Turbo geeks/gurus and anyone else ;)

[StaceyS3]

Well yesterday I took my k26 apart to inspect it and well im just nosey

Ive always thought there was more to extract from this turbo/set up but thought 2 of the main things holding me back (figure wise) was 8.5 cr and hotside restriction (possibly wheel size or ar of the housing)

Just me being me have always thought of what was possible with this tubby or framed size on this car with some subtle changes, as got a friend weighing up what could extract out of it?

Heres a few pics of the wheels and housings

Compressor side







Hotside







Hotside housing



The obvious upgrade would be a newer more modern and efficient billet wheel which would in effect need less energy to turn the turbine?

The main thing that I would have thought should gain some is a bigger ar turbine housing or something of that nature to aid hotside flow

The manifold seems to flow enough and the flange port size is in between a t25 and t3 so that shouldnt be holding it back? When was on the dyno Bill did say looked like the hotside was the restriction as could tell that was where the heat was building up first

Just after opinions of what this could perform at on a higher cr set up or (what would expect the wheels to perform at due to size) and also sensible upgrades as believe theres some more gains to be had out of this turbo

 

[Goubo1]

Will be watching this thread closely as I wouldn't mind getting my k26 worked on if there was enough benefit of getting it done

 

[beachbuggy]

The thing with all the k16/k24 and k16 are is that they produced wheels , both turbine and compressor with low ratio sit-ups so in your case the inducer of the compressor is quite a low % of the exducer. The k16/24/26 never really made great power on the original sit-ups and looking at you compressor wheel it was definitely designed to be faster spooling that than high flow.

The turbine is a good size, considerably bigger than either the current tfsi or my custom made k16/k04 wheels which all make decent power.


Your best option and cheapest would be rebuild the turbo and upgrade the compressor wheel to a billet one, probably of a better design but same size. What it will allow is less weight in the wheel so faster spool and great volume between the blades thus more airflow,


If you look at blade design it's a 6+6 design of equal length which is very similar to the k03 wheels.


At the end of the day any shape or sized wheel can be made to fit

 

[StaceyS3]

Cheers for that dan you was one of the main people was hoping would chime in

Do you think a billet wheel will make much difference to egts as they have always seemed the limitation like the k04

I understand that a billet is usually lighter and more efficient so will need less energy input to the turbine for the same amount of flow but not surr how much difference could hope for (all guessing and subjective at best)

Would have thought the turbine on this should flow a little more than the k04 rs6 turbine when you compare size difference but like you say the blade design will also come into it?

Mine had reached just over 350 iirc when bill turned the boost up a tad more but he settled on a lower boost level for more consistent power



Wish id got a billet wheel put on one of the times I had the turbo off as am really curious to what its could be capable of but had been distracted by the gtx

 

[StaceyS3]

I found some interesting info on my turbo eventually as never been able to find much, not sure if its the exact wheels but seems like the bigger comp and smaller turbine pretty close to mine if not them (within half a mm but will check part numbers when near the turbo)

Looking at the comp map I must of been getting nearly every ounce of air out of the comp wheel possible

It seems they do also a bigger turbine with the exducer being pretty much same size as a gt30 where as mine is neary the same exducer as a gt28 im comparison

 

[superkarl]

I see they list the turbine a/r as cm^2, 6cm is VERY small if thats yours, 8 isnt a great deal bigger either.
Its hard to equate them to usual garrett a/r ratios but theres info out there that compares the two.

 

[StaceyS3]

Only summising with my limited online learnt knowledge lol that the bigger turbine, housing and a lovely billet wheel would have you near an equivilent journal gt30 sized billet turbo....may be a nice upgrade for rob (goubo) when he goes to upgrade his??

 

[superkarl]

A quick google suggests .41 a/r. Which in the garrett world is naff all.
I think even in upgrading the comp wheel you'l not see its potential with a housing so small choking the turbine.
That turbine wheel is like inbetween 28/30 size, imagine having a gt30 with a .41 a/r housing, not gonna fair too well

 

[Goubo1]

Only summising with my limited online learnt knowledge lol that the bigger turbine, housing and a lovely billet wheel would have you near an equivilent journal gt30 sized billet turbo....may be a nice upgrade for rob (goubo) when he goes to upgrade his??

i will be defiantly looking into doing something with the k26 as I'm going to have a spare one soon so my original one can be the guinea pig

 

[StaceyS3]

Pretty sure I read somewhere that there is the .4x option and a .56 or something..... a bit of dremmeling could always aid a little

 

[badger5]

no wonder it lit up like a light bulb and had egt's thru the roof.. not like it spooled uber fast because of it..

odd sizing for 1.8t application.

 

[Goubo1]

no wonder it lit up like a light bulb and had egt's thru the roof.. not like it spooled uber fast because of it..

odd sizing for 1.8t application.

what other turbo options are there that can still use the k26 mtm manifold bill ?

 

[badger5]

i dont know.. sorry

I dont use them

 

[Goubo1]

Is it possible to buy a larger hotside that would still mate up to mani and down pipe that I have just now ?

 

[superkarl]

Prob very difficult sourcing one.

 

[Goubo1]

Prob very difficult sourcing one.

Wonder if they are available.

off work and sat bored so was having a look at my k26 I have and just got me thinking as with a billet wheel and hotside how much could be gained.. Or would it be very little for the cost

 

[superkarl]

Well its a fairly old design, so a better designed compressor is bound to yield something.

As for the housing, its small, and Bill did always say it was the restriction, and if a direct comparison was .41 a/r then bigger will almost certainly gain some top end.
However they were never the most responsive turbo, so a bigger housing will only introduce more lag.
I dunno really, i just speculate, try to think about it logically.

Might be worth speaking to a company like owens or TD.

 

[Goubo1]

Well its a fairly old design, so a better designed compressor is bound to yield something.

As for the housing, its small, and Bill did always say it was the restriction, and if a direct comparison was .41 a/r then bigger will almost certainly gain some top end.
However they were never the most responsive turbo, so a bigger housing will only introduce more lag.
I dunno really, i just speculate, try to think about it logically.

Might be worth speaking to a company like owens or TD.

Wonder if the lighter compressor would help cancel out the extra lag of the larger hotside ? It's defo something I'm going to be looking into (once I get work sorted out as I'm suspended just now as got caught with no hard hat on)it's more or less free power as it would be making the best of my existing hardware

 

[beachbuggy]

Wonder if the lighter compressor would help cancel out the extra lag of the larger hotside ? It's defo something I'm going to be looking into (once I get work sorted out as I'm suspended just now as got caught with no hard hat on)it's more or less free power as it would be making the best of my existing hardware

The compressor inducer isn't that much larger than the current 2283 wheels so probably a 35lb wheel.. The bigger inducer compared with the 2283 just spins the air out faster and allows higher pressure ratios.. A billet wheel is lighter but also has thiner blades so can move more air, so the initial force needed to turn it is less as it weighs less but then you need more torque to move the larger volume of air.. Now considering the turbine is massive when you think and rs6 turbine is 50mm/44.5mm I think you'd be better off putting a bigger compressor wheel in it.. An 80% exducer to inducer ratio seems to be the best... I personally think that the comp / turbine you've got is pretty badly matched... And by the time the turbine has got going the compressor wheel is totally out of its efficiency range... Something like a 2480 comp wheel would be better suited ..

 

[Goubo1]

The compressor inducer isn't that much larger than the current 2283 wheels so probably a 35lb wheel.. The bigger inducer compared with the 2283 just spins the air out faster and allows higher pressure ratios.. A billet wheel is lighter but also has thiner blades so can move more air, so the initial force needed to turn it is less as it weighs less but then you need more torque to move the larger volume of air.. Now considering the turbine is massive when you think and rs6 turbine is 50mm/44.5mm I think you'd be better off putting a bigger compressor wheel in it.. An 80% exducer to inducer ratio seems to be the best... I personally think that the comp / turbine you've got is pretty badly matched... And by the time the turbine has got going the compressor wheel is totally out of its efficiency range... Something like a 2480 comp wheel would be better suited ..

your the man with knowledge ,you got a rough price to do this ?

 

[beachbuggy]

your the man with knowledge ,you got a rough price to do this ?

Youll get me in trouble

 

[Goubo1]

Youll get me in trouble

???