As the topic says,how can i measure back pressure.
I've heard different ways of doing it,1 being drilling a hole in the exhaust housing and using a gauge.
any output would be useful input,as far as what kind of gauge to use and where to drill..
thanks.

 

We have just been using copper tubing and coiling it up and running it into a 100psi guage and take it off when we are done.

 

Buy some sort of data acquisition device such as Racepak etc... with a pressure tansducer to record back pressure at the turbo manifold, tap in to the collector.

 

Off of the exhaust housing?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by uglyasscivic &raquo;</TD></TR><TR><TD CLASS="quote">We have just been using copper tubing and coiling it up and running it into a 100psi guage and take it off when we are done.</TD></TR></TABLE>

exactly


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aggressive Racing &raquo;</TD></TR><TR><TD CLASS="quote">Off of the exhaust housing?</TD></TR></TABLE>


yes right off of the exhaust housing is where i usually place the fitting. usually about 1" up from the flange.

 

you're going for turbine inlet pressure, so right in the exh housing or low in the collector will work

fyi, if you have AEM you can wire up a map sensor into any of the extra 5v inputs to log it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">you're going for turbine inlet pressure, so right in the exh housing or low in the collector will work

fyi, if you have AEM you can wire up a map sensor into any of the extra 5v inputs to log it.</TD></TR></TABLE>

Thanks for the 411 guys.

 

same thing for me, hole in the exhaust housing, long piece of hard alum. brake line coiled up, and an AEM 150psi sensor...

learned a lot on the first pass.

 

can you expand on what you learned? Any comparisons?

 

I am also very curious as to the benefits of logging exhaust backpressure and what types of changes you would make ect. after viewing the info...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by g2turbo &raquo;</TD></TR><TR><TD CLASS="quote">I am also very curious as to the benefits of logging exhaust backpressure and what types of changes you would make ect. after viewing the info...</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by uglyasscivic &raquo;</TD></TR><TR><TD CLASS="quote">We have just been using copper tubing and coiling it up and running it into a 100psi guage and take it off when we are done.</TD></TR></TABLE>


Thats how we did it before

 

It wasnt a revelation or anything, but we were having some doubts about my combination and wanted to start ruling out potential root causes of the problems we were dealing with.

in my situation, we were trying to determine the correct WG spring combination to use in conjunction with the AEM EMS boost control... and make sure that I wasnt outgrowing the turbine side of the turbo...
it was a typical top port vs. side port setup, but we couldnt build the proper boost levels on the 2step or ramp up the higher boost quickly enough, so we thought that perhaps there was too much backpressure in the turbine housing that wasnt allowing us to force more through... But after the first pass we saw that the backpressure was minor, and determined that the exhaust housing/turbine wasnt the problem.. after trying a higher pressure WG spring, things started to behave more the way that we would expect them to... after that, we stopped logging that channel, since we saw what we needed to see... and wanted the resolution for other things.

 

just curious.. to add to stuff i have been seeing... what problems were you having and what was the inital wg spring/turbine combo that was giving you issues? which wastegate also

 

whats the proper way to place the tube in the exhaust pipe.... and where?

 

i measure back pressure on the diesel engines i work on at work (these engines have cats and particulate filters after the turbo) and when we have a problem with the back pressure (well first we check the reader and check to see what the back pressure sensor is reading) and then we compare that reading to a mercury manometer to verify that it is reading witin spec. i just tap into the exhaust pipe when i take the readings.

 

OK guys i did the bung on the housing with copper tubing,the results were,
@35psi there was about 30 psi of pressure in the backhousing.
Now can anyone confirm if thats good, decent or bad.

Hector.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aggressive Racing &raquo;</TD></TR><TR><TD CLASS="quote">OK guys i did the bung on the housing with copper tubing,the results were,
@35psi there was about 30 psi of pressure in the backhousing.
Now can anyone confirm if thats good, decent or bad.

Hector.</TD></TR></TABLE>

from what i have been told, that you want the pressure in the turbine to be the same or i would guess less than the manifold pressure, you are deffinitely not seeing a backpressure problem at that boost level

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aggressive Racing &raquo;</TD></TR><TR><TD CLASS="quote">OK guys i did the bung on the housing with copper tubing,the results were,
@35psi there was about 30 psi of pressure in the backhousing.
Now can anyone confirm if thats good, decent or bad.

Hector.</TD></TR></TABLE>

pm'd


Modified by miller at 7:54 PM 11/11/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by miller &raquo;</TD></TR><TR><TD CLASS="quote">

something dosent seem right though.</TD></TR></TABLE>

?

 

Idealy you want a 1:1 ratio

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by E Town DSM &raquo;</TD></TR><TR><TD CLASS="quote">Idealy you want a 1:1 ratio</TD></TR></TABLE>

Yes, at anything other than 1:1...

If Intake pressures are higher than exhaust, air will blow through the chamber, you will produce less power, run richer but show leaner on the wideband.

If Exhaust pressures are higher, obviously burnt exhaust wont completely be expelled from the chamber causing less power, lower boost (EGR).

Bout right?

 

you want the pressure in the exh manifold to be as low as possible.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">you want the pressure in the exh manifold to be as low as possible. </TD></TR></TABLE>

I'm sure there's a limit to how low you want the exhaust backpressure (for the turbos sake, not the engine), but i haven't found it yet...

 

what is being accomplished by having backpressure @ the turbo? are you thinking in terms of spool time?