Dbro172

Dbro172

Well Known Member
Building an RV-9A here (may not matter to this...).

What are your thoughts on benefits of either the injected or carburetor Lycomings. I've flown both, in regards to brand new engines it seems the small price to pay for the "IO" over the "O" is a no brainer... but i havent settled on a "brand-new" engine yet. I would like to select an engine in order to finalize avionics harnesses, tank lines, and well, everything else.... it's just nice to commit and put it behind you.

So, any advice?

Thanks,

Derek RV-9A #92103
Empennage - Complete
Wings - leaving Vans tomorrow :D
 
Injection

IO engines are much more likely to tolerate lean of peak operation. Even rich of peak the fuel consumption will be noticeably less on the IO, as much as one gallon hour less.
 
IO vs carb

Make a decision on the engine before ordering the cowl. I decided on the IO 320 D1A after ordering the cowl. The fuel injection servo hangs down more than a carb requiring the cowl with a deeper snout. Had to cut the origional snout out of the cowl and order the deeper snout to glass in. Could have ordered the correct cowl for the IO engine to start with and saved a lot of labor. The throttle and mixture cables will need a somewhat different routing thru the firewall so they won't be too short.

I ordered the IO 320 D1A w/ prop from Vans. Has the roller tappets. Runs great.
 
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If you buy an O-320 you can convert it to an IO-320. Just call up Don Revira at Airflow Performance an he will set you up. Yes, it is costly but you can always sell your O-320 carb to help ofset the cost.

There are some advantages to running a carb, but I'll let the other tell you what they are.
 
Computor Threats

Be careful before clicking on that web site link above, I did and my Norton site check went haywire.

It says it has 62 computor threats associated with it!!!!

Norton just blocked it in my case, perhaps someone in the states can ring the site owner and tell them.
 
Derek,

I'm right around with you (#92087 finishing my emp... your wings are already shipping? :eek:). I'm kind of interested whether there's any difference between carb'd and injected when it comes to running on mogas. If there's really up to a 1 GPH difference in operating costs, I may have to reconsider (was initially thinking O-320 myself).

Personally, and this may be bunked advice, but some builders I spoke to last year before starting my project seemed to be leery about having fuel running at much higher pressure for injected vs carb'd running under their seats in the cockpit. They seemed to think a fuel line rupturing inside spewing on a few PSI was somehow more manageable than a line running at who-knows-what PSI (20 PSI+?).
 
fuel

The high pressure fuel is only between the pump and the injector. On the lyc the electric pump is used for takeoff and landing and is turned off at all other times unless the engine driven pump fails. If you're concerned about the high pressure fuel, put the electric pump near the firewall and build a stainless box around it.On the Continental powered airplanes many operators leave the electric pump on all the time. Thousands of airplanes out there with fuel injection and plumbing in fuselage. No problem if everything is properly maintained.
 
WAM120RV said:
Be careful before clicking on that web site link above, I did and my Norton site check went haywire.

It says it has 62 computor threats associated with it!!!!

Norton just blocked it in my case, perhaps someone in the states can ring the site owner and tell them.
Click to expand...

OK, try this site.
 
Same result

Sorry Bill,

I am getting the same results Norton just blocks it saying malicious site.

I do not want to do these people harm as I am interested in their products but something is wrong. Can someone ring them to see whats going on?
 
Derek,

Have you seen this thread?

Fuel Consumption.
Lycoming's 0-320 Operators Manual, gives the same fuel consumption for the carb and injected engines for rich (best power) mixture settings. For example at 65% and 2,350 rpm both engines use 8.8 g/h.

Also from the Operators Manual it seems to show the injected engine having slightly better fuel consumption at Best Economy (around Peak EGT) than the carb engine. For example 7.2 g/h verses 7.5 g/h at 65% power. These figures may be a bit rubbery as I had to compare two different types of graphs.

The actual situation with RVs is a bit more complicated because many RVs with carbs have at least one electronic ignition which may make it possible to run LOP and achieve similar fuel economy to injected engines running LOP.

Most RV9/9As have either an 0-320 or a I0-320 and the best fuel economy figures I have ever seen quoted for these aircraft on VAF were from Pete Howell's carb 0 320 9A with dual P mags. My dual EI, carb 0-320 9A uses about 0.2/0.3 g/h more than Pete's and I suspect that this is partly due to having to retard the timing by 5 degrees (as per Lightspeeds instructions) for my higher compression engine.

Fin
9A
 
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fuel consumption

The examples I gave were for the 160 hp Piper Apache with carbs vs the injected Twin Commanche engines. The carb engines of that era had horrible fuel distribution problems. Most current carb engines have much better fuel distribution but still nowhere near as good as injection. So it is not entirely the fuel injection but rather the much better induction system performance of the injected engines. Max Conrad ran the Twin Commanche on something like 3.5 gallons per side towards the end of his non stop flight from Capetown South Africa to St. Petersburg FL. He had the fuel to continue to at least New Orleans but that whole area was fogged in.
 
WAM120RV said:
Sorry Bill,

I am getting the same results Norton just blocks it saying malicious site.

I do not want to do these people harm as I am interested in their products but something is wrong. Can someone ring them to see whats going on?
Click to expand...

I agree with you regarding harming someone's system.

Don and I exchanged some an emails on this subject, including the link to this thread. He said it was an issue with Norton and that there is no virus on his site.

Just to check, I ran two different scan tools against my system after visiting his site and neither picked up a virus. Your mileage my vary.

However, you may contact them the old fashioned way. Here's his info:

AIRFLOW PERFORMANCE, INC.
111 Airflow Drive
Spartanburg, SC - 29306

Phone: (864) 576-4512
Fax: (864) 576-0201

E-mail: [email protected]
 
jrs14855 said:
The carb engines of that era had horrible fuel distribution problems.
Click to expand...
The problem is that the air distribution isn't improved much with the IO. The best solution would include both fuel injection and a tuned and balanced air induction system.
 
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