Chris,
I agree with Steve.  This does not make sense on a couple of levels.
Something is not right for sure, very likely two things.  Hard to fix
without being there.  However, the stuck (non spinning) turbo makes
the most sense as a single issue.

Was it working normally before the detonation issue?

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net


On 8/20/12, Steven W. Boese <SBoese@uwyo.edu> wrote:
> Chris,
>
> The attached image shows a comparison of RPM vs MAP for a 13B on an engine
> test stand for a turbo installation, a supercharger installation, and a
> normally aspirated setup along with the data you reported.  The test stand
> prop was the same for each installation and the same intercooler was used
> with the turbo and the supercharger.  The altitude here limits the NA MAP to
> 23" Hg.  No claim is made that the turbo or supercharger installations were
> completely optimized, however the trends should be valid.  The NA intake was
> the dynamic chamber intake as found in a 1986 RX7 car.  The NA installation
> had the turbo and supercharger completely removed: that is, the turbo was
> not connected to either the intake or exhaust system, and the supercharger
> was not being belt driven and was not connected to the intake system.
>
> From the data you reported, you got similar max static RPM with the turbo
> with about 6" less MAP than normally aspirated (similar situation at 5000
> RPM).  That is difficult to accept since it takes energy to drive the turbo
> in the form of increased exhaust gas backpressure which would raise the MAP
> requirement rather than decrease it.
>
> If your data for the turbo and normally aspirated cases were reversed, then
> the data makes sense.  If the normally aspirated MAP was limited to 24.5",
> the max MAP of 29.8 would correspond quite well with boost being limited to
> 3 psi by the wastegate spring.  The turbo system would appear to be working
> correctly if this unlikely scenario were to be the case, but unfortunately,
> the indication of a free lunch would be gone.
>
> Steve Boese
> RV6A, 1986 13B NA, RD1A, EC2
>
>
>
> ________________________________________
> From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of
> Chris Barber [cbarber@texasattorney.net]
> Sent: Monday, August 20, 2012 7:17 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Turbo question.
>
> 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
> --
> Homepage:  http://www.flyrotary.com/
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