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Home > Help Needed / General Tech Chat > Bore sizes exhaust and induction

boostjunkie

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Northampton

Hi hoping you guys could answer a couple of questions,

firstly, the best size for intercooler tubing,

and.. the biggest bore size for the down pipe and subsecuent exhaust piping, for a standard mini turbo engine.

thanks in advance :)

Confessed addiction to everything mini


wil_h

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Betwix Harrogate and York

Firstly. TD once calulated the optimum sise bore for IC tubing. But it was not a commonly available hose size, so most people use 50mm.

I have a mix of 50mm and 45mm.

And. Down pipe and exhaust are generally 2". Robert recently showed that there is an advantage to a slightly larger bore over 200 bananas.

I find getting more than a 2" pipe past the selector tight.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph



On 2nd Jan, 2013 fastcarl said:

the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


John

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Mongo

Barnsley, South Flatcapshire

You could move the selector inside?

If something is worth doing, it's worth doing half of.


boostjunkie

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Member #: 9117
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Northampton

Thanks Wil_h perfect *wink* i was trying to find figures for the engine to work out the best sized IC but so far have had no luck

Confessed addiction to everything mini


fab

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Paris\' suburb

You could also use two exhaust short rubbers unstead of the long selectors ones.
a lot less hassle

On 25th Oct, 2010 John said:
You could move the selector inside?


fab

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Parisien Turbo Expert

Paris\' suburb

All these flow are related to your engine flow,
determine power output/compressor flow then you'll find the addeuate tubbing, a 200 bhp engine doesn't need the same ones as a 120 bhp one


turbodave16v
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SouthPark, Colorado




On 25th Oct, 2010 wil_h said:
Firstly. TD once calulated the optimum sise bore for IC tubing. But it was not a commonly available hose size, so most people use 50mm..


That was probably when most 'hot' turbo minis had 150hp, and only woodsie had a genuine 200... Oh how things change!

On 17th Nov, 2014 Tom Fenton said:
Sorry to say My Herpes are no better


Ready to feel Ancient ??? This is 26 years old as of 2022 https://youtu.be/YQQokcoOzeY



cossierick

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wakefield West Yorks


So whats your thaughts now dave ??

Rick



On 25th Oct, 2010 TurboDave said:



On 25th Oct, 2010 wil_h said:
Firstly. TD once calulated the optimum sise bore for IC tubing. But it was not a commonly available hose size, so most people use 50mm..


That was probably when most 'hot' turbo minis had 150hp, and only woodsie had a genuine 200... Oh how things change!


turbodave16v
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SouthPark, Colorado

No idea. I haven't exactly spent a lot of time working on the mini in the past year (or two)... I'm still muddling through Pauls efi posts trying to figure out what I want to do next...

On 17th Nov, 2014 Tom Fenton said:
Sorry to say My Herpes are no better


Ready to feel Ancient ??? This is 26 years old as of 2022 https://youtu.be/YQQokcoOzeY



Sprocket

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Preston On The Brook




On 25th Oct, 2010 wil_h said:


I find getting more than a 2" pipe past the selector tight.


I trialled a custom 2 1/4 down pipe on the mock up engine in the car, and it fitted nicely. Perhaps the difference is the hardy spicer?

2 1/4 looks really big *happy* so I will have to increase the tail pipe to 2 3/4 at the very least. I think 3" would be a bit Barry like.

On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be...
So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'...


On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........


tadge44

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Buckinghamshire

Humour a person who knows very little, but why would you need a tail pipe bigger than the rest of the system ?

I thought that as the exhaust would cooling from the point it left the turbo it would therefore contract slightly and the need would be less, not more ?.


Sprocket

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Preston On The Brook

nothing to do with performance, just the look. I currently have the Playmini 2" system which has a 2 1/2" tailpipe. It used to have a rolled end, but I cut it off as I didn't like the look, now it looks plain, but big, unlike some of that fancy shite that just does not look right on a mini. Maybe looks ok on a Saxo VTS.

On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be...
So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'...


On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........


quinton

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Swindon

what would happen if you ran a 2/5" through to say a 1"3/4 or 2" back box?




http://photobucket.com/quintonrose


fab

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Parisien Turbo Expert

Paris\' suburb

On the k16 set up I was using a 2.5" downpipe shape reduced to 2 just above potjoints,
this was to help the circular flow when exhaust left the turbine , then 2 is doing the job for laminar flow.

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