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  #11  
Old 01-18-2020, 08:20 PM
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Toobuilder Toobuilder is offline
 
Join Date: Jul 2009
Location: Mojave
Posts: 4,481
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Pretty impressive Mark. Gives me hope for the -8 yet. In my experience the Bendix system goes haywire below 2GPH/per cylinder, so I'll have to do some more work.

Also, 20 inches of MP at 11.5 is something to be proud of. It seems you have a well scienced combination.

BTW, you will see my -8 "Old Crow" tied down at VGT transient in a few days.
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
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Harmon Rocket II -SDS EFI - Flying
RV-8 - Flying
1940 Taylorcraft BL-65 -flying
1984 L39C - flyable, available for sale
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  #12  
Old 02-26-2020, 05:28 AM
Simon Hitchen Simon Hitchen is offline
 
Join Date: Apr 2006
Posts: 282
Default Great results

Thanks for the help guys. I contacted Don at Airflow performance, he recommended four new injector nozzles of differing sizes based on my Gami data.
I installed them last night and went flying. Took less than 10 minutes and $112.
The results are exactly what I wanted. All cylinders balanced and peaking at the same flow. I’m able to in 50 to 100 lean of peak smoothly and balanced. GAMI spread 0.1.
BEFORE

AFTER
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Port Perry, ON, Canada
7 Tip Up, Titan XIO-360, Sensenich FP Prop, Dynon Skyview, GTR-200, GTX-327
FLYING!
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  #13  
Old 02-26-2020, 11:42 AM
birddog486 birddog486 is offline
 
Join Date: Mar 2016
Location: WI
Posts: 102
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Looks great. What sizes did you end up with?
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  #14  
Old 02-27-2020, 05:57 AM
Simon Hitchen Simon Hitchen is offline
 
Join Date: Apr 2006
Posts: 282
Default Sizes

I went with 0.024” on cylinders 3 and 4,
0.023” on cylinder 1 and 0.0235” on cylinder 2.

Stock injector size is 0.028” so I enrichened the servo mixture slightly to Ensure I get adequate flow on take off. It seems to work as I get 17.0 gph on take off and a 50 rpm rise when aggressively leaning at 1000 rpm ground idle.

It may be my eager imagination but I’d swear it runs smoother too
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Simon Hitchen
Port Perry, ON, Canada
7 Tip Up, Titan XIO-360, Sensenich FP Prop, Dynon Skyview, GTR-200, GTX-327
FLYING!

Last edited by Simon Hitchen : 02-27-2020 at 06:00 AM.
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  #15  
Old 02-27-2020, 07:34 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by Simon Hitchen View Post

It may be my eager imagination but I’d swear it runs smoother too
The smaller injectors increase the downstream fuel pressure from the servo and help better atomize the fuel. It also helps a little in reducing the boiling point temp at low RPMs. Don recommended .024's for my 320 and 025's for my 540.

Larry
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  #16  
Old 02-27-2020, 08:16 AM
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airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
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Quote:
Originally Posted by lr172 View Post
The smaller injectors increase the downstream fuel pressure from the servo and help better atomize the fuel. It also helps a little in reducing the boiling point temp at low RPMs. Don recommended .024's for my 320 and 025's for my 540.

Larry
Yes, and I am (or was) running .022 in my IO360 on 91E10 fuel for that same reason. I had to boost my fuel pressure to the servo in order to get good takeoff fuel flow, with electric pumps and an adjustable regulator.

I'm currently in the process of installing the SDS EFI system.
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Greg Niehues - PPSEL, IFR, Repairman Cert.
Garden City, TX VAF 2020 dues paid
N16GN flying 560 hrs and counting! Built an off-plan 9A with too much fuel and too much HP. Should drop dead any minute now.
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  #17  
Old 03-19-2020, 09:13 PM
Bcone1381 Bcone1381 is offline
 
Join Date: Dec 2015
Location: Chelsea, MI
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Quote:
Originally Posted by airguy View Post

I'm currently in the process of installing the SDS EFI system.

What made you change from the Bendix to the SDS?
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  #18  
Old 03-20-2020, 06:52 PM
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airguy airguy is offline
 
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Location: Garden City, Tx
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Quote:
Originally Posted by Bcone1381 View Post
What made you change from the Bendix to the SDS?
More precise control over mixture distribution and ignition timing, especially LOP at high altitude where I spend a large amount of time. The RSA-5 and Lightspeed Plasma was good - the SDS is just better.

I did the install plus a full panel rebuild and annual inspection, and got the first engine start this afternoon on the new system. Tuning it now and I'll get some airtime tomorrow.
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Greg Niehues - PPSEL, IFR, Repairman Cert.
Garden City, TX VAF 2020 dues paid
N16GN flying 560 hrs and counting! Built an off-plan 9A with too much fuel and too much HP. Should drop dead any minute now.
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