VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #21  
Old 08-21-2018, 03:05 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,838
Default

Quote:
Originally Posted by Canadian_JOY View Post
Dumb question, full of "what if's"... Keep in mind I burn a fair bit of 91 octane premium mogas (zero ethanol).

For engines like our O-360 where a 4-into-1 Cessna-style muffled exhaust is installed (with the goal of harvesting maximum cabin heat), where would a WB O2 sensor be installed? It would seem the only logical location for a summative measurement would be in the final exhaust stack, downstream from the muffler, but this is a long way from the exhaust ports on the cylinders. Just wondering, simply because when my one magneto bites the dust I'll likely end up with an SDS system of some sort replacing it.
The O2 sensor needs to be at least 12 inches from atmosphere to avoid contamination from flow reversion between exhaust pulses. Hopefully that could be accomplished with your setup.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 426.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


Reply With Quote
  #22  
Old 08-21-2018, 03:29 PM
Mark33 Mark33 is offline
 
Join Date: May 2010
Location: Baton Rouge, La.
Posts: 423
Default

Quote:
Originally Posted by rv6ejguy View Post
The O2 sensor needs to be at least 12 inches from atmosphere to avoid contamination from flow reversion between exhaust pulses. Hopefully that could be accomplished with your setup.
Hey Ross,

I've also heard conflicting stories that the O2 sensor needs to be placed fairly close to the head (within a few inches). I'm assuming that's to help keep the lead burned off. But on the other hand, I've heard that it's not healthy to have the O2 sensor subjected to a direct flame. Your thoughts?

Mark
Reply With Quote
  #23  
Old 08-21-2018, 04:52 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,838
Default

Bosch says max intermittent use at 1880F and they like to see them sit below 1400F and control exact sensor temp via the internal heater.

Most naturally aspirated aircraft engines won't see 1400F down the pipe a bit so we recommend the sensors be mounted well back from the ports but more than 12 inches from the atmosphere end of the pipe.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 426.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


Reply With Quote
  #24  
Old 08-21-2018, 06:18 PM
1001001's Avatar
1001001 1001001 is offline
 
Join Date: Dec 2014
Location: Just Minutes from KBVI!
Posts: 782
Default

Quote:
Originally Posted by rv6ejguy View Post
Bosch says max intermittent use at 1880F and they like to see them sit below 1400F and control exact sensor temp via the internal heater.

Most naturally aspirated aircraft engines won't see 1400F down the pipe a bit so we recommend the sensors be mounted well back from the ports but more than 12 inches from the atmosphere end of the pipe.
Does the 12 inch rule also apply to junctions with other cylinders? I would imagine there would be significant backmixing between cylinders near the junctions.
Reply With Quote
  #25  
Old 08-21-2018, 07:57 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,838
Default

Quote:
Originally Posted by 1001001 View Post
Does the 12 inch rule also apply to junctions with other cylinders? I would imagine there would be significant backmixing between cylinders near the junctions.
No, we're mainly concerned with drawing in air from outside which makes the sensor give us a erroneous reading. Typically O2 sensors are reading an average AFR across all cylinders which is usually what we want so mixing of exhaust is encouraged.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 426.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


Reply With Quote
  #26  
Old 08-22-2018, 12:40 AM
skylor's Avatar
skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 636
Default

Quote:
Originally Posted by rv6ejguy View Post
The Bendix type injection works pretty well in cruise and high power with balanced nozzles actually. We see the majority of fuel savings using EFI in the start/ warmup/ taxi/ descent phases or at low power settings up high where the mechanical injection does not meter very accurately by comparison.
Ross,

I always appreciate your openness and honesty in discussing your EFI hardware and where it is beneficial relative to mechanical FI. Itís refreshing to see this honesty from a business owner in todayís marketing driven environment.

Skylor
Reply With Quote
  #27  
Old 08-22-2018, 07:39 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,838
Default

Quote:
Originally Posted by skylor View Post
Ross,

I always appreciate your openness and honesty in discussing your EFI hardware and where it is beneficial relative to mechanical FI. Itís refreshing to see this honesty from a business owner in todayís marketing driven environment.

Skylor
No point in BSing people out of their hard earned money as it will only come back at you down the road in some way. We pilots and RVers are a community of friends as far as I'm concerned and should be treated as such.

2 days ago I sent a guy over to Don at AFP because I thought mechanical injection would be a better fit for his skill set and mission.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 426.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


Reply With Quote
  #28  
Old 08-22-2018, 09:18 AM
Norcalrv7 Norcalrv7 is offline
 
Join Date: Jan 2015
Location: McKinleyville CA
Posts: 249
Default

Quote:
Originally Posted by rv6ejguy View Post
Caleb, are you using a narrow or wide band sensor?

With W/Bs, we've seen some die in as little as 2 hours on 100LL. Conversely one long time user had over 350 on his and it was still working. All Bosch 4.9s.

We are not sure why the variation in lifespan and are talking to suppliers to see if some counterfeit ones may be leaking into the supply chain perhaps. If we can regularly get at least 150 reliably hours out of a WB, we'd implement closed loop control on aviation systems like we've offered on our automotive ones for a couple of decades now.
I have my Bosch wide band sensor mounted about very close to the cylinder on a single runner. I attribute its lifespan to staying in this hot and clean environment. This would be no more than a guess though. My EGT's which are measured an inch more down the stacks usually run in the 1300os or low 1400's. I also think that my tune has a lot to do with it. My engine runs very clean and lean at low power settings, and only runs rich when needed. borescope inspections show little lead build up inside the cylinders. I also would imagine the advanced timing and hotter spark at these lower settings produces a more complete burn as well.


Caleb

20170207_101436 by Caleb Lesher, on Flickr
__________________
Flying RV-7A N542LC 800 hours+ With SDS Electronic fuel injection.
Pieces of an RV-8 in the back of the hangar
ATP CFI A&P
BE-200 Air Ambulance driver
Based at EKA, Northern CA
Reply With Quote
  #29  
Old 08-22-2018, 11:07 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,838
Default

There may be some correlation on the temperature and lead fouling. Maybe some other SDS users can comment on their sensor placement, EGTs and life span they've observed.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 426.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


Reply With Quote
  #30  
Old 08-22-2018, 11:10 AM
Mark33 Mark33 is offline
 
Join Date: May 2010
Location: Baton Rouge, La.
Posts: 423
Default

Quote:
Originally Posted by Norcalrv7 View Post
I have my Bosch wide band sensor mounted about very close to the cylinder on a single runner. I attribute its lifespan to staying in this hot and clean environment. This would be no more than a guess though. My EGT's which are measured an inch more down the stacks usually run in the 1300os or low 1400's. I also think that my tune has a lot to do with it. My engine runs very clean and lean at low power settings, and only runs rich when needed. borescope inspections show little lead build up inside the cylinders. I also would imagine the advanced timing and hotter spark at these lower settings produces a more complete burn as well.


Caleb

20170207_101436 by Caleb Lesher, on Flickr

Hey Caleb, I see that you have a fuel distribution block/logg mounted on your firewall and youíre not using an actual fuel rail. Have you experienced any hot fuel related issues such as vapor lock or hard starts due to not actually circulating the cold fresh fuel directly past the injectors as would be the case with a fuel rail?

Thanks,
Mark
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 08:19 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.