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Dave Anders Flying SDS EFI

rv6ejguy

Well Known Member
Over the weekend, Dave Anders flew his super fast RV4 with SDS EFI which replaces the Bendix style mechanical injection. He was never entirely happy with the GAMI spread across the whole range of power settings he flies at. With the EFI, he can quickly tune each cylinder in flight to get everything even.

He's starting to log some performance data and temperatures in his usual thorough way.

Dave's running a different setup that most Lycoming customers- using 2 LightSpeed PlasmaIIIs to do the ignition chores. These feed a tach signal to the SDS ECU.

He's running a 65mm throttle body and new pressure recovery ram intake design which is netting 1.5 inches more MAP than ambient and .6 better than his best previous design.

A Sky Dynamics plenum is fitted and he has his injectors mounted on the inside of the induction tubes due to cowling clearance issues. Heads are flow matched so he has the best possible combination of induction parts as far as equal airflow is concerned.

His new Lycon engine has a bit lower compression ratio than the previous one so it will be interesting to compare numbers when all tweaking is complete.

It's a pleasure to be associated with Dave. He does fabulous work and documents his testing very well.

Dave is reporting much better cold and hot starting than the mechanical FI offered and a super smooth idle down to 650 rpm.

One of his early comments: "I have 2500 hrs on my plane and it’s never run smoother!!!"

I'll update as more data comes in from Dave.
 
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A few initial numbers from Dave which certainly puts my RV to shame:

Density altitude 7848, rpm 2250, MAP 20, TAS 197mph (12.4 AFR)
Density altitude 8000, rpm 2800, MAP 26, TAS 243mph (12.4 AFR)
Density altitude 12450, rpm 2250, MAP 19.6, TAS 186mph LOP (AFR 18.5)

Dave is measuring injector temps as he had some concerns about the placement of these on his installation: "The max injector temp was 254 right after shut down when i landed for fuel. It was 241 when I restarted and reached 256 on the climb out and dropped immediately to 233 in cruise at 2000’ with OAT at 97." Note these are at very high OATs.

He's leaned to an amazing 19.7 AFR and the engine is still running smooth, just doesn't make much power, as expected.
 
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A few initial numbers from Dave which certainly puts my RV to shame:

Density altitude 8000, rpm 2800, MAP 26, TAS 243mph (12.4 AFR)

The heck with injection. I want to know how to get 26" Hg MAP at 8000 DA and 211 KTAS...other than buying the turbo kit in the classifieds.
 
The heck with injection. I want to know how to get 26" Hg MAP at 8000 DA and 211 KTAS...other than buying the turbo kit in the classifieds.

Dave's new magic intake duct and the elimination of the TB clutter it had before.

I'm not sure Dave wanted me to share the photos of the duct. He's done several iterations over the years and never stops experimenting and testing.
 
Ram Pressure Reoover vs DA

The heck with injection. I want to know how to get 26" Hg MAP at 8000 DA and 211 KTAS...other than buying the turbo kit in the classifieds.

Probably not a totally unreasonable number if he was flying at 4500' pressure altitude with an OAT of 95 degrees...
 
Pressure altitude was 5500.

Ahhh, shoot, I was hoping for black magic, and it's just an unusually hot day.

Ok, a DA of 8000 at 5500 works out to be 40F above standard, with a total pressure of about 26.14". 26" Mp is impressive.
 
Dave's new magic intake duct and the elimination of the TB clutter it had before.

What does TB mean? Throttle body?

does he have an open/close valve for RAM air?

I which I could contact him directly. I met him a long time ago at the Golden West fly-in but did not say much as he was talking to other folks.

Thanks for the info/data.
 
What does TB mean? Throttle body?

does he have an open/close valve for RAM air?

I which I could contact him directly. I met him a long time ago at the Golden West fly-in but did not say much as he was talking to other folks.

Thanks for the info/data.

Yes, TB is throttle body which is the term we use in the EFI world vs. servo in the Bendix/ AFP world.

The photos I have show no provision for a filter. Dave is all about speed, efficiency and light weight which is why his plane did so well in the CAFE competitions and other races. http://www.flyingmag.com/pilots-places/pilots-adventures-more/search-fuel-efficient-aircraft

https://www.youtube.com/watch?v=gCONImxbs7g

Dave is a very talented and super nice guy. I met him at Reno about 5 years ago.
 
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It's 106-108F where Dave is flying this week so he's going to wait for some cooler weather.

He observed a few more numbers on his last flight. These are without trimming fuel on any cylinders yet:

Max temp spreads in degrees F

WOT (for 25 mins) CHT 20 EGT 65
19.6" MAP cruise 2300 rpm CHT 20 EGT 20
16.0" MAP cruise 2250 rpm CHT 15 EGT 33

As I postulated in some previous threads on this topic, the Sky Dynamics intake and the EFI appear to do a better job of mixture distribution than many of the other intake brands. He does of course also have flow matched heads, making airflow as close to the same as possible, between cylinders.

Another comment from Dave:

"I wanted to add that already VERY apparent, is the increase in performance during take off and climb due to the mixture being always about 12.4. What a benefit to have that feature at Leadville, Colorado!" (10,000 MSL)
 
Here's a photo of Dave's SDS installation along with the magic TB scoop. Inside the scoop is a tight fitting, large diameter, velocity stack which clamps to the TB snout.

dave55_zpsahlo67tx.jpg


Another update from Dave after some more flying:

"I have always let guys see what I’ve done if they were interested. Over the years i have just continued looking for practical applications of sound theory. Decreasing drag is more effective than increasing HP. It gets increasingly more difficult to find performance gains as you continue working. All the easy ones are already done and then even when you do something you know is sound science sometimes, it isn’t easy to prove it worked. I have made over 30 changes to my plane and some took perhaps 3-4 small changes together to be able to see any improvement.

I like the experimenting and then testing. I can already tell that the better atomization the SDS provides for the mixture at high altitude is so far superior to the old system I had, and the improvement in runway acceleration and climb is obvious, let alone the ease of operation. It just makes sense to get the maximum pwr out of the fuel you’re using. I had to call off my test yesterday when I saw the fuel leak between my legs at 17500’ but I’ll get that corrected and continue testing. (Seeping pipe plug fitting on pump module)

I’m really anxious to be able to peak each cylinder to see how far apart they are from each other at max pwr WOT and compare it to low power economy high alt cruise. As I’ve said, the CHT spread is smaller than ever before and I haven’t even been able to try tuning each cylinder yet."

Dave has done some more tests on moving the injector thermocouple to other injectors to see what differences are present. He's compiling data on that now.
 
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Ross,

Any interest from Dave to try your new direct port injectors? As much as he likes to tinker, it seems a natural upgrade to aim the nozzle discharge right at the intake valve instead of the tube mounted setup.
 
Ross,

Any interest from Dave to try your new direct port injectors? As much as he likes to tinker, it seems a natural upgrade to aim the nozzle discharge right at the intake valve instead of the tube mounted setup.

He hasn't said much yet about it. He spent several months getting the new engine and EFI installed. Now that it's all together, I think he wants to have everything well tested and tweaked before he heads to Reno in September. Beware other RV class entries. This thing is wicked fast.

That being said, since we do have an angle valve, top mount injector solution now, it would be interesting to have Dave test them back to back after having a good baseline with the tube mounted setup.

In race car stuff, it's been found that the injector being placed further from the port actually makes a bit more power than right in the port on most engines. Throttle response and cold starting is usually a bit worse though.
 
Love looking under the "hood"

Like the exit chute w/side guides. I can't quite figure out the oil cooler exit? One day would be interested to see what he does under that plenum for cylinder and head shrouding and air flow management.

Thanks Ross. Thank Dave for us.
 
Dave sends me photos and test updates often. I have some more photos I can post here tomorrow if I get time, showing some different angles.

Airflow management in the cooling system is important for drag reduction and I know many people on VAF are interested in real world testing like Dave does.
Remember he's also cooling more hp than most other folks with similar sized engines.
 
Here's a photo of Dave's SDS installation along with the magic TB scoop. Inside the scoop is a tight fitting, large diameter, velocity stack which clamps to the TB snout.

No magic there, just the optimization Dave talks about. I think he has been running the basic concept (a diffuser teamed with a velocity stack) quite a while. Downside is running filterless all the time.

Like the exit chute w/side guides.

Dave has been doing that a long time too. He is not the only one.
 
No magic there, just the optimization Dave talks about. I think he has been running the basic concept (a diffuser teamed with a velocity stack) quite a while. Downside is running filterless all the time.



Dave has been doing that a long time too. He is not the only one.

The latest iteration is much better than his last design and filter use is not important for Dave's mission or engine situation which is almost strictly about best performance possible.

I use the word "magic" loosely to describe stuff which works better than what most folks are doing in whatever field is involved. Dave's been doing this stuff a long time as you point out, so is a pioneer here in many ways. It's easy to copy, harder to innovate. Few others can match his accomplishments with an RV.
 
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side chutes

Dave has been doing that a long time too. He is not the only one.

Yes, I know, you have some too, Bob Axsom did some, pretty standard for good exit collection . . . . not radical though . . . . I still like 'em :D

I downloaded a presentation by Dave posted in a local EAA meeting from a while back ( could have been 2000) , too bad the pictures were not along with the text. It seems he added these in 1995.
 
"Some further testing at 3000’ 2230 rpm 19.8”map 15.8 a/r 179 mph TAS 85 OAT.

#1 —— no trim required
#2 —— no trim required
#3 —— -3%
#4 —— -2%

Then they all peaked at the same time at 15.2 with mixture knob.

EGT spread during a 22 min flight was 34-50 degrees
CHT spread was 21-30 degrees"

Despite what some people have said, this test would seem to validate my earlier theory that certain manifolds/ heads are the root of poor mixture distribution and high GAMI spread like we saw in one instance a few months back with over a 10% imbalance in trim required to make all cylinder peak at the same time. The SD intake with the flowed heads keeps things pretty close.
 
Hot Start Testing

Dave completed some more testing in very hot conditions. It seems like hot starting will be no issue with the EFI:

"I don?t see vapor locking ever being a problem, because when I extremely heat soaked everything on the ground to 360 to 370 CHTs (the hottest i?ve ever seen) with an oil temp of 232 and the #4 injector reaching 324 after shut down, I let it sit for perhaps 4-5 mins and it started perfectly after 1 1/2-2 blades and idled smooth at 600 rpm. The fuel manifold seems to hold about 140-135 degrees."
 
Range and FF Testing

Another update from Dave this morning.

"I have used the individual cylinder trimming several times now at different altitudes, MAPS and pwr settings. Conditions seems to change the order of cylinders peaking. In my case, it’s never too much in one way or another. Depending on conditions, different cylinders require different % to peak, usually 2 or 3 of the cylinders require no change and the others require no more then -2% or the 1 cylinder that requires +1% when the other 3 require nothing.

I believe that under WOT I have seen 2 mph increase when all the cylinders peaked at the same time. It’s nice to know that you're getting maximum power out of the fuel from all the cylinders at the time. It’s easy to do! What a neat system.

I’m dialing in the SDS fuel flow signal now and it’s apparent that it will be the best mpg I’ve ever had. Can’t wait to get the real numbers at altitude leaned to best FF. Today it said I had 1000 miles range on 32 gals, but it’s still indicating more fuel used than I put in so it should get better and that was at only 5000’. This is exciting! Thanks for a great product!"
 
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FF EGT/CHT Data

"Diane and I flew to Arnold to see the carbon wing replacement project for RVs. The set we saw was for Bob Mills RV6. Really great work.

I think I have the FF from the SDS signal dialed in now, so we got to test cruise economy at 10500’.

Cruise conditions:
2220 RPM 21” MAP 55 F OAT 10500’ Palt 12826’ Dalt

I trimmed each cylinder to max CHT as follows: #1 “0" with the mixture knob and #2 “0", #3 “+1", #4 “-1" with the programmer trim window.
I leaned to an AFR 16.0 (that’s the max range my current lambda sensor will indicate) which resulted in:
200 MPH TAS at 6.8 GPH at about 29 MPG.
188 F oil temp
#1 injector 203 F
#4 injector 210 F

EGTs CHTs
1 1292 296
2 1304 295
3 1273 277
4 1253 295
spread 51 19

It has never run smoother under those conditions. It's truly amazing how smooth it runs at that lean an AFR. It used to miss and run kind of rough under lean conditions now it just loses power. Also, not a bad fuel burn at that speed.

Some of the difference in the EGT temps between 1 and 3 as compared to 2 and 4 could be the EGT probe locations because they are rotated differently on the pipes.

I’m not certain about #3 CHT because it has the same compression as the others- (more air to that cylinder maybe).

Bottom line is under those cruise conditions I think I’m getting 3-4 more MPG. I will do a maximum MPG test soon but that will be at 17500’ and slowed down to about 110 indicated. I would love to see nearly 50 mpg. my best previous was with higher compression pistons 12.2:1 and was 42 mpg in 2000.

When I did the personal air vehicle challenge in Santa Rosa, CA. in 2007 the best I ever got was 27.4 and that was flying at approximately 140 mph because that is speed that produced the greatest efficiency (mph x mpg) the way they judged it at gross wt at takeoff on a 400 mile course."
 
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Amazing Numbers

Dave was up testing again today.

" I finished testing the injector temps. It appears even with pretty high OATs 90-100 the injectors will never make the 284 degrees F. In a WOT climb at 120 mph IAS with an AFR 12.4 from 600’ to 17,500’ Palt. With a 23 degree F OAT at 17500, injectors #2 & #3 are the same ± 2-5 degrees. They start at 205 and decrease to 165 during the climb. #1 & #4 essentially parallel each other. #4 starts around 260 and decreases to about 205. #1 stays about 15 degrees lower.

By the way, I made 17500’ in 10 1/2 minutes. The plane was just the way I fly it everyday with all the extra stuff which includes my oxygen system in it and full fuel. However I normally just do an enroute climb at 140 mph IAS so things would be even cooler.

I have a dynamic pressure calculator and under those conditions accounting for Q you should have a MAP of 15.7” and i was getting 16.4” so it does seem I’m getting .7” boost above ambient + Q adjusted for OAT.
At 17500’ I was able to go 232 mph max speed at 9.7 gph with a MAP of 16.4 and AFR of 12.4. that’s a good fuel flow for that speed.

The best reasonable data I collected was 197 mph TAS with a fuel flow of 5.2 gph with an AFR of 18.0. so, it cost 4.5 gph to go 35 mph faster. It’s just not a slippery air frame and it has the wrong wing aspect ratio.
The best mpg was about 39.7 and that's lower then when I was running 12.2:1 compression. It seems as I leaned it further the plane just slows down. it runs great, just not making enough power to maintain the speed. The best it ever did with the high compression was 42 mpg at 14000’ but I haven’t tried that yet. I think it’s just all the power I can make and it's an RV metal airframe.

With the mixture knob centered on zero at 17500’ the AFR is 15.7. however, with a 16.2” MAP and 2170 rpm produced 209 mph TAS at 5.7 gph. It runs smooth to 19.0 AFR and produces 182 mph TAS at 4.8 gph. I’m getting some really good speed."

158 knots TAS on 4.8 GPH. This is a clear demonstration on what EFI and EI can do for the Lycoming. Doubt if a diesel can better that performance by much.
 
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Lower=better or less?

Dave was up testing again today.
<snip> The best mpg was about 39.7 and that's lower then when I was running 12.2:1 compression. It seems as I leaned it further the plane just slows down. it runs great, just not making enough power to maintain the speed.

Outstanding information - Thanks

Does he really mean "lower" mileage? Or "lower" efficiency? I see the 42 mpg at 14k with the higher Cr, but I am still a little confused.

Not surprised that leaner goes slower, I would have thought he would know that - maybe your other post with graphs will explain that. SFC will go up, but power down, it still only pumps so much air.
 
Outstanding information - Thanks

Does he really mean "lower" mileage? Or "lower" efficiency? I see the 42 mpg at 14k with the higher Cr, but I am still a little confused.

Not surprised that leaner goes slower, I would have thought he would know that - maybe your other post with graphs will explain that. SFC will go up, but power down, it still only pumps so much air.

I think he means lower on both counts- thermal efficiency is reduced with a 2 point drop in CR and as a result, mileage may also be down.

Dave knows leaner is slower but the tradeoff should be better right down to around 18 to 1 AFR.
 
Sky Dynamics plenum

Hi Ross,

I see Dave has the new tapered intake tubes from Sky Dynamics with his new plenum. No doubt this all helps with his impressive MP he is seeing along with the reduced restriction from the EFI TB.

Do you know of anyone testing on the IO-540 ?
I see the Sky Dynamic site appears to cater for the Aerobatic/Race guys.
It would be great to see this filter down to simple up grade path for us standard RV-10 drivers.

Thank Dave for sharing,I love it when someone "shakes the tree" to challenge the norm.

Cheers,
 
158 knots TAS on 4.8 GPH. This is a clear demonstration on what EFI and EI can do for the Lycoming.

...at 17,500, with a clean RV-4. Excellent numbers for sure, but it's important to maintain perspective.

Very few of us have an personal data at 17,500. Let's go back to the previous post for something more typical.

Cruise conditions:

2220 RPM 21” MAP 55 F OAT 10500’ Palt 12826’ Dalt

200 MPH TAS at 6.8 GPH at about 29 MPG.

Ok, so Dave reports 174 knots on 6.8 with the small RV-4 airframe and a modified 360.

Here's a clean RV-8, dead stock 390 with Slicks and AFP constant flow, similar altitude....hauling camping gear, clothes, and three half-cases of Spotted Cow back from OSH. 178 knots on 7.8:



25~30 LOP was the limits of smoothness with the Slicks, which is why I'm now converting to EI. Go a bit leaner, and the airplane will slow down and burn a little less fuel, closing the gap on that 174/6.8 benchmark. The catch will be mixture distribution with 0.028 restrictors as fuel flow drops closer to 7, and the flow divider starts playing a larger role in cylinder balance. Without question, the SDS EFI will maintain superior balance at very low flows, in particular with the new on-the-fly balancing capability.
 
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...at 17,500, with a clean RV-4. Excellent numbers for sure, but it's important to maintain perspective.

Very few of us have an personal data at 17,500. Let's go back to the previous post for something more typical.



Ok, so Dave reports 174 knots on 6.8 with the small RV-4 airframe and a modified 360.

Here's a clean RV-8, dead stock 390 with Slicks and AFP constant flow, similar altitude....hauling camping gear, clothes, and three half-cases of Spotted Cow back from OSH. 178 knots on 7.8:



25~30 LOP was the limits of smoothness with the Slicks, which is why I'm now converting to EI. Go a bit leaner, and the airplane will slow down and burn a little less fuel, closing the gap on that 174/6.8 benchmark. The catch will be mixture distribution with 0.028 restrictors as fuel flow drops closer to 7, and the flow divider starts playing a larger role in cylinder balance. Without question, the SDS EFI will maintain superior balance at very low flows, in particular with the new on-the-fly balancing capability.

And then here is a quote from the RV12 page......... "I just looked again at a D180 screen shot from the trip. 7500', OAT 18C, DA 9690, 22.3" MAP. The TAS was 119 knots, 5380 RPM and burning close to 7 GPH."
 
Your numbers are very impressive too Dan. Your -8 looks very slick in the photos and you've got that proper cowl flap and exit on there which we know helps a few more knots.

I guess I was more impressed with the 4.8/ 158 KTAS part. Doubt any other RV equipped with mechanical FI and mags will come close to that.
 
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Your -8 looks very slick...

Not as slick as Dave's RV-4. Larger too.

Readers unfamiliar with Dave Anders may enjoy this CAFE Foundation report from the January 1998 issue of Sport Aviation. If this link doesn't work, log in at eaa.org and use the publications search function.

file:///C:/Users/wks/Downloads/Article-10152.pdf

I guess I was more impressed with the 4.8/ 158 KTAS part. Doubt any other RV equipped with mechanical FI and mags will come close to that.

Yeah, and Seabiscuit was a fast horse because he drank beer ;)
 
Not as slick as Dave's RV-4. Larger too.

Readers unfamiliar with Dave Anders may enjoy this CAFE Foundation report from the January 1998 issue of Sport Aviation. If this link doesn't work, log in at eaa.org and use the publications search function.

file:///C:/Users/wks/Downloads/Article-10152.pdf



Yeah, and Seabiscuit was a fast horse because he drank beer ;)

I think Dave has some more wing than you. That may actually be helping him up high. In any case, Dave's always willing to put his plane in a side by side with anyone who's curious and in his locale.

There should be a new article upcoming in Kitplanes on Dave's RV-4 journey a few months down the road too.
 
Not to hijack the EFI glory, but here is a set of flight test data on a IO-340. While this customer was not looking for flying high LOP he was interested in going fast WOT low altitude. A box stock RV-6, standard Vans cowl, up draft sump, Vetterman cross over exhaust. This is with an Airflow Performance FM-150L Mechanical constant flow fuel injection system with one P-mag and one electronic ignition, and 9:1 compression.

WOT Take Off 2700 RPM, Fuel Flow 15.1 GPH, 29.7? MAP (MAP before engine start 30.2?)

3500 Feet, 2400 RPM, 24? MAP
Full Rich Fuel Flow10.5 GPH, EGT/CHT #1 1214/343, #2 1261/335, #3 1217/343, #4 1238/336
All cylinders peaked at 7.7 GPH with EGT #1 1412, #2 1465, #3 1428, #4 1452
The fuel rich fuel air ratio .086 (AF 11.6). Peak EGT fuel air ratio .065 (AF 15.4)
GAMI spread <0.1 GPH. CHT spread 8 degrees F

3500 Feet, 2500 RPM, 22? MAP
All cylinders peaked at 7.2 GPH with EGT #1 1431, #2 1478, #3 1445, #4 1468
GAMI spread <0.1 GPH

8500 Feet, 2500 RPM, 22? MAP
All cylinders peaked 7.8 GPH with EGT #1 1412, #2 1457, #3 1418, #4 1452
GAMI spread <0.1 GPH
LOP operation engine smooth 6.5 GPH with EGT #1 1280, #2 1309, #3 1294, #4 1309
Running approximately 125 degrees LOP with smooth engine operation the fuel air ratio was approximately .055 (AF 18.2)

Again not set up for efficiency but at 3300 feet ,2650 RPM, 22? MAP and 10.5 GPH, speed was 162 MPH.
All with old school mechanical fuel injection, no computers, no O2 sensors, no tuned intake pipes or plenum, no 4 into one tuned exhaust, no pressure cowling.
 
Not to hijack the EFI glory, but here is a set of flight test data on a IO-340. While this customer was not looking for flying high LOP he was interested in going fast WOT low altitude. A box stock RV-6, standard Vans cowl, up draft sump, Vetterman cross over exhaust. This is with an Airflow Performance FM-150L Mechanical constant flow fuel injection system with one P-mag and one electronic ignition, and 9:1 compression.

WOT Take Off 2700 RPM, Fuel Flow 15.1 GPH, 29.7? MAP (MAP before engine start 30.2?)

3500 Feet, 2400 RPM, 24? MAP
Full Rich Fuel Flow10.5 GPH, EGT/CHT #1 1214/343, #2 1261/335, #3 1217/343, #4 1238/336
All cylinders peaked at 7.7 GPH with EGT #1 1412, #2 1465, #3 1428, #4 1452
The fuel rich fuel air ratio .086 (AF 11.6). Peak EGT fuel air ratio .065 (AF 15.4)
GAMI spread <0.1 GPH. CHT spread 8 degrees F

3500 Feet, 2500 RPM, 22? MAP
All cylinders peaked at 7.2 GPH with EGT #1 1431, #2 1478, #3 1445, #4 1468
GAMI spread <0.1 GPH

8500 Feet, 2500 RPM, 22? MAP
All cylinders peaked 7.8 GPH with EGT #1 1412, #2 1457, #3 1418, #4 1452
GAMI spread <0.1 GPH
LOP operation engine smooth 6.5 GPH with EGT #1 1280, #2 1309, #3 1294, #4 1309
Running approximately 125 degrees LOP with smooth engine operation the fuel air ratio was approximately .055 (AF 18.2)

Again not set up for efficiency but at 3300 feet ,2650 RPM, 22? MAP and 10.5 GPH, speed was 162 MPH.
All with old school mechanical fuel injection, no computers, no O2 sensors, no tuned intake pipes or plenum, no 4 into one tuned exhaust, no pressure cowling.

The GAMI spreads here are very good but all at about the same rpms. I've had many mechanical FI users tell me- yes spreads can be very good if they cruise near the same rpms but often not good if they really drop the rpms and fly high. The point is that the EFI can have zero GAMI spread everywhere from 2000 to 2700 rpm and any altitude with any manifold pressure and any intake manifold, no screwing around changing nozzles trying to find the best compromise, no more hot or cold start issues, no more rough idle issues.

WOT, low altitude power is relatively easy and the EFI can do that well too.

The reason why Dave switched from mechanical FI was exactly this since he flies at all different altitudes and power settings. He wasn't satisfied with the mechanical injection. You can read his own comments in this thread.

Technology marches on and we see all new aviation engine manufacturers equipping their engines with EFI, not mechanical injection- Rotax, D-Motor, UL Power, Adept Airmotive etc.

Lycoming, Continental and Jabiru users are seeing the same benefits with EFI over legacy engine controls.

For many new builders, carbs, mags and mechanical FI are heading the same way as steam gauges in Experimental aircraft.
 
I suspect this debate will be going on a long time ;)

I am sure Anders likes the EFI system. With the new on-the-fly fuel trim, it can be tweaked to a zero GAMI spread at very low flows, something current constant flow systems can't do. Heck, I like that detail, and I'm very much in the KIS mindset. Who can resist perfect, even when there might not be a practical reason for it?

In terms of absolute numbers, it might be misleading to claim this RV-4's efficiency is due to EFI. Dave has been working on efficiency since he built the airplane, something like 25 or 30 years ago. It's simply a very efficient airplane. Here EFI is allowing the exploration of remote corners of the flight envelope. Such performance delights the experimenter, but frankly, very few RV owners have reason to care about low fuel flow at 17,500 feet. As we've seen, constant flow gets pretty close to the same numbers at common altitudes and power settings.

Hot starts and hot idle? Point to EFI. Simplicity, not electrically dependent? Point to constant flow. Right now it pretty much a draw, with choice going on what the buyer values most.

To Ross's point about the future, yes, EFI is the future, but perhaps not this EFI, which is actually quite old on the technology scale. When we start burning unleaded, and can go to closed loop control with an integrated spark and FI map, well, then aircraft EFI will enter the 21st century.
 
I suspect this debate will be going on a long time ;)

I am sure Anders likes the EFI system. With the new on-the-fly fuel trim, it can be tweaked to a zero GAMI spread at very low flows, something current constant flow systems can't do. Heck, I like that detail, and I'm very much in the KIS mindset. Who can resist perfect, even when there might not be a practical reason for it?

In terms of absolute numbers, it might be misleading to claim this RV-4's efficiency is due to EFI. Dave has been working on efficiency since he built the airplane, something like 25 or 30 years ago. It's simply a very efficient airplane. Here EFI is allowing the exploration of remote corners of the flight envelope. Such performance delights the experimenter, but frankly, very few RV owners have reason to care about low fuel flow at 17,500 feet. As we've seen, constant flow gets pretty close to the same numbers at common altitudes and power settings.

Hot starts and hot idle? Point to EFI. Simplicity, not electrically dependent? Point to constant flow. Right now it pretty much a draw, with choice going on what the buyer values most.

To Ross's point about the future, yes, EFI is the future, but perhaps not this EFI, which is actually quite old on the technology scale. When we start burning unleaded, and can go to closed loop control with an integrated spark and FI map, well, then aircraft EFI will enter the 21st century.

Never claimed the EFI was completely responsible for the numbers Dave is seeing. It certainly isn't. As you correctly state, Dave's airplane has been aerodynamically refined for many years along with the engine mods by Lycon. The first post in this thread covers Dave's initial observations of the EFI vs. the mechanical FI and yes, you're correct, the mechanical FI can deliver very good numbers within a narrower "more normal" cruise range as we've seen this many times.

You might be surprised how many folks fly high with O2. Certainly not over 15% in my estimation but quite a number. Lots do fly at 10-12K though. I think showing what can be done up high might make more people try that, at least below O2 levels.

I agree too on your point that one product does not fit all needs or missions or wants so it's good that people have more choices now.

As far as electrical needs, yes EFI needs that but these days many Experimentals already have a backup power source for the glass panel anyway. This fact does not make many decide to put steam gauges in any more however.

You are right again about this EFI being somewhat low tech compared to what the automakers are using today and the reason is mainly the leaded fuel. However, we have had closed loop technology now for over 20 years in the SDS product line and when unleaded avgas is introduced, people will already be set up to take full advantage of that feature too. We tested targeted AFR software 10 years ago in Florida on an RV and it was pretty magic. That's easily implemented with a reflash to current ECUs.

With this, we could also change ignition timing automatically with AFR and load, bringing our capabilities closer in line with the latest auto technology.
 
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Whoa! Wait just a cotton pickn' minute!!!!! Replacement carbon fibre RV6 wing? How did that slide past without anyone commenting??????:eek::eek::eek:
 
Whoa! Wait just a cotton pickn' minute!!!!! Replacement carbon fibre RV6 wing? How did that slide past without anyone commenting??????:eek::eek::eek:

Stop dreaming about carbon fibre and get back at bashing metal, or you'll never get that thing flying :D
 
Here's a clean RV-8, dead stock 390 with Slicks and AFP constant flow, similar altitude....hauling camping gear, clothes, and three half-cases of Spotted Cow back from OSH. 178 knots on 7.8:



25~30 LOP was the limits of smoothness with the Slicks, which is why I'm now converting to EI. Go a bit leaner, and the airplane will slow down and burn a little less fuel, closing the gap on that 174/6.8 benchmark. The catch will be mixture distribution with 0.028 restrictors as fuel flow drops closer to 7, and the flow divider starts playing a larger role in cylinder balance. Without question, the SDS EFI will maintain superior balance at very low flows, in particular with the new on-the-fly balancing capability.

I took my stock 180HP RV-8 up to 11,500 today to see how it would do compared to Dan's IO390 RV-8. My airplane has AFP FI with one mag and one EI from Robert Paisley. The EI runs at 30 BTDC, that is max advance.

No big surprise, I was about 10 knots slower.

...the numbers...
MP=19.9
RPM=2590
F/F=8.1 (-50/LOP)
TAS 167



Clearly, Dan's airplane is faster and more efficient. Could be the CS prop is a factor. He was running at 2360, mine is a Catto and runs 200 rpm faster, don't know if that is good or bad.

PS ...still like my 8..suppose I could rouse a speed passion and get it going faster..:)
 
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Here's a clean RV-8, dead stock 390 with Slicks and AFP constant flow, similar altitude....hauling camping gear, clothes, and three half-cases of Spotted Cow back from OSH. 178 knots on 7.8:

Did you leave the kid at Oshkosh? What a guy will do to bring home a few beers...

;-)
 
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Did you leave the kid at Oshkosh? What a guy will do to bring home a few beers.
;-)

Naaaa. Delivered him back to Birmingham. That photo was '14 or '15, can't remember. Got one EI on it now.

BTW, thanks for that shanty. It was good.
 
...My airplane has AFP FI with one mag and one EI from Robert Paisley. The EI runs at 30 BTDC, that is max advance.

No big surprise, I was about 10 knots slower.

...the numbers...
MP=19.9
RPM=2590
F/F=8.1 (-50/LOP)
TAS 167

Clearly, Dan's airplane is faster and more efficient. Could be the CS prop is a factor. He was running at 2360, mine is a Catto and runs 200 rpm faster, don't know if that is good or bad.

PS ...still like my 8..suppose I could rouse a speed passion and get it going faster..:)

At that altitude and that lean, I can say with near certainty you need at least 6 degrees more advance (assuming single EI). If you had a "LOP switch" and dialed in that extra 6 degrees you would pick up 3-4 knots at exactly the same fuel flow.
 
MPG Testing

Another update from Dave who got tired waiting for cooler weather.

"I flew down to see a friend even though they were forecasting 109 here today. There were no problems with any temps either with the engine or injectors.

Anyway, I saw the post from Dan Horton where he reported:
7.8 GPH 11500’ Palt 19.3” MAP 2360 RPM producing 178 KTAS.

Today, I had an opportunity to pretty much finish my MPG testing and I tested his numbers on my plane. At 11500’ I can get 20.7” MAP, so I used 19.3’’ map at that altitude so I would be using about the same HP as Dan was using.

My plane in that case was:
7.8 GPH 11500’ Palt 19.3” MAP 2360 RPM producing 188 KTAS
if i run the available MAP I can get at 11500':

7.8 GPH 11500’ Palt 20.7” MAP 2360 RPM producing 198.3 KTAS, however I never cruise at that high an RPM so these are the numbers to produce a 178 KTAS cruise: 5.8 GPH 11500’ Palt 19.3” MAP 2190 RPM 178 KTAS-that’s 25.6% lower fuel flow.

The best MPG I can get now with my lower compression engine is around 41.3 MPG.
In my past data records I found in march 1997 I was running the same compression I am now. In those records I had a FF at 14000’ and the records I have now are at 14500’ so it’s similar.

Then, I was able to get 36.2 MPG and today I am getting 41.2 MPG. That seems to be about 14% better. I did do the fast back on my plane to further the drag reduction since then and that added about 4 MPH to the top end, so that would have less effect at these lower speeds and my guess is that I’m getting about 10-12% better MPG today with the EFI than back then. sorry I don’t have better data to compare."
 
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Anyway, I saw the post from Dan Horton where he reported:
7.8 GPH 11500’ Palt 19.3” MAP 2360 RPM producing 178 KTAS. (snip)
My plane in that case was:
7.8 GPH 11500’ Palt 19.3” MAP 2360 RPM producing 188 KTAS
if i run the available MAP I can get at 11500':
7.8 GPH 11500’ Palt 20.7” MAP 2360 RPM producing 198.3 KTAS

Very cool....but how much beer was Dave hauling?

Apples to apples, add a week's worth of clothes, camping gear, and my big butt too. ;)

my guess is that I’m getting about 10-12% better MPG today with the EFI than back then. sorry I don’t have better data to compare."

All kidding aside, that's not a crazy guess. At very small fuel flows the EFI can produce great cylinder balance with the new on-the-fly trim, and with dual EI's to fire it, get very lean. An optimized constant flow (small restrictors, and tuned for the specific conditions) could probably get close, but certainly would not be as easy to tune.

Remember this?

Returning to Fig.2, that is 35X higher than the mechanical system's pressure at a 6 GPH economy cruise flow. At idle the difference is even greater. The injector open time can be tailored for a small flow quantity, but the pressurized spray remains consistent and well atomized. You can expect the EFi system to be smoother at idle and partial power.

And this?



That's a 540 with a Bendix RSA-10 and Slicks (in beige) and dual EI and EFI (in blue). On the dyno, the EI/EFI combination would pull much leaner without significant torque loss. Here, the difference was 1.5 GPH saved with minimal loss of power. BSFC went from .525 to .483. That's an EI/EFI win, and precisely the sort of thing Dave is now demonstrating live with his RV-4.

It's from Kitplanes. At the time I was handed a lot of grief because the peak HP numbers were not what EFii fans wanted to see. The knowledgeable guy who did not find fault was Ross.

Folks, this is what EI/EFI does really well.
 
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