Mailing List flyrotary@lancaironline.net Message #58792
From: Chris Barber <cbarber@texasattorney.net>
Subject: Re: [FlyRotary] Re: Turbo question.
Date: Tue, 21 Aug 2012 01:57:32 +0000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Cc: Rotary motors in aircraft <flyrotary@lancaironline.net>
I am taking the MP reading from the intake before the injectors but after the turbo, pop off valve and intercooler, in that order. I only have a 3 lb spring in the wastegate currently to control boost. Since I had a detonation issue a while back requiring a teardown to replace apex seals, likely due to too low of octane fuel, I wanted to start with just a little boost at first.



Sent from my iPhone 4

On Aug 20, 2012, at 8:42 PM, "Ed Anderson" <eanderson@carolina.rr.com> wrote:

> Chris,
>
> Exactly where are you taking your manifold pressure from-
>
> I presume it is after the turbocharger compressor - somewhere  between the turbo and the intake manifold OR  at the manifold.
>
> The only way I can make sense of your reading based on information provided thus far is that you are taking your manifold pressure reading before the turbocharger compressor inlet.  Then the increased airflow caused by the turbocharger could cause the pressure drop before the compressor due to filter or other restriction.
>
> Even if you have a restrictive filter, the pressure on the compressor outlet side of the turbo, the turbocharger on pressure in your manifold should be higher than without the turbo.
>
> You are not spinning your turbo backwards are you?{:>)
>
> Ed
> --------------------------------------------------
> From: "Chris Barber" <cbarber@texasattorney.net>
> Sent: Monday, August 20, 2012 9:17 PM
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> 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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>>
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>
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