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Location:
SYDNEY
Registered:
November 2004
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exhaust manifold pressures
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Fri, 19 August 2005 11:43
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guys,
has anyone ever measured the gauge pressure in the exhaust manifold on a turbo car ? especially under load ?
Just looking at getting some feedback as to if anyone had done this or any experience.
also what sort of temps was the exhaust manifold at full boost.
This is for a 3sgte but any turbo will at least give us an idea.
basically this is just to test the manifold befor it goes in the car.
Thanks
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Location:
brisbane
Registered:
December 2004
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Re: exhaust manifold pressures
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Sat, 20 August 2005 00:01
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cant help you with the temp but mine glows red after a bit of punishment
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Location:
SYDNEY
Registered:
November 2004
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Re: exhaust manifold pressures
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Wed, 24 August 2005 10:19
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Thanks but come on someone must know about this ?????????????
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Location:
On your mum!
Registered:
May 2002
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Re: exhaust manifold pressures
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Wed, 24 August 2005 10:31
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I have not measured the turbine inlet pressure BUT according to Corky Bell's book "Maximum Boost", turbine inlet pressure should not exceed 2 x that of the intake manifold, and that any more is a poorly designed system.
Pressures would no doubt vary a great deal between different systems. So I cannot see how you are going to learn about your manifold from someone elses measurements; remember that whatever the system pressure after the turbo is going to add to the TIP.
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Location:
SYDNEY
Registered:
November 2004
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Re: exhaust manifold pressures
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Wed, 24 August 2005 10:35
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Sounds good thanks for the feed back, it was just to get an idea so we can pressure test the manifold.
So if it runs say 15 PSI max exhaust pressure is say 30 so if we add a factor of safety of say 10 PSI and pressure test it to say 45 PSI that should cover it i would think 
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: exhaust manifold pressures
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Wed, 24 August 2005 11:45
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The steel should be regarded in a dark or faintly lighted room and must not be exposes to direct light. The colour chart should be regarded in normal diffused daylight and not in sunlight or artificial light.
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Location:
On your mum!
Registered:
May 2002
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Re: exhaust manifold pressures
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Wed, 24 August 2005 22:06
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Your pressure test theory may be flawed, as it is not that uncommon to have the exhaust manifold glowing red hot.
Is your pressure test going to involve heating the manifold until it is glowing?
What manifold are you planing to use?
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Location:
On your mum!
Registered:
May 2002
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Re: exhaust manifold pressures
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Wed, 24 August 2005 22:07
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nice work Stew 
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: exhaust manifold pressures
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Thu, 25 August 2005 06:09
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so what temp does yours get to???
we should have at look at 1JZ747'S video and see what temps his were getting to also...
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Location:
On your mum!
Registered:
May 2002
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Re: exhaust manifold pressures
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Thu, 25 August 2005 06:16
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800+
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Registered:
May 2002
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Re: exhaust manifold pressures
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Thu, 25 August 2005 06:40
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I can understand YelloRolla statment from Corky Bells book which states that by measuring the exhaust manifold pressure you could identify manifold design inefficiencies.
But in what street applications (even most race applications) would the exhaust manifold pressure reach a point where it would/could cause structural damage or detrimental failure?
So I guess my question is: measuring pressure for efficiency purposes would be useful, but how necessary is it to try and measure exhaust manifold pressure when inlet pressures are not going to be exceedingly high i.e <30psi ????
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So if it runs say 15 PSI max exhaust pressure is say 30 so if we add a factor of safety of say 10 PSI and pressure test it to say 45 PSI that should cover it i would think
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I would have thought even the flimsiest (technical term) thin walled manifolds I have seen would cope with 3 bar of pressure, even at higher temps?????
A plastic 375ml coke bottle is capable of holding approximately 300psi before catastrophic failure, so I assume a well constructed tig welded steam pipe manifold would cope easily with 3 bar of pressure until the metal reached a temperature point where it became plastic?????
I am rambling now, someone with knowledge (a metalurgist) enlighten us
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Location:
On your mum!
Registered:
May 2002
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Re: exhaust manifold pressures
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Thu, 25 August 2005 06:45
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| ke382TG wrote on Thu, 25 August 2005 16:40 |
I can understand YelloRolla statment from Corky Bells book which states that by measuring the exhaust manifold pressure you could identify manifold design inefficiencies.
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Or just to determine that the turbine is big enough for the job. One hopes that even the poorest manifold is not going to be a greater restriction than that of the turbine.
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Registered:
May 2002
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Re: exhaust manifold pressures
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Thu, 25 August 2005 06:55
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Or just to determine that the turbine is big enough for the job. One hopes that even the poorest manifold is not going to be a greater restriction than that of the turbine.
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Ah yep. Thanks.
I really should try and find a manifold pic that I had, I have never laughed so hard at a car part in my life, it was the only manifold I have ever seen that was definitely a HUGE restriction. It looked like a Year 7 metal work student made it using heavy duty curtain rods and an arc welder with no instruction or prior welding experience what so ever  Sadly a local exhaust shop actually made it 
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Location:
On your mum!
Registered:
May 2002
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Re: exhaust manifold pressures
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Thu, 25 August 2005 07:00
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Hey, do you know where I can get some heavy duty curtain rods cheap?
Time to build me a manifold for <$25!
Step 1 - procure curtain rods
Step 2 - Arc weld to flange (cut from std cast iron manifold)
Step 3 - ?????
Step 4 - Profit
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: exhaust manifold pressures
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Thu, 25 August 2005 07:32
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| ke382TG wrote on Thu, 25 August 2005 16:40 |
A plastic 375ml coke bottle is capable of holding approximately 300psi before catastrophic failure, so I assume a well constructed tig welded steam pipe manifold would cope easily with 3 bar of pressure until the metal reached a temperature point where it became plastic?????
I am rambling now, someone with knowledge (a metalurgist) enlighten us
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well.. just had a quick look for conditions of steam secondary superheater headers.... although the vessels are much much thicker than what is used for cars, the pressure and temps are around 550C, and 2400-3800Psi...
http://www.babcock.com/pgg/tt/pdf/BR-1586.pdf
this means that the little pipes off it have to be rated for thhat pressure too..
and a neat little flash
http://www.aes.hu/ENG/Movie5.swf
which also states 2500psi
so i guess it depends on what "steam pipe" is actually being used... when you talk about operating temps and pressures of pipes.. you are talking YEARS to failure..
i think what is more important for a turbo header is the weight of the turbo itself, and the vibration it generates..
with the turbo hanging of, you have a certain load which for some part of the header is tension, but the vibration now makes this a cyclic tensile load, which is perfect for fatigue..
that said tho, don't most turbo headers fail by crackign at welds/joins rather than the pipe itself?? oh, and occasionl overtemp is important too... 800deg is pretty high, and that temp combined with loading, even for a short time can cause damage (if design/material is not adequate).
fwiw, turbine blades run at around 1000C, but they fail from creep and oxidation, and we are talking about 20-30,000hrs AT temperature...
Cya, Stewart
[Updated on: Thu, 25 August 2005 07:32]
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: exhaust manifold pressures
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Thu, 25 August 2005 07:36
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so anyone know what alloys they use?
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