REFLECTOR: Turbo concerns

[Alex Balic]

Hi Chris-

Even with the 3 pound spring (that's 3psi max of boost, not 3 actual pounds
to compress the spring) you should be getting better than non-turbo in
everything above say 2000 rpm, depending on the Turbo you have. It seems
that possibly the turbocharger has bad bearings/is frozen, and is causing
restriction to the intake instead of providing boost- do you have a
water-cooled center section? Also you need to make sure that your bearings
are getting proper lube, but I would guess that the turbo is either not
turning at all, or it is dragging for some reason, or your wastegate is not
hooked up to the proper manifold pressure port, and it is in full bypass all
of the time- the pop-off valve should have nothing to do with what you are
showing, it would only relieve over-pressure, not cause a restriction.

Alex

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Chris Barber
Sent: Monday, August 20, 2012 9:11 PM
To: Velocity Aircraft Owners and Builders list
Cc: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Turbo concerns

 

Thanks Mark. I shall. I had a destination issue due to low octane fuel
requiring a replacement of the apex seals so I started with minimal boost.
But it would seem even minimal boost should give some boost. 

 

I have two mp gauges. They are not reading exactly the same but within a few
tenths of each other. 

Sent from my iPhone 4


On Aug 20, 2012, at 8:52 PM, "Mark Magee" <edjonesbrady at gmail.com> wrote:

Hi Chris,
I would say to look at two things: 1) Turbo waste gate setting and 2) MP
sender or guage.
I don't know what MP PSI the 3lb spring on the wastegate controller equals,
but it sounds low. I just installed a manual wastegate on the family trip
wagon, a 1998 6.5TD Suburban and the spring tension is much more than 3 lbs,
more like 15 to 20lbs to open, is set in inches of spring span and equals
14PSI MP to open. I would think you should start with investigating the
wastegate settings first.

Mark Magee
N34XL
Brady TX

On Mon, Aug 20, 2012 at 8:18 PM, Chris Barber <cbarber at texasattorney.net>
wrote:


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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