Downpipes and "cat" stuff

[Pisobiker]

Took some mesurements over 3B, ABY and ADU (RS2) catalytic converters, downpipes and 1 in 2 pipes.
Since I have all of them unbolted for the moment, I tought this might be of some interest:

1) Downpipes and splitters:

1.1) Turbine outlet flange:

3B 58mm internal Ø;
ABY 58mm internal Ø;
ADU 58mm internal Ø;

1.2) Downpipe Ø:

3B ~62mm internal Ø;
ABY ~62mm internal Ø;
ADU ~66mm internal Ø;

1.3) 1 in 2 splitters:

3B ~1 x 62mm to ~ 2 x 50mm internal Ø;
ABY ~1 x 62mm to ~ 2 x 50mm internal Ø;
ADU ~1 x 66mm to ~ 2 x 50mm internal Ø;


Following picture show RS2 downpipe with splitter (same layout as ABY) and 3B splitter

[Pisobiker]

2) Catalytic converters:


2.1) Catalytic material:

3B ceramic;
ABY ceramic;
ADU metallic;

2.2) Approximate internal flow section:

3B 82 square cm;
ABY 75 square cm;
ADU 70 square cm;

2.3) Approximate # of cells per sqare inch:

3B 400;
ABY 400;
ADU 200;


While figuring out flow differences among different layouts some considerations must be taken into account:


a) at same cell dimensions metallic converter could have less frictional losses thus higher flow;

b) increasing cell dimensions allows a more than proportional increase in flow (because of proportionally smaller "limit stratus" and smaller overall frictional interactions with walls);

c) while going from a single pipe layout to a 2 pipe layout having same total cross sectional areas, 2 pipe layout will have higher internal frictional losses proportional to the bigger total wall surfaces compared to the single pipe;

d) While going through different pipe shapes, at same cross sectional areas the circle shape will have the smallest frictional losses beacuse of best "cross sectional area / wall diameter " ratio.


here are some pics:
left to right: 3B, ABY, ADU

[Pisobiker]

here is an internal close up of 3B converter

[Pisobiker]

close up of ABY converter (picture isn't very good, but it seems to me same converter type as the 3B one)

[Pisobiker]

close up of ADU (RS2) converter

[Jamo]

So is it possible to fit the ADU cats on an ABY with modifications? or will modifications be required?

[dan_b]

Cats? Ha! Get a pre 92-car and you don't need them

Good info though

[Jamo]

Cats? Ha! Get a pre 92-car and you don't need them

Good info though

Yeh yeh show off!!!!

[dan_b]

Yeh yeh show off!!!!

Who, me?

[Jamo]

Who, me?

Yeh you!!! can see why you've got a Reb S2 now


Is it hot in hell? - sorry i meant london!

lol

[dan_b]

Yeh you!!! can see why you've got a Reb S2 now


Is it hot in hell? - sorry i meant london!

lol

It is quite nice and warm already yes, had the sunroof open and the windows down driving through Richmond Park yesterday, looking at the Deer - lovely.
I was up in Birmingham 2 weeks back, nice to go back to put the Ming back in Bham, used to go to University there...

Sorry, going off-topic.

Would be interesting to know what dimensions/specs the aftermarket systems/cats have for comparison's sake?

[Jamo]

It is quite nice and warm already yes, had the sunroof open and the windows down driving through Richmond Park yesterday, looking at the Deer - lovely.
I was up in Birmingham 2 weeks back, nice to go back to put the Ming back in Bham, used to go to University there...

Sorry, going off-topic.

Would be interesting to know what dimensions/specs the aftermarket systems/cats have for comparison's sake?

Haha, mate theres enough ming in birmingham to go around!
Which uni, Aston, Birmingham or the dreaded UCE?

[Tizer.B]

Haha, mate theres enough ming in birmingham to go around!
Which uni, Aston, Birmingham or the dreaded UCE?

What part of Birmingham are you from Jamo? .


Tyrone

[dan_b]

Haha, mate theres enough ming in birmingham to go around!
Which uni, Aston, Birmingham or the dreaded UCE?

Birmingham, the nice redbrick one in Edgbaston. Lived in Selly Oak behind the Old Varsity Tavern. Did Biochemistry (for my sins).


ADU engine type - that's the designation for the RS2 motor isn't it?

[Jamo]

What part of Birmingham are you from Jamo? .


Tyrone

Near the West Bromich Albion ground (no not smethick!!! and yep i've got a B post code )


Nice i used to go drinking in them parts on the "hunt" ahem

Changed a bit recently they've modernised it a bit.