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Injecting the 0-320

R

rossdn

I'm New Here
Hi all,
We are heading for engine installation in the RV8, currently have a 0-320 (160hp) and am looking at the possibilities of injection for it (probably a silverhawk). A couple of questions for those 'in the know'. May be stupid but is the silverhawk mechanical injection? What could an expected power increase and fuel economy increase be?
How have you all found the silverhawk and is there a better option?
And any other thoughts/opinions you might have...

Cheers
Ross
 
rossdn said:
Hi all,
We are heading for engine installation in the RV8, currently have a 0-320 (160hp) and am looking at the possibilities of injection for it (probably a silverhawk). A couple of questions for those 'in the know'. May be stupid but is the silverhawk mechanical injection? What could an expected power increase and fuel economy increase be?
How have you all found the silverhawk and is there a better option?
And any other thoughts/opinions you might have...

Cheers
Ross
Click to expand...

Yes the Silverhawk is a mechanical injection system.
No power increase.
Economy should increase because of better (equal) fuel flow to each cylinder and much better leaning. (Guess would be no greater than 8% better / less fuel flow. Actual fuel savings may not be measurable.)
As I understand it, the SilverHawk is an EXPERIMENTAL clone of the certificated Bendix RSA-5 unit.

Another option is the Airflow Performance fuel inject system. It is reported by engine building shops to have less pressure drop across the servo / air flow sensor and that would possibility mean slight more horsepower.

Hope this helps. I am sure others will chime in with more info.
 
Silverhawk/Bendix is horizontal induction. Your cowl will be different. My understanding is the parts are interchangeable with Bendix servos.
 
Silverhawk

I converted my O-320 D3G (vertical induction) to Silverhawk FI and I love it! Easy starting, even hot starts, never fails. Vertical induction requires the 0-360 bottom cowl.
 
Awesome! - Sorry can't help with the injection question, but I am building a RV-8 QB in Wellington, feel free to drop by if you're ever in town.. Hugh 021901099
 
jcbarker said:
Silverhawk/Bendix is horizontal induction. Your cowl will be different. My understanding is the parts are interchangeable with Bendix servos.
Click to expand...

The Silverhawk on my new Mattituck IO-320 is vertical induction, so it obviously comes both ways.
 
jcbarker said:
Silverhawk/Bendix is horizontal induction. Your cowl will be different. My understanding is the parts are interchangeable with Bendix servos.
Click to expand...

The fuel injection can be mounted in ANY position. Only the carb with a float is sensitive to mounting position. There are some carbs that can be mounted horizontal.
 
Bendix

The Bendix/Silverhawk or Airflow Performance can be also be adapted to a bottom mount sump using an Airflow Performance angle adapter. Facing the injector forward will provide some ram air increase which does translate to increased power. The important factor is better fuel economy, Typically arount 1 gallon hour better than carb on four cylinder. Increased fuel economy depends on how bad the original carb setup was-none are perfect, some are really bad.
 
Find a copy of the Lycoming Operating Manual - you will see that the Injected engine requires approx 0.5" additional manifold pressure to achieve the same power when other parameters are the same. So don't change to FI for extra power.

Cost is a negative for the retrofit since you will need to purchase the silverhawk plus an installation kit with the injector tubing and other mounting hardware. (Lycoming has a service instruction outlining the location of fittings and brackets. Approx $2000+ for the kit (talk to Aerosport). Don't foget the sniffle valve.

The marginal cost for the IO-320 versus the O-320 is minimal if you are buying a new engine.

The electric fuel pump/filter/bypass valve is another $500+

As someone saiid -you will need the 360 cowl. The Silverhawk servo is nearly 1" longer than the MA4-SPA carby. So either you have to get creative with how you mount the servo and revamp your FAB or spring for the new cowl.

It's all doable but only you can decide if it is worth the effort.

Doug Gray
 
Thanks all...
I'm becoming less enthusiastic by the day. We have the engine with the carb/mag setup and have ordered the appropriate cowling. The more I think about the cost+labour+hassle to set it up, when all I want to do is fly the plane, the more I think... keep it simple.. The additional cost would take 300 hours + to pay off.

Thanks all

Cheers
Ross
 
Ross, another option you might consider is a throttle-body injector. Ellison made the only one for years, but now that their patent has run out others are entering the market at more reasonable prices. Rotec being the most mature design as near as I can tell.

A few people have them installed in RV's now, search here to find a couple of threads on the Rotec. I'm just waiting until I have the spare money... :). The main benefit is that it's a drop-in replacement for your stock carb... No changes to cowling. You just need to figure out control cable routing.
 
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