REFLECTOR: Turbo concerns

Tue Aug 21 16:36:57 CDT 2012

Chris,
When I heard you start it up and run it a few weeks ago nothing sounded
wrong, you didn't run up high statics as I recall however. I would ensure
you're fueled with high octane fuel and then set the waste gate controller
for a higher pop-off setting, maybe 10 psi. The run your static max RPM's
with a piece of yarn siliconed to the inside of your wastegate exhaust.
Next note if: a) your numbers look better and b) have an observer see if
the wastegate is opening as prescribed by blowing the yarn.
With only 3 PSI set on the wastegate controller due to low octane fuel,
IMHO you should start with getting the wastegate set to normal parameters
w/proper octane fuel before troubleshooting further. Your current setup has
the potential to produce all types of feedback mechanism problems for the
ECU.

Regards
Mark Magee
N34XL

On Tue, Aug 21, 2012 at 4:16 PM, Chris Barber <cbarber at texasattorney.net>wrote:

> Replaced my plugs yesterday and they looked exactly as I had hoped.
> Textbook example of "normal"
>
> Sent from my iPhone 4
>
> On Aug 21, 2012, at 3:59 PM, "Scott Derrick" <scott at tnstaafl.net> wrote:
>
> > The mixture would be screwed up as the servo is expecting a certain
> amount of air with the turbo but is not getting it.  I imagine its running
> really rich with or without the turbo.  You could verify that by checking a
> plug.
> >
> > Scott
> >
> > -------- Original Message --------
> > Subject: Re: REFLECTOR: Turbo concerns
> > From: Laurence Coen <lwcoen at hotmail.com>
> > To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> > Date: 08/21/2012 12:56 PM
> >
> >> Chris,
> >>
> >> I think you do have a turbo problem but I think there is more too it
> >> than that.  The numbers that you supplied suggest that the computer
> >> controlling the spark advance and gas air ratio is getting different
> >> information with the turbo connected and disconnected.  If you look at
> >> the 2000 RPM data the engine gets the same RPM with two very different
> >> manifold pressures.  In both cases the engine load is the same (the
> >> prop).  The only way you could get the same RPM with an increase of 1.8"
> >> manifold pressure is to retard the ignition or screw up the mixture.
> >>
> >> Larry Coen
> >> N136LC
> >>
> >>
> >> --------------------------------------------------
> >> From: "Chris Barber" <cbarber at texasattorney.net>
> >> Sent: Tuesday, August 21, 2012 9:32 AM
> >> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> >> Subject: Re: REFLECTOR: Turbo concerns
> >>
> >>> Scott,
> >>>
> >>> Thanks, that gives me some specifics.
> >>>
> >>> Chris
> >>>
> >>> Sent from my iPhone 4
> >>>
> >>> On Aug 21, 2012, at 8:56 AM, "Scott Derrick" <scott at tnstaafl.net>
> wrote:
> >>>
> >>>> You definitely have something not working in your turbo setup. I'm
> >>>> assuming you measuring upper deck pressure?  Ala intake pressure
> >>>> after the intercooler and servo?
> >>>>
> >>>> problems.
> >>>>
> >>>> 1.) turbo is not spinning freely due to internal obstruction(I've
> >>>> seen rags), bad or incorrectly installed bearings, bent fan, etc.  It
> >>>> should spin very freely by hand, take a long time to come to a stop.
> >>>> Blow a vacuum cleaner through the turbo and see how she spins, with
> >>>> an open turbo(no back pressure) it should spin up very fast with a
> >>>> large canister style vacuum.
> >>>>
> >>>> 2.) waste-gate opening prematurely. In your case immediately. Can you
> >>>> see the waste-gate operation when the engine is running? Make bright
> >>>> marks on the moving parts to make this easier.  Note its position
> >>>> before start, then at idle, then a varying degrees of throttle
> >>>> position. It should be completely closed until close to mid throttle.
> >>>> At least the tio520 operated in that manner.
> >>>>
> >>>> 3.) pop-off opening too soon.  Tie a rag or something to the opening
> >>>> that will flutter around when it opens. Do this at the same time your
> >>>> observing the wastegate.
> >>>>
> >>>> 4.) If all the above are OK, its possible your intercooler is
> >>>> restricting flow. remove the intercooler and run without it.
> >>>>
> >>>> Scott
> >>>>
> >>>>
> >>>> -------- Original Message --------
> >>>> Subject: REFLECTOR: Turbo concerns
> >>>> From: Chris Barber <cbarber at texasattorney.net>
> >>>> To: REFLECTOR <reflector at tvbf.org>
> >>>> Date: 08/20/2012 07:18 PM
> >>>>
> >>>>>
> >>>>> As I have mentioned I have had what I think are incongruent readings
> >>>>> regarding my manifold pressure (mp)and engine rpm. It seems I am
> >>>>> getting quite low mp as I add power to higher rpm.
> >>>>>
> >>>>> I am not well versed in this area but my thought is that as I add
> >>>>> power, even with slight boost (currently using a 3 lb spring in my
> >>>>> wastegate) eventually my mp should raise a bit more.
> >>>>>
> >>>>> Today I did some static test. I recorded engine RPM with the  turbo
> >>>>> hooked up and recorded the mp at 1000 rpm increments. Then I removed
> >>>>> the turbo plumbing from my intake and recorded the same info My
> >>>>> results currently confuse me.
> >>>>>
> >>>>> With the turbo hooked up I am getting
> >>>>>
> >>>>> RPM.   MP inches
> >>>>> 2000 - 14.0
> >>>>> 3000 - 15.5
> >>>>> 4000 - 19.3
> >>>>> 5000 - 21.6
> >>>>> 5700 - 24.5 (topped out)
> >>>>>
> >>>>> With the turbo removed.
> >>>>>
> >>>>> 2000 - 15.8
> >>>>> 3000 - 15.3
> >>>>> 4000 - 19.7
> >>>>> 5000 - 24.8
> >>>>> 5833 - 29.8
> >>>>>
> >>>>> Is this indicative of restriction in my plumbing? Perhaps in the
> >>>>> inter cooler? A dirty air filter? A bad pop off valve or a leak not
> >>>>> allowing the air pressure getting to the intake. Or????
> >>>>>
> >>>>> I am uncertain what other permitters I need to check and provide. I
> >>>>> am just starting my diagnosis in my Phase One testing. I only have
> >>>>> 1.6 hours in the air so far. I value ya'll's direction and input.
> >>>>>
> >>>>> Heck, perhaps this is working properly but it just doesn't seem
> >>>>> right/comfortable.
> >>>>>
> >>>>> Thanks folks.
> >>>>>
> >>>>> Chris Barber
> >>>>> Houston
> >>>>> Velocity SE
> >>>>> Rotary 13b turbo (?) :-)
> >>>>>
> >>>>> Sent from my iPhone 4
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