Fuel Servo Selection: Bendix vs. Airflow Perf

[Redwagon]

So the engine shop has come back to me with a great question re the IO360M1B destined for my RV8. They are giving me a choice between the Bendix/Precision Airmotive RSA-5 (or silverhawk experimental version) and the Airflow performance FM200. This large & well known shop actually prefers the Silverhawk and feels more comfortable with that over the FM200, but has indicated that there is less pressure loss (more HP) from the FM200 and they'll go that route if I prefer. (as a funny aside, they have all their FI servos rebuilt by AFP anyway)

I've talked to Don at Airflow Performance (very helpful!) and have seen some of his posts here. Looks like the downside of the AFP system is that its 3/4" longer out the front and not as many shops are familiar with it. There is also the purge valve return line to install, but thats not a big deal.

So of course I want more MP at altitude (the throttle body on the AFP is 3 1/16" vs 2 5/16" on the PA Silverhawk), but a little voice in me likes the conservative bendix standard. So there I'm stranded. :-)

I'm planning on using the Rod Bower ram air induction, not sure if that 3/4" extra length will cause me grief as I'm a ways away from cowl work etc.

Looking to the group here for input/comments and reasoning on one versus the other......

Tim

[dav1111]

Go with the Silverhawk. I just installed one I bought from Aircraft Spruce on my ECI kit engine and it is really nice looking.

[revenson]

I'm facing the same decison right now.

I'm leaning towards AFP. I appreciate the support Don has provided on this site, and secondly, their kit is complete for RV's (except for hoses). I haven't seen a complete kit available for Silverhawk. If someone knows differently, I'd sure like to hear about it.

Roger, Tucson, AZ

[erich weaver]

Don at AFP goes the extra mile and works with you on any issues you have till its right, will help you set up your injectors to go lean of peak when you are ready, and seems to monitor the VAF forums and reply as warranted. Couldnt ask for more.

erich

[rocketbob]

Price a replacement diaphram or any other part from Precision, then price the equivalent from Don. I'll bet you'll quickly make up your mind then.

[Geico266]

There is no choice. AFP is the only way to fly.

Call Don @ Airflow Performance and interview him, then call Precision. Precision was going to enforce their $200 minimum on my order when I called to buy a $.70 gasket to conform to THEIR AD on the hex nut. They told me "No exceptions", then a month later they were giving the gaskets away for free at SnF.

http://www.airflowperformance.com/

Call Don.

[mannanj]

Originally Posted by rocketbob

Price a replacement diaphram or any other part from Precision, then price the equivalent from Don. I'll bet you'll quickly make up your mind then.

Ditto! If AFP's servo and Rod's air inlet will fit your cowl, I would definitely go that route. If the 3/4 inch extra length gets you; the Bendix RSA-5 would be my next choice.

Ditto on Don's service. All the people in his shop are top notch. They all go out of their way to help

[AlexPeterson]

A representative from Precision who came to one of our local RV meetings indicated that even though the system is similar/identical to the certified systems, authorized shops are not supposed to work on the experimental ones (Silverhawk), requiring work to be done by the factory only. This was 6 or 7 months ago, don't know if it is still the case. I've heard many say that they want the Precision experimental one so on the road work will be easier. May not be the case.

[Geico266]

Originally Posted by AlexPeterson

A representative from Precision who came to one of our local RV meetings indicated that even though the system is similar/identical to the certified systems, authorized shops are not supposed to work on the experimental ones (Silverhawk), requiring work to be done by the factory only.

This is precisely why you should NOT use Precision, they do not support experimental aviation. Airflow Performance is in business to serve experimental aviation, support them.

[f1rocket]

Just another ditto for Don at Aiflow Performance. I went to his shop to have my Rocket injectors tuned. Great people, great service, and he supports us in experimental aviation. We need more vendors like Don.