GT1544 Chat
Turbo Mini Forums

So I asked Garret what was the difference between the two 44s that thay have on their website, as the wheel dimentions appeared to be the same. The answer they gave is as follows:

"The compressor wheel is shared among the two turbos. The differences are found in the inlet/outlet geometry of the housings."

Just when I thought that I was getting the hang of flow, boost, trim.........etc.

Anyway, below are the two maps, same wheel, just different inlet/outlet geometry. Can anyone explain what might be different in the geometry, to change the efficiency?

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

At a guess, I would say that the "smaller" one in the upper graph has a reduced inlet eye diameter so that the compressor wheel will achieve optimum inlet air velocity at a lower flow rate.

On the outlet, as it is the same A/R (Area/Radius) then they must have reduced both the volute area and radius to achieve similar gains at lower flows.

Although the upper one has a higher peak efficiency, the fact that it falls off quicker at higher flows would suggest that the compressor housing is smaller.

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."

According to those maps the wheels are different sizes. 43.9mm vs. 44mm. The site suggests that the flange dimensions are the same so I would guess the housings are the same but the wheels are different, despite that email. I have the 44mm if you want me to take any pics

EDIT: That was a far more convincing answer ^

Edited by GaryOS on 2nd Dec, 2009.

On 12th Nov, 2009 Paul S said:

I think Gary OS has taken over my role as the forum smart arse

gary ,heres the wheel specs for both p/n turbos


p/n433287-0004

od44,00

id32,95

tip 3,50

shaft(can you dig it )5,00

trim(or blow)56




some thing that may be different is the diffuser paralell wall section ,makeing it thinner here and longer to the volute can create greater eff and less total flow .

Edited by robert on 2nd Dec, 2009.

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

Yes it says theey are different on the maps, but on the info here http://www.turbobygarrett.com/turbobygarre...44_454083_2.htm they are both specified as 43.9mm (which is what mine measures as). his was one of the reasons why I questioned Garrett.

Would 0.1mm make such a differance.

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

interestingly ,the part nos for the compressor housing, are the same.

comp housing 435842-0017

back plates are different

082 turbo
700593-0001

083 turbo
433254-0001

Edited by robert on 2nd Dec, 2009.

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

So the difference must just be the parallel diffuser gap ????

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."

yes paul ,less gap, less reversion and less total flow ..

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

Don't the backplates usually have the part number painted on them? If so then Wil could identify the one he has

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."

yes or just say the p/n on the turbo , heres a flight of fancy , imagine machining the back plate to create a slow taper ,say 1.5mm over its length out to the volute ..

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

well my comp housing is 454088-1, which was what got me searching to try and find which one I have in the first place.

If you do a bit of digging you find lots of GT1544s with the 454??? numbers. I presumed that in most cases it just means different fitments, like actuator placement.

The only number on my back plate is printed - 150981498187.

The thing is, both comp maps would be ok for my purpose, but it'd be nice to know which one I might have.

Just for completness, my turbine is the 0.35 one off the 083 (the wheel diameters and trim are the same anyway).

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

454088-1 =tbo271 , a t2 turbo not a gt ?
citroen 1.9 diesel .

but that would then have this wheel if its the same as tbo272

410450-0013
48,00
35,65

hmmm so thats not it .looks like a t2 housing on a gt turbo ..

Edited by robert on 2nd Dec, 2009.

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

it couldnt have read 454098-1 could it wil ?

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

It definately has GT15 stamped on the same plate.

On closer inspection on of the 8s could be a 9. so 454098-1

http://www.crturbos.co.uk/product_list.php

Seem to be of 82bhp vauxhall engines

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

aha ,,sorted .
back plate 433254-0001
wheel 433287-0004
housing 433471-0001

Edited by robert on 2nd Dec, 2009.

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

sorry to dig up this again

Im looking at a gt1544 with:

P/N 754-4231
452195-1
A/R .33
A/R .36 TW1

how can i tell which one it is?

cheers

joe

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

"did you know you can toast potato waffles?"

found the family on this website with all maps bar the one i need ha, typical:

http://www.tracklab.biz/AirInduction/Turbo...frame.html#gt15

and cant find it on the garrett website:

http://www.turbobygarrett.com/turbobygarre...bochargers.html

Edited by joeybaby83 on 8th Feb, 2010.

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

"did you know you can toast potato waffles?"

I have exactly the same turbo, exact same numbers except mine is .35 A/R on the turbine side.

I'm also looking for a compressor map, so if you manage to dig one up, can you post it on here please? I'll be looking too

No expense spent