchased a used aircraft and called Dan to discuss some issues. I have not purchased anything from him and was not even sure it was his unit. He took my call, researched the airframe and identified the unit and answered all my questions. I know who I would purchase from in the future.
G
 
All that has been mentioned are differences in installation and customer service.
Are there any notable performance differences?
 
All that has been mentioned are differences in installation and customer service.
Are there any notable performance differences?

When benched at 1560 lbs per hour, pressure drops were 10" H2O for an AFP FM-150, vs 12.75" for an RSA-5, which has the same bore configuration as an AvStar. 2.75" H20 is 0.2" Hg, not a big deal....until neck and neck with your buddy ;)

BTW, the online 10% Black Friday code at AFP is "Turkey 19". Monday is a little late, but...
 
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