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Home > Help Needed / General Tech Chat > T£ A/R ratios

tadge44

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Buckinghamshire

26th Nov, 2009 at 12:22:20pm

I have searched, but dont seem to be able to find what I want so here is another question from someone who should perhaps know better.

My T3 has an A/R ratio cast into the compressor housing of .42.

Is this standard M/T ?

I dont get full boost until over 3500 rpm - is this what I should expect ?

It goes reasonably from about 2800, picks up well over 3500 and goes totally BOK at 4000.

Rod S

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5988 Posts
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Formally Retired

Rural Suffolk

26th Nov, 2009 at 12:47:23pm

Standard compressor housing is 0.42 but look at the exhaust housing casting A/R number. A Metro T3 would be 0.25 (the smallest ever made for a T3) but a lot out there could have the 0.36 from an early Escort turbo (1600cc) as these are now the smallest ones made and available to reconditioners. A larger turbine A/R would certainly spool up later (higher RPM) but the actual point in the RPM range will be derived from lots of other factors of the engine specification.

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

wil_h

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Betwix Harrogate and York

26th Nov, 2009 at 01:13:19pm

Sounds right for a T3.

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.


tadge44

3006 Posts
Member #: 2500
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Buckinghamshire

26th Nov, 2009 at 02:55:55pm

Thanks guys.

Maybe start looking at the GT series for more low speed boost ?

Any comments ?.

robert

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uranus

26th Nov, 2009 at 03:16:04pm

i was running the .25 a/r on my t3 ,genuine metro ,and boost came in at 15 to 1800 rpm , thats on a 1312cc engine ,so if you can ,get one of those .i think they may be pretty rare now ?
regards
robert .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

apbellamy

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King Gaycharger, butt plug dealer, Sheldon Cooper and a BAC but generally a niceish fella if you dont mind a northerner

Rotherham, South Yorkshire

26th Nov, 2009 at 03:18:56pm

Do it!

On 26th Nov, 2009 tadge44 said:
Thanks guys.

Maybe start looking at the GT series for more low speed boost ?

Any comments ?.

On 11th Feb, 2015 robert said:
i tried putting soap on it , and heating it to brown , then slathered my new lube on it

*hehe!*

John

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10023 Posts
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Mongo

Barnsley, South Flatcapshire

26th Nov, 2009 at 03:24:05pm

I reckon there a plenty of original .25ar metro turbo's around. Some in worse con than others, but they are still plentiful in useable condition.

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

tadge44

3006 Posts
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Buckinghamshire

26th Nov, 2009 at 06:27:57pm

I cant see any markings on the cast iron exhaust housing. The impeller seems to be 50mm in diameter if than indicates anything.

The turbo is a new one, not reconditioned, with the original Garrett plate on it.

Rod S

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5988 Posts
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Formally Retired

Rural Suffolk

26th Nov, 2009 at 07:14:14pm

It's there if you look hard enough but you might need some Mr Magoo reading glasses like me !!!



EDIT, upsidedown and the A/R text got washed out with the flash.

Edited by Rod S on 26th Nov, 2009.

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

tadge44

3006 Posts
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Buckinghamshire

26th Nov, 2009 at 09:53:42pm

I can see it - ta !!
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