Donations towards server fund so far this month.

 
£0.00 / £100.00 per month
Page:
Home > Paul S trials and testing > AFR Sample Chambers

Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland

Knocked this out as a first attempt.



Any thoughts before I make the other one?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Kean

User Avatar

2401 Posts
Member #: 341
aka T2clubby

South Staffs

Is the stainless take off for EGT?


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland

No, stainless take-off for wideband sensor pre-turbo, so that you don't pressurise the sensor and damage it.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

User Avatar

5847 Posts
Member #: 2024
Formally Retired

Rural Suffolk

My only thought would be make the "chamber" a little bit bigger relative to the downstream pipe. It just "looks" as if downsteam flow conditions may distort the flow from the small stainless pipe.

Also, perhaps, drill a bung and stick a thermocouple in first to see what temperature that chamber is experiencing in practice.

Without seeing the lengths of the two pipes to the manifold/exhaust, it's hard to visualise the potential temperature gradient.

But the principle is exactly what I was expecting from your earlier posts.

EDIT - it may be deceptive from the photo, what is the internal diameter of the chamber and the downstream pipe ???

Edited by Rod S on 19th Jun, 2009.

Schrödinger's cat - so which one am I ???


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland

The actual sensor ports are in line with the incoming pipe that is 4mm bore.

The sensor is 15mm diameter. The bore of the chamber is 21mm and the downstream pipe bore is about 13mm.

There is approx 12mm of chamber before going to the smaller diameter.

It will get hot enough as the outlet pipe is going to be welded to the bend on the turbo outlet.

I've made the other one now.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Kean

User Avatar

2401 Posts
Member #: 341
aka T2clubby

South Staffs

Ah I understand now, nice work.


jbelanger

1244 Posts
Member #: 831
Post Whore

Montreal, Canada

I don't know if you intend to put it on the same exhaust as the one you were using before but if it's the case and you still have the sensor bungs on it, you could put one sensor in the original bung and one on this new chamber and compare readings.

Other than that it looks good.

Jean

http://www.jbperf.com/


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland

No, its for the turbo manifold, so all new.

I will compare readings with the existing setup, though.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland

Now tacked on the downpipe:



Need to add a couple of bosses to the manifold near the flanges and make up the pipes.

I think I'll make up the actuator bracket first just to ensure nothing clashes.

Off to watch the Big Pricks now though.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


miniminor63

User Avatar

1849 Posts
Member #: 672
The oversills police

Oslo, Norway

I thought this was for the sidemount turbo engine?


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland


On 20th Jun, 2009 miniminor63 said:
I thought this was for the sidemount turbo engine?


This one is for the 998 Turbo.

I'll be doing something similar for the side mount turbo in the Miglia if this works OK.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland

Nearly finished, just didn't buy enough of the 6mm tube.



Also need some rod to extend the actuator.

Avon looks like a possibility at this point.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Joe C

User Avatar

12172 Posts
Member #: 565
Carlos Fandango

Burnham-on-Crouch, Essex

very nice Paul :)

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



Rod S

User Avatar

5847 Posts
Member #: 2024
Formally Retired

Rural Suffolk

The only potential issue I see is length of the small bore tubes, or are you going to run the second one in such a way it is the same length as the first ???

Schrödinger's cat - so which one am I ???


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland

No, I plan on taking the shortest route.

I suppose that the inners are going to be a few revs behind the outers. The logs will show up if there is an issue.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


stevieturbo

3374 Posts
Member #: 655
Post Whore

Northern Ireland

Might have been better dumping them further down the exhaust, so there is less chance of the ex-tubine gasses shooting up the tube, contaminating your sample.

Or better still, vent the post sensor to atmos

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland


On 21st Jun, 2009 stevieturbo said:
Might have been better dumping them further down the exhaust, so there is less chance of the ex-tubine gasses shooting up the tube, contaminating your sample.

Or better still, vent the post sensor to atmos


Good point.

That may well happen at low load. I'm hoping that under boost there will be enough pressure to keep things moving in the right direction.

I'm planning on having a proven setup in NA mode, so that I'll only need to be concerned with AFRs under boost.

Can always modify it later.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


tadge44

2959 Posts
Member #: 2500
Post Whore

Buckinghamshire

You guys are so far ahead of me I dont really follow these threads, but can you tell me why you want to move the oxygen sensor away from the manifold instead of just putting it in a boss close to the turbo outlet ?.Is it because you want to sample for each exhaust port ?.


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland

Yes, with port injection, the inner and outer cylinders run at different AFRs unless the timing of the injection is precise, so we need to measure inner and outer AFRs separately.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


stevieturbo

3374 Posts
Member #: 655
Post Whore

Northern Ireland




On 21st Jun, 2009 Paul S said:

On 21st Jun, 2009 stevieturbo said:
Might have been better dumping them further down the exhaust, so there is less chance of the ex-tubine gasses shooting up the tube, contaminating your sample.

Or better still, vent the post sensor to atmos


Good point.

That may well happen at low load. I'm hoping that under boost there will be enough pressure to keep things moving in the right direction.

I'm planning on having a proven setup in NA mode, so that I'll only need to be concerned with AFRs under boost.

Can always modify it later.



Given the small diameter of the feed tubes ( for obvious reasons ), I think the exhaust gases exiting the turbo, could shoot straight up the tube. More so as the tubes are almost pointing at the turbine exit.
There simply wouldnt be enough volumne of gas at the higher pressure to resist it.


Even if the tubes were cut/welded in at an extreme angle....

In fact at an angle like some of the crankcase evac systems use, so that it actually tends to draw any gases into the exhaust stream.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


stevieturbo

3374 Posts
Member #: 655
Post Whore

Northern Ireland

http://www.summitracing.com/parts/DTC-85-100950/?image=large

http://www.summitracing.com/search/Part-Ty...yword=crankcase

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Paul S

User Avatar

8565 Posts
Member #: 573
Formerly Axel

Podland

Ideally the two pipes would join the downpipe after the join but that would be a fabrication and installation nightmare.

Let's see if this works. If this doesn't show variation in AFR between the inner and outer cylinders, then I shall have to reconfigure it.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


robert

User Avatar

6471 Posts
Member #: 828
Post Whore

uranus

i think both paul and steve are right ,at low rpm i can see steves scenario playing out ,particularly between pulses ,and once the turbo creats some back pressure then it changes around to reading as it should..

fitting a tap in the big return that could be adjusted ,would ,perhaps make it a bit adjustable .

Bicester scramble ,Medusa enjoyed the trip. https://www.youtube.com/watch?v=Q-7I7-nA19U


jbelanger

1244 Posts
Member #: 831
Post Whore

Montreal, Canada

At low RPM. it will also depend on where the exhaust gas speed is higher. Due to venturi effect it will have a tendency to go where the speed is higher.

Jean

http://www.jbperf.com/


joeybaby83

User Avatar

6274 Posts
Member #: 509
Post Whore

Isle of Man

i just looked at the first pic, and thought you had welded your wb sensor to its boss

i had written a long post raising several issues with you doing this, then realised i had imagined it all

its been a long weekend, and i think its time for bed


p.s not that my opinion is worth an awful lot in this area, but i agree with stevie and the others about the pipe angle etc

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"


Home > Paul S trials and testing > AFR Sample Chambers
Users viewing this thread: none. (+ 1 Guests)   Next ->
To post messages you must be logged in!
Username: Password:
Page: