Pro's Con's Lycoming O360 vs IO360 (180HP)

Hi guys,

I'm interested to know the main Pro's Con's between the O360 and IO360 engines.

I see Vans advertise the O360 @ $23,500 and the IO360 @ $28,300.

What does that the additional $4,800 buy me in real life flying, performance, maintenance, reliability, consumption and every other aspect of aviation engine related topic I can't think of now.

The bottom line is, is the extra $4,800 worth it?
Or maybe I should one consider a completely other engine option for my RV7?
Or maybe spend the $4,800 on lycoming engine upgrades?

Experiences and Advice appreciated.

Regards
Rudi

For just one guy's opinion, scroll down to the "Carb vs. Fuel Injection" article on this page:
http://www.vansairforce.net/engines.htm

Vern
RV7-A

Rudi,
I think you have to break you query down into two parts. One, the difference between A carbureted engine and a fuel injected engine and the benefits of each and two, the difference between a vertical sump engine and a forward facing sump engine and the benefits of the two.
I will try to do that and I hope I don't confuse you too much.
The fuel injected engine will deliver better fuel economy, when leaning, then the carbureted engine. Normally in the area of 1/2 to 1 gph more efficiency to the fuel injected engine. The fuel injector servo on the engine does not care what orientation it is in so inverted flight with it is not a problem.
The fuel injected engine can not get carburetor ice as the carbureted engine can. Van's doesn't sell a fuel injected vertical sump engine. (this would be an O-360-A1A with fuel injection instead of carburetor) All of the experimental Lycoming engine clone suppliers do. This engine will basically glove fit where a carbureted O-360 would. The only thing you will need do is install a 1 inch thick spacer between the fuel injector and air box and use a different throttle mixture control brace on the engine end, that Vans sells for around 20.00. You will need to install a high pressure aircraft pump instead of the low pressure carburetor airframe boost pump. So from an aircraft perspective the changes are very minor and from an engine perspective the fuel injected engine is more efficient and fits in the same hole. These vertical sump engines normally run about $1800.00 more for fuel injected from the experimental clone engine sources. In the case of the all new part TMX engine which the company I work for sells, the carbureted engine runs $18,490.00 and he fuel injected engine runs $20,190.00. Other places sell similar products but the difference between carbureted and fuel injected runs about the same from those sources. If you wanted a new certified vertical sump fuel injected engine the only way to get it would be to buy an O-360-A1A from Vans and then install the fuel injection system on it, but at that point it wouldn't be certified any longer.
The IO-360 180 HP engine that vans sells is basically the same engine as the O-360 except the engine is fuel injected but also has a horizontal sump( the fuel injection is mounted horizontally instead of vertically) This engine actually produces more power that it's vertical sump counterparts. Although Lycoming certified the engine as 180 HP engine it actually put out 6-7 more horsepower than the vertical ones in our test cell. This is because the air going into the engine isn?t heated by the oil that is housed in the oil sump as much with this engine as with a vertical sump engine. So in reality you get more power from this engine. Other than the sump design you just have a fuel injected engine that has all of the benefits mentioned above. So from Vans the increase in cost over a carbureted engine gets you fuel injection and a more efficient induction system. If you were to go with the clone engine suppliers this forward facing sump version normally adds anywhere from 1,000.00 to 2300.00 dollars to the cost of a vertical sump fuel injected engine. Again in the case of the TMX engine the forward facing sump clone of the IO-360-M1B that Vans sells is $22,390.00. The same engine from other clone suppliers is normally within a $1,000.00 of that one way or the other.
When you use this style engine you are able to not install the snorkel on the outside of the lower cowling resulting in a cleaner and possibly faster aircraft.
So if you are dealing in certified engines from Vans for the extra money, you are getting a more efficient, more powerful engine that will allow you to clean up the aircraft a bit. If you are dealing with the clone type suppliers you are getting the same benefits for a bit less expenditure.
If you need further explanations about this feel free to ask!
Good Luck,
Mahlon

Thank you so far guys. It is starting to become clear...

mahlon_r
Thank you for the detailed write up.
Q-1) I do not understand the main pro's and con's of the Horizontal / Vertical Sump, can you make that a little clearer?

Thanx

Hi Mahlon!

One question I failed to ask you during your seminar was about Ellison carbs and your personal view of them. From my experience in speaking with folks who own them, they either love them or hate them.

I have had responses from A++ to, they leak fuel... can't get the engine to run right and the like.

I DO like the "unusual attitude" benefit of IO and/or Ellison, so either will be in my future.

Do we have any Ellison users that could add their own experiences to this discussion?

CJ

Rudi,
Lycoming uses two style oil sumps on the 180 HP engines that Van's uses
(By the way you might want to check on the prices of the engines they sell as I believe there was a price increase at the end of last year) The vertical sump engine mounts the carburetor or fuel injector if you go with that option so that they stick down from the bottom of the engine when mounted. This assembly has three basic purposes, one; to hold the engine oil, two; to mount the carb or fuel injection and three; duct the air from the carb/ fuel injector to the cylinders. The tubing that is installed in this style sump is surrounded with engine oil when it is installed on a running engine. When the oil gets hot this heat is transferred though the ducting and heats up the induction air going from the carb/ fuel servo to the cylinders. In the case of the carbureted engine this warmer air helps keep the fuel vaporized and the air is a bit cooler due to this vaporization process. So at operating temperature these tubes are totally submerged and surrounded by very hot oil. This isn't a problem but it is a power deterrent. Warm induction air makes less power than colder induction air due to its density. This warm air induction is built in and works fine but it doesn't produce as much power as cold air does. In reality the carbureted engine makes more power than the fuel injected engine with this style sump. This is due to the fact that the fuel is introduced into the inlet air stream at the carb and has some time to have a cooling effect on the induction air thus the air is cooler entering the cylinders than it is on a fuel injected engine where the fuel is introduced at the intake port, because the cooling effect and duration isn't as long or as great as when introduced at the carb.
This is he sump hat is installed on all O-360's that would go in a Vans aircraft.
There is another sump style hat van's aircraft can use and that is the horizontal sump. It differs from the sump described above, as far as fuel injection mounting location, in that he fuel injection servo is mounted pointing forward off the front wall instead of downward from the bottom. This style sump is only used with fuel injected engines and there isn't a very easy way to get to a carburetor with this set up. It can be done but Lycoming doesn't make an engine like that you have to engineer it your self. Besides the fuel injection locattion ther is also a very big difference in the induction air pluming inside of the sump assembly. The function of his assembly is the same as the sump above; to house the fuel injection, hold the oil and duct the air but it does that all differently. The servo mounts horizontally instead of vertically as discussed. Now to how the oil is stored and the air is ducted. Think of the sump as a two storey house with no outlet in between the two floors. The top floor although part of the whole assembly is separate from the bottom with only the ceiling of the bottom floor or the floor of the top floor being common to the two. In this style sump the oil is stored in the top floor separate from the first floor which is like one big room (plenum) that is used to feed the four intake pipes used to deliver induction air to the cylinders. This big room isn't surrounded or submerged in oil like the vertical sump duct work is. Thus the air traveling through the room doesn't get heated as much as the vertical sump style induction system. The only portion of that 1st floor room that has hot oil exposed to it from the second floor is a very, very small amount of the first floors roof. Thus we have much cooler induction air at the cylinders, when the engine is running, due to less ability of the oil to transfer heat to the induction air. Remember that colder air = more power. That is where the extra 6 HP comes from when using this style sump. To put it simply the air going to the cylinders is colder than with a vertical sump and thus more power from an engine equipped with a horizontal sump. This style sump is often referred to as a horizontal cols air sump for obvious reasons.
That's the differences.
Iam trying to insert a picture of the two sumps to show you but I can't get that feature to work. I will try to attach them and see what happens.
Good Luck,
Mahlon
The file attachement thing didn't work either so I will try to email them to you seperately.

John,
My experience with the Ellison carb is very limited. It seems that when it works it works well and when it doesn't, it doesn't. Most of all my knowledge about the carb is hearsay rather then actual personal experiences.
I am sure others in the group can ad have a broader experience level than I do.
Good luck,
Mahlon

Hi mahlon_r,

Thanks again for the detailed post:

Here are the pictures Mahlon emailed me for future reference:
Horisontal Sump


Vertical Sump

Different Sumps

It may be worth adding that the hoizontal sump is significantly heavier that the vertical sump (in the order of 8 lbs I think). Superior were offering an alternative sump made from a composite material that offered cold air induction, but was lighter than the vertical sump. A company called Sky Dynamics Corporation also offer cold air induction systems and separate sumps (mainly designed for aerobatic use), they also do exhaust systems.

I like fuel injected engines because the do not get carb ice, can be leaned better, make more power (for reasons already covered) and don't have to use that ugly air intake scoop on the bottom of the cowl. Injected engines can be more difficult to start when hot, but it is a matter of technique. After a while you will rarely have a problem. Airflow Performance make a bypass purge valve that helps circulate cool fuel around the system and can help.

Pete

The economy of fuel injection

On Sunday, I flew with two RV-6's, both of which have 180hp O-360-A1A + Hartzell powerplants. I have the 200hp IO-360-A1B6. All three of us topped off, then flew the same route together, then topped off again. Here were the quantities of fuel burned:

RV-6A, O-360-A1A 10:1, plenum, mags: 29.7 gal
RV-6, O-360-A1A, plenum, Lasar: 28.9 gal
RV-7, IO-360-A1B6, baffles, Lightspeed+mag: 27.0 gal

Despite having the "big engine," I consistently burn less fuel than everybody I fly with. Maybe it's how I operate the engine. Maybe the electronic ignition plays into it. Who knows. My theory is that by having fuel injection it affords me the ability to run leaner with precision -- having balanced injectors (my cyls peak at the same fuel flow). I run 50 ROP in almost every condition of flight other than takeoff and prolonged climb.

When flying formation practice lately, I've been flying with people with 160hp O-320s. I burn consistently less fuel than they do. The guy with the big engine is burning less than the folks with the "small" economical engine? Yep.

I know another RV-6A O-360 pilot from my home base who has 10:1 pistons, and he says that in order to maintain a safe detonation margin, he essentially has to flood 3 out of 4 cylinders to keep one cylinder cool enough. He's seriously considering biting the bullet and upgrading to fuel injection. I'm all for it.

Will fuel injection ever "pay for itself"? Maybe over the entire course of TBO, sure. In theory I'm saving about $3 per hour. Over 2000 hours, that will definitely add up. Or maybe not. But it definitely does allow me to run more economically, that's for sure. I believe the engine is happier and healthier when all four cylinders are running evenly -- meaning they're all peaking at the same fuel flow. I don't have anything scientific to back this up, it's just a "hunch" that the engine is happier. Who knows.

Anyway, I'm personally biased, but I would definitely consider fuel injection. I wouldn't run a carb on my plane. If you do go with fuel injection, though, in order to take FULL advantage of it, you should instrument the engine so that you have accurate EGT & CHT readings on all cylinders. My engine monitor has 1 degree resolution and displays all four cylinders' temps simultaneously on screen -- this sure makes precision leaning easier.

Expensive system, expensive instrumentation. May never pay for itself. But hey, it's your airplane and it's your choice.

)_( Dan
RV-7 N714D
http://www.rvproject.com

fuel injection

during the run to 1st LOE 3 rv's left Oxford Ks together. there was a 160 HP -6, a 150 HP-6 both with carbs. the 3rd aircraft was an 8 with light speed ignition, and carb. 2 1/2 hours later upon landing at tucumcari NM, the 160 hp-6 burned 26 gals of gas. the 150 hp-6 burned 24 gals and the 160 hp -8 with lightspeed ignition burned 19.5 gls of gas. I was flyiing the -8. IMHO opinion I think your electronic ignition has more to do with your economy than the more expensive fuel injection, not to mention easier starting ect...
jerry driskill, RV-8,srr rvotw # 69.

differences

Great gouge! It is always nice to read about this when trying to make the big "E" decision.
A couple more questions. What about auto fuel and fuel injection? I have heard both ways, yes you can... and no you can't. Any thoughts?
Also, how about the different types of fuel injection. Like Silverhawk, non certified vs certified.
Still trying to learn as much as possible.

Hwood

Carb or Injected: 3 reasons

I have elected to go Injected for my -8 for three reasons:

IFR: I've been flying a carbureted O-360 in IMC for the last 8 years. On the carbureted Lyc, I have had carb ice on numerous occaisions while flying in visible moisture (in clouds and rain), so while IMC, I run with carb heat full on. This degrades my GPS groundspeed on average by 5-8kts regardless of wind. On a 550 mile trip, (I love long hauls) this speed degradation can inclease trip-time by 20 minutes, which makes a considerable dent in IFR fuel reserves. For carb ice reason, I am going with an injected engine.

Acro, I'm going injected (and inverted fuel and oil) for sustained upside down tme.

Fuel distribution: I cannot operate my carbureted Lyc anywhere near the efficiency I'd like to. I may have intake leaks, or something, but one cyl peaks way before the others do, which means I have to run richer than I'd like to. My guess has been that a carb atomizes the fuel and then it's up to the intake ports to deliver it equally to all the cyls. In an injected engine, the fuel is metered to each cyl individually, so I'm hoping I'll be able to tweak my fuel burn hopefully on cyls that are running close to each other on EGT.

Observation on Fuel burn: Three years ago,two friends from NC in Skybolts made the trip to OSH. One had a 200HP IO-360, the other a 350HP IO-540. They flew together in formation the whole way. The lower HP engine ran at a higher power setting and burned more gas. The higher HP engine ran at a much lower power setting and burned less gas. Shame on me for not knowing the reason this is true, but I like the story, anyway, as it makes me feel better about mounting a heavier (angle valve) engine up front.

IO-360, 180 vs 200hp

Dan,

I set my RV-8 up with an O-360, 180hp, parallel valve, but converted it to horizontal sump w/Bendix fuel injection, snorkle air induction, plenum, 1 mag/ 1 Jeff Rose electronic ign. Last year I went on a 1500 mile trip with an RV-8 with standard IO-360 200hp with 1 mag, 1 EI. So both airframes and fuel systems were essentially the same, just different cylinders. At each 3+ hour refueling, he would typically take about 1 gal less than me. I also monitor all 4 CHT/EGT and lean to 50 ROP, as did he.

Dan,
My engine choice was part of a decision to attempt to make a very efficient powerplant that would result in lower fuel consumption than the norm while also making as much power as possible when I needed it. I contacted Bart Lalonde at AeroSport power and discussed what I was looking for with him. What I ended up with was a AeroSport IO-320-D1A, including 9.2/1 pistons, LightSpeed Electronic ignition (Slick backup mag), and Airflow Performance F/I driving a C/S Hartzell prop.
Bart thought that the engine would produce about 170-175 HP at sea level at full throttle depending on conditions. This met the overall H/P criteria.

I am also able to operate the engine on cross counties at 50 deg. Lean of Peak (LOP) power settings (<65% power). This has several benefits. Lower CHT, lower fuel consumption, longer TBO, etc. At this time, I am seeing fuel burn rates of 5.7-6.2 GPH at about 22"MPx2300RPM @ 4500 MSL, and runs very smooth. This results in around 160 MPH IAS. This met the efficiency criteria.
This is pretty low from what I am used to running 50 deg. Rich of Peak (ROP) 8.0-8.4 GPH, although I am still experimenting with this process. My CHT's when running LOP are around 270-290 deg F. This has been during the cooler Northwest winter weather though. My cruise oil temps are actually too low at this time and I need to gate off the oil cooler at least in the winter. Engine data is displayed on a VM1000 engine monitor. Through some experimentation, all of my CHT's and EGT's are within 8-10 deg F during LOP and ROP operations consistently. I feel that without Fuel Injection, Electronic Ignition, and AeroSport none of this would have been possible.
Hope this helps.

Joe Blank
RV-6
N6810B
108.5 hours

Lop

Joe, regarding running LOP (lean of peak), I'm with ya. But I run LOP usually only in two scenarios...

1) I'm in no big hurry, and...I'm just putzing around, say 18" @ 2300 RPM or so.

2) I'm in no big hurry, and...I'm trying to stretch the range out. Did that last summer from Chicago to Boston non-stop on 31 gallons.

As you mentioned, cylinder head and oil temp both drop off quickly LOP, and the engine seems pretty darn happy. I don't buy into the old wives tales about LOP causing damage to the engine...but on the flip side, I normally don't end up running LOP only because I'm kind of a speed addict -- and running LOP equates to a chunky speed reduction in my case.

If I'm travelling, I usually run ROP since I'm willing to pay the extra few bucks to save time -- i.e. Jen's with me and she can't wait to get there. If I'm flying around locally with friends, it's usually in formation -- and with the bit of throttle jockeying going on there I feel ROP is a better bet (can't focus my attention enough on engine management).

I just had a conversation with an RV-6 pilot from my home base, and he's stickin' with a carb on his next plane (-8A). I don't blame him. He wants simplicity, and that's definitely the simpler, cheaper way to go. He also brought up the point about a carb "starting up every time." That's a valid point.

Fuel injection and hot starts...I've only had TWO times over the past year when the engine didn't start with conventional techniques, and one was just last weekend. If the engine gets really heat soaked, it's tough to start without using the purge valve. I've used the purge valve on startup maybe 4x total over the past year. Most of the time if you just don't touch anything (leave the throttle & mixture where they were when you shut down), crank it, it'll fire right off in a couple of blades.

Come to think of it, I know people with O-360s who have had "heat soaking" issues preventing them from starting up. So I don't know if a carb vs. FI is really all that different. I think technique may have more to do with it than anything else.

I'd rather not be working, but you've probably had enough of my typing and rambling...have to do work at some point...

)_( Dan
RV-7 N714D
http://www.rvproject.com

Rop/lop

Dan,
I agree with your observations. LOP is generally for low power economy cruise settings on longer trip legs at higher altitudes. (This also requires the extended range pilot bladder mod) Saving gas = cheaper cost per hour operations overall.

I definitely run ROP when formation flying, flying at lower altitudes, or anytime over 65% power. This is important. You may have already read GAMI's data on this method of engine operation. Their gig is to perform the necessary injector balancing process so that all EGT's peak at the same time in the leaning process. I would agree with you that LOP ops absolutley do not harm a F/I engine if it is set up and operated properly. The airlines used to run LOP all of the time (so I've read) when they were flying the older piston pounders (DC-4's 6's 7s, Super Connie's, etc) and extended their engine TBO's. (Maybe some listers with experience in this area would care to comment) Less CHT heat translates to longer cylinder life.

Yes, hot starts can be a problem. I am still getting the hang up getting her to light off without a lot of cranking. Any hints? I have used the purge valve on a couple of occasions, but all starts seem to result in a little bit more cranking than a carburated engine. I also was told by my buddy who did my final inspection (he's FAA and runs the same setup) that AFP recommended to him to shut the engine down by pulling the purge valve and dumping the pressure rather than pulling the mixture control. He said that in the long run it would save the mixture and throttle valve seats in the Fuel Controller if you did this, and then additionally left the throttle and the mixture settings just off the stops.(partially open) One would definitely want to ensure that their mag switch was well grounded! It seems to work real well but I'm not sure how widespread this advice is.

Joe Blank
RV-6
N6810B
In need of a paint job....

Hot Starting FI Engine

Joe,

You asked about hot starting the fuel injected engine, so here are my thoughts. And this is probably like picking a primer...there's a method for every pilot.

First of all, keep in mind that this applies only to my setup, which has the Airflow Performance FM-200 and a purge valve. This may not have a direct application for Bendix/Precision injection operators...although I think the concepts are generally the same.

Second of all, understand that I always shut down with the purge valve...but I also pull the mixture to cutoff right after pulling the purge valve. In some ways, I think I'm complicating things for myself by doing this. I think the *best* way to shut the engine down is to leave the mixture right where it is, usually pulled about halfway back, and just pull the purge valve. BUT...the self-conscious part of me forces me to pull the mixture as well. I'm just not comfortable seeing the mixture pushed in, even part-way, when the plane is sitting. Even though I *KNOW* it's fine with the purge valve pulled, there's something about seeing that mixture knob anywhere but all the way back that bugs me.

Ok, with that in mind, here's how I do hot starts... For me it depends on how long the hot engine has been sitting, and ambient temps to some degree as well.

***** 0 to 2 minutes *****
- purge valve in ("R" position)
- crank
- as it catches, mixture half forward
It usually catches almost immediately, as long as the plane hasn't been sitting for more than a couple of minutes.

***** 3 minutes or more *****
- purge valve in ("R" position)
- boost pump on for about 2-3 seconds -- this builds up pressure WITHOUT priming (note mixture is left pulled back all the way), and I believe this provides a little "back pressure" to aid in squirting a bit during the first few cranks
- crank
- as it catches, throttle open rapidly, mixture half forward, then close throttle as the RPM builds

***** VERY HOT start *****
- keep purge valve out ("ICO" position)
- throttle wide open
- mixture wide open
- boost pump on for about 20-30 seconds
- throttle closed
- mixture cutoff
- boost pump off
- crank til it catches, then same as above, throttle-mixture-throttle juggle

NOTE that the only time when I ever move the throttle or mixture before hot starting is when deliberately purging. Otherwise I don't touch 'em.

If I had Bendix/Precision injection (had it on a couple of "tightly cowled" Mooneys), I would do everything the same as above, just no purge valve and no purge option when VERY HOT. The key (imho) is not touching throttle or mixture, just cranking until it catches.

Electronic ignition sure earns much of its keep when starting a fuel injected engine, that's for sure.

Hope this helps,
)_( Dan
RV-7 N714D
http://www.rvproject.com

Ellison

Hi, bit out of sequence, may be of interest to CJ. I'm new here.

Have RV-4 scratchbuilt with O-360-A1a from Vans. Been flying with M-S carb last 1.5yrs, now modding to Ellison and Raven inverted oil system. Fit up of Ellison was pretty straightforward, needed spacer to attach to existing FAB-360 airbox. Made spacer from mild steel sheet as extension of bellmouth inlet to Ellison. Mounted Ellison laterally, as recommended by them. Control connections easy. Am installing vapour return line from carb inlet and had to add Vans solenoid primer system, I relied on the M-S carb accel. pump for priming previously, which worked fine in my warm climate. I'm happy with the fit of it all, hope to fire it up this weekend. Will conduct usual test flights with new system and give you some feedback (hopefully positive!).

Pipes

Dan,

Can you give any numbers regarding the Ram Air? Are you seeing a MP increase? And if so, is that affecting your lean/rich settings and CHTs? Think that might be helping you on the efficiency scale?

I spoke with Stu last week and he said he's seeing 1 to 2 inches. That seems a bit high since my readings on the subject seem to indicate that the MP increase is noticeable at around 300kts, but not much where we fly. He has the smiley inlet and is a Rocket. Nice one too, freshly painted.

I'm in the final stages of forming the inlet. You created a rounded outside "lip" and I have been considering that too since the air being forced into the inlet is more than the engine can consume, and it has to flow around the lip as there is sort of an air dam there. Did you fabricate that with cloth or flox or a combo?

My inlet is parallel with the front edge of the cowl, a bit closer to the prop than yours but I could not help that since my cowl is a bit shorter due to the WW prop. I wonder what effect that will have. Only time and testing will tell.

--
walter
http://rv7-a.com

RAM Air

Walter,

I've mentioned to you before that I see only 0.3" to 0.4" max boost on my ram air setup. That said, I spent a lot of time making sure my filtered airbox is baby's ass smooth on the inside. I've seen some airboxes that look pretty butt ugly. One guy I know claims he gets 1" of boost. When I finally saw his airbox recently, it was pretty darned obvious WHY he's getting a pronounced boost -- because his filtered airbox is downright "draggy." My personal impression is that...the cleaner the filtered airbox, the less drastic the RAM air boost is gonna be. This is what Van himself preaches, if I'm not mistaken, and it's why he recommended not bothering with RAM air.

In my case it was a "I gotta at least try it" type of thing.

I believe that if I got rid of my RAM air setup and simply fabricated an absolutely beautifully smooth one-piece filtered airbox, I could recover that 0.3" anyway without RAM air. I may try this at some point. If it works, I will almost definitely do away with the alternate air duct, the snout in the cowl, etc.

However, 0.3" is 0.3" no matter how you slice it. People have asked me "do you feel it?" Well, it's not really a seat-of-the-pants boost, but hey, like I said, who wouldn't want another 0.3" of manifold pressure when the balls are to the wall? Manifold pressure rules all when it comes to cruising and climbing mo fasta. Even without RAM air, I'm getting slightly more manifold pressure in any given condition at full throttle than others that I'm flying with. I believe taking filtered air off the pressurized plenum chamber has much to do with that.

Ok, enought out of ass conjecture.

You asked about RAM air boost affecting lean/rich settings and CHTs. Remember, it doesn't matter where the manifold pressure rise comes from -- whether I just push the throttle open, or if I open the RAM air door, it's just more manifold pressure to the engine. Fuel burn goes up. It doesn't "feel" any different to the engine than just pushing the throttle open a bit.

Speaking of proximity of the RAM air inlet to the prop -- I've actually wondered whether some of the "high vibration" issues I've experienced are due in part (or in whole) to the RAM air inlet pulses, pressure on the prop, etc. It has crossed my mind more than once. Somebody like me whips a fargin' RAM air inlet out of his butt, and hey, "That looks about right." Not exactly scientific. Who knows what's goin' on up there aerodynamically. Who knows what you'll experience on your setup -- you have a different engine, different fuel injection servo (iirc), different prop, and obviously a totally different custom inlet. It's about as apples and oranges as it gets, I think.

You'll know how yours performs soon enough!

Hey, remember when I said I would never paint before flying? Well, this is just one of many items where you might want to tinker once, twice... Only the really confident builders paint before they fly.

)_( Dan
RV-7 N714D
http://www.rvproject.com

When I decided to build my RV, simplicity was most on my mind (Simple Minded?). Not being real familiar with airplane engines in general, not knowing anything about fuel injection, but having had a Cherokee with an 0-360 carbureted engine, I decided that was my best bet for success. I was originally going to go FP, but got talked into C/S. A decision that turned out to be right for me and my needs.

I wanted to keep the project as simple as possible so I went with Van's standard offerings. I purchased the 0-360 A1A from Van's along with the FWF kit recommended for that engine. The only thing I changed was to add a throttle quaudrant, so I substituted the control cables. The install and subsequent engine setup was very simple and straightforward, never having to reinvent the wheel. Many builders like to experiment and customize their plane. This is great! But for me, I just wanted a simple, easy to build, uncomplicated flying machine.

There are many options and ways of getting your RV in the air. Some way better than what I did, but if you are like me, looking for an already proven, simple, reliable way to get your plane done, then I recommend the 0-360 A1A with Van's FWF kit. At 204 mph (8000 msl), a fuel burn of about 10 gph using a Hartzell BA C/S prop, and about 1800 fpm CR, I'm uncomplicatingly happy. Sometimes a KISS is good.

Roberta
(I think the paint makes it go faster!!)

Ram air

I have a RV-4 with a 0-360 A1A with C/S prop & Ellison throttle body FWD facing. When I purchased the -4 it had a exceptional large scoop opening under the prop with no filter. I built a filter and purchased a ram air valve from John Huft (Lazy 8 ranch). I used a different type of filter than he uses. Like him I pull intake filtered air from inside the cowl. The ram air valve allows me to then pull unfiltered air from a 2.5? tube below the prop & about 2? behind the blade. I get a 1? increase in MP & can feel it. In formation it can be seen. I wrapped my exhaust pipes & then sealed the wrap to keep the heat down & protect against oil soaking the pipes. Works well for me. I also run 50' LOP other than formation. I have used LOP on several A/C and helps keep the temps down while extending range. I also run high compression pistons.

Gary

" Question Pro's Con's Lycoming O360 vs IO360 (180HP)"

A Rookie Question concerning the IO-360 and O-360A1A.

Other than extended Inverted zero or negative G flight,
Will a O-360-A1A engine in a RV-8 be just fine for Gentlemen Aerobatics?

NightFlyer312 said:

" Question Pro's Con's Lycoming O360 vs IO360 (180HP)"

A Rookie Question concerning the IO-360 and O-360A1A.

Other than extended Inverted zero or negative G flight,
Will a O-360-A1A engine in a RV-8 be just fine for Gentlemen Aerobatics?

Click to expand...

If you define ?Gentleman Aerobatics? as always positive Gs, yes, the carb will be fine. For me this more than fits my aerobatic envelope.

But - for the wide range of things an RV can do, standard injection has many advantages over a carb.

Carl

Third option-

I?m not sure about availability, but we did a LOT of work in the heyday of the CAFE Foundation fine tuning the induction system on an angle-valve 200 HP Lyc on a Mooney whose FI had been replaced with an Ellison throttle-body injector. Eventually, we fine-tuned it to the point where, at 12,000 density altitude, we were making 195 mph TAS at 7.2 gph. Mind you, that is a fully loaded four place with 58 gallons capacity, and On several occasions I flew fully loaded, 1000 mile legs and landed with 1+ hr reserve. We achieved this by repeatedly modifying the lengths of the induction tubes inside the sump. It was possible to go all the way from full rich to flameout with all four cylinders tracking absolutely parallel EGT?s with no roughness, especially through peak and LOP to flameout. I?ll never forget the feeling of pressure on the seatback as you gently went from flameout to power using the mixture control. The numbers above were around 60-70? LOP. Fun times!

The Ellison could just as well replace the carb on an 0-360- Otis