So I believe the 5 minute hold test (29psi)  is a test of the regulator (and likely the entire fuel system including a check for leaking injectors?) to hold the decay to at least 29 psi after 5 minutes.  But, it appears that the desired operating pressure might be closer to 56 psi based on the fuel flow test (presumably conducted at 56 psi sinces it comes right after the leak test at 56 PSI and no indication that the pressure was changed for the flow test).

Looking at the fuel diagram and seeing no indication of a manifold reference tube going back to the fuel tank where the regulator is, I would bet a beer that the fuel pressure is controlled by the CPU either through fuel pump speed control or perhaps electronic control of the regulator in the tank.  My bet is on fuel pump speed.

The only reason I hesitate  at all is that in the Fuel Line Pressure Inspection check, there is a jumper wire used to ground a Fuel Pump related terminal.  This might be just to provide signal to the pump to run OR it might possible by-pass the fuel pressure regulation function and drive line pressure up just for the test.  Could be either one. 

8. Ground the check connector terminal F/P using the jumper wire.

But,  until I see/find or have someone point out something that shows different operating pressure, I’m inclined to agree with Bill’s conclusion. Most tests including the flow test appears to be conducted with 56.9 psi as the value. 

Good find, Bill, certain to stimulate discussion on the topic – and somebody may know for certain {:>). 

Assessing how much impact this would have requires a bit of math  Generally, if you have a fuel pressure change then the new flow rate = old flowrate * sqrt(New Fuel Pressure/Old Fuel Pressure).

So if you were using 43 psi and 295 cc/min injectors and then went to 56 psi, you would have

New Flow rate = 295 * sqrt(56/43) = 295 * 1.1411 = 336 cc/min.  or about a 14% difference.  However, I’m not certain that would be signficant using the Ec2/EC3 as you have the ability to tune the flow of your injectors in a number of ways.  You can use the mode 6 in normal staging/operation mode, you can use the mixture control, and using the EM2/3 change the fuel map bar heights. 

So if the 56psi is the required pressure to achieve the rate flow (normally 43 psi is used) then the injectors are passing less fuel than rated – but, whether this would have any material effect on good operation of the EC2/EC2 I personally rather doubt.  But, only Tracy can authoritatively respond to that.

Ed

Ed

Ed Anderson

Rv-6A N494BW Rotary Powered

Matthews, NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.rotaryaviation.com/Rotorhead%20Truth.htm

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bill Bradburry
Sent: Friday, June 19, 2009 1:13 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: 295cc vs 495 cc was [FlyRotary] responses to responses, not developing full power

By the way, I just discovered that the fuel pressure spec for the RX-8 is over 56 lbs! See the link.

 http://www.myrotarycar.com/portal/forum/uploads/RX8TX/Manuals/CD05-xx-03le/index.html

Most of us have our pressure way lower than that and that will greatly lower the output of the stock injectors since they are sized to deliver fuel at that pressure.  Could be why some of us are not getting throttle response above 2/3 throttle?  What about you guys with superchargers?  Do you go lean?

Bill B

Oh,

If you happen to be using the 6 port and plan to use only 4 of the yellow injectors, they are only good for between 173 and 197 HP at 80% duty cycle and BSFC of .5.  You would have to use all 6 to realize that higher HP that they are supposed to make.

I am thinking that they are sized small in the car because they don’t expect you to be at WOT for long in the car and they will have a chance to cool down.  In our case they will be at WOT for hours and could overheat if they were at a high duty cycle.

Thoughts??

Bill B 

Bryan,

Well, ain’t that interesting!

That indicates that the injectors (according to calculators I found on the web) will support between 183 and 206 HP with a duty cycle of 80% and an BSFC of .5.

So much for all these wild guesses we have been making about how much power we will get with the Renesis.

Bill B

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bill Bradburry
Sent: Friday, June 19, 2009 9:44 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: 295cc vs 495 cc was [FlyRotary] responses to responses, not developing full power

What is the actual size of the stock Renesis injectors?  I was under the understanding that the red primary was 295 ccm and the blue secondary was 610 ccm.  I heard that the yellow injectors from the hi power 6 port were a different size, but have never heard what size they were supposed to be.

Don, did you say you had your injectors cleaned and flowed?  What did they flow? 

Where can this information be found? Is is listed in a Mazda book somewhere?

Bill B

On Fri, Jun 19, 2009 at 10:17 AM, Al Gietzen <ALVentures@cox.net> wrote: